EH3RC-Y TaA::'SF0PJ'tA.TI01T3 DUPJITG 
 HORIZOIITAL WALimTCr 
 
 Benedict and Murschhauser 
 
 
LIBRARY OF THE 
 NEW YORK STATE COLLEGE 
 OF HOME ECONOMICS 
 
 CORNELL UNIVERSITY 
 ITHACA, NEW YORK 
 
ENERGY TRANSFORMATIONS DURING 
 HORIZONTAL WALKING 
 
 BY 
 
 FRANCIS G. BENEDICT 
 
 AND 
 
 HANS MURSCHHAUSER 
 
 WASHINGTON, D. C. 
 
 Published by the Carnegie Institution of Washington 
 
 1915 
 
Cornell University 
 Library 
 
 The original of tiiis book is in 
 tine Cornell University Library. 
 
 There are no known copyright restrictions in 
 the United States on the use of the text. 
 
 http://www.archive.org/details/cu31924003145848 
 
ENERGY TRANSFORMATIONS DURING 
 HORIZONTAL WALKING 
 
 BY 
 FRANCIS G. BENEDICT 
 
 AND 
 
 HANS MURSCHHAUSER 
 
 WASHINGTON, D. C. 
 
 Published bt the Carnegie Institution of Washington 
 
 1915 
 
CONTENTS. 
 
 Page 
 
 Introduction 5 
 
 Methods of determining the energy transformations during walking 7 
 
 Methods of studying the gaseous exchange during walking 8 
 
 Fimdamental principle of studying the gaseous exchange incidental to walking. . 9 
 
 Units of measurement used in walking experiments 10 
 
 Previous researches on the gaseous exchange during walking 12 
 
 Summary of results of previous observations 21 
 
 Methods and apparatus for studies of muscular work 29 
 
 Description of apparatus used in this research 31 
 
 Universal respiration apparatus 31 
 
 TreadmiU 34 
 
 Accessory apparatus 36 
 
 Method of recording the respiration-rate 37 
 
 Method of recording the pulse-rate 37 
 
 Step counter 38 
 
 Method of measuring height to which the body is raised 39 
 
 Plan of research 42 
 
 General routine of the experiments 44 
 
 Standing experiments • 44 
 
 Sitting experiments 45 
 
 Walking and running experiments 46 
 
 Experiments with food 46 
 
 Subjects 47 
 
 Statistics of experiments 48 
 
 Discussion of results 61 
 
 Basal values 61 
 
 Basal metabolism of subject 1 62 
 
 Influence of food and body position 65 
 
 Basal metabohsm of subject II 66 
 
 Metabolism in the lying position 66 
 
 Metabolism in the sitting position 67 
 
 Comparison of the metabohsm in the lying and sitting positions 69 
 
 Metabolism in various standing positions 70 
 
 Influence of food upon metabohsm in the standing position 72 
 
 Metabolism during walking 76 
 
 Walking experiments with subject 1 76 
 
 Experiments without food 77 
 
 Experiments with food 80 
 
 Energy required for the elevation of the body '. 80 
 
 Walking experiments with subject II 81 
 
 Experiments without food 82 
 
 Experiments with food 87 
 
 Influence of the character of diet on the heat-output per unit of work 93 
 
 Influence of fatigue upon the heat-output per unit of work 94 
 
 Comparison of the heat-output per unit of work dtu:ing running with 
 
 that obtained during walking 96 
 
 Analysis of the mechanics of locomotion 98 
 
 ILLUSTRATIONS. 
 
 Fig. 1. General view of apparatus used for walking experiments 32 
 
 2. Schematic outline of universal respiration apparatus 34 
 
 3. TreadmiU designed by E. H. Metcalf 35 
 
 4. Detail of ball bearing for stedl tubes on the treadmill 38 
 
 5. Step counter 38 
 
 6. Apparatus for recording the height to which the body is lifted, and step 
 
 counter with connections 40 
 
 7. Typical kymograph record showing character of step 41 
 
 3 
 
ENERGY TRANSFORMATIONS DURING HORIZONTAL 
 
 WALKING. 
 
 INTRODUCTION. 
 
 This investigation was undertaken after several long conferences 
 with Professor Zuntz of Berlin and Professor Durig of Vienna, whose 
 researches on the work of forward progression are classical. The pre- 
 liminary experiments were made during the sojourn at the Nutrition 
 Laboratory of Dr. Carl Tigerstedt of Helsingfors. Subsequently data 
 were acquired by Messrs. H. L. Higgins and L. E. Emmes of the 
 Laboratory staff. We wish to express our thanks to these gentlemen 
 and particularly to Dr. Tigerstedt for the data regarding Subject I. 
 
 A certain amount of walking on a level inevitably forms a part of 
 the daily routine of nearly every Uving person, for even those who are 
 designated as sedentary in their habits do a not inconsiderable amount 
 of walking in the house or in short distances upon the street. To 
 one who has not computed the actual distance traversed by the 
 housewife during a day, the sum total of the distance walked is 
 smprising. Such a control may readily be obtained with a simple 
 pedometer, for although a pedometer can not be classified as an 
 instrument of precision and is subject to many errors that are fre- 
 quently overlooked, nevertheless it shows in a striking manner that 
 very few individuals close a day of ordinary fife without having moved 
 in forward progression a distance of not less than 2 or 3 kilometers. 
 
 Not infrequently this distance is doubled or trebled by those who 
 would ordinarily assume that they had not taken a particularly long 
 walk. The personal experience of one of us while writing a report 
 showed that the walking for a day consisted in going twice to and from 
 the house, which was 400 meters from the laboratory, i. e., a total 
 distance of 1,600 meters, and in walking about the laboratory while 
 engaged in instruction and research. Throughout a period of several 
 months the pedometer, which was carefully controlled and tested, 
 showed that the average distance walked per day amounted to 7 miles 
 (11.27 kilometers).^ Undoubtedly innumerable instances even more 
 striking than this may be cited, which would show that it is reasonable 
 to assume that practically aU persons do considerable walking during 
 the course of 24 hours. Inasmuch as there are many individuals whose 
 habit of life or profession requires a large amount of walking — for 
 example, those walking to and from business, mail carriers, and espe^ 
 
 'Benedict, Proc. Am. Phil. Soc, 1910, 49, p. 162. 
 
6 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 daily soldiers — an intimate knowledge of the physiology of walking is 
 obviously of great importance. 
 
 Practically all of the previous researches on the physiology of walking 
 have been conducted either from a desire to study the conditions inci- 
 dental to walking done in mountain chmbing, the results being of 
 importance to physicians and those taking regular exercise, or, as in the 
 case of the classical researches of Zuntz and Schumburg, from a desire 
 to study the influence of walking on the metabolism, with a view to 
 applying the results directly to army movements. In the present day, 
 when special attention is directed towards efficiency, the minimizing 
 of extraneous muscular movements, and the transportation of material 
 by hand and leg motion with the least possible expenditure of physical 
 energy, we may assume that there is every incentive for studying care- 
 fully the physiology incidental to walking in a horizontal direction. 
 
 While from the abstract physiological standpoint a study of all of 
 the various factors incidental to walking is of great value, perhaps the 
 most important phase of the investigation is the study of the energy 
 transformations and the determination of the amount of nutrients in 
 the food necessary to provide for such activity. The results of such 
 study are of especial practical value in determining the energy require- 
 ments of an army engaged in marching a certain distance over a level 
 country. As previously stated, this thought dominated the study 
 of Zuntz and Schumburg. A more universal appUcation of the results 
 may be made by the physician who, if he knows the energy involved in 
 walking, is able to prescribe more intelligently a definite amount of 
 exercise for the ambulatory patient. Furthermore, as physical exercise, 
 particularly walking, is an important factor in weight reduction and 
 in athletic training, exact information as to the energy required may 
 be put to practical use in such connection. 
 
 Theoretically the movement of 1 kilogram 1 meter would call for no 
 positive work other than that in overcoming the resistance of the air; 
 nevertheless a considerable amount of work is required of the human 
 body as a machine in accomplishing this feat of moving the mass in a 
 horizontal direction. The apportionment of the total energy output 
 of the body between that required for the maintenance of the vital 
 functions and that required for walking is not, however, simple. When 
 a person is walking, not only is energy required for the external mus- 
 cular exercise, but a heat production is necessary for the entire main- 
 tenance of the body activities, including muscular tonus, the work of 
 circulation, respiratory muscles, and the external work of balancing the 
 body in an upright position, none of these activities contributing 
 directly to the work required to move the body in a horizontal direction. 
 With only a knowledge of the amount of food eaten, it is impossible to 
 estimate the proportion of food required for the activity of walking and 
 that for vital maintenance. A closer analysis is therefore essential. 
 
INTRODUCTION. / 
 
 METHODS OF DETERMINING THE ENERGY TRANSFORMATIONS 
 DURING WALKING. 
 
 It is necessary, first of all, to study the energy transformations which 
 are pecuHarly incidental to walking. Thus, in the simplest case, if 
 the person could walk directly in a vertical direction, a definite amount 
 of external muscular work would be performed which would be repre- 
 sented by the product of the weight of the body and the height walked. 
 In walking in a horizontal direction, theoretically no external work is 
 performed and there is no change in the potential energy of the body. 
 We are thus unable to measure the energy output by the kilogram- 
 meter, the unit most commonly used, or by any of the other ordinary 
 work units. Consequently we have very Uttle information regarding 
 the energy output. 
 
 It is true that we must not disregard the extremely illuminating 
 researches of earlier workers, who have attempted to estabhsh a con- 
 stant, although with wide variations, which would show approximately 
 the amount of energy required to move 1 kilogram 1 meter in a hori- 
 zontal direction. These researches will be referred to in a subsequent 
 section. It is important for us to note, however, that aside from such 
 methods of calculation as are based upon the constant estabhshed by 
 the earUer physiologists, we have no means of calculating the energy 
 output required in walking. 
 
 A possible method of measurement would be to determine the energy 
 output directly by having the subject walk inside of a calorimeter. 
 This has been attempted, although in an imperfect manner, by certain 
 French investigators, including Hirn^ and Chauveau,^ who used the 
 so-called "emission calorimeter" with a tread wheel. In these studies, 
 however, a large proportion of the work was done in lifting the body, 
 and hence the amount of forward progression, which is of special interest 
 to us, is complicated by the very much greater work involved in the 
 elevation of the body. 
 
 Finally, it is possible, owing to the valuable computations and 
 methods of research established by Zuntz, to study the respiratory 
 exchange, namely, the carbon-dioxide output and the oxygen intake, 
 and thus compute indirectly the total calorific output. This last 
 method has been adopted by aU physiologists as the most suitable for 
 the purpose. Practically all previous research has therefore been 
 based upon the general principle of determining the total respiratory 
 exchange both while the subject is walking and during rest when lying, 
 sitting, or standing, and noting the increment in the carbon-dioxide 
 output and oxygen intake due to walking. 
 
 From the heat of combustion and analysis of pure nutrients, such 
 as carbohydrate and fat, it has been computed that for each Hter of 
 
 'Hirn, Recherches sur I'fiquivalent m^oanique de la chaleur, Paris, 1858. 
 ^Chaveau, Compt. rend., 1899, 129, p. 249. 
 
8 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 oxygen required in the combustion, there are produced from 4.686 to 
 5.047 calories. When pure carbohydrate is burned, each Uter of oxygen 
 utiUzed in the combustion corresponds to 5.047 calories, but when pure 
 fat is burned each Uter of oxygen corresponds to 4.686 calories. Zuntz 
 and his co-workers have prepared a table showing the calorific equivalent 
 of the oxygen consumption when fat and carbohydrate are burned.^ This 
 has been most ingeniously elaborated by WiUiams, Riche, and Lusk." 
 
 By studjdng the output of carbon dioxide and the intake of oxygen, 
 not only is information secured regarding the total oxidation of material, 
 but also some idea is gained of the character of the combustion by 
 noting the relationship between the volume of carbon dioxide given off 
 and the oxygen absorbed. With equal volumes of carbon dioxide and 
 oxygen, this relationship or "respiratory quotient" is 1.0 and indicates 
 that carbohydrate has been exclusively burned. When the respiratory 
 quotient approximates 0.7 the indication is that fat has exclusively 
 been burned. By this means, therefore, it is possible to compute with 
 great accuracy the heat output from the total oxygen consumption and 
 the respiratory quotient. 
 
 In certain earlier researches, and especially prior to the time when 
 methods were devised by which oxygen absorption could be more 
 easily determined than formerly, the measurements of the carbon- 
 dioxide output alone were used, but a much greater error is introduced 
 into the computations by this method. Unfortunately, of the two 
 factors, carbon dioxide and oxygen, that which is of the greater sig- 
 nificance, namely, oxygen, is the more difiicult of determination, while 
 the measurement of the carbon-dioxide excretion is relatively a simple 
 matter. 
 
 METHODS OF STUDYING THE GASEOUS EXCHANGE DURING 
 
 WALKING. 
 
 Inasmuch as a study of the problem of the energy transformations 
 during walking demands a careful study of the gaseous exchange, we 
 find all the methods used based upon this principle. The simplest is 
 that in which the subject walks inside a closed chamber by means of 
 which the product of respiration — carbon dioxide — ^is easily collected. 
 This method was first employed by Sond^n and Tigerstedt^ in the clas- 
 sical research with their large respiration chamber in the Karolinska 
 Institute in Stockholm. This chamber had a capacity of 100 cubic 
 meters and, unlike any respiration chamber previously used, permitted 
 the subject free movement. When the subject walked back and forth 
 across the room, a considerable distance could be traversed. At that 
 time only the carbon-dioxide output was determined with this method. 
 
 ^Zuutz and Schumburg, Physiologie des Marsches, Berlin, 1901, p. 361. 
 ^WilUams, Bdche, and Lusk, Journ. Biol. Chem., 1912, 12, p. 357. 
 'Sond6n and Tigerstedt, Skand. Archiv f. Physiol., 1895, 6, p. 165. 
 
INTEODUCTION. 9 
 
 A second method involves the attachment of certain breathing apph- 
 ances, either nosepieces or mouthpiece, with an apparatus for meas- 
 uring the volume of the expired air. When the breathing appliances 
 have been adjusted, the subject assumes a certain body position and 
 then walks along a movable path, such as a treadmill. This method 
 was frequently used by Zuntz and Durig and their co-workers. 
 
 A modification of this method is that in which the apparatus for 
 measuring and samphng the expired air is carried upon the back of the 
 subject, somewhat as a knapsack would be carried. The subject is 
 then no longer confined to walking upon a treadmill, but may walk 
 on level ground anywhere. This method was used extensively by 
 Zuntz and Durig and their associates and by Douglas. Instead of 
 having the apparatus carried by the subject, it may be transported 
 by an assistant walking a suitable distance behind him. The subject 
 thus breathes through the nose or mouth apphance, but is not obliged 
 to support the heavy apparatus. This method was employed by Burgi, 
 Schnyder, and, in certain experiments, by Kolmer and Brezina. 
 
 Finally, it is possible to have the gas measuring and sampling appa- 
 ratus in a fixed position and the subject attached to it by a long tube. 
 He then walks in a clearly defined path, either back and forth across the 
 room or in a circle of which the apparatus is the center. This method, 
 which obviously limits appreciably the distance to be covered and the 
 general freedom of the subject, has found slight use with certain French 
 observers, particularly Amar. 
 
 FUNDAMENTAL PRINCIPLE OF STUDYING THE GASEOUS EXCHANGE 
 INCIDENTAL TO WALKING. 
 
 The method of superimposition is the only one feasible for these 
 studies. By this method the gaseous exchange during walking in dif- 
 ferent positions must be carefully studied by one or more of the methods 
 previously referred to; subsequently, in order to apportion specifically 
 the energy transformation due to walking, it is necessary that a certain 
 part due to the metaboHsm of maintenance be subtracted from the 
 result obtained for the total gaseous exchange. 
 
 The exact selection of the amount of energy transformed for main- 
 tenance to be deducted from the total energy transformation has been 
 a matter of considerable discussion. We have now come to realize that 
 a human individual may subsist on numerous metabolic levels. The. 
 subject sound asleep, without food in the stomach, has a minimum 
 metaboHsm, but is utterly incapable of intellectual or physical activity. 
 It would obviously be impracticable, if not indeed undesirable, to 
 deduct this minimum metabolism from the measurement of the total 
 metaboHsm and assume that the difference would be wholly due to 
 the energy transformation due to walking. Even when the subject 
 is lying awake, we still have a base-Hne which is far removed from the 
 
10 ENEEGY TRANSFOBMATIONB DUBING HORIZONTAL WALKING. 
 
 process of walking. To obtain the best expression of the superimposed 
 energy requirement for forward progression, it is necessary to secure, as 
 nearly as possible, the energy requirement of the subject in a position 
 which involves all of the extraneous muscular movements incidental to 
 the waking condition and in a vertical position. This may be obtained 
 by deducting the metaboUsm required for the standing position. And 
 yet the earUer researches have been most unsatisfactory in the attempts 
 to measure the metabolism under these conditions. 
 
 With the standing position we again have numerous possible varia- 
 tions. The subject may stand in a completely relaxed position; he 
 may possibly eliminate in a large part the effort of balancing by leaning 
 on a staff or lying back shghtly out of the vertical against a support ; or he 
 may stand in a fixed position with rigid muscles, such as that of "atten- 
 tion." We should, theoretically at least, expect to find a considerable 
 difference in the metabohsm necessary for these various upright positions. 
 
 Durig has clearly pointed out^ that there are numerous arguments 
 against assuming that the metaboUsm while standing in any one of 
 these positions can rightly be deducted from that during walking to 
 obtain the true energy transformation due to the walking, for it is quite 
 possible that certain of the external muscular movements incidental to 
 balancing and sustaining the body in an upright position may be greatly 
 modified, if not indeed dispensed with, in the ordinary motions of for- 
 ward progression. Consequently, one finds that, in previous researches, 
 the base-line used almost universally among physiologists has been the 
 metabolism observed with the subject lying awake without food in the 
 stomach, i. e., in the post-absorptive condition. The assumption is then 
 made that the incrementof metabolism duringwalking over that observed 
 with the subject lying awake is a true measure of the metabolism due to 
 the muscular exercise of moving the body in a horizontal direction. 
 
 UNITS OF MEASUREMENT USED IN WALKING EXPERIMENTS. 
 
 While under ordinary conditions the amount of work performed in 
 any inanimate or animate motions is expressed in terms of foot-pounds, 
 kilogrammeters, or calories, it is obvious that no one of these units can 
 be appropriately employed for indicating the energy transformations 
 during walking. In walking, a given weight is carried through a given 
 distance. To be sure, there is inevitably a sUght lifting of the total 
 weight of the body at each step due to the anatomical arrangement of 
 the feet and leg-muscles, but this weight is again immediately lowered 
 to the same position, so that, mechanically at least, there is no effective 
 work accompUshed. The only external evidence of performance is that 
 a given weight is moved forward a given distance. 
 
 In this discussion we may for the present appropriately eliminate the 
 possible effect of wind resistance produced by the body in walking or the 
 
 'Durig, Denksohriften d. math.-natur. Klasse d. kaieerl. Akad. d. Wissensch., 1909, 86, p. 267, 
 
INTRODUCTION. 11 
 
 external influence of the wind in a direction either favorable or unfav- 
 orable for forward progression. But in practically all walking done 
 by man considerable differences exist in the weight moved forward . With 
 the bather walking on a flat sandy beach we have simply the weight of the 
 body plus the negligible weight of the bathing-suit. On the other hand, 
 with a pedestrian taking his "constitutional," we have the weight of the 
 clothing, amounting to 3 or 4 kilograms, possibly supplemented by the 
 weight of knapsack, camera, and other accessories. Finally we have the 
 exaggerated case of the fully equipped trooper carrying knapsack, emer- 
 gency rations, and a considerable quantity of ammunition. Thus we 
 have the possible necessity of distinguishing between the movement due 
 to the Ufting of body-weight and that due to lifting inert or dead weight. 
 The subject is further comphcated when we attempt to analyze the 
 weight of the living organism. The body is made up of bone, muscle, 
 and fat. Fat may be looked upon as inert body-material, and when 
 there is an excessive accumulation of fat, as with obese persons, it is 
 possible that it may be considered in great part as dead weight. It 
 is thus seen that the problem of studying the physiology of forward 
 progression involves the question of analyzing the character of the 
 weight transported. For the present the unit of accompUshment in 
 the work of forward progression on a horizontal plane must be con- 
 sidered as the transportation of 1 kilogram 1 meter, i. e., 1 "horizontal 
 kilogrammeter . ' ' 
 
12 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 PREVIOUS RESEARCHES ON THE GASEOUS EXCHANGE 
 DURING WALKING. 
 
 Before reporting and discussing the results of our own experiments, a 
 brief abstract is given of all previous research in which the metabolism 
 during walking has been studied. In thus reviewing the work of other 
 investigators, it has seemed advisable to record the results on the basis 
 of the movement of 1 kilogram over 1 meter of level path, i. e., 1 hori- 
 zontal kUogranmieter, and to compare them in a large summary table 
 rather than to give them under each research. This is done in table 
 
 1 (see pages 22 to 27). 
 
 Observations of Smith, 1859. — The earliest attempt to measure the 
 gaseous metaboUsm during walking was made by Edward Smith, who, 
 in his memoirs entitled "Experimental inquiries into the chemical and 
 other phenomena of respiration and their modifications by various 
 physical agencies,"^ gives the details of two walking experiments. In 
 these experiments Smith collected the products of respiration by attach- 
 ing a mask to the face and forcing the expired air through specially 
 constructed boxes, containing caustic potash to absorb the carbon 
 dioxide. The mask had two openings, one for inspired air and the 
 other for expired air, a valve system providing for the separation of the 
 two currents of air. A dry gas-meter was attached at the intake point. 
 The expired air was first passed through a Woulff bottle containing 
 pumice-stone and sulphuric acid, then into a gutta-percha box contain- 
 ing a solution of caustic potash, and finally through a second Woulfif 
 bottle containing pumice-stone and sulphuric acid. The walking was 
 done inside of a room and covered a distance of approximately 10 
 meters in each direction. All of the precautions incidental to modern 
 experiments as to recording the barometric temperature and pressure 
 were taken, and a further factor, which is only too frequently neglected 
 in modern work, namely, pulse-rate, was also recorded. The subject 
 carried a spirometer which weighed 7 pounds, but the exact method of 
 transportation is not clear from Smith's description. Both experiments 
 were made in one afternoon, with an intermission of an hour. During 
 the first experiment he walked at the rate of 2 miles an hour and during 
 the second at the rate of 3 miles an hour. For a base-line he deter- 
 mined the metabohsm at rest without food and in a sitting position. 
 
 Smith's values, which are given in English grains, were recomputed 
 to grams by Sonden and Tigerstedt.'' While walking at the rate of 
 
 2 miles an hour, the carbon dioxide per minute was 1.173 grams; at 3 
 miles an hour, 1.674 grams; and sitting at rest without food, 0.482 
 gram. The energy per horizontal kilogrammeter computed from these 
 values is given in table 1, page 22. The results obtained by Smith 
 have been criticized by Gruber^ and Voit,* who both consider them 
 
 'Smith, Phil. Trans. Roy. Soc, London, 1859, 149, p. 681. 
 ''SondSn and Tigerstedt, Skand. Arohiv f. Physiol., 1895, 6, p. 166 
 'Gruber, Zeitschr. f. Biol., 1891, 28, p. 470. 
 *Voit, Hermann's Handbuch der Physiologie, 1881, 6, p. 201. 
 
PREVIOUS RESEARCHES ON GASEOUS EXCHANGE. 
 
 13 
 
 somewhat high. Katzenstein^ likewise considers the values too high 
 and inexact and regrets that Smith did not state whether the walking 
 was done on a level or on an incline. Although Smith gives the weight 
 of the subject and the apparatus in one instance, Katzenstein criticizes 
 the absence of body-weights for each experiment. Katzenstein's 
 further criticism, that the carrying of the apparatus by the subject was 
 a fault in the technique, is of special interest in view of the subsequent 
 use of a portable gas-meter by Zuntz and his co-workers. 
 
 Observations of Gruber, 1891. — The unusual interest in mountaineer- 
 ing, which is particularly active in Switzerland, has resulted in a large 
 number of physiological observations upon the effect of high altitudes 
 on the human body. One of the earliest of the observations, which 
 included measurements of the gaseous metabolism, was that of Gruber,^ 
 who pubhshed the results of a research carried out in the Physiological 
 Institute at Berne under the direction of Professor Kronecker. Gruber 
 himself was the subject of the study. 
 
 Instead of using a mask with two valves, Gruber employed a tube in 
 the mouth for expiration, the nose being closed by the fingers of the 
 left hand. During inspiration the rubber tube leading to the mouth 
 was tightly closed by the teeth and air was inspired through the nose. 
 The inspired air was passed into a U-tube containing soda to absorb the 
 carbon dioxide. A rubber air-cushion, which could be compressed by 
 the arm of the subject, permitted the accumulation of the excess of air 
 during the expiration, and dm-ing inspiration this air was forced out 
 through the absorbing vessels by pressure with the arm. 
 
 Three experiments are reported in which the subject walked without 
 other load than the apparatus. The rate of walking in the first 
 experiment was 80 steps per minute. Two of the three experiments 
 consisted of 10 minutes of walking followed by 10 minutes of sitting, 
 Gruber concluding from his results that apparently as much carbon 
 dioxide is excreted in the 10-minute rest after the short walking-period 
 as during the walking. He also made three experiments while sitting 
 in a chair prior to walking and two experiments after walking. On the 
 basis of the sitting values he contends that with walking on a level 
 the carbon-dioxide production is twice as great as with sitting. Both 
 the rest and walking experiments were made 5 or 6 hours after food. 
 Comparing the results of observations made both in trained and 
 imtrained condition and considering the amount of carbon dioxide 
 produced during rest as 1, he obtained the following figures:^ 
 
 
 Rest. 
 
 Walking. 
 
 Ascent 
 (untrained). 
 
 Ascent 
 (trained) . 
 
 Series 1 . . . 
 Series 2 . . . 
 
 1 
 1 
 
 '2.00 
 1.75 
 
 4.1 
 3.05 
 
 3.3 
 
 2.42 
 
 'Incorrectly stated as 1.89 by Gruber and recalculated by us. 
 
 'Katzenstein, Archiv f. d. ges. Physiol., 1891, 49, p. 331. 
 Gruber, Zeitschr. f. Biol., 1891, 28, p. 466. HUd., p. 490. 
 
14 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 From these data he concludes that the carbon-dioxide production of 
 a working man is not a function of his work, since the metabolism 
 decreases with practice. 
 
 Observations of Katzenstein, 1891. — ^In the walking experiments of 
 Smith and Gruber, only the carbon-dioxide production was deter- 
 mined, and the first investigations, in which the oxygen consumption 
 was also measured, were those carried out by Katzenstein^ in Zuntz's 
 laboratory in Berlin. Emplojdng the Zuntz mouthpiece and valves 
 for separating the inspired air from the expired air, Katzenstein 
 sampled and analyzed the expired air, the measurement of the total 
 amount of air expired being made with a gas-meter. There is consider- 
 able doubt as to the conditions of the experiments. In certain instances 
 it is specifically stated that the subjects were in the post-absorptive 
 state, i. e., without food for 12 hours, but the general impression is given 
 that in the majority of instances the experiments were not made with 
 the subject in the post-absorptive condition. The rate of walking was 
 from 51 to 92 meters per minute. The criticism was subsequently 
 raised by Durig^ that the treadmill was not completely level, there 
 being a sUght elevation of somewhat less than 1 degree. To provide 
 a base-line for these observations, the metabolism of the subject was 
 measured while he stood quietly upon the treadmill. Observations 
 were likewise obtained with the subject in a lying position. The author 
 concludes that the oxygen consumption for the unit of effective work is 
 greater for small amounts of work than for large amounts, and that the 
 respiratory quotient during work remains essentially unaltered. The 
 computation of the values per horizontal kilogrammeter is given in 
 table 1, page 22. 
 
 Observations of Sonden and Tiger stedt, 1895. — The large respiration 
 chamber in Stockholm afforded suflScient space for experiments in 
 which the work of walking could be measured.* The carbon dioxide 
 alone was determined and with most of the experiments moderate 
 amounts of food were taken. The body-weight with clothing was 
 recorded before and after the experiment. The subjects walked 
 from 3,000 to 6,920 steps per hour without a load. As a base-line the 
 authors used a value found for three resting periods when the subject 
 was sitting, these periods being between periods of walking; large 
 differences are shown in the carbon-dioxide output per hour during the 
 resting periods. The energy per horizontal kilogrammeter, as com- 
 puted from the carbon-dioxide output during the walking experiments, 
 is given in table 1, page 22. 
 
 Observations of Schumburg and Zuntz, 1896. — In connection with a 
 series of experiments made in the Alps, Schumburg and Zuntz carried 
 
 ^Katzenstein, Archiv f. d. ges. Physiol., 1891, 49, p. 330. 
 
 ^Durig, Denkschritt. d. math.-natur. Klasse d. kaiserl. Akad. d. Wiasenaoh., 1909, 86, p 250 
 
 'Sonden and Tigerstedt, Skand. Archiv f. Physiol., 1895, 6, p. 1. 
 
PREVIOUS RESEARCHES ON GASEOUS EXCHANGE. 15 
 
 out a number of observations in Zuntz's laboratory in Berlin, using the 
 treadmill.^ A dry gas-meter weighing 7 kilograms was employed and 
 was carried by the subject. In most of the experiments the inspired 
 and expired air were separated by a valve system and a mouthpiece and 
 nose-clamp were used. It is interesting to note that in the severe work 
 of going uphill in this series of experiments, the authors record that the 
 breathing appliances were very uncomfortable, particularly the nose- 
 clip. They accordingly trained themselves to inspire through the nose 
 and expire through the mouth, a procedure which they satisfied them- 
 selves gave accurate results. To estabhsh a base-hne, numerous exper- 
 iments were made with the subject ia a sitting position, these being 
 carried out in the laboratory in Berlia, in the hotel at Zermatt, and also 
 in the camp and on the glacier in the mountains. Three walking 
 experiments were made with Zuntz as subject in a room of the labora- 
 tory buildiag and two on the treadmill, which was in a practically hori- 
 zontal position. Two treadmill experiments were also made with 
 Schumburg as a subject. The energy per horizontal kilogrammeter, as 
 computed from the difference between the sitting values and the walk- 
 ing values, is given in table 1, page 22. 
 
 Observations of A. Loewy, J. Loewy, and L. Zuntz, 1897. — In connec- 
 tion with their studies in the Alps, A. Loewy, J. Loewy, and L. Zuntz 
 made several experiments in Berhn on the treadmill in the Landwirt- 
 schafthche Hochschule.^ Two experiments were made with A. Loewy, 
 three with J. Loewy, and five with L. Zuntz. A 6.6 kilogram dry gas- 
 meter was carried by the subject on his back and connected with the 
 Lob valve attached to the mouthpiece. The nose was closed with a 
 clamp. For the experiments made with A. Loewy, a base-hne was used 
 which was founded upon earUer observations. The resting values for 
 J. Loewy and L. Zuntz were determined presumably with the subject 
 sitting. No statement is made as to whether the subjects were in a 
 post-absorptive condition or not. Certain experiments were also made 
 at Col d'Olen, in which the subject likewise carried the dry gas-meter, 
 but for these experiments the resting values were obtained with the 
 subject in a lying position. The results for the observations with the 
 subject walking on a level are summarized in table 1, page 22. 
 
 Observations of L. Zuntz, 1899.— In his observations regarding the 
 gaseous-exchange of bicycle-riders, Leo Zuntz included a number of 
 experiments made on the treadmill in the Landwirtschafthche Hoch- 
 schule.^ The statement is inade that the treadmill had an incHnation 
 of approximately 1 degree. Of special interest in these observations 
 is the fact that Leo Zuntz paid particular attention to the influence of 
 speed upon the gaseous metaboHsm, varying the rate of walking from 
 
 'Schumburg and Zuntz, Arohiv f. d. ges. Physiol., 1896, 63, p. 461. 
 ^A. Loewy, J. Loewy, and L. Zuntz, Archiv f. d. ges. Physiol., 1897, 66, p. 477. 
 'L. Zuntz, Untersuohungen ilber den Gasweohsel uud Energieumsatz dea Rad ahresHirsch- 
 wald, Berlin, 1899. 
 
16 ENERGY TRANSFORMATIONS DURING HORIZOIWAL WALKING. 
 
 53.45 meters per minute to 145.53 meters per minute. In the treadmill 
 experiments the stationary wet gas-meter was used and consequently 
 the subject was not obUged to carry an excessive load. The author 
 discusses the absence of wind-resistance and points out that at the 
 forced speeds, the treadmill ran so irregularly that it was frequently 
 necessary for him to run two or three steps. The research is especially 
 worthy of note as representing an attempt to secure unusual accuracy, 
 although one could wish that the experiments had been made with the 
 subject in the post-absorptive condition. An abstract of the results 
 obtained at the different speeds is recorded in table 1, page 22. 
 
 Observations of Setschenow and Schatemikow, 1900. — Setschenow and 
 Schatermkow^ report a research made at the physiological institute of 
 the University of Moscow, which included six waUdng experiments, 
 the length varying from 64 to 75 minutes. Three of these experiments 
 were preceded by a preliminary period of 6 to 9 minutes in which the 
 subject stood. Basal values were obtained in two additional experi- 
 ments with the subject at complete rest. In the walking periods the 
 subject, who was the fireman of the institution, walked back and forth 
 in the courtyard, the speed averaging 62.47 meters per minute; the 
 distance walked in each experiment was usually 4,455 meters. All of 
 the experiments were made 3 to 4 hours after a Ught breakfast of white 
 bread and tea. As the data given are unfortunately insufficient for 
 computing the values per horizontal kilogrammeter and do not lend 
 themselves to tabular presentation, this research is not included in 
 table 1.' 
 
 Observations of Frentzel and Rea^h, 1901 . — In studying the influence 
 of an unbalanced diet upon muscular work, Frentzel and Reach made a 
 number of observations with the subject walking on the Zuntz treadmill 
 in the level position in the LandwirtschaftUche Hochschule in Berlin.^ 
 The rate of walking varied from 31.39 to 80.15 meters per minute. 
 The resting metabolism was determined with the subject lying upon a 
 couch, but both the resting and walking experiments were made with 
 food in the stomach. Resting experiments were made on 16 days with 
 subject F and on 12 days with subject R. A considerable number of 
 resting experiments were made prior to the walking period and on days 
 •other than the walking days. Durig has criticized the experiments 
 as showing imusuaUy large fluctuations in the energy required per hori- 
 zontal kilogrammeter. A summary of the results is given in table 1, 
 page 22. 
 
 Observations of Zuntz and Schumburg, 1901. — In their extensive 
 research on the physiology of walking, Zuntz and Schumburg made 
 
 'Setschenow and Schatemikow, Le Physiol. Russe, 1900, 2, p. 44. 
 
 *War conditions make it impracticable for me to commvmicate with my personal friend. Professor 
 Schatemikow, regarding the figures in this research. As they stand, if a body-weight is assumed 
 and » resting base-line deducted, values representing only about 50 per cent of those found in 
 other published researches are obtained. — F. G. B. 
 
 •Frentzel and Reach, Archiv f. d. ges. Physiol., 1901, 83, p. 477. 
 
PREVIOUS RESEARCHES ON GASEOUS EXCHANGE. 17 
 
 numerous observations of the respiratory exchange of two students, 
 B and P.^ The experiments were made in Zuntz's laboratory and the 
 treadmill was used. In most of the experiments the subjects carried 
 the German army equipment with a considerable load, the maximum 
 weight of the load being 31.5 kilograms. In some of the experiments 
 they carried no load, and it is these latter experiments with which we 
 are chiefly concerned. The basal values were obtained with the sub- 
 ject lying upon a sofa. Both the resting and walking experiments 
 were made after the subject had taken a Ught breakfast. The usual 
 correction for the sUght elevation of the treadmill is considered. The 
 experiments were so adjusted that both subjects could walk at the same 
 time upon the treadmill and two complete sets of respiration apparatus, 
 including gas-meters, were employed. The energy per horizontal 
 kilogrammeter is given in table 1, page 22. 
 
 Observations of Dwig and Zuntz, 1904- — Observations on the metabo- 
 lism during walking on a horizontal level were carried out in Vienna, Col 
 d'Olen, and Capanna Margherita by Durig and Zuntz, and their results 
 were pubUshed in 1904.^ The dry gas-meter and the mouthpiece, 
 valves, and nose-clamp were employed. The resting experiments were 
 made every morning with the subject in bed, except when a study was 
 made of the after-effect of work. Some of the resting vahies used for 
 experiments with Zuntz as a subject were taken from the published 
 results of a previous research. Both the resting and walking experi- 
 ments were without food. After the basal values obtained with the 
 subject lying in bed had been deducted, the energy per horizontal kilo- 
 grammeter was computed and is given in table 1, page 22. 
 
 Observations of Caspari, 1905. — In his study of vegetarianism, Cas- 
 pari^ had an opportunity of studying the metaboUsm of two compet- 
 itors in a walking-match from Dresden to Berhn, one of whom was a 
 vegetarian and the other subsisted on a mixed diet. The experiments 
 were made upon a treadmill in Zuntz's laboratory and presumably the 
 Zuntz technique was carried out in all details. Striking differences 
 in the gait of the two subjects were noted. One of the subjects, K. M., 
 won the match, proving himself a particularly efficient walker. The 
 basal values were obtained while the subject was lying in absolute rest. 
 The walking experiments were made with food, and probably the rest 
 experiments also, although no statement is given in regard to the food 
 with the rest experiments. After the basal values had been deducted 
 from the values found with the treadmill, the energy per horizontal 
 kilogrammeter was computed and is given in table 1, page 24. 
 
 Observations of Zuntz, Loewy, Mvller, and Caspari, 1906. — In con- 
 nection with the classical research on the physiology of man in high 
 
 'Zuntz and Schumburg, Studien zu einer Physiologie des Marsches. Hiraohwald, Berlin, 1901. 
 *Durig and Zuntz, Travaux de I'annfee 1903, Laboratoire soientifique international du Monte 
 Rosa, Turin, 1904, p. 65; also Archiv f. Anat. u. Phyeiol., Physiol. Abth., 1904, Suppbd., p. 417. 
 "Caspari, Archiv f . d. ges. Physiol., 1905, 109, p. 473. 
 
18 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 altitudes, which was made m the Alps, Zuntz, Loewy, Muller, and 
 Caspari^ carried out a series of resting and horizontal walking experi- 
 ments in Berlin. The resting experiments were all made with the sub- 
 ject lying in bed in the morning before taking food. The experiments 
 on horizontal walking were presumably without food and hence it is 
 permissible to deduct the basal values directly to compute the energy 
 per horizontal kilogrammeter. (See table 1, page 24.) The large wet 
 gas-meter was doubtless employed in the Berlin experiments, together 
 with the rest of the Zuntz technique. The walking experiments on the 
 treadmill were as follows: With Waldenburg, 9; with Kolmer, 4; with 
 Caspari, 5; with Muller, 6. The especially high values found with 
 Kolmer in this research are commented upon at length by Durig.^ 
 
 Observations ofDurig, 1906. — In connection with an expedition in the 
 Alps, Durig and his wife were the subjects of a number of resting and 
 horizontal walking experiments.^ Both the basal and walking experi- 
 ments were made with the subject in the post-absorptive condition, 
 that is, several hours after the taking of food. The dry gas-meter 
 was used and the Zuntz technique. 18 resting experiments and 8 
 horizontal walking experiments were made with Durig and 11 resting 
 experiments and 6 walking experiments with Frau Durig, all of these 
 being in the mountains. In addition the average value is given for a 
 number of horizontal walking experiments with Frau Durig in Vienna. 
 Special comment should be made of the extraordinarily heavy appa- 
 ratus — 16.5 kilograms — carried by Frau Durig, who weighed but 45.7 
 kilograms. The basal values have been deducted from the values 
 obtained in the walking experiments and the energy per horizontal 
 kilogrammeter has been computed; this is given in table 1, page 24. 
 
 Observations of Durig, Kolmer, Rainer, Reichel, and Campari, 1909. — 
 The extraordinary care which characterizes all of the researches of 
 Durig is manifest in his classical contributions on the physiology of man 
 in the Alps; of particular value are his keen criticisms and summation 
 of earlier research.* Indeed, nowhere do we find so sharp a recognition 
 of aU of the fundamental tenets of careful experimentation in gaseous 
 metabohsm, and particularly in the physiology of walking with special 
 reference to the physiology of man in high altitudes, as in this series 
 of contributions from Durig's laboratory. The observations were all 
 made with the portable dry gas-meter which, with the equipment, 
 weighed 11 kilograms. The experiments were made in the morning, 
 either without food or after taking a cup of weak tea. 32 observations 
 were made on a level road 200 meters long in Vienna and 12 observa- 
 
 'Zuntz, Loewy, Muller, and Caspari, Hoheuklima und Bergwanderungen in ihrer Wirkung auf 
 den Mensohen, 1 Aufl., Berlin, 1906. 
 
 ^Durig, Denkschriften d. math.-natur. Kl. d. kaiserl. Akad. der Wisaensoh., 1909, 86, pp. 253 
 and 254. 
 
 »D>irig,.Arohiv f. d. gea. Physiol., 1906, 113, p. 213. 
 
 *Durig, Kolmer, Rainer, Reichel, and Caspari, Denkachrift. d. math.-natur. Kl. d. kaiserl. 
 \.kad. der Wiasenaoh., 1909, 86, p. 242. 
 
PREVIOUS RESEARCHES ON GASEOUS EXCHANGE. 19 
 
 tions were made on the Semmering. Durig discusses carefully all of 
 the factors which should be taken into consideration in experiments of 
 this nature and in the interpretation of their results. Of especial inter- 
 est is his discussion of the suitable base-line to be deducted from the 
 values found in the walking experiments. It should be noted that he 
 adheres to the basal values found with the subject lying, as he considers 
 the evidence in regard to the standing position wholly inadequate. 
 His final computations for the energy required per horizontal kilo- 
 grammeter are given in table 1, page 24. 
 
 Observations of Amar, 1910. — In a research on the metaboUsm of 
 Arabs/ Amar made numerous walking experiments with 15 subjects, 
 who ranged in weight from 59 to 78 kilograms. The experiments were 
 not made with the subject in the post-absorptive condition and loads 
 weighing from 45 to 60 kilograms were carried. The Thiry metaUic 
 valve and a dry gas-meter were used. The author gives a very inade- 
 quate description of his technique. It appears, however, that Amar 
 probably calculated the heat output of his subjects from the energy of 
 the food and obtained an approximate control of his results by com- 
 puting the heat output from the actual determinations of the oxygen 
 intake and the calorific value of oxygen. Averages computed from the 
 individual figures given by the author are included in table 1, page 24. 
 
 Observations of Amar, 1911. — In a series of walking experiments 
 reported in 1911, Amar^ used Thiry respiration valves which were con- 
 nected with a dry gas-meter. The apparatus was placed upon a table, 
 which was pushed behind the subject as he walked, and samples were 
 withdrawn and analyzed, apparently for oxygen alone. The experi- 
 ments were made in the morning, 10 or 12 hours after the taking of 
 food. Control experiments were made with the subject standing and 
 also with the subject sitting, Amar noting an increase in the metabo- 
 Hsm during standing as compared with sitting. His computations are 
 based upon the increase in energy expenditure while walking above 
 that in a state of repose. Especial attention is given in his discussion 
 to the variations in the load and the economic value of the rate of 
 walking. The experiments have been criticized by Brezina and Kol- 
 mer,' who protest against the lack of information as to the details of the 
 experiments and the technique and state that the barometric pressure, 
 temperature, and carbon-dioxide output were apparently not taken into 
 consideration. An abstract of Amar's results is given in table 1 , page 24. 
 
 Observations of Brezina and Kolmer, 1912. — ^A series of walking exper- 
 iments was made by Brezina and Kolmer in Durig's laboratory in 
 Vienna.* In one set of experiments the subject carried on his back a 
 
 'Amar, Le rendement de la machine humaine, Paris, 1910; also, Le moteur humain, Paris, 
 1914, pp. 493 and 494. 
 'Amar, Joiiru. de Phyaiol. et de Pathol, gen., 1911, 13, p. 212. 
 'Brezina and Kolmer, Biochem. Zeitschr., 1912, 38, p. 132. 
 ^Ibid, p. 129. 
 
20 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 dry gas-meter and the ordinary equipment was used, including the 
 mouthpiece and valves. This, with additional weights, made a load 
 of 11 Idlograms. In one set of the experiments in which heavier loads 
 were used, the gas-meter was carried by the subject, but in later experi- 
 ments the meter was carried by an assistant who walked behind the sub- 
 ject. All of the experiments were made on a path near the laboratory 
 and after the subject had taken a cup of tea with sugar. The authors 
 maintain that the last heavy meal was taken 12 hours previous to the 
 experiment, and that the influence of the ingestion of food was there- 
 fore ehminated. In computing the results, a basal value of 1,083 gram- 
 calories per minute was assumed for the subject. The authors point 
 out that this is, to a certain degree, arbitrary. It should be noted that 
 some of the experiments are considered less accurate than the others, 
 owing to difficulties with the gas-meter. Special emphasis is laid upon 
 variations in load and in the rate of walking. In a subsequent paper 
 Brezina and ReicheP review the earher paper of Brezina and Kolmer 
 and make certain corrections in the values. These corrected values 
 are used by us in our summation of the results of Brezina and Kolmer 
 in table 1, pages 24 and 26. 
 
 Observations of Douglas, Haldane, Henderson, and Schneider, 191S. — 
 In connection with researches carried out on Pike's Peak by Douglas, 
 Haldane, Henderson, and Schneider, a number of observations were 
 made on Douglas, both at Oxford and on Pike's Peak.^ The special 
 form of respiration apparatus devised by Douglas was used, consisting 
 of a mouthpiece and a pair of valves connected by tubing with a large 
 rubber bag carried on the back of the subject. The experiments were 
 made with the subject hpng in bed, in a standing position, and walking 
 on a horizontal plane at the rate of 2 to 5 miles an hour. The basal 
 values were assumed to be those measured when the subject was stand- 
 iag quiet with the muscles relaxed. Apparently some of the lying 
 experiments were made with the subject in a post-absorptive condition, 
 while the standing and walking experiments were made after food had 
 been taken. No attention was paid to the character or amounts of food 
 eaten and the possible influence upon the measurements, as the observa- 
 tions were not made primarily for the purpose of studying the absolute 
 metabolism. A summary of the results is given in table 1, page 26. 
 
 Observations of Brezina and Kolmer, 1914- — To carry out the plan 
 conceived by Durig of studying the metabohsm during wa lkin g under 
 every possible condition and to complete their own earher experiments, 
 in which they studied the influence of speed and load during walking 
 on a horizontal path, Brezina and Kohner made a second research, in 
 which they studied the influence of the work of ascent upon the metabo- 
 
 ^Brezina and Reichel, Biochem. Zeitschr., 1914, 63, p. 170. 
 
 ^Douglas, Haldane, Henderson, and Schneider, Phil. Trans. Roy. Soc. London, 1913, ser B 
 203, p. 185. 
 
PREVIOXTS RESEARCHES ON GASEOUS EXCHANGE. 21 
 
 lism.^ Numerous experiments were carried out in the Hoschschule 
 f. Bodenkultur in Vienna, with the treadmill both horizontal and 
 incUned, and with and without load. Presumably the wet gas-meter 
 was used. In the load experiments the subject carried a knapsack 
 with weights in it. In the 15 experiments with the treadmill horizontal, 
 the rate of walking ranged from 30.1 to 55.2 meters per minute, the 
 speed being low to correspond with the rate of walking in the experi- 
 ments with the treadmill inclined. Brezina himself was the subject. 
 The experiments were made in the forenoon, 1| hours after the taking 
 of a cup of sweetened tea. The base-line used was probably the values 
 obtained with the subject lying down, and the Zuntz method for deter- 
 mining the respiratory metabohsm was employed. The caorlies 
 required per horizontal kilogrammeter are given in table 1, page 26. 
 
 Observations of Galeotti, Barkan, Giuliani, Higgins, Signorelli, and 
 Viale, 1914- — On an expedition to Col d'Olen on Monte Rosa in 1913 
 Galeotti, Barkan, Giuhani, Higgins, Signorelli, and Viale made a 
 number of observations on the gaseous metabohsm of four individuals 
 while the subjects were walking on a level.^ Since basal values were 
 obtained in only one instance, it was necessary to assume these for the 
 other subjects. The Douglas bag and the Siebe-Gorman valves were 
 used, except in one experiment when the Tissot valves were substituted. 
 Strict attention was given to the use of food, certain tests being specifi- 
 cally made after breakfast. The experiments which are reported here, 
 however, were made with the subjects in the post-absorptive condition. 
 An abstract of the values for the horizontal kilogrammeter is given in 
 table 1, page 26. 
 
 SUMMARY OF RESULTS OF PREVIOUS OBSERVATIONS. 
 
 In an attempt to arrange in chronological order a mathematical 
 expression of the values on a comparable basis, we have gathered 
 together all of the hterature available on horizontal walking and sum- 
 marized the results of previous researches in table 1. In some of the 
 work, particularly in the earher observations, certain assumptions were 
 essential. These assumptions, which were based upon careful analyses 
 of all of the experiments, upon deductions drawn from the experience of 
 this laboratory in metabolism experiments, and upon known and recog- 
 nized errors in technique are, we believe, justifiable and in all proba- 
 bility are not greatly in error. The table gives the name of the author 
 and the date of reporting the results of the research; the name or initials 
 of the subjects of the walking experiments; the conditions under which 
 the experiments were made; the method of measuring the respiratory 
 exchange; the kind of walking, i. e., in a room, out of doors, or on a 
 
 'Brezina and Kolmer, Biochem. Zeitschr., 1914, 65, p. 16. 
 
 'Galeotti, Barkan, Giuliani, Higgins, Signorelli, and Viale, Reale Accademia dei Lincei, Rome, 
 1914, and Arch. d. Pisiol., 1914, 12, p. 277. 
 
22 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 Table 1.— Historical summary of walking 
 
 Author, date of publica- 
 tion, and subject. 
 
 Smith, 1859: 
 Smith... 
 
 Gruber, 1891: 
 Gruber . . 
 
 Katzenstein, 1891: 
 Kohansky .... 
 
 Krzywy 
 
 Wellnitz 
 
 Zimm 
 
 Sond^n and Tigerstedt, 
 1895: 
 
 F. A. W 
 
 G.J 
 
 L. B 
 
 F 
 
 Condition during 
 walking. 
 
 6 hours after 
 food (?). 
 
 5 to 6 hrs. after 
 food. 
 
 >With food (?) . . 
 
 Schumburg and Zuntz, 
 1896: 
 
 N. Zuntz 
 
 Schumburg 
 
 N. Zuntz 
 
 A. Loewy, J. Loewy, 
 and L. Zuntz, 1897: 
 
 A. Loewy' 
 
 J. Loewy' 
 
 L. Zuntz' 
 
 A. Loewy' 
 
 J. Loewy' 
 
 L. Zuntz' 
 
 L. Zuntz, 1899: 
 
 L. Zuntz 
 
 Frentzel and Reach, 
 1901: 
 
 Frentzel 
 
 Reach 
 
 With food . 
 
 Method of measuring respura- 
 tory exchange. 
 
 Mask for resting; mouth- 
 piece for walking; spirome- 
 ter carried. 
 
 Tube in mouth; absorption 
 apparatus in knapsack car- 
 ried on breast. 
 
 Zuntz and Lehmann . 
 
 Respiration chamber . 
 
 Not stated . 
 
 .do. 
 
 Zuntz and Schumburg, 
 1901: 
 
 B 
 
 P 
 
 Durig and Zuntz, 1904 : 
 
 Durig*' 
 
 Durig' 
 
 N. Zuntz' 
 
 Durig" 
 
 N. Zuntz" 
 
 A few hours after 
 ■ light, liquid 
 breakfast. 
 
 Moderate break- 
 fast. 
 
 •With food . 
 
 After a light 
 breakfast. 
 
 Without food (?). 
 
 Zuntz and Geppert; dry gas- 
 meter on back. 
 
 Kind of walking. 
 
 Indoors, 11 yds. 
 in each direc- 
 tion. 
 
 In room, back 
 and forth. 
 
 Zuntz treadmill. 
 
 In chamber. 
 
 ...do. 
 ...do. 
 
 Zuntz; wet gas-meter near 
 treadmill. 
 
 Zuntz . 
 
 Zuntz and Geppert. 
 
 Zuntz and Schumburg; dry 
 gas-meter on back. 
 
 do 
 
 Zuntz treadmill. 
 
 ....do 
 
 In room. 
 
 Zuntz treadmiU. . 
 
 Small plateau in 
 front of hoteL 
 
 Zimtz treadmill. 
 
 .do. 
 
 .do. 
 
 Free path, out- 
 doors (?). 
 
 In hut 
 
 
 'The summarized data in this table are based on published material cited on pp. 11 to 21. 
 
 'Calculated from the data available, assuming a respiratory quotient of 0.85 and 1,609.35 
 meters per mile. 
 
 'Computed with several necessary assvraiptions, i. e., length of step, 0.680 meter; number of 
 steps, 80 per minute for second figure as well as for the first; respiratory quotient, 0.85. 
 
 'Values computed by Duiig (Denkschrift. d. math.-natur. Kl. Akad. Wissensch., 1909, 86, 
 p. 242), including correction for angle of ascent as indicated by Katzenstein. 
 
 'All heat values computed by Durig (loc. cit., p. 256), assuming respiratory quotient of 0.85. 
 Corresponding figures assuming a quotient of 0.7.«i T»pro- n .i.'io n .q'ra n kik ^^a n quo 
 
StTMMAKY OF EESULTS OF PREVIOUS OBSERVATIONS. 
 experiments on horizontal plane.^ ' 
 
 23 
 
 Resting value. 
 
 Average 
 weight 
 moved. 
 
 Distance per minute. 
 
 Range. 
 
 Average. 
 
 Heat computed per hori- 
 zontal kilogrammeter. 
 
 Range. Average. 
 
 Sitting, 6 hrs. after food 
 
 Sitting, 5 to 6 hrs. after food . 
 
 Standing, leaning against tread- 
 miU; with food (?). 
 
 Sitting, with food . 
 
 Sitting . 
 
 Lying, without food . 
 do 
 
 kilos. 
 92.08 
 
 72.00 
 
 meters. 
 
 "Ruhewert" 
 
 Sitting 
 
 .....do 
 
 Lying, without food 
 "Ruhewert" 
 
 Lying, with food . . . 
 
 Lying, after light breakfast . . . 
 
 62.73 
 78.25 
 70.09 
 68.77 
 
 80.00 
 88.20 
 80.00 
 
 72.60 
 81.10 
 80.00 
 72.60 
 81.10 
 80.30 
 
 72.94 
 
 87.10 
 66.40 
 
 67.92 
 72.93 
 
 f"91.80 
 \ "73.80 
 ["82.50 
 /"74.90 
 1 "78.70 
 
 56.00- 92.00 
 51.00- 75.00 
 58.00- 71.00 
 64.00- 66.00 
 
 58.70- 62.40 
 62.20- 67.90 
 
 47.80- 52.40 
 
 61.60- 62.40 
 59.00- 62.80 
 64.50- 59.20 
 61.80- 70.21 
 59.40- 62.04 
 63.21- 67.33 
 
 r 53.45- 59.35 
 
 92.41-103.40 
 
 135.74-145.53 
 
 57.80- 80.15 
 31.39- 39.91 
 60.28- 66.88 
 31.58- 37.23 
 
 70.66- 89.21 
 68.21- 82.38 
 
 95.70-111.50 
 57.34^ 96.42 
 78.66- 80.66 
 66.26- 91.69 
 60.03- 66.67 
 
 meters. 
 ' 53.64 
 , 80.46 
 
 ■ 54.40 
 54.40 
 
 74.48 
 61.80 
 63.50 
 66.05 
 
 60.60 
 60.10 
 65.10 
 32.00 
 
 61.20 
 42.00 
 50.10 
 
 62.00 
 60.90 
 66.40 
 67.10 
 60.54 
 66.24 
 
 66.76 
 
 98.67 
 
 140.11 
 
 66.94 
 35.92 
 63.95 
 34.68 
 
 76.60 
 73.50 
 
 99.60 
 85.56 
 79.93 
 84.21 
 62.86 
 
 gm.-cals. 
 
 0.506-0.506 
 .603- .427 
 
 «.606- .803 
 
 .636- .706 
 
 .511- .560 
 
 .446- .636 
 
 .661- .724 
 
 .769- .877 
 
 .548- .712 
 
 '.538- .561 
 
 9.621- .693 
 
 n. 015-1. 168 
 
 .442- .626 
 
 .511- .620 
 
 .507- .696 
 
 .464^ .676 
 
 .474r- .571 
 .448- .681 
 .574- .714 
 .633- .699 
 .742- .796 
 
 gm.-cals. 
 
 ^0.407 
 
 ^468 
 
 3.360 
 ^356 
 
 *.526 
 •.786 
 «.564 
 '426 
 
 '.606 
 '.337 
 '.465 
 '.324 
 
 '.678 
 '.616 
 '.718 
 
 .670 
 .635 
 .570 
 .681 
 .821 
 .616 
 
 ».664 
 
 9.663 
 
 91.072 
 
 .627 
 .660 
 .553 
 .558 
 
 19.627 
 '9.609 
 
 .527 
 .584 
 .663 
 .668 
 .774 
 
 •Values given by Durig (loc. cit., pp. 248 and 261). Figures for treadmill experiments were 
 corrected by Durig for angle of ascent. 
 
 'Experiments conducted at Berlin. 'Experiments conducted at Col d'Olen. 
 
 9A11 heat values calculated by Durig (loc. cit., p. 270). 
 
 '•Corrected by authors for slight elevation of treadmill. Values for load experiments may be 
 found on pages 247, 265, and 278 of the original publication, but not corrected for angle of ascent 
 
 "Experiments conducted at Vienna. 
 
 "Not given by authors; these weights were accordingly computed from other data which had 
 been obtained by means of the body weight. ''Experiments conducted at Capanna Margherita. 
 
24 ENERGY TKANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 Table 1. — Historical summary of walking 
 
 Author, date of publica- 
 tion, and subject. 
 
 Condition during 
 walking. 
 
 Method of measuring respira- 
 tory exchange. 
 
 Kind of walking. 
 
 Caspari, 1905: 
 K. M 
 
 With food . 
 
 Zuntz . 
 
 Zuntz treadmill. 
 
 J. B. 
 
 .do. 
 
 .do. 
 
 .do. 
 
 Zuntz, Loewy, Miiller, 
 and Caspari, 1906: 
 
 Waldenburg 
 
 Kolmer 
 
 Muller 
 
 Caspari 
 
 Durig, 1906: 
 
 Frau D.2 
 
 Frau D.' 
 
 Durig' 
 
 Durig,' Kolmer, 
 Rainer, Reichel, and 
 Caspari, 1909: 
 
 Durig* 
 
 [without food . 
 
 Without food . 
 
 Without food, or 
 after cup of 
 weak, sweet- 
 ened tea. 
 
 Zuntz andGeppert; presum- 
 ably wet gas-meter. 
 
 Zuntz and Schumburg; dry 
 gas-meter on back. 
 
 'Zuntz ; dry gaa-meter on back . 
 
 Zuntz treadmill. 
 
 Free path . 
 
 Outdoors . 
 
 Durig' . . 
 Kolmer' . 
 
 Rainer^ . 
 
 Reichel'' . 
 Reichel* . 
 
 .do. 
 .do. 
 
 .do. 
 
 .do. 
 .do. 
 
 .do. 
 .do. 
 
 .do. 
 
 .do. 
 .do. 
 
 .do. 
 .do. 
 
 .do. 
 
 .do. 
 do. 
 
 Amar, 1910: 
 Arabs . . 
 
 With food. 
 
 Amar, 1911: 
 S. L. . . 
 
 Brezina and 
 1912: 
 Brezina . 
 
 Kolmer,' 
 
 10 to 12 hrs. after 
 food. 
 
 12 hrs. after food, 
 or at least 2 
 hrs. after cup 
 of sweetened 
 tea. 
 
 Chauveau valve; dry gas- 
 meter. 
 
 Chauveau valve; dry gas- 
 meter; apparatus on table 
 moved with subject. 
 
 Dry gas-meter carried by 
 assistant in first aeries of 
 experiments, and in last 3 
 series; in 2d and 3d series, 
 subject carried meter. 
 
 Circular path 
 outdoors. 
 
 In room, 11 me- 
 ters in each 
 direction. 
 
 Level path out- 
 ■ doors, involv- 
 ing turns. 
 
 •Average values as corrected by the authors. 
 
 'Experiments conducted at Vienna. 
 
 'Experiments conducted at Spomer Alps. 
 
 •Not given by the author, but computed from other data in which the body weight was involved 
 There is a possible error of about 2 kilograms in this weight. 
 
 'The data from these experiments have been grouped for this summary, with special attention 
 to place and rate of waUdng. 
 
 'Experiments conducted at Semmering. 
 
SUMMARY OF RESULTS OF PREVIOUS OBSERVATIONS. 
 
 25 
 
 experiments on horizontal plane — Continued. 
 
 Resting value. 
 
 Average 
 weight 
 moved. 
 
 Distance per minute. 
 
 Range. 
 
 Average. 
 
 Heat computed per hori- 
 zontal Mlogrammeter. 
 
 Range. 
 
 Average. 
 
 Lying. . 
 do. 
 
 Lying, without food . 
 
 Lying, without food. 
 
 Lying. 
 
 .do. 
 .do. 
 
 .do. 
 
 .do. 
 .do. 
 
 'Repos" with food. 
 
 Standing or sitting. 
 
 I " Erhaltungsumsatz ' 
 I gram-calories. 
 
 of 1083 
 
 kilos. meters. 
 
 63.18 134.90-142.90 
 
 63.47 172.00-182.60 
 
 65.35 122.20-135.70 
 
 74.08 44.14- 78.85 
 
 85.10 37.00-48.45 
 
 87.40 73.29- 86.52 
 
 81.95 67.47- 82.69 
 
 *57.50 
 
 63.38 66.07- 79.63 
 
 79.25 88.49- 99.63 
 
 76.20 72.30-102.30 
 116.6 
 126.0 
 
 76.10 1 141.8 
 
 152.5 
 
 76.30 100.70-103.20 
 76.50 105.40-110.30 
 
 49.2 
 94.20 -I 62.40- 69.20 
 100.00-105.20 
 
 47.2 
 
 75.40 <, jj^g g 
 
 129.5 
 
 100.30 59.30-100.80 
 
 95.45 
 . 95.45 
 
 113.80 
 .134.10 
 
 ■ 66.00 
 73.30 
 
 70.10 
 70.90 
 69.90 
 70.50 
 70.50 
 
 93.20- 99.20 
 103.50-103.90 
 
 72.00- 90.00 
 72.00- 80.40 
 
 32.40- 89.83 
 30.33- 78.08 
 
 46.10- 72.20 
 
 81.80- 98.60 
 
 103.10-115.80 
 
 120.10-131.20 
 
 140.60-141.00 
 
 meters. 
 139.40 
 177.30 
 131.70 
 
 60.20 
 43.16 
 81.17 
 76.76 
 
 65.00 
 71.90 
 95.44 
 
 90.10 
 116.60 
 126.00 
 141.80 
 152.50 
 
 102.20 
 107.90 
 
 49.20 
 
 66.30 
 
 102.50 
 
 47.20 
 
 87.20 
 
 115.80 
 
 129.50 
 
 88.20 
 
 96.30 
 103.70 
 
 79.20 
 74.80 
 
 59.43 
 55.06 
 
 62.40 
 
 88.90 
 
 111.20 
 
 125.20 
 
 140.80 
 
 gm.-ecUs. 
 .952-1.018 
 1 . 154-1 . 184 
 .906-1.020 
 
 gm.-caU. 
 
 .979 
 
 1.169 
 
 .972 
 
 1.636 
 1.845 
 1.613 
 1.643 
 
 .629- .691 
 .620- .660 
 
 .517- .559 
 
 0.628 
 
 .735 
 
 .854 
 
 1.023 
 
 0.566-0.587 
 .622- .636 
 
 0.542 
 0.535-0.591 
 .635- .659 
 
 0.538 
 
 0.533-0.584 
 
 0.772 
 
 .954 
 
 0.510-0.583 
 
 .563- .591 
 .641- .659 
 
 .257- .402 
 .310- .335 
 
 .315- 
 
 .577 
 
 .365- 
 
 .535 
 
 4844- 
 
 .6033 
 
 5615- 
 
 .5985 
 
 7266- 
 
 .7684 
 
 8172- 
 
 .8777 
 
 .9347-1.0070 
 
 .604 
 .668 
 .641 
 
 .539 
 .628 
 .735 
 .854 
 1.023 
 
 0.573 
 .629 
 
 .542 
 .562 
 .648 
 
 .538 
 .567 
 .772 
 .954 
 
 .548 
 
 .573 
 .650 
 
 '.308 
 '.323 
 
 8.410 
 8.422 
 
 '.534 
 
 .574 
 .743 
 .846 
 .971 
 
 'Averages computed from results given by the author for 15 different subjects. The results 
 are grouped for the two loads carried. 
 
 'AU heat values computed from the oxygen increment during walking as given by the author 
 and with an assumed respiratory quotient of 0.85. Assuming a quotient of 0.75, the results for 
 the two series are: range 0.307 to 0.562; average, 0.400; range 0.356 to 0.521, average 0.411. 
 
 •The results in each of these series have been grouped for this summary according to the rates 
 of walking, the Umit of the first group being set at about 80 meters in agreement with the treat- 
 ment given the material in the original publications. The values for distance and calories are 
 given as corrected by Brezina and Reichel. 
 
26 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 Table 1. — HisUrrical summary of walking 
 
 Author, date of publican 
 tion, and subject. 
 
 Condition during 
 walking. 
 
 Method of measuring respira- 
 tory exchange. 
 
 Kind of walking 
 
 Brezina and Kolmer,' 
 1912 (continued): 
 Brezina 
 
 Do. 
 
 12 hrs. after food, 
 or at least 2 
 hrs. after cup 
 of sweetened 
 tea. 
 
 .do. 
 
 Dry gas-meter carried by 
 assistant in first series of 
 experiments, and in last 3 
 series; in 2d and 3d series, 
 subject carried meter. 
 
 .do. 
 
 Do. 
 
 .do. 
 
 .do. 
 
 Do. 
 
 .do. 
 
 -do. 
 
 Do. 
 
 Douglas, Haldane, Hen- 
 derson and Schneider, 
 1913: 
 
 Douglas 
 
 Do. 
 
 Do. 
 
 Brezina and Kolmer, 
 1914: 
 Brezina 
 
 Galeotti, Barkan, Giu- 
 liani, Higgins, Sig- 
 norelli, and Viale, 
 1914: 
 
 Barkan 
 
 Higgins 
 
 Signorelli 
 
 Viale 
 
 .do. 
 
 .do. 
 
 With food Dougli 
 
 .do. 
 
 .do. 
 
 lyi hrs. after cup 
 of sweetened 
 
 > Without food . 
 
 .do. 
 
 Level path out- 
 doors, involv- 
 ing turns. 
 
 .do. 
 
 .do. 
 
 .do. 
 
 .do. 
 
 .do. 
 
 Zuntz . 
 
 Douglas bag 
 
 ....do 
 
 ....do 
 
 ....do 
 
 f Room in labora- 
 tory at Ox- 
 ford; circular 
 path. 
 
 Railway track. 
 Pike's Peak, 
 back and forth. 
 
 {Grass track, Ox- 
 ford, back and 
 .forth. 
 
 Zuntz treadmill. 
 
 Half indoors, 
 half outdoors, 
 with a turn 
 (all indoors in 
 bad weather.) 
 
 'The results in each of these series have been grouped for this summary according to the rates 
 of walking, the limit of the first group being set at about 80 meters in agreement with the treat- 
 ment given the material in the original publications. The values for distance and calories are 
 given as corrected by Brezina and Beichel. 
 
 ^The body-weights in all the series with Douglas have been computed from the distance and 
 the total oxygen and the oxygen per kilogram per meter as given by the authors. The subject's 
 naked weight at Oxford was about 63.5 kilograms; at Pike's Peak, 60.8 kilograms. 
 
StTMMAKY OF EESTJLTS OF PEEVIOUS OBSERVATIONS. 
 
 27 
 
 experiments on horizontal plane — Continued. 
 
 Resting value. 
 
 Average 
 weight 
 moved. 
 
 Distance per minute. 
 
 Range. 
 
 Average, 
 
 Heat computed per hori- 
 zontal kilogrammeter. 
 
 Range. Average. 
 
 "Erhaltungsumsatz" of 1083 
 gram-calories. 
 
 .do. 
 
 .do. 
 
 .do. 
 
 .do. 
 
 ^Standing, with food . 
 
 .do. 
 
 ....do. 
 
 'Ruhewert". 
 
 Lying, without food . 
 
 103.50 
 103.60 
 103.20 
 .103.00 
 
 112.60 
 113.00 
 113.00 
 
 ri23.00 
 \123.00 
 
 "72.45 
 72.77 
 73.76 
 72.73 
 72.78 
 
 270.71 
 70.48 
 70.70 
 70.88 
 70.89 
 
 272.94 
 72.59 
 73.77 
 74.36 
 73.42 
 
 meters. 
 37.40- 73.30 
 78.20- 84.20 
 92.80- 94.50 
 
 105.7 
 
 118.1 
 125.60-129.00 
 
 43.50- 77.70 
 
 84.60- 94.90 
 
 104.70-105.10 
 
 115.80-115.80 
 
 32.80- 74.00 
 86.00- 90.60 
 
 100.0 
 
 111.4 
 
 37.00- 76.70 
 78.10- 82.20 
 89.90- 94.70 
 
 48.60- 68.90 
 90.9 
 
 '52.03- 54.18 
 77.25- 82.88 
 102.73-107.83 
 119.90-121.77 
 134.65-137.87 
 
 351.77- 54.98 
 77.52- 81.55 
 102.73-111.32 
 112.67-116.15 
 132.77-132.77 
 
 '53.12- 54.98 
 79.13- 84.50 
 105.42-111.58 
 120.43-126.33 
 130.63-139.48 
 
 31.00- 51.70 
 
 51.40- 55.20 
 
 49.40- 52.40 
 
 30.1 
 
 meters. 
 
 53.10 
 
 81.50 
 
 93.40 
 
 105.70 
 
 118.10 
 
 127.30 
 
 62.00 
 
 91.00 
 
 104.90 
 
 115.80 
 
 54.80 
 
 88.30 
 
 100.00 
 
 111.40 
 
 55.00 
 80.20 
 92.30 
 
 58.80 
 90.90 
 
 '53.38 
 81.00 
 105.95 
 120.97 
 136.26 
 
 '53 . 64 
 79.66 
 108.09 
 114.53 
 132.77 
 
 '53.91 
 82.88 
 108.36 
 123.38 
 136.26 
 
 46.10 
 53.80 
 51.10 
 30.10 
 
 86.70 
 65.00 
 86.70 
 86.70 
 
 gm.-cals. 
 
 0.4709-0.5278 
 
 .5040- .5411 
 
 .6088- .6213 
 
 0.7107 
 
 .9281 
 
 0.9626-0.9720 
 
 .4502- .5716 
 .5651- .5933 
 .7232- .7982 
 .9121- .9122 
 
 .4766- .5883 
 
 .5439- .6436 
 
 0.7256 
 
 .9143 
 
 0.5433-0.6391 
 .5450- .6778 
 .8143- .8796 
 
 .5858- .5884 
 0.7747 
 
 '0.366 
 .440 
 .523 
 .638 
 .889 
 
 '.524 
 .568 
 .713 
 .768 
 .919 
 
 '.547 
 .588 ■ 
 .704 
 .770 
 .978 ■ 
 
 -0.448 
 
 - .490 
 
 - .549 
 
 - .682 
 
 - .907 
 
 - .607 
 
 - .634 
 
 - .862 
 
 - .897 
 
 - .964 
 
 - .609 
 
 - .600 
 
 - .873 
 -1.009 
 -1.126 
 
 .50 - .56 
 
 .48 - .56 
 
 .42 - .55 
 
 0.51 
 
 0.570 -0.395 
 .374 - .398 
 
 gm.-cals. 
 1.489 
 .520 
 .616 
 .711 
 .928 
 .967 
 
 1.506 
 .581 
 .761 
 .912 
 
 1.529 
 .594 
 .726 
 .914 
 
 '.577 
 .611 
 .847 
 
 1.587 
 .775 
 
 '.402 
 .460 
 .531 
 .656 
 .898 
 
 '.562 
 .600 
 .789 
 .833 
 .942 
 
 '.571 
 .595 
 .776 
 .897 
 
 1.066 
 
 <0.53 
 
 * .50 
 
 * .50 
 ' .51 
 
 «0.448 
 ' .550 
 » .386 
 » .375 
 
 'It was necessary to convert the distances from miles to meters and to compute the heat from 
 the oxygen consumption. 
 
 'Averages of individual heat values given for the groups in the original publication. 
 
 'In computing all heat values for Barkan and Viale, the value for lying without food was 
 assumed to be represented by 255 c.c. of oxygen; for Signorelli, 225 c.c. of oxygen. In one 
 experiment with Higgins, a corresponding value of 203 c.c. of carbon dioxide and of 265 c.c. of 
 oxygen was obtained. The weight of the clothing and the Douglas bag was about 7 kilograms 
 in each case. 
 
28 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 treadmill; the basal or resting value for the individual subjects; the 
 total weight of the material moved in a horizontal direction, including 
 the weight of the body, clothing, apparatus, and any supplementary 
 weight which the subject may have carried; the distance walked per 
 minute; and finally, the calories per horizontal kUogrammeter. 
 
 The speed of the walking, which is shown by the distance walked per 
 minute, is a factor of considerable importance; the range and average 
 are therefore both given. Whenever there is a great difiference in the 
 speed for the same subject, a special line is assigned to it. Wide varia- 
 tions are shown in the average distance walked per minute in the several 
 researches, the figures ranging from 32 meters in the Sonden and 
 Tigerstedt experiments pubUshed in 1894 to 177.3 meters in an experi- 
 ment by Caspari reported in 1905. 
 
 As a result of a careful analysis of the earlier literature of Durig and 
 of Zuntz and his co-workers, the unit adopted for expressing the work 
 of forward progression is the calories required to move 1 kilogram 1 
 meter or, as we shall here designate it, the calories per horizontal kilo- 
 grammeter. The range and average are both given for these values, 
 but the average values have here the greater significance, and it is the 
 last colunm of the table which we shall particularly consider. Examin- 
 ing these data, we find that they range from 0.308 gram-calorie in the 
 series of experiments made by Amar and reported in 1910 to 1.169 
 gram-calories in the experiment by Caspari pubUshed in 1905. Con- 
 sidering the varied technique, there is, on the whole, a rather remark- 
 able agreement of the values found for the movement of 1 kilogram of 
 body-weight per meter in a horizontal direction, particularly when we 
 consider those values obtained at moderate walking speed. 
 
 Comparing the data for the average distance walked per minute and 
 those for the average calories per horizontal kilogrammeter, we find 
 that the rate of walking has a considerable influence upon the results 
 and that the higher values are invariably found with the greater speeds, 
 although the reverse is by no means true. In general, when the rate of 
 walking does not exceed 80 to 90 meters per minute, the values lie 
 between 0.3 and 0.7 gram-calorie, with a distinct tendency for them 
 to approach 0.55 gram-calorie. This value has been especially con- 
 sidered by Durig in his admirable review of the literature of this 
 subject. It is clear, then, that we have here to do with an intimate 
 relationship between the rate of walking and the expenditure of energy 
 required to move 1 kilogram 1 meter in a horizontal direction, and that 
 the superimposed load has relatively little influence upon the results. 
 
METHODS AND APPARATUS. 29 
 
 METHODS AND APPARATUS FOR STUDIES OF 
 MUSCULAR WORK. 
 
 Judging from the results as published in the earlier Uterature and 
 summarized in the preceding section, there is apparently httle choice 
 as to the various methods of study. A large majority of the observa- 
 tions have been made with the Zuntz respiration apparatus or some of 
 its modifications; it is obvious that any criticisms applying to this 
 apparatus affect greatly the averages of the values obtained with it. 
 While the construction of the Zuntz apparatus and the various types 
 of valves, particularly the later form of valve used by Durig, is such as 
 to ehminate resistance as far as possible, nevertheless the employment 
 of this type of apparatus for studying muscular work is distinctly open 
 to criticism. 
 
 The use of a wet gas-meter of the size ordinarily employed with the 
 Zuntz respiration apparatus may be seriously objected to for muscular- 
 work experiments, since in these experiments the volumes of expired 
 air may exceed 80 or 90 hters per minute. The caUbration of such a 
 meter at the rate of ventilation used in severe-work experiments is 
 by no means a simple matter, the ordinary method being to allow the 
 water in a 10-Uter spirometer to flow out and draw the air in after it. 
 On the ordinary Elster gas-meter 10 hters correspond to one or at most 
 two revolutions of the drum, and the possibihties of error at the begin- 
 ning and the end in tests of this kind are obvious. Indeed, both Durig 
 and Zuntz have recognized this difficulty and, to avoid errors in the 
 measurement of the large volume of air expired from the lungs, have 
 "made experiments with a very large gas-meter formerly used in studies 
 with horses. If the value obtained for the volume of air be too small 
 (and the error, if any, would be in this direction), obviously that for the 
 total metaboUsm will likewise be too small, and hence the values com- 
 puted for the horizontal kilogrammeter will be too low. 
 
 The importance of knowing the energy requirement of the body for 
 direct forward progression is so great as to justify further observations 
 upon it, particularly if an apparatus is used in which an entirely dif- 
 ferent principle is employed for measuring the metabohsm. One of 
 the main lines of research planned for the Nutrition Laboratory is a 
 study of muscular work in its various phases. Obviously innumerable 
 problems, of both physiological and economic importance, can be 
 studied with suitable apparatus. A special calorimeter has been 
 constructed in this laboratory for research on muscular work, but it is 
 not yet ready for actual use. Prior to experimentation with this 
 calorimeter, it seemed important to make a number of preliminary 
 studies of the metabolism during muscular work with the universal 
 respiration apparatus. This apparatus had previously been used in a 
 study of the metabohsm incidental to riding a bicycle ergometer, in 
 
30 ENEEGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 which it was shown that it was capable of measuring the metabolism 
 with an oxygen consumption as high as 3 liters per minute.'^ Careful 
 control tests of the apparatus have proved conclusively that, so far as the 
 mechanical construction is concerned, the measurement of the carbon- 
 dioxide production and the oxygen consumption is accurate. 
 
 As a part of the plan for studying the metaboUsm during the various 
 phases of muscular work, a special type of treadmill was devised and 
 constructed in this laboratory several years previous to the present 
 research. Certain features of this treadmill, which will be described 
 subsequently, make it especially apphcable for use in experiments with 
 men. Having, therefore, an exceptionally satisfactory treadmill and 
 a respiration apparatus capable of measuring the metabohsm incidental 
 to severe muscular work, it was possible, in 1913-14, to make a study 
 of the metaboUsm of a subject while he was walking on a level. 
 
 As soon as the respiration calorimeter for muscular work is ready for 
 use, the treadmill wiU be placed inside this apparatus and certain of 
 the experiments repeated. The indirect calorimetry computed from 
 the gaseous exchange as measured by the respiration apparatus can 
 thus be controlled by direct determinations of the energy output. 
 This control is of particular importance, since the use of any form of 
 respiration appUance, such as a mouthpiece or nosepieces, is open to 
 legitimate criticism in that the use of such artificial methods of breath- 
 ing, particularly with a very great ventilation of the lungs, may lead to 
 a disturbance in the mechanics of ventilation, thus causing a distur- 
 bance in the respiratory exchange. Although the universal respiration 
 apparatus has been carefully controlled as to the measurement of both 
 carbon dioxide and oxygen, nevertheless if there is a disturbance in the 
 mechanics of ventilation, as, for instance, an over-ventilation of the 
 lungs, there may be a considerable amount of carbon dioxide exhaled 
 that was not simultaneously produced. The retention of carbon 
 dioxide by altered respiratory mechanics is also not improbable. By 
 means of the studies with the respiration calorimeter, therefore, it will 
 be possible not only to determine the metabohsm by direct calorimetry, 
 but also to obtain the gaseous exchange with free breathing without 
 the use of either mouth or nose apphance. 
 
 It should furthermore be borne in mind that while the method of 
 computing the calorimetry from the gaseous exchange has, according 
 to our experience up to the present time, given highly satisfactory 
 results with muscular repose, there is always the possibihty of a dis- 
 turbance in the character of the metabohsm during severe muscular 
 work and a consequent disturbance in the relationship between the 
 gaseous exchange and total heat production. It is thus seen that the 
 final tests with the respiration calorimeter are essential for a complete 
 understanding of this problem. On the other hand, the previous 
 
 ^Benedict and Cathcart, Carnegie Inst. Waah. Pub. No. 187, 1913. 
 
DESCRIPTION OF APPARATUS. 
 
 31 
 
 research with the professional bicycle rider, in which the universal res- 
 piration apparatus was employed, was so successful and the problem of 
 the metabolism during the work of forward progression is so important 
 that, pending the completion and testing of the special calorimeter, the 
 study of this problem with the universal respiration apparatus and the 
 treadmill has seemed entirely justifiable. 
 
 DESCRIPTION OF APPARATUS USED IN THIS RESEARCH. 
 
 UNIVERSAL RESPIRATION APPARATUS. 
 
 The researches of Zuntz and his co-workers have shown that in walk- 
 ing at a somewhat high rate of speed and carrying a load, the amount of 
 muscular exertion required, even on a level path, is very considerable, 
 approximating that required for bicycle riding under severe stress. 
 Obviously, therefore, any respiration apparatus used in a study of the 
 metaboUsm under these conditions must be capable of accurately 
 measuring a maximum oxygen consumption per minute of 3,000 c.c. 
 and a maximum carbon-dioxide production of 2,500 c.c. Fortunately 
 the modified form of the universal respiration apparatus employed by 
 Cathcart had already demonstrated its abihty to fulfill these conditions. 
 The form of apparatus used in this later research was therefore essen- 
 tially that employed for the earher study.^ A general view of the 
 apparatus with its relations to the subject and the accessory apparatus 
 is shown in figure 1. 
 
 Siace the completion of the research on the bicycle rider, various 
 minor modifications have been made in the apparatus, chiefly with a 
 view to f acihtating operation and contributing to its accuracy. Certain 
 other changes were also necessary to adapt it to the type of experiment 
 planned for this research, namely, walking upon a treadmill at varying 
 rates of speed. These changes were considered of sufficient importance 
 for us to give here a schematic outhne of the apparatus as actually 
 employed in the research. (See figure 2.) 
 
 As will be seen from the diagram in figure 2, by turning a 3-way 
 valve N, the subject, breathing through a mouthpiece P, can be con- 
 nected with the ventilating air-current, which is kept in motion by a 
 rotary blower. The air leaving the blower is first passed through a 
 glass WilUams bottle which serves as a safety trap against back-suction 
 of acid. The air is next forced through two Wilhams bottles, each 
 having a capacity of 2.5 liters and half filled with sulphuric acid, 
 which removes the moistiu-e from the air. The ventilating current 
 is then deflected by means of the 2-way valve V^ into either one of two 
 
 'Brezina and Kolmer in a recent paper from Durig's laboratory (Biochem. Zeitschr., 1914, 65, p. 
 33) have questioned the accuracy of the respiratory quotients obtained with this apparatus by 
 Benedict and Cathcart in their study of a bicycle rider. Durig in a private communication says 
 that the method used by Benedict and Cathcart for obtaining the respiratory quotients was accu- 
 rate and that the criticisms of Brezina and Kolmer were founded upon an insufficient study of the 
 results. 
 
32 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 carbon-dioxide absorbing systems. Each series of absorbers include 
 two bottles filled with moist soda lime for absorbing the carbon dioxide, 
 and also a small WiUiams bottle, containing sulphuric acid to absorb 
 the moisture given up to the dry air by the soda lime. The air, which 
 is at this point free from carbon dioxide and water, passes through the 
 2-way valve 7^ and after being moistened in a small WiUiams bottle 
 to a comfortable degree for respiration, it continues until it passes 
 
 Fig. 1. — General view of apparatus used for walking experiments, with subject in position. 
 A, absorption apparatus; B, treadmill; C and D, oxygen supply; E, step counter and 
 
 accessory apparatus. 
 
 by the opening of the tube connected with the mouthpiece P and into 
 the tension equalizer. This tension equalizer is a large copper can, 
 over the top of which is fitted a rubber bathing-cap. From this copper 
 can the air finally returns to the intake side of the blower, oxygen being 
 admitted as required from a cylinder of the gas. Thus we have a com- 
 plete closed-circuit system, with the rubber bathing-cap acting as a 
 tension equalizer to compensate for changes in the volume of air as the 
 subject breathes in and out. 
 
DESCRIPTION OF APPARATUS. 33 
 
 The algebraic increase in weight of the soda-Ume bottles and the 
 following Williams bottle in the carbon-dioxide absorbing system gives 
 the weight of the carbon dioxide absorbed during the experimental 
 period. The volume of oxygen introduced may be determined from 
 the loss in weight of a small cylinder or, as indicated in figure 1, meas- 
 ured by conducting it from a large cyUnder through a carefully calibrated 
 gas-meter which is immersed in water to prevent sudden fluctuations in 
 temperature. To prove the efficacy of the soda lime as an absorbent, 
 a part of the air current may be deflected through two petcocks and 
 passed through a solution of barium hydroxide in a small Erlenmeyer 
 flask. The sUghtest trace of carbon dioxide will produce a turbidity 
 in the solution. 
 
 To ehminate the effect of the long dead space between the mouth- 
 piece, P, and the main ventilating air-pipe, a supplementary pipe E is 
 connected from a point near the mouthpiece to the main air-pipe. By 
 this means the air-current may be deflected so that It will pass directly 
 by the mouthpiece and within a few centimeters of the lips of the sub- 
 ject. The rubber tubes connecting the subject with the ventilating 
 system are of sufficient length and flexibihty to permit considerable 
 lateral and vertical head-motion by the subject while walking, this 
 beiag essential to his comfort. 
 
 In actual experimenting, before the experimental period is begun, 
 the 3-way valve N is so turned that the subject breathes room air. 
 Then, at the end of a normal expiration, the 3-way valve is again turned, 
 connecting the subject with the main ventilating air-current as seen in 
 the diagram. Immediately afterwards the valve M (which has previ- 
 ously been open, giving free passage of the air into the metal tee leading 
 to the tension equahzer) is also turned, thus deflecting the air-current 
 through the supplementary pipe E, so that it passes near the mouth of 
 the subject. 
 
 Before connecting the subject with the ventilating system, the motor 
 is started to equalize pressure throughout the system and then stopped. 
 Sufficient oxygen is next admitted to distend the rubber bathing-cap 
 until a slight positive pressure is observed on the manometer. On 
 starting the blower again, the rubber bathing-cap sinks somewhat, due 
 to the compression of the air in forcing its way through the sulphuric 
 acid and the various absorbing-vessels. At the first inspiration the 
 rubber cap sinks down into the can, rising again with each expiration. 
 As the oxygen is consumed, the height to which the rubber cap fills 
 decreases and oxygen is admitted to keep the fluctuations of the 
 bathing-cap to approximately the same range. At the conclusion of 
 the experiment, the valve M is first turned and shortly afterwards the 
 valve N is also turned, always at the end of a normal expiration. At 
 this point the experimental period is concluded so far as the subject is 
 concerned. The motor is next allowed to run for a minute or two to 
 
34 
 
 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 sweep out completely the carbon dioxide in the system. When the 
 motor is stopped sufficient oxygen is admitted to bring the tension to 
 the original point; the volume of air in the system is then exactly the 
 same as at the beginning. The carbon-dioxide absorbers and the accom- 
 panying WilUams bottle are weighed and a reading taken of the amount 
 of oxygen which has passed through the gas-meter, the data being used 
 subsequently for computing the carbon dioxide produced and the 
 oxygen consumed during the experimental period. 
 
 H" 
 
 ^^fr^iT 
 
 HjSOt 
 
 HjSO,. TRAP ^CnS-' METER 
 
 Fig. 2. — Schematic outline of vmiversal respiration apparatus. 
 
 The general course of the ventilating current is shown by arrows. P, mouthpiece; N, 3-way 
 valve connecting subject with ventilating current; V- and Y^, 2-way valves for carbon- 
 dioxide absorbing system; M, valve connecting with supplementary pipe E for eliminating 
 the dead-air space; S, petcock connection for tambour and kymograph for recording the 
 respiration. 
 
 TREADMILL. 
 
 In many of the earlier iavestigations for measuring the carbon- 
 dioxide output and oxygen consumption of a walking man, the subject 
 has been obhged to carry a respiration apparatus upon his back or 
 drag behind him a long tube attached to the breathing appliance. 
 In other studies the apparatus has been pushed along behind the 
 subject by an assistant. Obviously none of these methods are suitable 
 for experiments in which there is rapid movement. Furthermore, 
 whUe we have no desire to minimize the value of the Zuntz apparatus — 
 an apparatus which has contributed largely to our knowledge of the 
 physiology of man, particularly for high altitudes — it should be said 
 that the transportation of an unwieldy gas-meter and accessory appa- 
 ratus by a subject is open to serious objection. It has been shown 
 
DESCRIPTION OF APPARATUS. 
 
 35 
 
 by Zuntz and his co-workers that a subject may be trained in a rela- 
 tively short time to carry such an apparatus successfully; nevertheless 
 its transportation is at best difficult, and the method is more fitted for 
 studies of that type of walking in which loads would normally be carried 
 upon the back. Both Zuntz and Durig have shown that they recognize 
 this fact, as they have made studies in which the gas-meter was not 
 carried by the subject, and the walking was done upon a treadmill. 
 
 Several years previous to our research, Mr. E. H. Metcalf, then a 
 member of the staff of the Nutrition Laboratory, designed a tread- 
 mill and had it constructed under his supervision in the machine-shop 
 of the Laboratory. This treadmill was used for the first time in the 
 research carried out in 1913-14 and the fact that it satisfactorily sus- 
 tained a severe test at this time testifies to the designing abihty of Mr. 
 Metcalf and the constructive skill of Mr. W. E. CoUins, the mechan- 
 ician of the Laboratory. A general view of the treadmill and its dispo- 
 sition with regard to the other apparatus is shown in figure 1. A more 
 detailed perspective drawing is given in figure 3. 
 
 Fig. 3. — Treadmill designed by E. H. Metcalf. 
 
 The endless leather belt travels over two wooden pulleys A and B, the actuating] mechanism 
 being an electric motor. The tension on the belt may be adjusted by the bolt and nut C. 
 A revolution counter is shown at R. 
 
 The treadmill is provided with an endless belt, 60 cm. wide, 435 
 cm. long, and approximately 10 mm. thick. This belt travels over 
 two wooden pulleys, A and B, having a width of 60 cm. and a 
 diameter of 41 cm. The pulleys are supported on ball bearings at the 
 ends of a wooden frame. On the rear pulley is attached a sprocket- 
 wheel, which connects with the reducing-gear actuated by a one-half 
 horsepower electric motor. The tension on the belt may be easily 
 adjusted by means of the screw C, thus preventing the belt from sUp- 
 ping. To support the belt between the pulleys and provide a surface 
 for the man to walk upon, steel tubes, 46 in number, with an external 
 diameter of 25 mm. and a length of 61 cm., are set into a steel frame- 
 work, the distance between the centers of the tubes being 27 mm. 
 These steel tubes are fitted at each end with annular steel ball bearings. 
 
36 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 The detail of the bearmgs is given in figure 4, which shows the method 
 of support on the angle frame of the treadmill. The thick belt thus 
 rests upon a roUing, frictionless surface throughout the whole length of 
 the space over which the man is to walk, providing a substantial, 
 perfectly smooth path for the subject. It is impossible to feel the 
 numerous steel rolls, as the space between them is so small. The 
 leather belt gives a particularly satisfactory footing. The speed of the 
 motor may be modified at will and tests may be made at rates of speed 
 varying from less than 50 meters per minute, the equivalent of a very 
 slow walk, to 150 meters per minute, or a rapid walk, if not, indeed, 
 running. 
 
 Since the driving of the treadmill belt is from the rear wheel, all tend- 
 ency to slip is at this point. Consequently, by counting the revolutions 
 of the forward wheel, where no sUp can possibly take place, we have an 
 accurate measure of the total distance traveled. Upon the periphery 
 of the forward wheel are attached two revolution counters (one on 
 each side)^ which can be read intermittently. One runs continuously; 
 the other may be connected or disconnected at will. In use, the 
 subject walks upon the treadmill for several minutes before the experi- 
 mental period commences. At the exact moment of beginning the 
 measurements of the respiratory exchange, one of the revolution 
 counters is put in action, so that the distance covered during the 
 period is accurately known. It is thus unnecessary to assume con- 
 stancy in the revolution of the motor or to apportion the distance 
 walked during the period from the total measurement of the revolutions 
 of the front wheel during the entire time the subject is walking. 
 
 Considering the number of the various bearings and the size of the 
 apparatus it produces much less noise and vibration than any treadmill 
 that we have thus far seen. By means of adjusting screws at the for- 
 ward end of the treadmill, which are not shown in figure 3, any desired 
 elevation can be readily secured. In this research, however, the tread- 
 mill was invariably used in a perfectly level position. At the date of 
 writing (June 1915), after two years of use, the apparatus shows no 
 signs of wear and gives most satisfactory service. 
 
 ACCESSORY APPARATUS. 
 The universal respiration apparatus and the treadmill provide accu- 
 rate measurements of the total carbon-dioxide production and the 
 oxygen consumption and of the distance walked by the subject. In 
 addition to this, certain observations are important, particularly in 
 studying the physiology of walking, and it was therefore necessary to 
 have some means of recording accurately the respiration, the pulse, 
 the number of steps taken by the subject, and the height to which the 
 body was raised with each step. 
 
 'But one of these (R) is shown in figure 3. 
 
DESCRIPTION OF APPARATUS. 37 
 
 METHOD OF RECORDING THE RESPIRATION-RATE. 
 
 The rise and fall of the rubber bag or tension equaUzer with each 
 expiration and inspiration can be readily counted by an observer, 
 thus giving an admirable index of the respiration. As a matter of 
 fact, during the conduct of a severe-work experiment of this type, the 
 other observations are so numerous that it is at best very difficult for 
 an observer to concentrate his attention upon such counting. A 
 tambour has therefore been connected to the petcock S (see fig. 2) 
 which is moved by the difference in pressure existing in the connection 
 between the mouthpiece and the tension equalizer. With each exhala- 
 tion a shght pressure is exerted upon the tambour which records upon 
 a kymograph drum. Subsequently an accurate count of the number of 
 respirations per minute and for the entire experimental period may be 
 made from the tambour record and that of a time marker. 
 
 METHOD OF RECORDING THE PULSE-RATE. 
 
 The important relationship between total metabohsm and the pulse- 
 rate, which has been so frequently observed in this Laboratory^ made it 
 desirable to secure records of the pulse-rate of the subject during the 
 walking periods. The difficulties experienced in securing counts of the 
 pulse-rate in the earher research with the bicycle rider have been freely 
 commented upon in the publication giving the report of that study, and 
 it was hoped that some graphic method could be found which would give 
 accurate records of the pulse-rate of a walking man. Unfortunately 
 such a method was not available at the beginning of our research, and 
 counts were therefore made at the wrist or with a stethoscope. Even 
 Yirith a stethoscope at some distance, as employed by Krogh,^ the noise 
 of the treadmill was such as to make the counting of the pulse-rate 
 extremely difficult. Variousforms of tambours^were also experimented 
 with in an attempt to register the pulse graphically, but without result. 
 Finally, by using body leads and the Bock-Thoma oscillograph or the 
 Einthoven string galvanometer, we were able to secure graphic records 
 of the pulse-rate of the subject while he was walking upon the treadmill. 
 
 Great difficulty was experienced in such photographic registration 
 with the dehcate oscillograph and string galvanometer, for not only 
 were there leakages of the 220-volt current used for the motor, but also 
 a static charge on the rapidly revolving belt. Various devices were 
 used for obviating these difficulties, such as having the subject wear 
 rubber-soled shoes and even rubbers over the shoes, but with Uttle 
 success. Finally a metalUc brush was made of a piece of brass tubing, 
 69 cm. long, to which pieces of brass chain, 7 to 9 cm. long, were 
 attached at intervals of approximately 1.5 cm. This brush was so 
 attached to the treadmill that the ends of the chains lay upon the 
 
 'Krogh, Skand. Aichiv f. Physiol., 1913, 30, p. 375. 
 
 ^Bowen, Contributions to Medical Research dedicated to Victor Clarence Vaughan, June 1903, 
 p. 462, Ann Arbor, Mich. 
 
38 
 
 ENERGY TRANSFORMATIONS DTTRING HORIZONTAL WALKING. 
 
 surface of the leather belt. As one end of the chain brush was grounded 
 to the brass tube, when the ends of the chain dragged over the surface 
 of the revolving belt the stray electric currents were picked up and 
 grounded. Satisfactory records could thus be obtained. Unfor- 
 tunately the conditions of the experimental work in the Laboratory 
 at that time prevented our freeing a galvanometer and oscillograph 
 for the particular purpose of determining the pulse-rate; consequently 
 records could not be regularly secured. Indeed, the few observations 
 obtained were of so striking a character that we can not adequately 
 discuss them in this monograph.^ 
 
 STEP COUNTER. 
 
 With a steady electric current, the rate of revolution of the treadmill 
 per minute is presumably fairly constant and the length of the steps 
 in ordinary walking is also doubtless approximately the same; neverthe- 
 less it is important to show in these tests the exact number of steps 
 taken, so as to indicate the distance per step and thus furnish an added 
 factor for analyzing the mechanics and physiology of walking. To 
 count the steps automatically was imperative, as even with several 
 assistants an accurate record of the steps during exceedingly rapid 
 
 Fig. 4. 
 
 Fig. 5. 
 
 Fig. 4. — Detail of ball bearing for steel tubes on the treadmill. 
 
 Fig. 5.— Step counter. A pulley A is attached to the extended shaft of a revolution counter; 
 a small cord passes over this pulley and is protected by a guard C. The shaft automat- 
 ically stops at B and B'. 
 
 walking would be very difficult to obtain. A small device was there- 
 fore employed which counted automatically each vertical motion of 
 the body produced in walking. 
 
 To a belt about the waist of the subject was attached a cord leading 
 over two pulleys on the ceihng to a small spring which maintained 
 a tension on the cord. The general arrangement of this device is shown 
 in figure 1 and the details in figures 5 and 6. At each step the sub- 
 ject lifted the body a certain distance and lowered it again. Advan- 
 tage was taken of this lifting and lowering of the body to raise and lower 
 a small weight (.B,fig. 6) at the end of a cord which rested upon a pulley 
 (A, fig. 5, and D, fig. 6) on the shaft of a revolution counter (see fig. 5). 
 
 'See pp. 85 and 92. 
 
DESCRIPTION OF APPARATUS. 
 
 39 
 
 Automatic stops, B and B', controlled the distance traveled by the 
 pulley. At each upward movement of the body the cord was lowered 
 and the counter pulled in one direction to the stop, the cord simply 
 sUpping over the pulley if the movement continued. As the body 
 returned to its ordinary position, the weight drew the counter back to 
 the second stop. In this way each upward movement of the body was 
 accurately recorded. 
 
 Records obtained with this counter of the number of steps taken by 
 one of our subjects in several walking experiments are given in table 2. 
 These are compared with the number of steps counted for the same 
 periods from kymograph records obtained by a method subsequently 
 described.^ A large number of controls, which were made by counting 
 the movements of the body from the kymograph records and by obser- 
 vations of the counter, showed that this step-counter could be relied 
 upon. 
 
 Table 2. — Comparison of steps recorded by step-counter with those counted from 
 kymograph records. 
 
 Date. 
 
 Period 
 
 No. 
 
 Distance 
 (meters) 
 
 per 
 minute. 
 
 Steps 
 
 per 
 
 minute 
 
 (counter). 
 
 Total number of steps. 
 
 Counter 
 record. 
 
 Counted from kymo- 
 graph record by 
 
 Observer 
 I. 
 
 Observer 
 II. 
 
 1914 
 Apr. 24.... 
 
 Apr. 27.... 
 May 4 . . . . 
 
 May 5 
 
 il 
 
 I 1 
 
 2 
 
 I 3 
 
 f 2 
 
 { 3 
 I 4 
 
 76.4 
 
 78.4 
 
 73.5 
 
 78.1 
 
 114.5 
 
 109.1 
 
 102.0 
 
 106.0 
 
 102.6 
 
 103.6 
 
 116.2 
 117.1 
 114.8 
 116.0 
 138.3 
 133.9 
 127.8 
 133.1 
 126.5 
 126.3 
 
 1,687 
 1,452 
 1,596 
 1,442 
 1,470 
 1,491 
 1,459 
 1,338 
 1,402 
 1,269 
 
 1,700 
 1,454 
 1,588 
 1,418 
 1,472 
 1,508 
 1,476 
 1,340 
 1,428 
 1,274 
 
 1,704 
 1,444 
 1,596 
 1,400 
 1,472 
 1,516 
 1,458 
 1,356 
 1,420 
 1,262 
 
 METHOD OF MEASURING HEIGHT TO WHICH THE BODY IS RAISED. 
 
 One factor of the mechanics of walking has hitherto been neglected 
 for the most part by writers, particularly when studies of the gaseous 
 metaboUsm have been made, that is, the height that the body is raised 
 during the process of walking. At each step the body is raised and 
 lowered a distance of approximately 25 to 50 mm., and even higher in 
 running.^ In any careful research on the physiology of walking in 
 which the efficiency of the body for moving a certain weight a certain 
 distance forward is studied, it is necessary to note the height of this 
 upward movement. For this purpose Dr. Carl Tigerstedt used a device 
 
 'See p. 40. 
 
 ^See table 20, p. 98. 
 
40 
 
 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 which, in principle, was much like that used by him in studsdng mus- 
 cular work done with the foot.^ 
 
 This apparatus, shown in figure 6, consists of a small pointer A, 
 travehng on a brass block between two upright guides. The cord G, 
 attached to the pointer, passes over a pulley to the belt of the subject, 
 as shown in figure 1. The spiral spring F, previously referred to 
 in the description of the step-counter, keeps a tension upon the cord. 
 Obviously as the body is raised the tension of the spiral spring draws 
 the pointer down and as the body is lowered the cord draws the pointer 
 up. Each upward and downward movement of the body- may be 
 recorded on a rotating kymograph drum, thus giving a graphic record 
 of the character of each step. A typical record is given in figure 7. 
 
 It can be seen that the height to which the body is lifted may be 
 obtained from the kymograph record by measuring each downward 
 stroke of the pointer and adding the sum of the 
 values. Experimental conditions prevented us 
 from using a kymograph with a rapidly rotating 
 drum or a long paper kymograph, and the con- 
 sequent superimposing of the records shown in 
 figure 7 obviously makes the counting of the 
 number of steps somewhat difficult; neverthe- 
 less it is possible and has been done in a number 
 of instances (see table 2). By measuring several 
 points in the curve, an approximate average 
 height of step may easily be obtained; these 
 averages may then be multiplied by the total 
 number of steps recorded on the step-counter 
 and the distance to which the body is raised 
 computed. 
 
 In an attempt to sum up these upward move- 
 ments by means of some automatic arrangement, 
 a special form of work adder-wheel was devised 
 for the purpose. This work adder-wheel, which 
 is shown as B in figure 6, relied upon the friction 
 
 Fig. 6. — ^Apparatys for recording the height to which the body is 
 lifted, and step-counter with connections. 
 
 The cord G, connected with the body of the subject, passes over a 
 grooved wheel B attached to the shaft of a revolution-counter 
 C, a pawl p, preventing backward motion. It then passes 
 to a pointer A (the marker of Dr. Carl Tigerstedt), tension 
 being supplied by the light spring F. An upright cord 
 travels over a grooved pulley on the step-counter D, with the 
 tension produced by the small weight traveling in a tube E. 
 The height to which the body is raised at each step is thus 
 recorded in a dual manner, first, by the excursions of the 
 pointer A over a kymograph dram and second by the accumu- 
 lated movement of the wheel B. 
 
 'C. Tigerstedt, Skand. Archiv f. Physiol., 1913, 30, p. 299. 
 
Fig. 7. — Typical kymograph record showing character of step. 
 
 The upper line shows the admission of oxygen to the apparatus, each section representing 1 liter; 
 the second line the steps taken by the subject; the third line the respiration; and the lowest line the 
 time in minutes. 
 
DESCRIPTION OF APPABATUS. 41 
 
 of a cord passing over a groove in the wheel to rotate it in one direction 
 as the body was hfted, a pawl -p preventing any backward motion. 
 When the body returned to the normal position, the cord slipped over 
 the pulley without producing any movement of the wheel. Each 
 upward movement of the body accordingly resulted in a forward 
 motion of the wheel. The work adder-wheel was directly connected 
 to the shaft of a revolution-counter, and a record of the total move- 
 ment of the wheel was thus obtained. (See C, fig. 6.) The total dis- 
 tance the body was raised would theoretically be that found by multi- 
 plying the number of revolutions of the wheel by its circumference. 
 
 At the very rapid rate of walking used in some of these experiments, 
 great difficulty was experienced in the earlier development of the appa- 
 ratus in securing an accurate record. The cord would frequently 
 slip and there was considerable reverse movement, for it was not easy 
 to find a pawl arrangement which would work perfectly. This reverse 
 movement or "back-lash" was not overcome until practically the end of 
 the series of observations; recently, however, a very thin laminated 
 spring has been used as a pawl, which has practically ehminated this lost 
 motion. The apparatus as described represents the completed form. 
 As a matter of fact, in many of our experiments we were unable to use 
 the records obtained from this wheel. The height to which the body 
 was raised was therefore determined by the method previously referred 
 to, i. e., measuring on the kymograph curve the general average dis- 
 tance to which the body was raised and multiplying this by the record 
 of the number of steps on the step-counter. 
 
 In order to have these measurements of absolute value, the distance 
 traveled by the pointer on the kymograph or that traveled by the cord 
 passing over the work adder-wheel must represent exactly the distance 
 over which the body is elevated or lowered. This assumes that there 
 is no disturbance in the attachment of the cord to the body and that 
 the tension of the spring is such as to prevent any diag or inequality 
 in the movement of the pointer over the drum. As may be seen from 
 the kymograph curve reproduced in figure 7, the constancy in the 
 movement of the pointer was very satisfactory. On the other hand, 
 the method of attaching the cord to the subject was certainly open to 
 serious criticism. Wire was used for the most part, vioHn string being 
 substituted for such portions as passed over the flexible parts, thus 
 minimizing the tension and the danger of alterations in the length. 
 There was, however, opportunity for considerable flexibility in the play 
 of this cord at the point where it was attached to the belt holding up the 
 trousers of the subject ; accordingly, the records obtained with the kymo- 
 graph and with the work adder-wheel are without doubt invariably some- 
 what too small and the body was in all instances raised to a higher point 
 than that indicated in table 2. The expediency of attaching a wire 
 direct to the body by means of sxu-geon's plaster was not resorted to, 
 although the omission was undoubtedly an error in our observations. 
 
42 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 PLAN OF RESEARCH. 
 
 While this investigation was undertaken primarily with the object of 
 studying the metabolism of walking on a level, certain preliminary 
 observations were necessary, particularly for the purpose of estabhshing 
 a base-Une for comparison with the metaboUsm during walking. As 
 has previously been stated, certain investigators, in studying the 
 metabohsm during walking, have been incUned to employ as a basis 
 of comparison the metaboUsm determined with the subject in the lying 
 position and without food in the stomach, i. e., maintenance metabo- 
 hsm. Many attempts have also been made to study the metabohsm 
 with the subject in the standing or the sitting position, these values 
 being deducted from the total metaboUsm obtained with the subject 
 walking, the increment being considered as due to the work of forward 
 progression. It was therefore necessary in our research to study the 
 metaboUsm not only during walking but also under other conditions, 
 thus increasing the number of problems to be studied. 
 
 A considerable number of experiments were carried out with the 
 subject standing in different positions, those used being (1) with the 
 subject standing with the body relaxed, as one would stand quietly 
 without external support; (2) leaning against a support at the back; 
 (3) leaning upon a staff; and (4) standing with muscles tense in the 
 position of "attention." By determining the metaboUsm in these 
 various resting or standing attitudes, all conceivable base-lines could 
 be obtained. Furthermore, it was found that during experiments with 
 rapid walking there was considerable lateral motion of the arms, as is 
 the habit with many walkers, particularly professional pedestrians. 
 Consequently certain experiments were made with the subject standing 
 and swinging the arms from side to side as in a fast walk, but without 
 moving the feet. A number of observations were also made of the 
 metaboUsm with the subject sitting, with the idea that the values thus 
 obtained might be used for the basal metaboUsm. As a matter of 
 fact, only a few of the sitting experiments were made with the subject 
 in the post-absorptive condition and the values secured have not been 
 used for actual comparison purposes. 
 
 The main object of the research was, of course, the study of the 
 metaboUsm during walking and specificaUy the study of the increase 
 in the metaboUsm due to walking at increasing speeds. In the series 
 of walking experiments, therefore, the subject was required to walk at 
 a very slow speed, then at a medium speed, and finaUy at a very fast 
 speed. In a few experiments the subject actuaUy ran, thus giving data 
 for comparing the work of forward progression while the subject was 
 waUdng with that while he was running, two entu-ely distinct methods 
 of forward progression. Certain observations were also made regard- 
 ing the effect upon the metaboUsm of fatigue due to long-continued 
 
is 
 PLAN OF RESEARCH. 43 
 
 walking, the subject being required on several days to walk for a con- 
 siderable length of time. 
 
 While, in common with several other investigators, we have beheved 
 that the most sharply defined results can be obtained in experiments 
 without food, nevertheless the experimental conditions were such as to 
 make it relatively simple for us to obtain values after the ingestion of 
 food. With this end in view, we made specific studies of the metabo- 
 lism under the various conditions of standing, walking at various 
 speeds, running, and after fatigue, not only when the subject was with- 
 out food in the stomach but also after food had been taken. The 
 experiments carried out after food duphcated the experiments with the 
 subject in the post-absorptive condition; it was therefore possible to 
 note whether or not there was a summation effect on the metaboHsm 
 due to the ingestion of food and to the work. 
 
 While in some of the experiments the diet was uncontrolled, in a 
 number of them it was prescribed. The constituents of the meal 
 varied widely in these latter experiments, a special protein diet being 
 supphed on some days, on others a diet containing an excess of fat, and 
 again a diet with a large proportion of carbohydrate. The results 
 of these experiments accordingly gave data as to the effect of a special 
 diet upon the metaboUsm during walking. 
 
 This, in brief, was our plan of research at the beginning of the series 
 of observations. Incidentally a number of other important physio- 
 logical details were developed as the research progressed. These will 
 be taken up specifically in the discussion of the results of the experi- 
 ments. 
 
44 ENEEGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 GENERAL ROUTINE OF THE EXPERIMENTS. 
 
 It will be seen from the foregoing that the experiments in this research 
 fall naturally into four classes: standing experiments, sitting experi- 
 ments, walking and running experiments, and experiments with food. 
 From the earUer experience of Cathcart with a subject riding a bicycle, 
 it seemed inadvisable to attempt the estabhshment of a standard test- 
 ing base-Une:4;o be deducted from the total metaboHsm of the subject 
 while walking. It was therefore decided that each morning, prior to 
 the walking experiment, measurements should be made of the standing 
 resting metabolism; consequently the research included a large number 
 of standing experiments. 
 
 STANDING EXPERIMENTS. 
 
 The respiration apparatus used for this research and previously 
 described was designed more especially for measuring the large amounts 
 of carbon dioxide exhaled during severe muscular exercise, and was, in 
 consequence, fitted with two soda-lime bottles, each of which must be 
 weighed. If only the resting metabolism had been determined, a 
 slightly different arrangement would have been preferred, with the use 
 of but one soda-lime bottle, a spirometer form of apparatus being 
 substituted for the rubber bathing-cap and tension-equaUzer. Never- 
 theless, since the resting metaboHsm with the subject standing was to be 
 used primarily as a base-hne to be deducted from the greatly increased 
 metabolism during walking, it was considered that this method of 
 measuring the metaboHsm during standing would be sufficiently 
 satisfactory for the purpose, and hence the standing metaboHsm was 
 determined on exactly the same apparatus as that used in the walking 
 experiments. As a matter of fact, the experiments made by Cathcart, 
 and more especiaUy those of Carpenter,^ have shown that the tension- 
 equaHzer form of the unit apparatus gives as accurate measurements of 
 the metaboHsm during rest as does the spirometer type. In this par- 
 ticular apparatus, however, we could readily have dispensed with the 
 second soda-Hme bottle. 
 
 After arriving at the Laboratory, the subject arranged his clothing 
 for an ordinary walking experiment and assumed the standing position 
 on the treadmiU, this position being maintained for some time prior to 
 the actual experimentation. After the effect of the sHght exertion of 
 coming to the Laboratory and of ascending the stairs had passed away, 
 the mouthpiece was inserted, the nosecHp attached, and at the proper 
 time, i. e., at the end of a normal expiration, the 3-way valve connecting 
 the subject with the ventilating system of the respu-ation apparatus 
 was turned. The experiment was then continued in the usual manner 
 
 ^Carpenter, Carnegie Inst. Waah. Pub. 216, 1915, pp. Ill to 118. 
 
GENERAL ROUTINE OF THE EXPERIMENTS. 45 
 
 for approximately 15 minutes. At the end of a normal expiration the 
 valve was again turned and the experiment was completed. During 
 the entire experiment oxygen was admitted regularly from a cylinder, 
 the gas being passed through a carefully cahbrated Bohr gas-meter 
 immersed in water. At the conclusion of the experiment the ventila- 
 tion was continued for a few minutes to insure the thorough sweeping 
 out of all the carbon dioxide; finally the tension-equahzer was filled 
 with oxygen to the same tension that existed at the beginning of the 
 experiment. 
 
 Owing to the greatly increased carbon-dioxide production during 
 severe muscular work, the ventilating current was so adjusted that 
 the ventilating pump would cause 80 to 90 Uters of air to pass by the 
 mouth of the subject per minute, thus minimizing the danger of the 
 rebreathing of the air. Furthermore, by means of the supplementary 
 valve M (see fig. 2, page 34), the dead space in the rubber tube leading 
 from the mouthpiece to the main air-pipe was wholly eliminated, for 
 when the valve N had been turned after the beginning of the experi- 
 ment, all of the air passed immediately by the mouthpiece. While 
 this deflection of the air-current was unnecessary in the experiments 
 with the subject standing, nevertheless it was also used in these experi- 
 ments in order that the procedure might be the same in both series. 
 
 Since it is important to note whether or not the subject remained in 
 essentially the same degree of muscular repose throughout the standing 
 experiments, a graphic record was obtained of the degree of movement 
 by connecting the subject with a cord attached to a movable pointer 
 traveling over a smoked-paper kymograph. In an ideal experiment 
 the course of the pointer would be a straight hne. While it was impos- 
 sible for the subject to remain as perfectly quiet as he would when lying 
 upon a comfortable couch, nevertheless the regularity and constancy 
 of the muscular repose of the subject from experiment to experiment 
 was, to say the least, very striking. We are therefore safe in assuming 
 that in practically no experiment were the irregularities in the metabo- 
 lism for the standing position attributable to changes in the degree 
 of muscular repose of the individual, except in those tests in which 
 special positions while standing were assumed, such as the position of 
 "attention." 
 
 SITTING EXPERIMENTS. 
 
 A few sitting experiments were also made with one of the subjects. 
 These were not used as a base-Une, but are recorded simply to show that 
 an endeavor was made to secure the best possible base-line for deduc- 
 tion from the total metabolism obtained during walking. The incre- 
 ment in the metaboUsm for the sitting position was unfortunately not 
 studied with sufficient sharpness to make a definite conclusion possible. 
 
46 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 WALKING AND RUNNING EXPERIMENTS. 
 
 In the walking and running experiments the routine was essentially 
 that previously outlined for the standing experiments, save that during 
 the entire period and for several minutes before the experiment began 
 the subject was walking upon an electrically driven treadmill which 
 was kept in motion at a definite rate of speed. These rates of speed 
 varied from 53 meters per minute to 149 meters per minute. The 
 flexibility of the mouthpiece and its attendant by-pass made it possible 
 for the subject to walk with perfect comfort at these varying speeds and 
 the vertical movement of the body with each step did not interfere in 
 the shghtest with the correct measurement of the gaseous exchange. 
 With a slow speed, there was no noticeable extraneous muscular effort 
 other than that of walking; with a high speed the subject made vig- 
 orous lateral motions of the arms, as is quite common with profes- 
 sional pedestrians when walking at high speed. As previously noted, 
 an attempt was made to measure the influence of this lateral motion by 
 studjdng the metaboUsm with the subject standing and swinging the 
 arms. In a number of the experiments the subject ran, although the 
 rate of progression was but little higher than in the experiments with 
 fast walking. 
 
 EXPERIMENTS WITH FOOD. 
 
 , A considerable number of experiments were made after a breakfast 
 selected by the subject; a few were also made after dinner, the diet being 
 uncontrolled. In the experiments in which a study was made of the 
 possible influence of diets containing a preponderance of protein, fat, or 
 carbohydrate, the first meal of the day was given to the subject at the 
 Laboratory after a walking experiment in the forenoon in which he 
 was in the post-absorptive state. This meal consisted of steak, rice, 
 potatoes, or various fats. A second walking experiment was then made 
 under otherwise identical conditions. The exact weight of food was 
 not recorded, since our only aim was to make sure that the body was 
 plentifully suppHed with the special food constituent being studied. 
 In general, the subject ate aU that he possibly could and as a con- 
 sequence was frequently disincUned to walk in the afternoon. 
 
 A careful study of the effect of muscular work upon the urine was 
 impracticable, hence no analyses of the urine accompany these observa- 
 tions. Previous tests with one of the subjects have shown, however, 
 that the accompUshment of a large amount of severe muscular work was 
 not accompanied by an excessive excretion of nitrogenous products in 
 the urine.^ 
 
 'Benedict and Cathoart, Carnegie Inst. Wash. Pub. 187, 1913, p. 98. 
 
SUBJECTS. 47 
 
 SUBJECTS. 
 
 In this series of observations two subjects were used, both of whom 
 were more or less trained to severe muscular activity, as one (A. J. O.) 
 was a semi-professional baseball player and the other (M. A. M.) a 
 professional bicycUst. The preUminary observations in this research 
 were carried out by Dr. Carl Tigerstedt with the subject A. J. O. (sub- 
 ject I), a man of athletic buUd, who readily adapted himself to the 
 observations on the treadmill and with the respiration apparatus. He 
 was 29 years of age, 180 cm. in height, and had a body-weight with 
 clothing varying from 72.1 kilograms to 74.8 kilograms and without 
 clothing of 69.7 kilograms. Since in this study one of the prime objects 
 was to note the energy required to move 1 kilogram of material in the 
 forward direction 1 meter, i. e., 1 horizontal kilogrammeter, the body- 
 weight with clothing is of importance in each experiment. These 
 weights are given in detail in table 13 (page 78). 
 
 The major portion of the research was devoted to a study of forward 
 progression at varying speeds with the subject M. A. M., who had 
 previously served as the subject of Cathcart in the study of the mus- 
 cular work of bicycle-riding. This subject, who in this pubhcation is 
 designated as subject 11,^ was 31 years of age, 177 cm. in height, and 
 had a body-weight with clothing varying from 69.9 to 72.4 kilograms. 
 The average body-weight without clothing during this series of experi- 
 ments was 68.3 kilograms. The body-weight with clothing is given for 
 each experiment in tables 14 and 16 (pages 83 and 88). 
 
 'Further data regarding the body measurements, etc., of this subject may be found in the report 
 of the previous study on muscular work. See Benedict and Cathcart, Carnegie Inst. Wash. Pub. 
 187, 1913, p. 35. 
 
48 
 
 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 STATISTICS OF EXPERIMENTS. 
 
 The data regarding the experimental conditions, the respiratory 
 exchange, and the mechanics of walking for the experiments with sub- 
 ject I (A. J. O.) are given in table 3; the data for subject II (M. A. M.) 
 appear in table 4. 
 
 Table 3. — Summary of results obtained with subject I in experiments withovi food, during the 
 
 period from Nov. 26, 1913, to Dec. Z7, 191S. 
 
 [Observations made by Dr. Carl Tigerstedt. Values per minute.] 
 
 Date and condition. 
 
 Dura- 
 tion. 
 
 Nmi. se.' 
 
 Standing,'' 10'' 10" a. m. . 
 Standing,* lO*" 45™ a. m. . 
 
 Food about 1 p. m. 
 Standing, 2'' 25" p. m . . . 
 Standing, 2'' 45" p. m . . . 
 Walking,^ S"" 24" p.m... 
 
 Nov. S8. , 
 
 Standing, lO*" 29" a. m . . 
 Standing, ll"" 03" a. m . . 
 Standing, ll"" 30" a. m . . 
 
 Nov. B9. 
 
 Standing, Oi" 16" a. m . . . 
 Standing, g"" 50" a. m . . . 
 Walking,' lO"" 22" a. m . . 
 
 Dec 1. 
 
 Standing, Q* 30" a. m . . . 
 Standing, O"" 57" a. m . . . 
 Walking,' lO^" 51" a. m. . 
 Walking,' 11'' 34" a. m. . 
 
 Dec. 2. 
 
 Standing, S'' 54" a. m . . . 
 Standing, Q"" 17" a. m . . . 
 Standing, lO'' 15" a. m . . 
 Walking,' 10'' 30" a. m. . 
 Walking,' 11'' 18" a.m. . 
 
 Dec. S. 
 
 Standing, O"" 10" a. m . . . 
 
 Standing, Q"" 38" a. m 
 
 Standing, lO"- 06" a. m . . , 
 Walking,' 10'' 45" a. m . . , 
 Walking,' 11'' 05" a. m. . . 
 Walking,' 111" 35" a. m. . . 
 Standing, ll"" 56" a. m . . . 
 Standing, 12'' 20"p. m . . . 
 
 mm. sec. 
 15 17 
 15 45 
 
 15 04 
 15 35 
 15 15 
 
 IS 07 
 15 06 
 15 48 
 
 15 18 
 15 19 
 15 02 
 
 Car- 
 bon 
 diox- 
 ide. 
 
 15 
 
 11 
 
 15 
 
 12 
 
 9 
 
 59 
 
 9 
 
 57 
 
 15 
 
 28 
 
 15 
 
 22 
 
 IS 
 
 25 
 
 4 
 
 44 
 
 10 
 
 16 
 
 16 
 
 07 
 
 15 
 
 07 
 
 15 
 
 05 
 
 10 
 
 47 
 
 10 
 
 17 
 
 10 
 
 17 
 
 13 
 
 55 
 
 15 
 
 09 
 
 c.c. 
 283 
 278 
 
 277 
 268 
 943 
 
 226 
 222 
 218 
 
 228 
 219 
 
 886 
 
 222 
 217 
 692 
 731 
 
 Oxy- 
 gen. 
 
 c.c. 
 343 
 321 
 
 341 
 
 328 
 
 1015 
 
 284 
 291 
 279 
 
 282 
 282 
 873 
 
 276 
 
 282 
 852 
 904 
 
 Respi- 
 ratory 
 quo- 
 tient. 
 
 234 
 
 290 
 
 223 
 
 289 
 
 214 
 
 280 
 
 630 
 
 853 
 
 695 
 
 849 
 
 226 
 
 286 
 
 214 
 
 269 
 
 209 
 
 270 
 
 685 
 
 845 
 
 701 
 
 842 
 
 697 
 
 872 
 
 215 
 
 270 
 
 206 
 
 267 
 
 0.82 
 .86 
 
 .81 
 .82 
 .93 
 
 .80 
 .76 
 
 .78 
 
 .81 
 
 .78 
 
 1.02 
 
 .81 
 .77 
 .81 
 .81 
 
 .81 
 .77 
 .77 
 .74 
 .82 
 
 .79 
 .80 
 .78 
 .81 
 .83 
 .80 
 .80 
 .77 
 
 Aver- 
 age 
 
 pulse- 
 rate. 
 
 80 
 
 87 
 
 85 
 96 
 95 
 
 91 
 94 
 
 90 
 94 
 
 90 
 
 88 
 
 90 
 99 
 97 
 
 85 
 89 
 
 Average 
 respi- 
 ration- 
 rate. 
 
 Dis- 
 tance, 
 
 Rais- 
 ing of 
 body. 
 
 18.3 
 
 18.0 
 18.4 
 27.9 
 
 16.3 
 17.2 
 17.7 
 
 18.6 
 18.3 
 25'. 7 
 
 19.0 
 19.5 
 25.4 
 24.5 
 
 19.4 
 21.1 
 21.5 
 26.8 
 25.3 
 
 19.5 
 21.8 
 21.9 
 27.3 
 26.7 
 25.5 
 23.0 
 23.0 
 
 meters. 
 
 75.3 
 
 meters, 
 
 3.57 
 
 75.1 3.15 
 
 76.0 
 76.6 
 
 76.2 
 76.8 
 
 76.5 
 
 77.2 
 77.5 
 
 3.26 
 3.36 
 
 3.20 
 4.62 
 
 3.57 
 3.62 
 3.68 
 
 'The subject had breakfast at about 7 a. m. 
 
 'Throughout this summary of resets, the designation "standing" signifies standing in a 
 relaxed position unless otherwise specified. --/iiuuius m a 
 
 'Subject I walked at a rate of not far from 105 steps per minute th7-niiir><r».4- +»,o „ n ■ 
 except on December 22 23 and 27. The total distaVe du'^nTtleSr fct^aVl^Ts 
 meters; on Nov. 29, 1,129 meters; dunng the periods on Dec. 1, 1,520 meters- Dec ^^a 1 iIq 
 meters; Dec. 3, 2,415 meters. The subject did not walk between periods. ' 
 
STATISTICS OF EXPERIMENTS. 
 
 Table 3. — Summary of results obtained with subject I in experiments without food, 
 period from Nov. 26, 1913, to Dec. $7, 75^3— Continued. 
 
 [Observations made by Dr. Carl Tigerstedt. Values per minute.] 
 
 49 
 
 the 
 
 
 
 
 Car- 
 
 
 Respi- 
 
 Aver- 
 
 Average 
 
 
 Rais- 
 ing of 
 body. 
 
 Date and condition. 
 
 Dura- 
 
 bon 
 
 Oxy- 
 
 ratory 
 
 age 
 
 respi- 
 
 Dis- 
 
 
 tion. 
 
 diox- 
 
 gen. 
 
 quo- 
 
 pulse- 
 
 ration- 
 
 tance 
 
 
 
 
 ide. 
 
 
 tient. 
 
 rate. 
 
 rate. 
 
 
 Dec. 4. 
 
 min 
 
 sec 
 
 c.c. 
 
 c.c. 
 
 
 
 
 meters. 
 
 meters. 
 
 Standing, 9'' 12" a. m 
 
 15 
 
 02 
 
 220 
 
 267 
 
 0.82 
 
 86 
 
 22.5 
 
 
 
 Standing, g*" 21"" a. m . . . . 
 
 15 
 
 10 
 
 208 
 
 269 
 
 .77 
 
 97 
 
 22.8 
 
 
 
 Standing, 10'' 04°' a. m . . . 
 
 15 
 
 10 
 
 213 
 
 265 
 
 .80 
 
 88 
 
 22.4 
 
 
 
 Walking,' 10'' SS"" a. m... 
 
 10 
 
 19 
 
 690 
 
 874 
 
 .79 
 
 
 24.9 
 
 77.7 
 
 3.41 
 
 Walking,' 11'' 30" a. m. .. 
 
 10 
 
 04 
 
 695 
 
 882 
 
 .79 
 
 
 26.4 
 
 77.7 
 
 3.68 
 
 Walking,' 12'' OS" p. m . . . 
 
 10 
 
 06 
 
 703 
 
 857 
 
 .82 
 
 
 25.2 
 
 78.2 
 
 3.57 
 
 Dec. B. 
 
 
 
 
 
 
 
 
 
 
 Standing, 9'' 18"" a. m 
 
 16 
 
 03 
 
 239 
 
 335 
 
 .71 
 
 100 
 
 21.8 
 
 
 
 Standing, g"" iS"" a. m 
 
 15 
 
 08 
 
 240 
 
 340 
 
 .71 
 
 110 
 
 23.6 
 
 
 
 Standing, lO"" IS" a. m . . , 
 
 IS 
 
 07 
 
 230 
 
 328 
 
 .70 
 
 105 
 
 24.3 
 
 
 
 Walking,' 10'' 52" a. m . . . 
 
 10 
 
 03 
 
 720 
 
 928 
 
 .78 
 
 
 26.9 
 
 75!7 
 
 3!S7 
 
 Walking,' 11'' 12'» a. m. . . 
 
 10 
 
 06 
 
 790 
 
 92S 
 
 .85 
 
 
 27.5 
 
 78.2 
 
 4.10 
 
 Walking,' 11'' 37" a.m... 
 
 10 
 
 OS 
 
 761 
 
 983 
 
 .77 
 
 
 29.9 
 
 79.0 
 
 4.10 
 
 Dec. 8. 
 
 
 
 
 
 
 
 
 
 
 Standing, 9'' 17" a. m 
 
 15 
 
 01 
 
 205 
 
 272 
 
 .75 
 
 89 
 
 20.3 
 
 
 
 Standing, 9'' 42" a. m 
 
 15 
 
 06 
 
 209 
 
 270 
 
 .77 
 
 91 
 
 20.9 
 
 
 
 Standing, IC" 11" a. m. . , 
 
 IS 
 
 09 
 
 205 
 
 271 
 
 .76 
 
 93 
 
 22.4 
 
 
 
 Walking,M0''46"a. m... 
 
 11 
 
 57 
 
 692 
 
 829 
 
 .84 
 
 
 24.7 
 
 76. S 
 
 3.52 
 
 Walking,Ml''15"a. m... 
 
 11 
 
 59 
 
 729 
 
 889 
 
 .82 
 
 
 24.8 
 
 78.6 
 
 3.78 
 
 Walking,Ml''41"a. m... 
 
 12 
 
 04 
 
 721 
 
 887 
 
 .81 
 
 
 23.9 
 
 79.3 
 
 4.04 
 
 Walking,* 12'' 07" p. m . . . 
 
 11 
 
 54 
 
 722 
 
 920 
 
 .78 
 
 
 27.2 
 
 79.7 
 
 4.15 
 
 Dec. 9.' 
 
 
 
 
 
 
 
 
 
 
 Standing, 9 a. m 
 
 15 
 
 06 
 
 25S 
 
 357 
 
 .71 
 
 120 
 
 22.6 
 
 
 
 Standing, 9'' 39" a. m 
 
 15 
 
 10 
 
 248 
 
 345 
 
 .72 
 
 110 
 
 22.8 
 
 
 
 Standing, 10'' 25" a. m . . . 
 
 15 
 
 35 
 
 242 
 
 320 
 
 .76 
 
 lOS 
 
 23.2 
 
 
 
 Walking,* 11'' 07" a. m. . . 
 
 13 
 
 54 
 
 792 
 
 952 
 
 .83 
 
 
 23.6 
 
 76.0 
 
 3.'%9. 
 
 Walking,* 11'' 33" a. m... 
 
 14 
 
 00 
 
 782 
 
 899 
 
 .87 
 
 
 26.9 
 
 78.3 
 
 3.89 
 
 Walking,* 12'' 11" p.m... 
 
 14 
 
 03 
 
 753 
 
 891 
 
 .85 
 
 
 27.0 
 
 79.1 
 
 4.04 
 
 Dec. IB. 
 
 
 
 
 
 
 
 
 
 
 Standing, 9'' 06" a. m 
 
 IS 
 
 08 
 
 233 
 
 279 
 
 .83 
 
 89 
 
 21.6 
 
 
 
 Standing, 9'' 37" a. m 
 
 15 
 
 17 
 
 212 
 
 268 
 
 .79 
 
 91 
 
 22.3 
 
 
 
 Standing, 10'' 04" a. m . . . 
 
 IS 
 
 12 
 
 220 
 
 278 
 
 .79 
 
 88 
 
 22.8 
 
 
 
 Walking,* 10'' 32" a. m. . . 
 
 15 
 
 02 
 
 808 
 
 980 
 
 .82 
 
 
 23.0 
 
 74 !2 
 
 3.68 
 
 "Walking,* 10'' 58" a. m . . . 
 
 15 
 
 OS 
 
 757 
 
 891 
 
 .85 
 
 
 26.4 
 
 75.6 
 
 3.83 
 
 Walking,* 11'' 25" a. m... 
 
 15 
 
 02 
 
 734 
 
 875 
 
 .84 
 
 
 26.2 
 
 76.3 
 
 3.94 
 
 Walking,* 11'' 50" a. m... 
 
 17 
 
 18 
 
 727 
 
 
 
 
 28.3 
 
 76.3 
 
 3.99 
 
 Dec. 16. 
 
 
 
 
 
 
 
 
 
 
 Standing, 9'' 17" a. m . . . . 
 
 20 
 
 07 
 
 220 
 
 290 
 
 .76 
 
 103 
 
 21.8 
 
 
 
 Standing, 9'' 48" a. m . . . . 
 
 20 
 
 12 
 
 221 
 
 284 
 
 .78 
 
 100 
 
 22.3 
 
 
 
 Standing, 10'' 17" a. m . . . 
 
 20 
 
 10 
 
 229 
 
 283 
 
 .81 
 
 99 
 
 22.4 
 
 
 
 Walking,* 11'' 05" a. m. . . 
 
 20 
 
 06 
 
 758 
 
 882 
 
 .86 
 
 
 23.5 
 
 75.1 
 
 sisg 
 
 Walking,* 11'' 37" a.m... 
 
 20 
 
 00 
 
 754 
 
 853 
 
 .88 
 
 
 26.2 
 
 76.7 
 
 3.99 
 
 Walking,* 12'' 19" p. m . . . 
 
 20 
 
 08 
 
 721 
 
 793 
 
 .91 
 
 
 28.1 
 
 77.6 
 
 4.20 
 
 'Subject I walked at a rate of not far from 105 steps per minute throughout the walking series, 
 except on December 22, 23, and 27. The total distance walked during the periods on Dec. 4 
 was 2,374 meters; Dec. 6, 4,303 meters. The subject did not walk between periods. 
 
 *The total distance walked on Dec. 8 was 7,363 meters; on Dec. 9, 6,114 meters; Dec. 15, 7,219 
 meters; Dec. 16, 7,247 meters. The subject walked between periods. 
 
 'Previous to the experiment of Dec. 9 the subject took an egg-phosphate. 
 
50 
 
 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 Tabui; 3. — Summary of results obtained with svbject I in experiments unthmitfood, during the 
 period from Nov. S6, 191S, to Dec. 27, /9iS— Concluded. 
 
 [Observations made by Dr. Carl Tigerstedt. Values per minute.] 
 
 
 
 
 Car- 
 
 
 Respi- 
 
 Aver- 
 
 Average 
 
 
 Rais- 
 ing of 
 body. 
 
 Date and condition. 
 
 Dura- 
 tion. 
 
 bon 
 diox- 
 
 Oxy- 
 gen. 
 
 ratory 
 quo- 
 
 age 
 piilse- 
 
 respi- 
 ration- 
 
 Dis- 
 tance 
 
 
 
 
 ide. 
 
 
 tient. 
 
 rate. 
 
 rate. 
 
 
 Dec. n. 
 
 min 
 
 sec. 
 
 c.e. 
 
 c.c. 
 
 
 
 
 meters. 
 
 meters. 
 
 Standing, S"- 57" a. m 
 
 25 
 
 00 
 
 230 
 
 277 
 
 0.83 
 
 89 
 
 20.5 
 
 
 
 Standing, g"- 32" a. m 
 
 25 
 
 07 
 
 221 
 
 270 
 
 .82 
 
 92 
 
 21.4 
 
 
 
 Standing, lO*" 07" a. m . . . 
 
 25 
 
 07 
 
 217 
 
 266 
 
 .82 
 
 93 
 
 22.1 
 
 
 
 Walking,! iQh 4401 a. m. . . 
 
 20 
 
 09 
 
 695 
 
 823 
 
 .84 
 
 
 25.3 
 
 75.0 
 
 3.73 
 
 Walking,! Ill" 14" a.m... 
 
 20 
 
 07 
 
 708 
 
 851 
 
 .83 
 
 
 24.9 
 
 76.4 
 
 3.89 
 
 Walking,' ll"- 45" a. m . . . 
 
 20 
 
 16 
 
 706 
 
 872 
 
 .81 
 
 
 26.5 
 
 78.1 
 
 4.15 
 
 Walking,! 12>' 18" p.m... 
 
 20 
 
 08 
 
 719 
 
 905 
 
 .79 
 
 
 26.5 
 
 78.6 
 
 4.15 
 
 Dee. 18. 
 
 
 
 
 
 
 
 
 
 
 Standing, 9^ 03" a. m 
 
 25 
 
 05 
 
 238 
 
 272 
 
 .88 
 
 88 
 
 21.1 
 
 
 
 Standing, Q"" 54" a. m . . . . 
 
 25 
 
 33 
 
 230 
 
 263 
 
 .87 
 
 88 
 
 21.3 
 
 
 
 Standing, Vf" 34" a. m . . . 
 
 25 
 
 13 
 
 220 
 
 255 
 
 .86 
 
 83 
 
 21.6 
 
 
 
 Walking,! ll* 08" a. m... 
 
 20 
 
 04 
 
 726 
 
 811 
 
 .89 
 
 
 23.9 
 
 75.3 
 
 3.52 
 
 Walking,! 11'' 40" a. m . . . 
 
 20 
 
 28 
 
 740 
 
 833 
 
 .89 
 
 
 25.2 
 
 76.4 
 
 3.68 
 
 Walking,! 12>> 10" p. m. . . 
 
 20 
 
 04 
 
 730 
 
 864 
 
 .84 
 
 
 27.7 
 
 76.7 
 
 3.68 
 
 Walking,! 12'' 39" p. m. . . 
 
 20 
 
 12 
 
 734 
 
 867 
 
 .85 
 
 
 27.3 
 
 76.9 
 
 3.73 
 
 Dee. 19. 
 
 
 
 
 
 
 
 
 
 
 Standing, gi" 43" a. m 
 
 25 
 
 03 
 
 238 
 
 279 
 
 .85 
 
 96 
 
 22.5 
 
 
 
 Standing, Itf^ 16" a. m . . . 
 
 25 
 
 06 
 
 239 
 
 282 
 
 .85 
 
 97 
 
 23.3 
 
 
 
 Standing, Itf- 49" a. m . . . 
 
 25 
 
 06 
 
 241 
 
 275 
 
 .88 
 
 100 
 
 23.1 
 
 
 
 Walking,! iiii25"a. m. . . 
 
 20 
 
 06 
 
 789 
 
 869 
 
 .91 
 
 
 23.9 
 
 76.1 
 
 3.83 
 
 Walking,! ll"" 54" a. m... 
 
 20 
 
 06 
 
 772 
 
 860 
 
 .90 
 
 
 28.1 
 
 77.9 
 
 3.99 
 
 Walking,! 12'' 21" p. m . . . 
 
 20 
 
 10 
 
 755 
 
 871 
 
 .87 
 
 
 29.0 
 
 78.3 
 
 4.10 
 
 Walking,! 12'' 52" p. m. . . 
 
 10 
 
 40 
 
 759 
 
 872 
 
 .87 
 
 
 29.8 
 
 78.7 
 
 4.20 
 
 Dec. SO. 
 
 
 
 
 
 
 
 
 
 
 Standing, 8'' 55" a. m 
 
 25 
 
 06 
 
 237 
 
 272 
 
 .87 
 
 99 
 
 23.3 
 
 
 
 Standing, 9'' 29" a. m 
 
 25 
 
 17 
 
 
 271 
 
 
 106 
 
 22.5 
 
 
 
 Standing, 10'' 06" a. m . . . 
 
 25 
 
 10 
 
 224 
 
 273 
 
 '.'82 
 
 106 
 
 23.2 
 
 
 
 Standing, 11'' 10" a. m . . . 
 
 24 
 
 56 
 
 216 
 
 263 
 
 .82 
 
 100 
 
 22.5 
 
 
 
 Walking,! nk 44m a. m. . . 
 
 20 
 
 04 
 
 690 
 
 825 
 
 .84 
 
 
 26.1 
 
 76^2 
 
 S.6S 
 
 Walking,! 12'' ll"p. m. . . 
 
 20 
 
 07 
 
 735 
 
 884 
 
 .83 
 
 
 28.5 
 
 77.7 
 
 4.04 
 
 Walking,! 12'' 40" p. m . . . 
 
 20 
 
 02 
 
 731 
 
 924 
 
 .79 
 
 
 30.1 
 
 78.6 
 
 4.20 
 
 Walking,! l*" 02" p. m 
 
 19 
 
 59 
 
 747 
 
 934 
 
 .80 
 
 
 31.3 
 
 78.9 
 
 4.25 
 
 Dec. SS. 
 
 
 
 
 
 
 
 
 
 
 Walking,! ^Qk 17" a. m. . . 
 
 20 
 
 15 
 
 718 
 
 873 
 
 .82 
 
 
 27.4 
 
 76.3 
 
 4.07 
 
 Walking,! iQh 47m a. m. . . 
 
 20 
 
 06 
 
 610 
 
 790 
 
 .77 
 
 
 28.6 
 
 65.9 
 
 3.17 
 
 Walking,! 11'' 20" a. m. . . 
 
 20 
 
 07 
 
 641 
 
 901 
 
 .71 
 
 
 30.2 
 
 77.4 
 
 4.28 
 
 Walking,! ll''48"a. m. . . 
 
 20 
 
 06 
 
 600 
 
 788 
 
 .76 
 
 
 29.7 
 
 67.5 
 
 3.41 
 
 Dec. gS. 
 
 
 
 
 
 
 
 
 
 
 Walking,! 9'' 25" a. m... 
 
 20 
 
 29 
 
 695 
 
 833 
 
 .83 
 
 
 25.7 
 
 75.9 
 
 3.97 
 
 Walking,! gh 59m a. m 
 
 20 
 
 47 
 
 589 
 
 740 
 
 .80 
 
 
 24.2 
 
 66.4 
 
 3.07 
 
 Walking,! 10'' 38" a. m... 
 
 20 
 
 18 
 
 694 
 
 863 
 
 .80 
 
 
 27.2 
 
 76.9 
 
 4.08 
 
 Walking,! n'' I2"a. m. . . 
 
 20 
 
 06 
 
 602 
 
 764 
 
 .79 
 
 
 26.0 
 
 66.4 
 
 3.30 
 
 Dec.g7. 
 
 
 
 
 
 
 
 
 
 
 Walking,! 9'' 56" a.m.... 
 
 21 
 
 53 
 
 685 
 
 846 
 
 .81 
 
 
 27.0 
 
 78.4 
 
 4.06 
 
 Walking,! 10^41" a. m. . . 
 
 20 
 
 43 
 
 563 
 
 725 
 
 .78 
 
 
 26.9 
 
 65.2 
 
 3.02 
 
 Walking,! 11'' 15" a. m. . . 
 
 20 
 
 52 
 
 664 
 
 852 
 
 .78 
 
 
 28.6 
 
 78.6 
 
 4.13 
 3.02 
 
 Walking,! 11'' 48" a. m... 
 
 20 
 
 11 
 
 560 732 
 
 .76 
 
 
 29.1 
 
 65.1 
 
 !Subject I walked at a rate of not far from 105 steps per minute throughout the waUdns series 
 except on Dec. 22, 23, and 27. The total distance walked on Dec. 17 was 8 798 meters- Dec 18 
 8,435 meters; Dec. 19, 7,581 meters; Dec. 20, 8,142 meters; Deo. 22, 10 075 meters-' Dec' 23* 
 10,338 meters; Dec. 27, 11,908 meters. The subject walked between periods. The stera ne^ 
 minute in the last three periods on Deo. 22 were 95, 101, and 95; during the periods on D^ 9<l 
 105,94, 103, and 96; onDec. 27, 106,94, 103, and 92, respectively. ">" on uec. -Sd, 
 
STATISTICS OF EXPERIMENTS. 
 
 51 
 
 Table 4. — Summary of results in experiments vdth subject II, during the period from 
 
 Mar. 16, 1914, to May 15, 1914. 
 
 [Values per minute.] 
 
 Date, condition, and time. 
 
 Dura- 
 tion. 
 
 Car- 
 bon 
 diox- 
 ide. 
 
 Oxy- 
 gen. 
 
 1^ 
 
 >-3 
 <i p. 
 
 " i ai 
 
 Dis- 
 tance. 
 
 Steps. 
 
 Rais- 
 ing 
 of 
 
 body. 
 
 Mar. 16. 
 Food, T"" 40°' a.m.: 
 
 Sitting,' 9'' SS" a. m 
 
 , Sitting,! lO* 26" a. m... 
 
 Standing,' 11'' 22"» a. m . 
 
 Standing.Ml'' 56"° a. m. 
 
 Walking,' 12'' 53"" p. m. . 
 Food, l''45™p. m.: 
 
 Sitting, S"" 05" p. m 
 
 Standing, S"" 52" p. m. . . 
 
 Walking,' 4'' 30" p. m . . . 
 
 Mar. 17. 
 Food, 12 noon: 
 
 Sitting, 3'' 45" p. m 
 
 Mar. 18. 
 Food, 7'' 30" a.m.: 
 
 Sitting, 9''08"a. m 
 
 Standing, 10 a. m 
 
 / Walking,* 10'' 55" a. m . . 
 Walking,* 11'" 35" a. m. . 
 Food, 12'' 30" p.m.. 
 
 Sitting, 3'' 09" p. m 
 
 Walking,* 3'' 54" p. m . . . 
 
 Mar. 19. 
 Food, 7''30"a. m.: 
 
 Sitting, 9'' 24" a. m 
 
 Standing, 10''37"a. m.. 
 
 Walking,* ll"" 21" a. m . . 
 Food, 12'' 30" p.m.: 
 
 Sitting, 2'' 18"p. m 
 
 Standing, 3'' 05" p. m . . . 
 
 Walking,' 3'' 50" p. m . . . 
 
 Mar. 20. 
 Without food : 
 
 Standing,' 9^ 58" a. m . . 
 
 Walking,' 10'' 51" a. m. . 
 Food, 12'' 30" p. m.: 
 
 Standing,' 3'' 56" p. m. . 
 
 Walking,' 4'' 34" p. m . . . 
 
 mm. sec. 
 
 21 26 
 
 23 44 
 
 20 13 
 
 20 14 
 19 45 
 
 21 28 
 18 29 
 21 27 
 
 18 36 
 
 20 
 18 
 18 
 19 
 
 21 
 20 
 
 18 
 17 
 20 
 
 18 
 17 
 18 
 
 18 
 17 
 
 16 
 19 
 
 c.c. 
 218 
 203 
 217 
 223 
 672 
 
 250 
 261 
 721 
 
 213 
 
 233 
 244 
 699 
 702 
 
 248 
 758 
 
 242 
 231 
 720 
 
 259 
 247 
 739 
 
 218 
 583 
 
 274 
 602 
 
 c.c. 
 281 
 256 
 274 
 286 
 810 
 
 304 
 319 
 815 
 
 272 
 
 286 
 293 
 840 
 
 297 
 808 
 
 282 
 295 
 870 
 
 322 
 303 
 833 
 
 275 
 725 
 
 318 
 634 
 
 0.77 
 .79 
 .79 
 .78 
 .83 
 
 .82 
 .82 
 
 .78 
 
 .82 
 .83 
 .83 
 
 .84 
 .94 
 
 .86 
 .78 
 .83 
 
 .80 
 
 .82 
 
 .79 
 .80 
 
 .95 
 
 77 
 
 18.7 
 18.3 
 18.7 
 20.2 
 26.4 
 
 19.9 
 22.1 
 29.2 
 
 18.1 
 
 19.2 
 18.2 
 25.1 
 27.0 
 
 19.3 
 26.9 
 
 18.7 
 19.3 
 26.9 
 
 21.0 
 20.7 
 28.1 
 
 16.8 
 20.4 
 
 20.3 
 22.6 
 
 meters. 
 
 74 
 
 75.3 
 
 107 
 
 97 
 
 2.88 
 
 3.17 
 
 76.0 
 78.0 
 
 76.3 
 
 74.9 
 
 74.9 
 
 52.7 
 
 98 
 105 
 
 99 
 
 99 
 
 96 
 
 92 
 
 92 
 
 3.34 
 3.62 
 
 3.75 
 
 3.16 
 
 3.55 
 
 2.61 
 
 2.39 
 
 'During "sitting" periods in this summary the subject sat comfortably in a chair and was as 
 quiet as possible. 
 
 *rhe designation "standing" signifies standing in a relaxed position unless otherwise specified. 
 The subject stood as quietly as possible. 
 
 "Total distance preliminary to and during period before lunch, 1,633 meters; after lunch, 
 1,740 meters. 
 
 *Total distance before lunch, 4,573 meters, the walking being continuous; after lunch, distance 
 preliminary to and during period, 1,690 meters. 
 
 'Total distance preliminary to and during period before lunch, 1,573 meters; after lunch, 
 1,462 meters. 
 
 'Standing on one leg, right leg relaxed, with hands in pockets. Subject found this more tmng 
 than standing on both legs. 
 
 'Total distance preliminary to and during period before lunch, about 1,057 meters; after lunch 
 the distance was 1,055 meters. The subject's hands swung loosely at his side as he walked. It 
 should be stated that this was the case except as otherwise indicated. 
 
 'Standing on both legs with hands in pockets. 
 
62 
 
 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 Table 4. — Summary of results in experiments with subject I J, during the period from 
 
 Mar. 16, 1914, to May IS, iSl^— Continued. 
 
 [Values per minute.] 
 
 Date, condition, and time. 
 
 Dura- 
 tion. 
 
 Car- 
 bon 
 diox- 
 ide. 
 
 Oxy- 
 gen. 
 
 .tfJ3 
 
 a Q 
 
 < ft 
 
 
 Dis- 
 tance. 
 
 Rais- 
 iag 
 of 
 
 body. 
 
 Mar. 21. 
 Food, l^ZO^B..m.: 
 
 Standing,' 9'' 15"° a. m 
 
 Standing, attention,' 10'' 09"° 
 a. m 
 
 Walking,' 11'' 15" a. m 
 
 Food, 12''30'°p. m.. 
 
 Standing,' 2'' 09" p. m 
 
 Standing, attention,* 2'' 48" p.m. 
 
 Walking,' 3'' 32" p. m 
 
 Mar. 23. 
 
 Food, 7 a. m. : 
 
 Standing, staff,* g"" 50" a. m . . 
 
 Walking,'' lO*" 37" a. m 
 
 Walking,' ll"- 34" a. m 
 
 Mar. 24. 
 
 Without food : 
 
 Standing, staff, 9'' 07" a. m . . 
 
 Standing, support,' 9'' 54" a. m. 
 
 Walking,' 11'' 05" a. m 
 
 Food, 12'' 15"° p.m.: 
 
 Standing, staff, 1'' 56" p. m . . 
 
 Standing, support,' 2'' 40" p. m. 
 
 Walking,' 3'' 34" p. m 
 
 Mar. 25. 
 
 Without food: 
 
 Sitting, 9'' SS" a. m 
 
 Standing, attention,' 10'' 57" 
 a. m 
 
 Walking,' 11'' 52" a. m 
 
 Food, 12'' 30" p. m.: 
 
 Sitting, 2'' 03'° p. m 
 
 Standing, attention,' 2*' 38" p.m. 
 
 Walking,' 3'' 39" p. m 
 
 rmn. 
 19 
 
 16 
 22 
 
 15 
 15 
 20 
 
 16 
 19 
 
 18 
 
 18 
 19 
 16 
 
 16 
 17 
 16 
 
 18 
 
 14 
 17 
 
 15 
 13 
 17 
 
 sec. 
 27 
 
 58 
 2 
 
 44 
 
 5 
 
 18 
 
 c.c. 
 271 
 
 249 
 675 
 
 275 
 270 
 593 
 
 282 
 625 
 670 
 
 217 
 196 
 628 
 
 289 
 254 
 734 
 
 192 
 
 206 
 570 
 
 272 
 292 
 704 
 
 c.c. 
 338 
 
 288 
 764 
 
 355 
 295 
 699 
 
 333 
 
 764 
 
 250 
 256 
 
 778 
 
 356 
 301 
 809 
 
 260 
 
 265 
 709 
 
 316 
 309 
 726 
 
 0.80 
 
 .87 
 .88 
 
 .78 
 .92 
 .85 
 
 .84 
 .91 
 
 .88 
 
 .87 
 .77 
 .81 
 
 .81 
 .84 
 .91 
 
 .74 
 
 .78 
 .80 
 
 .86 
 .95 
 .97 
 
 91 
 
 74 
 
 20.7 
 
 21.2 
 22.3 
 
 20.9 
 22.6 
 23.9 
 
 20.5 
 22.8 
 25.2 
 
 18.8 
 17.7 
 21.9 
 
 22.1 
 20.7 
 21.3 
 
 18.0 
 
 18.7 
 19.8 
 
 19.6 
 20.2 
 24.1 
 
 meters. 
 
 57.9 
 
 52.8 
 
 57.9 
 57.5 
 
 60.6 
 
 62.7 
 
 104 
 
 92 
 
 93 
 99 
 
 95 
 
 101 
 
 60.6 
 
 61.1 
 
 92 
 
 90 
 
 meters. 
 
 3.11 
 
 2.59 
 
 2.74 
 2.61 
 
 1.09 
 
 .81 
 
 1.77 
 
 1.50 
 
 'Standing with weight on one leg, the other leg relaxed; hands in pockets. 
 
 'Standing on both legs, with hands at sides, in tense position; subject stiff and tired after the 
 period was finished. 
 
 'Total distance before lunch, 1,362 meters; after lunch, 1,113 meters. 
 
 'Standing relaxed, leaning on long staff, with one hand above the other on the staff. 
 
 Total distance, 2,568 meters, the walking being continuous. During the first of the two periods 
 subject's hands were upon a support at either side; in the second period his hands were swinging 
 at his sides. 
 
 'Leaning against support. In the morning subject stood with hands in his pockets and was not 
 sufficiently comfortable; in the afternoon he placed his hands on his back. 
 
 'Total distance before lunch, 1,150 meters; after lunch, 1,190 meters. In the first period on 
 this day a counter was first used to obtain the nimiber of steps and a wheel for measuring the total 
 height of the raising of the body. Both these devices were generally in use during the remainder 
 of the series. 
 
 'Subject could not wholly secure the erect position desired; at the end of the afternoon period 
 he was not able to stand longer. 
 
 •Total distance before lunch, 1,189 meters; after lunch, 1,295 meters. In both periods, the 
 subject supported his hands on his legs. 
 
STATISTICS OF EXPERIMENTS. 53 
 
 Table 4. — Summary of resiilts in experiments with subject II, during the period from 
 Mar. 16, 1914, to May 15, i5i^— Continued. 
 [Values per minute.] 
 
 
 
 
 Car- 
 
 
 1^ 
 
 A Q 
 
 
 * A o5 
 
 
 
 Rais- 
 
 Date, condition, and time. 
 
 Dura- 
 tion. 
 
 bon 
 diox- 
 
 Oxy- 
 gen. 
 
 it 
 
 a.- g 
 « S 2 
 
 Dis- 
 tance. 
 
 Steps. 
 
 ing 
 of 
 
 
 
 
 ide. 
 
 
 1- 
 
 it 
 
 
 
 
 body. 
 
 Mar. 28. 
 
 
 
 
 
 
 
 
 
 
 
 Without food: 
 
 min. 
 
 sec. 
 
 C.C. 
 
 c.c. 
 
 
 
 
 meters. 
 
 
 meters. 
 
 Standing, staff, 9^ 10™ a. m . . . . 
 
 17 
 
 15 
 
 223 
 
 253 
 
 0.88 
 
 80 
 
 18.7 
 
 
 
 
 Standing, support,' g*" 49™ a. m . 
 
 18 
 
 18 
 
 201 
 
 238 
 
 .84 
 
 79 
 
 19.1 
 
 
 
 
 Walking,' 10^ 58" a. m 
 
 17 
 
 49 
 
 605 
 
 701 
 
 .86 
 
 
 22.0 
 
 62.7 
 
 99 
 
 3.09 
 
 Food, 12'' 30™ p.m.: 
 
 
 
 
 
 
 
 
 
 
 
 Standing, staff, 2 p. m 
 
 15 
 
 53 
 
 274 
 
 317 
 
 .86 
 
 94 
 
 20.6 
 
 
 
 
 Standing, support, 2'' 38™ p. m . 
 
 16 
 
 11 
 
 254 
 
 289 
 
 .88 
 
 93 
 
 21.8 
 
 
 
 
 Walking,' Si" 35™ p. m 
 
 18 
 
 35 
 
 694 
 
 738 
 
 .94 
 
 
 25.4 
 
 66.7 
 
 96 
 
 2.30 
 
 Mar. S7. 
 
 
 
 
 
 
 
 
 
 
 
 Without food: 
 
 
 
 
 
 
 
 
 
 
 
 Sitting. Q"" 18™ a. m 
 
 12 
 
 32 
 
 195 
 
 234 
 
 .83 
 
 58 
 
 17.6 
 
 
 
 
 Standing, attention, 10*» 03"" 
 
 
 
 
 
 
 
 
 
 
 
 a. m 
 
 15 
 
 18 
 
 5 
 
 8 
 
 219 
 544 
 
 272 
 652 
 
 .80 
 
 .83 
 
 71 
 
 18.9 
 22.8 
 
 5716 
 
 95 
 
 2.09 
 
 Walking,' ll"" 56™ a. m 
 
 Food, 12'' 45™ p.m.: 
 
 
 
 
 
 
 
 
 
 
 
 Standing, attention, 2'' 24™ p.m . 
 
 15 
 
 14 
 
 294 
 
 298 
 
 .99 
 
 95 
 
 22.4 
 
 
 
 
 Walking,' 2'' 57™ p. m 
 
 18 
 
 25 
 
 681 
 
 727 
 
 .94 
 
 
 27.1 
 
 58.6 
 
 91 
 
 2.15 
 
 Mar. SS. 
 
 Food, T"" 30™ a. m.: 
 
 
 
 
 
 
 
 
 
 
 
 Standing, support, 9'' 40™ a. m . . 
 
 13 
 
 43 
 
 279 
 
 304 
 
 .92 
 
 87 
 
 20.7 
 
 
 
 
 Standing, support, lO*" 15™ a. m . 
 
 17 
 
 43 
 
 246 
 
 276 
 
 .89 
 
 81 
 
 21.0 
 
 
 
 
 Walking,* ll"- 30™ a. m 
 
 16 
 
 16 
 
 654 
 
 702 
 
 .93 
 
 
 22.1 
 
 59 ^4 
 
 97 
 
 2.52 
 
 Food, 12'' 30™ p. m.: 
 
 
 
 
 
 
 
 
 
 
 
 Standing, support, l*" 44™ p. m . 
 
 16 
 
 48 
 
 280 
 
 314 
 
 .89 
 
 85 
 
 21.0 
 
 
 
 
 Walking,* 2'>24™p. m 
 
 17 
 
 12 
 
 743 
 
 759 
 
 .98 
 
 
 24.5 
 
 59.3 
 
 96 
 
 2.12 
 
 Mar. SO. 
 
 
 
 
 
 
 
 
 
 
 
 Food, 7'' 30™ a. m. : 
 
 
 
 
 
 
 
 
 
 
 
 Standing, attention, 9'' 36™ a. m . 
 
 15 
 
 54 
 
 261 
 
 271 
 
 .96 
 
 76 
 
 20.2 
 
 
 
 
 Standing, staff, lO"" 15™ a. m . . . 
 
 14 
 
 51 
 
 261 
 
 296 
 
 .88 
 
 71 
 
 18.9 
 
 
 
 
 Walking,* ll"- 17™ a. m 
 
 17 
 
 15 
 
 658 
 
 744 
 
 .88 
 
 ■ ■ 
 
 19.2 
 
 68^5 
 
 ioo 
 
 2.26 
 
 Food, 12''45™p. m.: 
 
 
 
 
 
 
 
 
 
 
 
 Standing, staff, l"" 50™ p. m 
 
 15 
 
 8 
 
 318 
 
 339 
 
 .94 
 
 95 
 
 21.3 
 
 
 
 
 Walking,' 2'' 27™ p. m 
 
 16 
 15 
 
 56 
 11 
 
 681 
 666 
 
 722 
 709 
 
 .94 
 .94 
 
 
 24.8 
 21.9 
 
 58,5 
 57.3 
 
 92 
 99 
 
 2!40 
 2.24 
 
 WaUdng," 3'' 26™ p. m 
 
 Mar. 31. 
 
 
 
 
 
 
 
 
 
 
 
 Without food: 
 
 
 
 
 
 
 
 
 
 
 
 Standing, support, &' 38™ a. m . . 
 
 17 
 
 48 
 
 214 
 
 239 
 
 .89 
 
 77 
 
 18.4 
 
 
 
 
 Standing, relaxed, 9^ 21™ a. m. . . 
 
 16 
 
 40 
 
 209 
 
 260 
 
 .80 
 
 71 
 
 17.8 
 
 
 
 
 Standing, attention, 10^ 02™ 
 
 
 
 
 
 
 
 
 
 
 
 a. m 
 
 13 
 15 
 
 9 
 59 
 
 233 
 571 
 
 272 
 673 
 
 .86 
 .85 
 
 75 
 
 19.4 
 21.6 
 
 57.2 
 
 98 
 
 2.01 
 
 Walking,' ll"" 47™ a. m 
 
 'Leaning comfortably against support, hands on back. 
 
 'Total distance before lunch, 1,286 meters; after lunch, 1,345 meters. Subject held his hands 
 on his legs as he walked. 
 
 'Total distance before lunch, 1,184 meters; after lunch, 1,266 meters. Subject held his hands 
 at his sides as he walked. 
 
 *Total distance before lunch, 1,158 meters; after lunch, 1,210 meters. In the morning, subject 
 walked with hands held on his legs; in the afternoon his hands were swinging at his sides. 
 
 'Total distance before lunch, 1,198 meters, subject walking with hands swinging. After lunch 
 distance was 2,229 meters, hands being on support in the first period and swinging at his sides in 
 the second period. Most of the time between periods he was not walking. 
 
 'Total distance before lunch, 1,085 meters; after lunch, 1,020 meters. 
 
54 
 
 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 Table 4. — Summary of results in experimerds with subject II, during the period from 
 Mar. 16, 1914, to May IS, 1914 — Continued. 
 [Values per minute.] 
 
 Date, condition, and time. 
 
 Dura- 
 tion. 
 
 Car- 
 bon 
 diox- 
 ide. 
 
 Oxy- 
 gen. 
 
 ■g a 
 
 & 2 
 
 O p. 
 
 
 Dis- 
 tance. 
 
 Steps. 
 
 Rais- 
 ing 
 of 
 
 body. 
 
 Mar. SI — Continued. 
 Food, 1 p. m.: 
 
 Walking,' 2'' OS" p. m 
 
 Standing, relaxed, 2'' 55" p. m . . 
 Standing, attention, S"" 40" p. m. 
 
 Apr. 1. 
 Without food: 
 
 Standing, 9^ 50™ a. m 
 
 Walking,* 11'' 21"° a. m 
 
 Food, 12 noon: 
 
 Standing, l"" 42°> p. m 
 
 mm. 
 14 
 15 
 11 
 
 15 
 15 
 
 sec. 
 57 
 36 
 52 
 
 16 30 
 
 Avr. S. 
 Food, 7''15"a. m.: 
 
 Standing, support, 8^ 44" a. m . 
 
 Standing, relaxed, 9*' 53" a. m . 
 
 Standing, attention, lO*" 46" 
 
 a. m 
 
 15 
 12 
 
 Apr. S. 
 Without food : 
 
 Sitting, g"" 46" a. m 
 
 Standing, staff, 9'' 26" a. m . . 
 
 Walking,' Itf- 33" a. m 
 
 Food, 12'' 45" p.m.: 
 
 Walking,' l"" 28" p. m 
 
 Walking,' 2'' 28" p. m 
 
 Walking,' S"" 35" p. m 
 
 Standing, 4'' 28" p. m 
 
 Apr. 4. 
 Food, 7''15"a. m.: 
 
 WaUdng,* lO"" 11" a. m 
 
 Walking,'' lO"" 56" a. m 
 
 Walking,* 11'' 29" a. m 
 
 Food, l''15"p. m.: 
 
 Walking,* 2 p. m 
 
 Walking,* 2'" 65" p. m 
 
 Apr. 6' 
 Without food : 
 
 Standing, 9^ 04" a. m 
 
 Walking,' 9^ 41" a. m 
 
 Walking,' 10'' 22" a. m 
 
 Walking,' 111" 13" a. m 
 
 Protein, 12'' 55" p. m.: 
 
 Standing, l"" 24" p. m 
 
 Walking,' 1'' 46" p. m 
 
 Walking,' 2'' 24" p. m 
 
 Walking,' S*" 05" p. m 
 
 12 18 
 
 15 20 
 
 15 
 
 7 
 
 13 
 
 43 
 
 14 
 
 18 
 
 14 
 
 7 
 
 14 
 
 52 
 
 16 
 
 24 
 
 15 
 
 35 
 
 15 
 
 42 
 
 14 
 
 18 
 
 13 
 
 57 
 
 15 
 
 46 
 
 16 
 
 9 
 
 16 
 
 11 
 
 15 
 
 41 
 
 17 
 
 14 
 
 13 
 
 16 
 
 15 
 
 59 
 
 14 
 
 36 
 
 16 
 
 49 
 
 c.c. 
 686 
 277 
 265 
 
 213 
 563 
 
 283 
 
 273 
 253 
 
 248 
 
 219 
 
 224 
 771 
 
 667 
 894 
 860 
 244 
 
 608 
 573 
 554 
 
 657 
 705 
 
 218 
 586 
 567 
 563 
 
 241 
 631 
 641 
 617 
 
 c.c. 
 706 
 345 
 326 
 
 266 
 699 
 
 319 
 
 306 
 281 
 
 268 
 
 246 
 278 
 903 
 
 686 
 938 
 895 
 293 
 
 651 
 
 620 
 669 
 
 707 
 755 
 
 246 
 681 
 668 
 659 
 
 296 
 726 
 712 
 708 
 
 0.97 
 80 
 81 
 
 .80 
 .81 
 
 .90 
 .93 
 
 .89 
 .81 
 .86 
 
 .97 
 .96 
 .96 
 .83 
 
 81 
 
 23.9 
 20.6 
 20.7 
 
 17.9 
 21.5 
 
 20.2 
 
 20.0 
 19.7 
 
 .93 
 
 '73 
 
 .92 
 
 '79 
 
 .83 
 
 
 93 
 
 
 93 
 
 
 89 
 
 674 
 
 86 
 
 '72 
 
 86 
 
 =74 
 
 84 
 
 '77 
 
 82 
 
 
 87 
 
 '78 
 
 90 
 
 
 87 
 
 '86 
 
 meters. 
 57.7 
 
 69.3 
 
 lO.O 
 
 19.4 
 
 
 19.1 
 
 
 20.6 
 
 76.2 
 
 23.4 
 
 67.0 
 
 22.2 
 
 77.0 
 
 22.8 
 
 78.9 
 
 22.0 
 
 
 20.7 
 
 55.1 
 
 22.6 
 
 66.8 
 
 21.3 
 
 66.2 
 
 23.3 
 
 54.4 
 
 24.6 
 
 58.1 
 
 19.8 
 
 
 17.3 
 
 57.8 
 
 20.9 
 
 56.8 
 
 21.6 
 
 56.0 
 
 19.2 
 
 
 19.4 
 
 67.5 
 
 21.6 
 
 57.2 
 
 23.7 
 
 56.3 
 
 99 
 
 100 
 
 114 
 
 100 
 110 
 112 
 
 100 
 
 100 
 
 99 
 
 101 
 101 
 
 104 
 106 
 102 
 
 mstert. 
 1.72 
 
 2.22 
 
 2.38 
 
 2.02 
 2.84 
 3.38 
 
 1.91 
 1.98 
 1.87 
 
 2.05 
 2.21 
 
 1.78 
 1.83 
 1.91 
 
 105 2.21 
 
 105 1.94 
 
 99 1.81 
 
 'Total distance before lunch, 1,085 meters; after lunch, 1,020 meters. 
 
 "Total distance preliminary to and during period, 1,164 meters. 
 
 'Total distance before lunch, l,244meters; after lunch, 7,296 meters. During about 43 minutes 
 between the first two periods of the afternoon subject was not walking. 
 
 *Total distance before lunch, 6,207 meters; after lunch, 4,132 meters. The walking was 
 continuous. 
 
 'Electrocardiograms were obtained during these periods by means of the string galvanometer. 
 
 •On and after Apr. 6, subject's food was prepared and eaten at the Laboratory. 
 
 'Total distance before lunch, 6,140 meters; after lunch, 5,433 meters. The walking, as was 
 usually the case in the days that follow, was continuous. 
 
STATISTICS OF EXPERIMENTS. 
 
 56 
 
 Table 4. — Summary of results in experiments urith subject II, during period from 
 
 Mar. 16, 1914, to May 15, J9i.^— Continued. 
 
 [Values per minute.] 
 
 Date, condition, and time. 
 
 Dura- 
 tion. 
 
 Car- 
 bon 
 diox- 
 ide. 
 
 Oxy- 
 gen. 
 
 
 "I 
 
 Average 
 respira- 
 tion-rate. 
 
 Dis- 
 tance. 
 
 Steps. 
 
 Rais- 
 ing 
 of 
 
 body. 
 
 min. sec. 
 
 c.c. 
 
 c.c. 
 
 
 
 
 meters. 
 
 
 Tneters 
 
 14 29 
 
 214 
 
 257 
 
 0.83 
 
 =^82 
 
 19.2 
 
 
 
 
 15 30 
 
 606 
 
 729 
 
 .83 
 
 275 
 
 20.1 
 
 59.6 
 
 109 
 
 i.98 
 
 15 59 
 
 544 
 
 660 
 
 .82 
 
 '79 
 
 22.1 
 
 58.2 
 
 105 
 
 1.95 
 
 14 8 
 
 198 
 
 235 
 
 .84 
 
 ■^0 
 
 21.4 
 
 
 
 
 13 23 
 
 217 
 
 289 
 
 .75 
 
 !'88 
 
 19.6 
 
 
 
 
 16 19 
 
 643 
 
 732 
 
 .88 
 
 =^81 
 
 20.4 
 
 68.8 
 
 107 
 
 1.78 
 
 13 36 
 
 671 
 
 772 
 
 .87 
 
 288 
 
 25.1 
 
 58.7 
 
 107 
 
 1.83 
 
 13 59 
 
 593 
 
 701 
 
 .85 
 
 
 24.5 
 
 56.9 
 
 99 
 
 1.82 
 
 14 6 
 
 204 
 
 265 
 
 .77 
 
 
 18.4 
 
 
 
 
 12 15 
 
 761 
 
 922 
 
 .82 
 
 
 21.0 
 
 76.1 
 
 121 
 
 3.01 
 
 14 22 
 
 662 
 
 826 
 
 .80 
 
 
 23.0 
 
 77.6 
 
 117 
 
 2.81 
 
 13 29 
 
 660 
 
 807 
 
 .82 
 
 
 24.4 
 
 78.3 
 
 113 
 
 2.85 
 
 12 54 
 
 230 
 
 275 
 
 .83 
 
 
 19.1 
 
 
 
 
 13 22 
 
 785 
 
 869 
 
 .90 
 
 , . 
 
 22.6 
 
 76.9 
 
 120 
 
 2.50 
 
 13 47 
 
 792 
 
 892 
 
 .89 
 
 
 25.7 
 
 78.0 
 
 117 
 
 3.01 
 
 13 1 
 
 782 
 
 917 
 
 .85 
 
 
 25.6 
 
 79.2 
 
 118 
 
 2.70 
 
 14 21 
 
 202 
 
 228 
 
 .89 
 
 82 
 
 18.7 
 
 
 
 
 15 15 
 
 590 
 
 701 
 
 .84 
 
 
 21.0 
 
 59.3 
 
 107 
 
 1.92 
 
 14 23 
 
 546 
 
 663 
 
 .82 
 
 
 22.5 
 
 58.8 
 
 105 
 
 2.05 
 
 14 34 
 
 568 
 
 697 
 
 .81 
 
 
 25.1 
 
 59.0 
 
 107 
 
 1.98 
 
 12 42 
 
 245 
 
 295 
 
 .83 
 
 76 
 
 19.4 
 
 
 
 
 15 32 
 
 649 
 
 704 
 
 .92 
 
 
 22.9 
 
 59.4 
 
 107 
 
 i.95 
 
 13 48 
 
 646 
 
 691 
 
 .93 
 
 
 26.2 
 
 59.0 
 
 106 
 
 1.94 
 
 15 37 
 
 651 
 
 715 
 
 .91 
 
 
 26.1 
 
 58.8 
 
 104 
 
 1.94 
 
 13 39 
 
 212 
 
 257 
 
 .83 
 
 78 
 
 19.3 
 
 
 
 
 14 22 
 
 795 
 
 814 
 
 .98 
 
 
 22.6 
 
 77.3 
 
 120 
 
 2.77 
 
 12 46 
 
 712 
 
 841 
 
 .85 
 
 
 24.4 
 
 78.9 
 
 114 
 
 3.21 
 
 13 13 
 
 264 
 
 301 
 
 .88 
 
 86 
 
 21.1 
 
 
 
 
 13 23 
 
 879 
 
 948 
 
 .93 
 
 
 23.1 
 
 78.0 
 
 lis 
 
 3.01 
 
 14 31 
 
 857 
 
 926 
 
 .93 
 
 
 26.0 
 
 79.1 
 
 116 
 
 3.17 
 
 14 25 
 
 823 
 
 881 
 
 .93 
 
 
 26.8 
 
 79.7 
 
 116 
 
 3.35 
 
 15 52 
 
 223 
 
 245 
 
 .91 
 
 94 
 
 19.0 
 
 
 
 
 13 51 
 
 630 
 
 695 
 
 .91 
 
 
 20.7 
 
 61.7 
 
 104 
 
 2.45 
 
 14 35 
 
 597 
 
 666 
 
 .90 
 
 
 23.6 
 
 62.1 
 
 103 
 
 2.34 
 
 14 59 
 
 563 
 
 672 
 
 .84 
 
 
 24.4 
 
 62.4 
 
 102 
 
 2.37 
 
 Apr. 7. 
 
 Without food: 
 
 Standing, 9'' 18™ a. m 
 
 Walking,' 9^ 56°' a. m 
 
 Walking,! 10'' 58" a. m. . . 
 Standing, ll"" 27°' a. m . . . 
 
 Protein, 1'' 03" p. m. : 
 
 Standing, l"" 31'° p. m 
 
 Walking,' 2'' 07"° p. m 
 
 WaUdng,' 3 p. m 
 
 Walking,' 3'' 42" p. m 
 
 Apr. 8. 
 Without food : 
 
 Standing, 9^ 10" a. m . . . . 
 
 Walking,' 9'' 40" a. m 
 
 Walking,' lO"" 14" a. m. . . 
 
 Walking,' 1 1'' 01" a. m... 
 Protein, 1 p. m.: 
 
 Standing, li- 23" p. m 
 
 Walking,' 2'' 01" p. m ... . 
 
 Walking,' 2'' 44" p. m.... 
 
 Walking,' 3'' 30" p. m ... . 
 
 Apr. 9. 
 
 Without food : 
 
 Standing, 8'' 42" a. m 
 
 Walking,* 9'' 22" a. m 
 
 Walking,* lO"" 07" a. m . . . 
 Walking,* lO*" 47" a. m . . . 
 
 Carbohydrate, 1 p. m.: 
 
 Standing, l"" 19" p. m 
 
 Walking,* l"* 45" p. m 
 
 Walking,* 2'' 26" p. m 
 
 Walking,* S^" 14" p. m 
 
 Apr. 10. 
 
 Without food : 
 
 Standing, 8'' 54" a. m 
 
 Walking,' 9'' 34" a. m 
 
 Walking,' lO*" 57" a. m . . . 
 
 Carbohydrate, 12'' 08" p. m. 
 Standing, 12'' 31" p. m... 
 
 Walking,' l"" 16" p. m 
 
 Walking,' l''50"p. m 
 
 Walking,' 2'' 30" p. m 
 
 Apr. 14. 
 Without food : 
 
 Standing, 9'' 02" a. m 
 
 Walking,' 9'' 48" a. m 
 
 Walking,' 10* 22" a. m . . . 
 Walking," 11'' 06" a. m . . . 
 
 'Total distance before lunch, 5,007 meters; after lunch, 6,560 meters. 
 
 Electrocardiograms were obtained during these periods by means of the string galvanometer. 
 
 'Total distance before lunch, 7,287 meters; after lunch, 7,933 meters. 
 
 *Total distance before lunch, 5,868 meters; after lunch, 6,141 meters. 
 
 Total distance before lunch, 8,372 meters; after lunch, 7,221 meters. 
 
 «Total distance before lunch, 6,157 meters; after lunch, 6,062 meters. 
 
56 
 
 ENERGY TEANSPORMATIONS DURING HORIZONTAL WALKING. 
 
 Table 4. — Summary of results in experiments with subject II, during the period from 
 Mar. le, 1914, to May IS, iSi^— Continued. 
 
 [Values per minute.] 
 
 Date, condition, and time. 
 
 Dura- 
 tion. 
 
 Car- 
 bon 
 diox- 
 ide. 
 
 Oxy- 
 gen. 
 
 as (O 
 
 .SS-.B 
 P. o 
 Da ^ 
 
 
 !>3 
 
 Dis- 
 tance. 
 
 Steps. 
 
 Rais- 
 ing 
 of 
 
 body. 
 
 Apr. 14 — Continued. 
 Carbohydrate, 1 p. m. ■} 
 
 Standing, l"" 23° p. m 
 
 Walking,'' l"" 59"° p. m 
 
 Walking,' 2'' 37"» p. m 
 
 Walking,=i S"" IS™ p. m 
 
 Apr. IB. 
 Without food: 
 
 Standing, S"- 48"° a. m 
 
 Walking,' Q"" 30° a. m 
 
 Walking,' 10'' 08° a. m 
 
 Walking,' lO* 53° a. m 
 
 Carbohydrate, 12'' 52° p. m.: 
 
 Standing, l"" 14° p. m 
 
 Walking,' l*" 52° p. m 
 
 Walking,' 2'' 29° p. m 
 
 Walking,' 3'' 05° p. m 
 
 Apr- IS. 
 Without food : 
 
 Standing, %^ 32° a. m 
 
 Walking,* 9'' 14° a. m 
 
 Walking,* 9'' 53° a. m 
 
 Walking,* 10'' 36° a. m 
 
 Fat, 11'' 30° a. m.: 
 
 Standing, 12'' 03-" p. m 
 
 Walking,* 12'' 44° p. m 
 
 Walking,* l"- 20° p. m . . . 
 
 Walking,* 2'' 14° p. m . . . 
 
 Walking,* 3'' 10° p. m . . . 
 
 Apr. 17. 
 Without food : 
 
 Standing, 8'' 31° a. m 
 
 Walking,'^ 9'' 08° a. m 
 
 Walking,^ 9'' 50° a. m 
 
 Walking,' lO"" 37° a. m 
 
 Fat, 11'' 30°' a.m.: 
 
 Standing, 12'' 09° p. m 
 
 Walking,' 12'' 48° p. m 
 
 Walking," l*" 34° p. m 
 
 Walking,' 2'' 18° p. m 
 
 Walking,' 3'' 17° p. m 
 
 Apr. m. 
 Without food : 
 
 Standing, 10'' 25° a. m 
 
 Walking,' 11'' 16° a. m 
 
 Fat, 12''30°'p. m.: 
 
 Standing, l''03°p. m 
 
 Walking,' l''45°p. m 
 
 Walking,' 2'' 25° p. m 
 
 Walking,' 3'' 10° p. m 
 
 Walking,' 4'' 01° p. m 
 
 mt/n. 
 14 
 14 
 15 
 14 
 
 15 
 12 
 15 
 14 
 
 14 
 14 
 14 
 
 17 
 
 14 
 15 
 12 
 14 
 
 14 
 14 
 15 
 15 
 18 
 
 14 
 13 
 14 
 14 
 
 16 
 14 
 13 
 14 
 16 
 
 13 
 15 
 
 12 
 14 
 14 
 14 
 16 
 
 c.c. 
 242 
 681 
 672 
 671 
 
 214 
 818 
 696 
 690 
 
 267 
 875 
 859 
 898 
 
 568 
 544 
 553 
 
 239 
 600 
 593 
 611 
 586 
 
 214 
 773 
 672 
 693 
 
 231 
 715 
 735 
 799 
 721 
 
 205 
 562 
 
 220 
 590 
 624 
 608 
 592 
 
 c.c. 
 295 
 674 
 711 
 693 
 
 252 
 934 
 829 
 837 
 
 277 
 902 
 878 
 924 
 
 258 
 644 
 668 
 661 
 
 292 
 683 
 635 
 701 
 707 
 
 265 
 895 
 816 
 862 
 
 281 
 832 
 883 
 938 
 856 
 
 242 
 639 
 
 301 
 683 
 699 
 705 
 709 
 
 0.82 
 
 1.01 
 
 .94 
 
 .97 
 
 .85 
 .88 
 .84 
 .82 
 
 .96 
 .97 
 .98 
 .97 
 
 .81 
 .86 
 .82 
 .80 
 
 .82 
 .86 
 .83 
 .85 
 .84 
 
 .85 
 
 .73 
 .86 
 .89 
 .86 
 .83 
 
 90 
 
 74 
 
 83 
 
 90 
 
 85 
 
 99 
 
 78 
 
 91 
 
 19.5 
 23.4 
 25.6 
 25.9 
 
 17.7 
 22.7 
 25.7 
 25.4 
 
 20.9 
 26.4 
 28.9 
 28.9 
 
 19.5 
 21.0 
 24.4 
 25.1 
 
 19.8 
 23.4 
 25.7 
 26.2 
 25.0 
 
 20.9 
 23.8 
 24.6 
 26.8 
 
 20.5 
 23.5 
 26.8 
 27.9 
 27.2 
 
 19.1 
 22.8 
 
 19.7 
 21.8 
 25.2 
 25.8 
 25.4 
 
 metere. 
 
 6i!2 
 62.0 
 62.2 
 
 77.2 
 79.4 
 80.2 
 
 78.2 
 80.1 
 80.6 
 
 61.9 
 62.3 
 61.8 
 
 61.6 
 62.3 
 62.2 
 61.9 
 
 76.6 
 
 78.1 
 79.3 
 
 77.6 
 79.5 
 80.0 
 80.0 
 
 60.8 
 
 60.4 
 60.6 
 60.5 
 60.5 
 
 102 
 102 
 104 
 
 119 
 115 
 114 
 
 117 
 115 
 
 117 
 
 105 
 106 
 106 
 
 107 
 105 
 105 
 103 
 
 118 
 117 
 117 
 
 118 
 117 
 119 
 115 
 
 105 
 
 104 
 104 
 103 
 105 
 
 meters. 
 
 2.38 
 2.20 
 2.27 
 
 3.33 
 3.52 
 3.49 
 
 3.88 
 3.72 
 3.88 
 
 2.38 
 2.37 
 2.20 
 
 2.49 
 2.48 
 2.24 
 2.21 
 
 3.36 
 3.45 
 3.80 
 
 3.96 
 3.78 
 3.85 
 3.67 
 
 2.32 
 
 2.45 
 2.56 
 2.34 
 2.23 
 
 'Subject did not eat so much as on other days. 
 
 'Total distance before lunch, 6,157 meters; after lunch, 6,062 meters. 
 'Total distance before lunch, 8,306 meters; after lunch, 7,657 meters. 
 *TotaI distance before lunch, 6,350 meters; after lunch, 10,547 meters. 
 'Total distance before lunch, 8,680 meters; after lunch, 13,566 meters. 
 
 'Total distance preliminary to and during period before lunch, 1,651 meters; after lunch 
 1,494 meters. ' ' 
 
STATISTICS OF EXPERIMENTS. 
 
 57 
 
 Table 4. — Summary of results in experments with subject II, during period from 
 Mar. 16, 1914, to May 16, iSi^— Continued. 
 [Values per minute.] 
 
 Date, condition, and time. 
 
 Dura- 
 tion. 
 
 Car- 
 bon 
 diox- 
 ide. 
 
 Oxy- 
 gen. 
 
 03 to 
 
 & 2 
 
 
 '2^ 
 
 Dis- 
 tance. 
 
 Steps. 
 
 Rais- 
 ing 
 of 
 
 body. 
 
 Apr. gS. 
 
 Without food: 
 
 Standing, S"- 39"° a. m 
 
 Walldng,' 9^ 27™ a. m 
 
 Walking,! Kfi 09" a. m 
 
 Walking,! loi" 44"" a. m 
 
 Fat, 11'' 40" a. m.: 
 
 Standing, 12'' 14'° p. m 
 
 Walking,' 12'' SS"" p. m 
 
 Walking,' 1'' 34"" p. m 
 
 Walking,! g"" 20" p. m 
 
 Walking,! 3I1 oi" p. m 
 
 Apr. S3. 
 
 Without food : 
 
 Standing, 8'' 40" a. m 
 
 Walking,' 9'' 34" a. m 
 
 Walking,' 10'' 15" a. m 
 
 Protein, 11'' 10" a.m.: 
 
 Standing, 11'' 40" a. m 
 
 Walking,^ 12'' 24" p. m 
 
 Walking,* li" 03" p. m 
 
 Walking,* l''47"p. m 
 
 Walking,' 2'' 28" p. m 
 
 Apr. Z4. 
 
 Without food : 
 
 Standing, 9'' 14" a. m 
 
 Walking,' 9'' 55" a. m 
 
 Walking,' 10'' 26" a. m 
 
 Protein, 11'' 15" a. m.: 
 
 Standing, 11'' 58" a. m 
 
 Walking," 12'' 35" p. m 
 
 Walking,' l"" 07" p. m 
 
 Walking,' l"" 42" p. m 
 
 Walking,' 2'' 15" p. m 
 
 Apr. SB, 
 
 Without food : 
 
 Standing, 9)^ 30" a. m 
 
 Walking,* 10 a. m 
 
 Walking,* 10'' 33" a. m 
 
 Carbohydrate, 11'' 20" a. m.. 
 
 Standing, 11'' 49" a. m . . . . 
 
 Walking,* 12'' 25" p. m 
 
 Walking,* 12'' 56" p. m 
 
 Walking,* l"" 40" p. m 
 
 Walking,* 2'' 30" p. m 
 
 mvn. sec. 
 
 14 20 
 
 15 17 
 13 26 
 
 13 48 
 
 14 11 
 14 30 
 13 37 
 
 13 18 
 
 14 03 
 
 15 57 
 
 15 23 
 
 16 37 
 
 14 7 
 13 
 13 18 
 13 56 
 
 15 5 
 
 12 43 
 
 14 31 
 
 12 24 
 
 14 19 
 
 14 21 
 
 13 9 
 
 13 54 
 
 14 
 
 12 59 
 
 13 24 
 
 13 25 
 
 12 21 
 
 14 37 
 17 17 
 
 15 23 
 15 13 
 
 c.c. 
 207 
 687 
 655 
 647 
 
 227 
 725 
 729 
 737 
 739 
 
 208 
 561 
 528 
 
 223 
 644 
 607 
 606 
 605 
 
 198 
 635 
 636 
 
 219 
 699 
 696 
 704 
 712 
 
 192 
 543 
 531 
 
 274 
 668 
 662 
 688 
 641 
 
 c.c. 
 251 
 804 
 829 
 822 
 
 299 
 833 
 
 877 
 877 
 858 
 
 252 
 675 
 660 
 
 254 
 722 
 705 
 707 
 707 
 
 790 
 
 828 
 
 299 
 835 
 853 
 890 
 880 
 
 264 
 665 
 695 
 
 324 
 708 
 711 
 694 
 
 0.83 
 .85 
 .79 
 .79 
 
 .76 
 .87 
 .83 
 .84 
 .86 
 
 .82 
 .83 
 .80 
 
 .88 
 .89 
 .86 
 .86 
 .86 
 
 .80 
 
 .77 
 
 .73 
 .84 
 .81 
 .79 
 .81 
 
 .73 
 .82 
 .76 
 
 .85 
 .94 
 .93 
 .99 
 
 84 
 
 93 
 
 74 
 
 81 
 
 82 
 
 94 
 
 79 
 
 83 
 
 18.0 
 23.5 
 26.1 
 25.7 
 
 20.8 
 26.0 
 28.7 
 28.4 
 28.4 
 
 19.3 
 20.5 
 24.2 
 
 20.1 
 19.7 
 24.6 
 25.0 
 24.3 
 
 18.7 
 21.4 
 25.8 
 
 20.3 
 22.9 
 26.3 
 26.3 
 25.4 
 
 19.6 
 20.2 
 23.3 
 
 20.6 
 22.2 
 24.4 
 25.7 
 25.2 
 
 meters. 
 
 76.8 
 78.6 
 79.2 
 
 77.3 
 78.7 
 79.5 
 79.7 
 
 61.1 
 
 61.2 
 61.6 
 61.6 
 61.7 
 
 76.4 
 78.4 
 
 77.0 
 78.8 
 80.0 
 80.0 
 
 63.0 
 64.0 
 
 63.1 
 63.8 
 63.7 
 63.3 
 
 118 
 118 
 115 
 
 116 
 118 
 118 
 116 
 
 105 
 105 
 
 106 
 105 
 104 
 103 
 
 116 
 117 
 
 114 
 115 
 115 
 115 
 
 105 
 107 
 
 104 
 105 
 106 
 104 
 
 meters. 
 
 3.33 
 3.44 
 3.42 
 
 3.86 
 3.86 
 3.92 
 3.84 
 
 2.53 
 2.46 
 
 2.74 
 2.57 
 2.48 
 2.63 
 
 3.60 
 3.69 
 
 3.74 
 3.88 
 3.84 
 3.88 
 
 2.65 
 2.69 
 
 2.88 
 2.70 
 2.85 
 2.64 
 
 'Total distance before lunch, 7,548 meters; after lunch, 11,466 meters. 
 'Total distance before lunch, about 4,300 meters; after lunch, 8,908 meters. 
 Total distance before lunch, 3,888 meters; after lunch, 9,414 meters. 
 *Total distance before lunch, 3,216 meters; after lunch, 9,089 meters. 
 
58 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 Table 4.— Summary of results in experimenis viith subject II, during period from 
 Mar. 16, 1914, to May 16, iSi^— Continued. 
 [Values per minute.] 
 
 Date, condition, and time. 
 
 Dura- 
 tion. 
 
 Car- 
 bon 
 diox- 
 ide. 
 
 Oxy- 
 gen. 
 
 
 i>3 
 
 ,a » 
 
 <".S 
 
 Dis- 
 tance. 
 
 Steps. 
 
 Rais- 
 ing 
 of 
 
 body. 
 
 Apr. 27. 
 
 Without food : 
 
 Standing, 9'' 10"° a. m 
 
 Walking,' Q"" 48°" a. m 
 
 Walking,! lo* 20°' a. m 
 
 Carbohydrate, ll"" lO"" a. m.: 
 
 Standing, ll"" 34"' a. m 
 
 Walking,' 12'' 12'° p. m 
 
 Walking,' 12'' 45'» p. m 
 
 Walking,' 1'' 21'» p. m 
 
 Walking,' 2'' 08"" p. m 
 
 Apr- ^8. 
 
 Without food: 
 
 Standing, 8'' 39" a. m 
 
 Walking,^ gi" 12'° a. m 
 
 Walking,^ 9'' 48'» a. m 
 
 Walking.ii 10'' 26'" a. m 
 
 Walking,* 11'' 07" a. m 
 
 Walking,2ll''51'»a. m.... 
 
 Walking,* 12'' 33'° p. m 
 
 Walking,* 1'' OG"" p. m 
 
 Walking,* l'' 49" p. m 
 
 Apr. 29. 
 
 Carbohydrate, 8'' 35" a. m.: 
 
 Walking," 9'' 08" a. m 
 
 Walking,' 9'' 45" a. m 
 
 Walking,' 10'' 24" a. m 
 
 Walking,' 11'' 04" a. m 
 
 Walking,' 11'' 40" a. m 
 
 Walking,' 12'' 18" p.m.... 
 
 Walking,' 12'' 58" p. m 
 
 Walking,' l"" 36" p. m 
 
 May 4- 
 
 Without food: 
 
 Walking,* 9'' 27" a. m 
 
 Walking,* 10'' 02" a. m 
 
 Walking,* 10'' 35" a. m 
 
 Carbohydrate, 11'' 19" a. m: 
 Walking,* 12'' 02" p. m ... . 
 
 Walking,* 12'' 43" p. m 
 
 Walking,* l''16"p. m 
 
 mm. 
 13 
 13 
 12 
 
 13 
 14 
 13 
 
 15 
 15 
 
 12 
 15 
 13 
 13 
 13 
 15 
 14 
 14 
 IS 
 
 14 
 14 
 14 
 14 
 14 
 13 
 14 
 15 
 
 10 
 11 
 11 
 
 10 
 11 
 10 
 
 c.e. 
 217 
 681 
 679 
 
 294 
 845 
 837 
 886 
 850 
 
 221 
 713 
 699 
 680 
 689 
 716 
 657 
 682 
 659 
 
 817 
 789 
 817 
 797 
 777 
 696 
 704 
 666 
 
 1183 
 
 1052 
 
 934 
 
 1212 
 1237 
 1177 
 
 c.c. 
 245 
 767 
 821 
 
 326 
 
 854 
 797 
 840 
 801 
 
 274 
 828 
 820 
 846 
 858 
 925 
 854 
 865 
 859 
 
 864 
 863 
 839 
 810 
 823 
 790 
 848 
 830 
 
 1377 
 1175 
 1117 
 
 1336 
 1295 
 1221 
 
 0.89 
 .89 
 .83 
 
 .90 
 
 .99 
 
 1.05 
 
 1.05 
 
 1.06 
 
 .81 
 .86 
 .85 
 .80 
 .80 
 .77 
 .77 
 .79 
 .77 
 
 .95 
 .91 
 .97 
 .98 
 .94 
 .88 
 .83 
 .80 
 
 .86 
 .90 
 
 .84 
 
 .91 
 .95 
 .96 
 
 77 
 
 75 
 
 82 
 
 20.5 
 23.3 
 26.5 
 
 21.0 
 24.7 
 27.5 
 28.6 
 27.6 
 
 19.6 
 23.0 
 26.4 
 26.1 
 26.5 
 27.4 
 27.2 
 28.1 
 27.8 
 
 27.1 
 27.2 
 27.8 
 26.9 
 26.6 
 27.2 
 26.9 
 27.1 
 
 25.1 
 27.7 
 26.9 
 
 27.1 
 28.6 
 28.6 
 
 meters. 
 
 73.5 
 78.1 
 
 77.5 
 78.9 
 79.8 
 80.2 
 
 78.2 
 79.8 
 80.0 
 80.7 
 80.4 
 80.2 
 80.2 
 80.4 
 
 76.9 
 78.2 
 79.5 
 80.9 
 81.1 
 80.9 
 81.0 
 81.1 
 
 114.5 
 109.1 
 102.0 
 
 113.4 
 112.3 
 110.3 
 
 115 
 116 
 
 116 
 115 
 116 
 116 
 
 118 
 116 
 116 
 118 
 121 
 116 
 119 
 116 
 
 114 
 114 
 114 
 117 
 116 
 115 
 120 
 116 
 
 138 
 134 
 128 
 
 134 
 131 
 128 
 
 meters. 
 
 3^25 
 3.64 
 
 3.60 
 3.56 
 3.88 
 3.74 
 
 .63 
 .56 
 .52 
 .74 
 .76 
 .29 
 3.73 
 3.69 
 
 6.43 
 6.16 
 5.88 
 
 6.84 
 7.88 
 7.41 
 
 'Total distance before lunch, 3,793 meters; after lunch, 10,612 meters. 
 
 *Total distance in about 5 hours of continuous walldng, 23,697 meters. Pulse-rate of subject 
 standing during 5 consecutive minutes immediately after walking, 100, 98, 96, 96, and 98 per 
 minute. 
 
 'Total distance in 4 hours and 52 minutes of continuous walking, 22,919 meters. Pulse-rate 
 during 4 minutes soon after the carbohydrate breakfast averaged 73 per minute with the subject 
 sitting; during 4 consecutive minutes immediately after walking it was 80, 79, 80, and 79 per 
 minute, with subject standing. 
 
 *Total distance before lunch, 6,949 meters; for about 20 minutes after the first period subject 
 was not walking. After lunch, the distance was 9,362 meters. 
 
STATISTICS OF EXPERIMENTS. 59 
 
 Table 4. — Summary of results in experiments with subject II, during the period from 
 
 Mar. 16, 1914, to May IS, iSi^— Continued. 
 
 [Values per minute.] 
 
 
 
 
 Car- 
 
 
 II 
 
 ^1 
 
 Ssl 
 
 
 
 Rais- 
 
 Date, condition, and time. 
 
 Dura- 
 tion. 
 
 bon 
 diox- 
 
 Oxy- 
 gen. 
 
 ii 
 
 
 era 
 espi 
 on-ri 
 
 Dis- 
 tance. 
 
 Steps. 
 
 ing 
 of 
 
 
 
 
 ide. 
 
 
 
 <- ft 
 
 > u-9 
 < 
 
 
 
 body. 
 
 May 5. 
 
 
 
 
 
 
 
 
 
 
 
 Without food: 
 
 min 
 
 . sec 
 
 . c.c. 
 
 c.c. 
 
 
 
 
 meters. 
 
 
 meters. 
 
 Standing, 8'' 24=' a. m 
 
 13 
 
 7 
 
 229 
 
 277 
 
 0.83 
 
 83 
 
 19.7 
 
 
 
 
 Walking,' gk 42°' a. m 
 
 10 
 
 3 
 
 1011 
 
 1124 
 
 .90 
 
 
 25.5 
 
 106.6 
 
 133 
 
 4.86 
 
 WaUdng,' 10'' 11" a. m 
 
 11 
 
 5 
 
 915 
 
 1101 
 
 .83 
 
 
 28.0 
 
 102.6 
 
 127 
 
 5.82 
 
 WaHring,' 10^ 44'» a. m 
 
 10 
 
 3 
 
 909 
 
 1151 
 
 .79 
 
 
 28.0 
 
 103.6 
 
 126 
 
 6.06 
 
 Protein, 11'' SI" a. m.: 
 
 
 
 
 
 
 
 
 
 
 
 Walking,' 11'' ST" a. m 
 
 9 
 
 25 
 
 1136 
 
 1298 
 
 .87 
 
 
 28.8 
 
 112.6 
 
 133 
 
 7.69 
 
 Walking,' 12'' 30'° p. m 
 
 10 
 
 39 
 
 1137 
 
 1318 
 
 .86 
 
 
 29.0 
 
 113.7 
 
 133 
 
 7.83 
 
 Walking,' 1'' IS" p. m 
 
 10 
 
 32 
 
 1035 
 
 1208 
 
 .86 
 
 
 28.5 
 
 106.0 
 
 128 
 
 6.40 
 
 Walking,' 1'' 46" p. m 
 
 9 
 
 31 
 
 1076 
 
 1307 
 
 .82 
 
 
 29.2 
 
 111.3 
 
 129 
 
 7.76 
 
 May 6. 
 
 
 
 
 
 
 
 
 
 
 
 Without food: 
 
 
 
 
 
 
 
 
 
 
 
 Walking," 9'' 08" a. m 
 
 8 
 
 65 
 
 1902 
 
 2068 
 
 .92 
 
 
 31.1 
 
 140.7 
 
 149 
 
 9.76 
 
 Walking,^' Itf' 31" a. m 
 
 9 
 
 30 
 
 1848 
 
 2125 
 
 .87 
 
 
 33.4 
 
 139.6 
 
 148 
 
 8.90 
 
 Walking.Ml'' 15" a. m 
 
 8 
 
 12 
 
 1796 
 
 2279 
 
 .79 
 
 
 36.1 
 
 142.9 
 
 152 
 
 8.79 
 
 Carbohydrate, 11'' 40" a. m.: 
 
 
 
 
 
 
 
 
 
 
 
 Walking,* 12'' 45" p. m 
 
 8 
 
 36 
 
 2058 
 
 2147 
 
 .96 
 
 
 35.5 
 
 143.0 
 
 146 
 
 7.82 
 
 May 10. 
 
 
 
 
 
 
 
 
 
 
 
 Without food : 
 
 
 
 
 
 
 
 
 
 
 
 Standing, 8'' 34" a. m 
 
 11 
 
 5 
 
 216 
 
 246 
 
 .87 
 
 74 
 
 18.4 
 
 
 
 
 Walking,' 9'' 44" a. m 
 
 8 
 
 22 
 
 2017 
 
 2232 
 
 .90 
 
 
 32.8 
 
 146.6 
 
 153 
 
 5.37 
 
 Walking,' 10'' 47" a. m 
 
 8 
 
 14 
 
 2101 
 
 2384 
 
 .88 
 
 
 38.6 
 
 146.8 
 
 157 
 
 6.59 
 
 Walking,' 11'' 33" a. m 
 
 9 
 
 2 
 
 2006 
 
 2234 
 
 .90 
 
 
 37.1 
 
 146.6 
 
 154 
 
 8.02 
 
 Protein, 12'' 15" p.m.: 
 
 
 
 
 
 
 
 
 
 
 
 Walking,' 12'' 43" p. m 
 
 8 
 
 14 
 
 2017 
 
 2244 
 
 .90 
 
 
 36.0 
 
 146.5 
 
 157 
 
 7.83 
 
 Walking,' 1'' 20" p. m 
 
 8 
 
 16 
 
 2020 
 
 2249 
 
 .90 
 
 
 40.1 
 
 146.9 
 
 156 
 
 8.28 
 
 May 11. 
 
 
 
 
 
 
 
 
 
 
 
 Without food: 
 
 
 
 
 
 
 
 
 
 
 
 Standing, 8'' 37" a. m 
 
 12 
 
 47 
 
 259 
 
 278 
 
 .93 
 
 85 
 
 20.9 
 
 
 
 
 Standing, swinging arms,* 
 
 
 
 
 
 
 
 
 
 
 
 9'' 16" a. m 
 
 10 
 
 8 
 
 52 
 19 
 
 456 
 1860 
 
 516 
 1886 
 
 .88 
 .98 
 
 
 20.9 
 35.7 
 
 146! 6 
 
 184 
 
 13.45 
 
 Rimning,* 10'' 01" a. m 
 
 Running,* 10'' 49" a. m 
 
 8 
 
 55 
 
 1765 
 
 1938 
 
 .91 
 
 
 36.8 
 
 146.7 
 
 183 
 
 13.89 
 
 Rxmning,' 11'' 35" a. m 
 
 8 
 
 24 
 
 1793 
 
 1964 
 
 .91 
 
 
 37.9 
 
 148.3 
 
 181 
 
 14.80 
 
 Carbohydrate, 12 noon: 
 
 
 
 
 
 
 
 
 
 
 
 Running,' 12'' 44" p. m 
 
 8 
 
 23 
 
 1795 
 
 1910 
 
 .94 
 
 
 36.6 
 
 148.7 
 
 181 
 
 13.95 
 
 'Total distance before lunch, 8,126 meters; after lunch, 9,193 meters. During about 40 
 minutes of the intervals between periods in the afternoon, subject was not walking but sitting. 
 
 ^otal distance before lunch, 5,571 meters; after lunch, 1,543 meters. Subject perspired very 
 much with this rate of walking and worked with arms and hands much more than at the other 
 speeds. For about 1 hour and 40 minutes of the intervals between periods in the morning he was 
 not walking. 
 
 'Total distance before lunch, 6,307 meters ; after lunch, 3,468 meters. During about 1 hour and 
 20 minutes of the intervals between periods in the morning and about 25 minutes in the afternoon, 
 subject was sitting or walking a little in the room. 
 
 *rhe subject swung his arms as vigorously as in the fastest walking. 
 
 'Total distance before lunch, 6,696 meters; after lunch, 1,729 meters. In running, the subject 
 held arms up in front of body and the only movement of the arms was that of the swaying body. 
 During about 1 hour and 10 minutes of the intervals between periods in the morning subject was 
 not running. 
 
60 
 
 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 Table 4 — Summary of results in experiments mth avbjed II, during period from 
 
 Mar. 16, 1914, to May IS, 19U— Concluded. 
 
 [Values per minute.] 
 
 Date, condition, and time. 
 
 Dura- 
 tion. 
 
 Car- 
 bon 
 diox- 
 ide. 
 
 Oxy- 
 gen. 
 
 ^■ 
 
 fi' S 
 
 ^ l-i 
 
 m 09 
 
 >1 
 
 oi. 
 
 0) " 9 
 
 Z "> 2 
 
 Dis- 
 tance. 
 
 Steps. 
 
 Rais- 
 ing 
 of 
 
 body. 
 
 May 12. 
 Without food: 
 
 Standing, g"" 01™ a. m 
 
 Running,' Q*" 45"' a. m 
 
 Running,' lO* 44™ a. m 
 
 Running,' 11'' 38™ a. m ... . 
 Running,' 12'' 26™ p. m. . . . 
 Running,' l"" 10™ p. m 
 
 May IS. 
 
 Without food : 
 
 Standing, lO"* 20™ a. m 
 
 Walking,' 11'' 08™ a. m 
 
 Walking,' 11'' 47™ a. m 
 
 Walking,' 12'' 31™ p. m 
 
 Walking,' l"" 16™ p. m 
 
 Walking,' 2'' 18™ p. m 
 
 Walking,' 3'' 06™ p. m 
 
 May 14. 
 
 Without food : 
 
 Standing, 8'' 32™ a. m 
 
 Walking,' 9'' 33™ a. m 
 
 Running,' 10'' 28™ a. m 
 
 Running,' 11'' 20™ a. m 
 
 Running,' 1 1"" 58™ a. m . . . . 
 Running,' 12'' 35™ p. m 
 
 May 15. 
 
 Without food : 
 
 Standing, swinging arms. 
 
 Si" 52™ a. m 
 
 Running,' 9'' 57™ a. m 
 
 Running,^ 10'' 37™ a. m 
 
 Running,' 111" 21™ a. m. . . . 
 
 mm. sec. 
 
 13 15 
 
 8 19 
 
 8 55 
 
 8 28 
 
 10 12 
 
 10 6 
 
 12 27 
 
 13 30 
 12 49 
 
 12 1 
 
 13 10 
 
 12 29 
 
 13 2 
 
 13 53 
 
 7 41 
 
 7 58 
 
 8 51 
 
 9 2 
 9 41 
 
 12 8 
 
 9 40 
 
 8 45 
 
 8 20 
 
 c.c. 
 
 226 
 1983 
 1758 
 1723 
 1752 
 1734 
 
 213 
 711 
 734 
 639 
 597 
 767 
 753 
 
 209 
 2046 
 1997 
 1646 
 1625 
 1701 
 
 554 
 1735 
 1727 
 1647 
 
 c.c. 
 
 293 
 2194 
 1843 
 2011 
 2050 
 2080 
 
 257 
 851 
 942 
 826 
 789 
 998 
 980 
 
 257 
 2281 
 2272 
 1867 
 1900 
 1982 
 
 643 
 1967 
 1978 
 1947 
 
 0.77 
 .90 
 .95 
 .86 
 .85 
 .83 
 
 .83 
 .84 
 .78 
 .77 
 .76 
 .74 
 .77 
 
 .81 
 
 80 
 
 .90 
 
 
 .88 
 
 
 .88 
 
 
 .86 
 
 
 .86 
 
 
 .86 
 .88 
 .87 
 .85 
 
 82 
 
 79 
 
 20.4 
 34.9 
 37.8 
 39.2 
 39.2 
 40.8 
 
 20.2 
 25.9 
 27.9 
 27.0 
 25.4 
 28.0 
 28.5 
 
 20.0 
 38.6 
 37.5 
 38.3 
 38.8 
 40.1 
 
 22.3 
 38.6 
 37.3 
 38.9 
 
 meters. 
 
 147. i 
 148.4 
 148.1 
 148.1 
 148.7 
 
 82.6 
 89.7 
 80.1 
 76.6 
 93.3 
 91.9 
 
 146.4 
 146.5 
 147.2 
 147.6 
 148.1 
 
 144.7 
 148.4 
 147.7 
 
 191 
 183 
 182 
 184 
 176 
 
 117 
 120 
 112 
 106 
 117 
 118 
 
 153 
 168 
 183 
 182 
 183 
 
 182 
 183 
 184 
 
 meters. 
 
 15.40 
 14.09 
 15.40 
 14.64 
 15.37 
 
 3.76 
 4.51 
 3.29 
 2.84 
 5.25 
 5.15 
 
 7.59 
 15.44 
 12.47 
 12.34 
 11.09 
 
 12.48 
 12.14 
 13.13 
 
 'The total distance was 10,111 meters. During 2| hours of the intervals between periods 
 subject was sitting or walking a Uttle in the room. 
 
 'Total distance, 21,724 meters, the walking being continuous. 
 
 •Total distance, walking and running, 9,432 meters. During about 2 hours and 11 minutes of 
 the intervals between periods, subject was sitting or standing. 
 
 'Subject swung his arms as vigorously aa in the fastest walking. 
 
 'Total distance, 5,711 meters. During about 58 minutes of the intervals between periods, 
 subject was not running or walking. 
 
DISCUSSION OF RESULTS. 61 
 
 DISCUSSION OF RESULTS. 
 BASAL VALUES. 
 
 In any study of walking in a horizontal direction, two main prob- 
 lems present themselves: first, the variations in the energy requirement 
 of different individuals for walking varying distances at varying 
 velocities, and second, the actual energy requirement for transporting 
 the body-weight or a superimposed load in a horizontal direction, i. e., 
 the calorie output per horizontal kilogrammeter. 
 
 As has already been noted, the mechanical processes incidental 
 to walking, even at a moderate pace, usually involve some extraneous 
 muscular movements apparently not directly connected with the motion 
 of forward progression, such as the more or less vigorous swinging of 
 the arms and a not inconsiderable raising of the body-weight with each 
 step. Since these extraneous muscular movements do not necessarily 
 have an effective value in transporting the body-weight or the super- 
 imposed load in a horizontal direction, the problem of finding the 
 calorie requirement for such transportation of weight becomes an 
 exceedingly complicated one. 
 
 If the principle of the deduction of basal values for determining the 
 energy required to move 1 kilogram 1 meter in a horizontal direction 
 may be legitimately employed, and this has been the method adopted 
 by all investigators, it becomes an important point as to what should 
 properly be considered as the basal maintenance metaboUsm in experi- 
 ments when the subject is walking in a horizontal direction. As will 
 be seen by reference to the summary of previous researches given in 
 table 1, investigators have varied considerably in their usage in this 
 respect. Certain members of the Zuntz school have almost invariably 
 employed the resting (lying) metaboUsm obtained with the subject in 
 the post-absorptive condition. The values found with the subject 
 sitting or standing quietly have also been used as a basis in determining 
 the metabolism due to the muscular activity of walking. Still another 
 basal value which may be considered is that found when the subject is 
 standing and moving his arms in a manner similar to that employed in 
 more or less rapid walking. Finally it may even be possible to use 
 the metaboUsm determined during slow walking for a basal value to 
 be deducted from the metaboUsm found while the subject was walking 
 at a rapid rate. The vaUdity of this assumption will be examined later. 
 
 Bearing in mind the experience of Benedict and Cathcart in attempt- 
 ing to secure a suitable base-line for their bicycle rider, we considered 
 it desirable to study our subjects in varying positions. The positions 
 selected have been outlined in a preceding section. Since we were to 
 make a large number of observations upon each subject, we concluded 
 that the period of adjustment to the type of the experiment would be so 
 short that a moderately constant value could be found in the standing 
 
62 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 position, and hence the greater part of our control data was obtained 
 in experiments with the subject standing in a relaxed position. 
 Although values for comparison are available for other standing posi- 
 tions and for the subject sitting, no studies were made by us with the 
 subject in complete muscular repose, i. e., lying upon a couch, in the 
 post-absorptive condition. 
 
 Obviously it is first necessary to examine the data thus secured to 
 determine the suitable basal values to be deducted from the total 
 metaboUsm while walking, such a critical examination being of funda- 
 mental importance. Since the total metaboUsm is made up of that for 
 maintenance, i. e., the basal value plus that for forward progression, 
 it is evident that the larger the value deducted for maintenance — as, 
 for instance, the value obtained with the subject standing as com- 
 pared with the subject lying on a couch — the smaller will be the result 
 obtained for the energy requirement for the work of forward pro- 
 gression. 
 
 BASAL METABOLISM OF SUBJECT L 
 
 As a result of a consideration of the experimental experience of 
 others, it was decided that in the preUminary observations in this 
 investigation, which were made with subject I by Dr. Carl Tigerstedt, 
 the basal value selected should be that necessary for maintenance 
 while the subject was standing quietly without support. Accordingly, 
 during November and December 1913 many observations were made 
 of the subject in this position. Subsequently it appeared that more 
 information was desirable with regard to the normal increment in 
 metabolism due to a change from the lying position to the standing 
 position, but as a study of this phase of the question was wholly 
 incidental to the main problem of the metabolism during forward 
 progression, the experimental routine did not permit such observations. 
 We have, however, the results of a study made in December 1914 by 
 Mr. H. L. Higgins, of the Laboratory staff, upon the lying and standing 
 metabolism of subject I, which were kindly supplied us for comparison 
 with our values. Unfortunately the data thus obtained are more or 
 less fragmentary and must therefore be considered as only subsidiary 
 to the results of the larger investigation. 
 
 The Thiry valves and Tissot spirometer and mouthpiece were used in 
 this study, both the resting metaboUsm and the standing metaboUsm 
 being observed with the subject in the post-absorptive condition. We 
 have no data as to the influence of food upon the resting metaboUsm 
 of this subject. The results" obtained by Mr. Higgins are recorded in 
 table 5. These values are typical of a large number secured by this 
 observer in another research with subject I, who shows a remarkably 
 uniform basal resting metaboUsm. As will be seen from the table, the 
 heat output per minute of this individual in the lying position was on 
 December 2 and 5, 1914, 1.23 and 1.22 calories respectively. 
 
DISCUSSION OF RESULTS. 
 
 63 
 
 The values found by Dr. Carl Tigerstedt for subject I in the standing 
 position, which was the only position used by Dr. Tigerstedt in deter- 
 mining the basal metaboUsm of this subject, are given in table 6. Since 
 the walking experiments were made in the morning and in the afternoon 
 and with and without food, the basal values were also obtained in both 
 the post-absorptive condition and after the taking of food. The appa- 
 ratus used for determining the respiratory exchange was the same as 
 that employed for the walking experiments. 
 
 Table 5. — Metdbolism of subject I in the lying and standing positions in experiments vrithmii 
 
 food, on Dec. S and Dec. 6, 1914. 
 
 [Observations made by Mr. H. L. Higgins with Thiry valves and Tissot spirometer. 
 
 Values per minute.] 
 
 Date and time. 
 
 Dura- 
 tion. 
 
 Carbon 
 dioxide. 
 
 Oxygen. 
 
 Heat 
 output 
 
 (com- 
 puted). 
 
 Pulse- 
 rate. 
 
 Respira- 
 tion-rate. 
 
 Dec. 2. 
 Lvine 8** 53™ a. m 
 
 mins. 
 10 
 
 8 
 
 8 
 10 
 10 
 
 c.c. 
 210 
 230 
 224 
 208 
 196 
 
 c.c. 
 249 
 297 
 287 
 256 
 262 
 
 cats. 
 
 62 
 84 
 85 
 61 
 61 
 
 22.0 
 
 25!7 
 24.8 
 24.1 
 
 Standing, 9'' IS"" a. m 
 
 Standing, Q"" 29™ a. m 
 
 Lying, lO"" 15"" a. m 
 
 
 
 Lvine 10^ 35™ a. m 
 
 Average, lying 
 
 Average, standing .... 
 
 Dec. 5. 
 Lvine 9** 02™ a. m 
 
 
 
 205 
 227 
 
 256 
 292 
 
 1.23 
 1.39 
 
 61 
 
 84 
 
 23.6 
 25.7 
 
 10 
 
 8 
 8 
 9 
 
 219 
 220 
 217 
 221 
 
 246 
 269 
 268 
 249 
 
 
 62 
 95 
 90 
 57 
 
 23.4 
 25.8 
 26.4 
 24.8 
 
 Standing, 9'' 27™ a. m 
 
 Standing, 9^ 44™ a. m 
 
 Ljring, 10'' 25™ a. m 
 
 Average, lying 
 
 Average, standing .... 
 
 
 220 
 219 
 
 248 
 269 
 
 1.22 
 1.29 
 
 60 
 93 
 
 24.1 
 26.1 
 
 As will be seen from table 6, the average post-absorptive values are 
 reasonably constant throughout the entire period from November 28 
 to December 20. A striking exception is shown on December 5, when 
 the average carbon-dioxide excretion was 236 c.c. per minute and the 
 oxygen consumption 334 c.c. per minute. The protocols for this 
 experiment show that "there was no sleep the night before, but much 
 alcohol." The pulse-rate was especially high on this particular day. 
 The general average for the observations without food shows a carbon- 
 dioxide excretion of 223 c.c. per minute and an oxygen consumption of 
 280 c.c. per minute. This corresponds to a heat output of 1.34 calories 
 per minute. The pulse-rate of this man was extremely high, averaging 
 94 beats per minute; the average respiration rate was 21.2 per minute. 
 
 All of these experiments were made with subject I standing with 
 muscles relaxed. The general uniformity of the data shows that for 
 the most part the subject must have assumed a standing position with 
 a relatively constant muscle strain, although variations are found in 
 
64 
 
 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 the experiments without food from 1.28 to 1.57 calories per minute. 
 Excluding the extraordinarily high value of December 6, which is at 
 least in part explained by the alcohoUc excesses of the preceding night, 
 the uniformity in the average values is for the most part striking. It 
 is also of interest to note that the average value obtained for all of the 
 standing experiments without food during December 1913, i. e., 1.34 
 calories, is the same as that of the average of two standing experiments 
 made by Mr. Higgins in December 1914. (See table 5.) It will be 
 seen, therefore, that for many purposes an average basal value may be 
 used for this subject with propriety and that it may be assumed that 
 when standing quietly and in the post-absorptive condition, his average 
 heat output would correspond to 1.34 calories per minute. 
 
 Table 6. — Metabolism of subject I in the standing position. 
 [Observations made by Dr. Carl Tigerstedt. Average values per minute.] 
 
 Date. 
 
 Carbon 
 dioxide. 
 
 Oxygen 
 
 Heat^ 
 output 
 
 (com- 
 puted). 
 
 Pulse- 
 rate. 
 
 Respira- 
 tion-rate. 
 
 1913. 
 Without food: 
 Nov. 28 . . 
 
 C.C. 
 
 222 
 224 
 220 
 224 
 214 
 214 
 236 
 206 
 222 
 223 
 223 
 229 
 239 
 226 
 
 c.c. 
 285 
 282 
 279 
 286 
 272 
 267 
 334 
 271 
 275 
 286 
 271 
 263 
 279 
 270 
 
 cals. 
 1.36 
 1.35 
 1.34 
 1.37 
 1.30 
 1.28 
 1.57 
 1.29 
 1.32 
 1.37 
 1.31 
 1.29 
 1.36 
 1.31 
 
 92 
 93 
 92 
 89 
 92 
 90 
 
 105 
 91 
 89 
 
 101 
 91 
 86 
 98 
 
 103 
 
 17.1 
 18.5 
 19.3 
 20.7 
 21.8 
 22.6 
 23.2 
 21.2 
 22.2 
 22.2 
 21.3 
 21.3 
 23.0 
 22.9 
 
 29 
 
 Dec. 1 
 
 2 
 
 3 
 
 4 
 
 5 
 
 8 
 
 15 
 
 16 
 
 17 
 
 18 
 
 19 
 
 20 
 
 Average, without food .... 
 
 After breakfast: 
 
 Nov. 26 
 
 223 
 
 280 
 
 1.34 
 
 94 
 
 21.2 
 
 281 
 248 
 
 273 
 
 332 
 341 
 
 335 
 
 1.61 
 1.61 
 
 1.61 
 
 112 
 84 
 
 22.9 
 18.2 
 
 Dec. 9 
 
 After dinner: 
 
 Nov. 26 
 
 Average, with food 
 
 267 
 
 336 
 
 1.61 
 
 98 
 
 19.8 
 
 When the superimposed factor in a metaboUsm experiment is suf- 
 ficiently great to increase the metabohsm several hundred per cent, as 
 is especially the case in muscular-work experiments, the use of a pre- 
 viously estabhshed average basal value is least hable to objection. 
 Although with this particular subject we may assume that we have a 
 fairly well-estabUshed basal value, as a matter of fact, to eliminate 
 possible wide variations we rarely used this average figure and the 
 absolutely determined basal value for each day, which was usually 
 available, was given the preference. 
 
DISCUSSION OF RESULTS. 65 
 
 INFLUENCE OF FOOD AND BODY POSITION. 
 
 In this preliminary study of subject I, we have two main factors to be 
 considered, namely, the influence of food and of body position. 
 
 Influence of food. — We have only three experiments in which obser- 
 vations were made of the standing metabohsm of subject I after the 
 ingestion of food. Singularly enough, the average on each of these 
 three days shows that the heat output after the ingestion of food when 
 measured with the subject in the standing position was the same in all 
 of the experiments, i. e., 1.61 calories. (See table 6.) As we have no 
 basal value without food which was determined on these three days, we 
 must be content to note that the average basal value of 1.34 calories was 
 increased 0.27 calorie per minute as the result of the ingestion of food, 
 an increment of approximately 20 per cent. It is thus clear that prior 
 to the actual walking tests after meals, the subject has a noticeably 
 larger basal metabolism than prior to the walking experiments in the 
 morning in the post-absorptive condition. The intelhgent use of these 
 basal values after food is a subject of subsequent discussion. 
 
 Influence of position. — In his experiments with subject I in December 
 1914, Mr. Higgins also obtained data regarding the metabohsm of this 
 subject in the standing position. Any comparison of these values with 
 those obtained by us a year earlier for the same position would be a 
 violation of a fundamental principle in the computation of metabo- 
 hsm experiments, notwithstanding the facts that the difference in the 
 body weight is but 2 kilograms and that the values obtained for the 
 metabohsm in both cases were extraordinarily constant. Neverthe- 
 less, in the hope of throwing some Ught on the probable increment in 
 the metabohsm to be expected from this man, when standing, we 
 have included in table 5 (page 63) Mr. Higgins's results of December 
 1914 for the standing position. 
 
 The observations on December 2 show an average heat output for the 
 standing position of 1.39 calories per minute, but three days later 
 (December 5), when the conditions were apparently identical, the heat 
 output was but 1.29 calories per minute. Using the average values for 
 the resting (lying) metabohsm on the same days, we note an increase in 
 the heat output on December 2 from 1.23 calories to 1.39 calories and 
 on December 5 from 1.22 calories to 1.29 calories, the average increase 
 being from 1.225 calories to 1.34 calories. This is equivalent to an 
 average increment of 0.115 calorie, or approximately 9 per cent, due to 
 the changing of the position from lying to standing. Since the average 
 value of 1.225 calories for the metabohsm in the lying position is true 
 not only for the two days referred to but also for an extensive series of 
 experiments made by Mr. Higgins on this subject in 1914, and since 
 the average of the two standing experiments made by the same observer 
 is identical with the average of the long series of standing experiments 
 made one year previous by Dr. Tigerstedt, we may properly maintain 
 
66 
 
 ENERGY TRANSFORMATIONS DURING HORIZONTAL "WALKING. 
 
 that with this subject a change in the body position from lying to 
 standing is accompanied by an increase of approximately 9 per cent 
 in the total metaboUsm. 
 
 BASAL METABOLISM OF SUBJECT IL 
 
 With the beginning of the prolonged research on the professional 
 athlete subject II (the bicycle-riding subject M. A. M. of Benedict and 
 Cathcart), we planned definitely to secure much more extended data 
 as to the metaboUsm during various standing positions, to supplement 
 the preliminary data obtained with subject I by observations made on 
 subject II after the ingestion of food, and to determine in addition 
 the metaboUsm of the subject in the sitting position. These studies 
 were whoUy incidental to the main problem of studying the motion 
 of forward progression and were made primarily with a view to iUum- 
 inating the possible selection of the most advantageous and the most 
 scientifically sound base-Unes. At the time the observations were made, 
 we were not certain of their ultimate use in the final computations, so 
 they may properly be considered as a study of the metaboUsm in the 
 standing and sitting positions, with and without food. 
 
 METABOLISM IN THE LYING POSITION. 
 
 The observation of the post-absorptive metaboUsm of this subject in 
 the Isang position was confined to one experiment which was made 
 through the kindness of Mr. L. E. Emmes, of the Laboratory staff, 
 but a large number of basal values for this position were also available 
 as a result of the previous study of the subject by Cathcart. The 
 results obtained in the experiment made by Mr. Emmes and an average 
 value for the results obtained by Cathcart are given in table 7. 
 
 Table 7. — Metabolism of subject II in the lying position in experiments mthout food. 
 [Observations made by Mr. L. E. Emmes. Values per minute.] 
 
 Date and time. 
 
 Carbon dioxide. 
 
 Oxygen. 
 
 Heat- 
 output 
 
 (com- 
 puted). 
 
 Pulse- 
 rate. 
 
 Respiia^ 
 tion-rate. 
 
 Total. 
 
 Per kilo- 
 gram. 
 
 Total. 
 
 Per kilo- 
 gram. 
 
 Apr. 18, 1914:1 
 
 8''24'»a. m 
 
 C.C. 
 
 198 
 186 
 196 
 193 
 
 c.c. 
 
 c.c. 
 226 
 229 
 229 
 232 
 
 c.c. 
 
 cals. 
 
 57 
 56 
 58 
 56 
 
 15.5 
 15.6 
 16.6 
 16.3 
 
 8 54 a. m 
 
 9 17 a. m 
 
 9 48 a. m 
 
 Average 
 
 193 
 205 
 
 2.86 
 3.12 
 
 229 
 242 
 
 3.39 
 3.67 
 
 1.11 
 1.17 
 
 57 
 63 
 
 15.9 
 20.0 
 
 Dec. 7, 1911, to Apr. 16, 1912^* 
 
 'The duration of each period on April 18 was about 15 minutes and 3 seconds. 
 'Average of experiments made by Benedict and Cathcart. See Carnegie Inst. Wash. Pub. 187, 
 1913, p. 78. 
 
DISCUSSION OF RESULTS. 
 
 67 
 
 The four periods of the respiration experiment made on April 18, 
 1914, by Mr. Emmes show an excellent agreement which is character- 
 istic of this subject. Although his nude body-weight was 1.6 Mlograms 
 greater than at the time of the study of Cathcart, being 67.5 kilograms 
 on April 18, 1914, and averaging 65.9 kilograms during the previous 
 research, the heat output per minute was but 1.11 calories per kilogram 
 per minute as compared to the average of the earher observations of 
 1.17 calories per kilogram per minute. While it is possible that direct 
 averaging in this instance is a mathematically unsound procedure, we 
 may state that the resting basal heat output of subject II in the post- 
 absorptive state may be considered to be, in round numbers, 1.14 
 calories. 
 
 METABOLISM IN THE SITTING POSITION. 
 
 In a further effort to secure all possible data for establishing various 
 scientifically sound base-Unes, we made a special study of the metabo- 
 lism of subject II while he sat comfortably in a chair. Three observa- 
 tions were made with the subject in the post-absorptive condition, 
 four after a Ught breakfast, and five after a heavier midday meal. 
 The data are sujHiciently extended to permit their classification accord- 
 ing to the character of the meal and such a classification is used in 
 presenting the results of the study of the sitting metabolism in table 8. 
 
 Table 8. — Metabolism of subject II in the sitting position. 
 [Values per minute.] 
 
 Date. 
 
 Carbon 
 dioxide. 
 
 Oxygen. 
 
 Heat- 
 output 
 
 (com- 
 puted). 
 
 Pulse- 
 rate. 
 
 Respira- 
 tion-rate. 
 
 1914 
 Without food: 
 
 Mar. 25 
 
 27 
 
 Apr. 3 
 
 Average 
 
 After light meal : 
 
 Mar. 16 
 
 16 
 
 18 
 
 19 
 
 Average 
 
 After heavy meal: 
 
 Mar. 16 
 
 17 
 
 18 
 
 19 
 
 25 
 
 Average 
 
 c.e. 
 192 
 195 
 219 
 
 C.C. 
 
 260 
 234 
 245 
 
 cats. 
 1.23 
 1.13 
 1.20 
 
 59 
 58 
 67 
 
 18.0 
 17.6 
 19.4 
 
 202 
 
 246 
 
 1.19 
 
 61 
 
 18.3 
 
 218 
 203 
 233 
 242 
 
 281 
 256 
 286 
 282 
 
 1.34 
 1.23 
 1.38 
 1.37 
 
 67 
 
 18.7 
 18.3 
 19.2 
 
 18.7 
 
 224 
 
 276 
 
 1.33 
 
 
 18.7 
 
 250 
 213 
 248 
 259 
 272 
 
 304 
 272 
 297 
 322 
 316 
 
 1.47 
 1.30 
 1.44 
 1.55 
 1.54 
 
 77 
 73 
 
 19.9 
 18.1 
 19.3 
 21.0 
 19.6 
 
 248 
 
 302 
 
 1.46 
 
 
 19.6 
 
68 
 
 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 With subject I no such classification could properly be made and, 
 indeed, the observations after the ingestion of food were but few in 
 number. 
 
 The metabolism with and without food are further compared in 
 table 9, to which is added the actual increase in the units of measure- 
 ment commonly employed for the various factors and the percentage 
 increase. From this table we see that as the result of a light meal the 
 carbon dioxide was increased 10.9 per cent, the oxygen consumption 
 12.2 per cent, and the heat output 11.8 per cent. After the heavy meal, 
 the percentage increase was essentially the same for all three factors, 
 i. e., 22.8 per cent. This percentage increment in the metabolism of 
 subject II after a heavy meal is almost identical with that noted for 
 subject I in the few experiments made with him. 
 
 Table 9.— Metabolism of subject II in the sitting 'position with and without food 
 [Average values per minute.] 
 
 
 Condition. 
 
 Carbon 
 dioxide. 
 
 Oxygen. 
 
 Heat output 
 (computed). 
 
 Pulse-rate. 
 
 Respira- 
 tion-rate. 
 
 Without food 
 
 After light meal 
 
 Increase -with food .... 
 
 After heavy meal 
 
 Increase with food .... 
 
 C.C. 
 
 202 
 
 224 
 (22 
 \ 10.9 p. ct. 
 
 248 
 f46 
 1 22.8 p. ct. 
 
 c.e. 
 
 246 
 
 276 
 r 30 
 I 12.2 p. ct. 
 
 302 
 r 56 
 1 22.8 p. ct. 
 
 cals. 
 1.19 
 1.33 
 
 r .14 
 
 111.8 p. ct. 
 1.46 
 
 r .27 
 
 122.7 p. ct. 
 
 61 
 •67 
 
 I ^ 
 
 \ 9.8 p. ct. 
 
 >75 
 
 f 14 
 
 \ 23.0 p. ct. 
 
 18 
 18 
 
 19 
 
 3 
 
 7 
 
 6 
 
 'The pulse-rate was obtained in only one of the four periods after the light meal; in but two of 
 the five periods after the heavy meal. (See table 8.) 
 
 One serious objection to this type of comparison, however, and an 
 objection that measurably lessens the mathematical value of the incre- 
 ment due to food, is the fact that the periods after the midday meal 
 followed the walking experiment in the morning, in which there was 
 considerable muscular activity. As a matter of fact, the long-con- 
 tinued walking experiments, in which the walking was done at a rapid 
 rate and the muscular activity was very severe, were not carried out 
 until later in the spring of 1914, and hence in all probability we have 
 not here to consider any great after-effect of the muscular activity of 
 the morning which persisted throughout the experiment in the after- 
 noon. Nevertheless, it is quite possible that at least a part of the 
 excess metaboUsm after the midday or "heavy" meal may be explained 
 by the fact that the subject had done considerable walking in the fore- 
 noon, while no such muscular activity preceded the after-breakfast 
 experiments. 
 
 Of special significance here is the apparent striking relationship 
 between the percentage increment in the total metaboUsm and the 
 percentage increment in the pulse-rate. The increase in the heat- 
 
DISCUSSION OF RESULTS. 69 
 
 output after a light meal was 12 per cent and that in the pulse-rate 
 10 per cent, while after a heavy meal the increase in the heat output 
 was 22.7 per cent and in the pulse-rate 23 per cent. This Laboratory- 
 has frequently emphasized in its pubUcations the important relation- 
 ship between the pulse-rate and the metabohsm, the statements usually 
 implying that an increase in the pulse-rate is simultaneous with an 
 increase in the metabolism. Recently, in pubHshing the results of 
 observations on a man who fasted 31 days,^ it was pointed out in com- 
 paring the metabohsm of the subject asleep and awake that the incre- 
 ment in the pulse-rate for the subject awake was directly proportional 
 to the percentage increase in the metabohsm. While it is by no means 
 maintained that the increment in the pulse-rate for subject II was in 
 direct proportion to the increase in the metabohsm, it is of special 
 interest to point out this second striking percentage relationship 
 between the pulse increment and the metabohsm increment, for such a 
 quantitative relationship, if not partaking of the nature of a physio- 
 logical law, at least serves to emphasize in a striking manner the im- 
 portance of records of the pulse-rate in all metabohsm experiments. 
 
 Occasion is here taken to note that a common error is found with 
 writers who misapply the measurements of the pulse-rate in attempting 
 to compare the pulse-rate of one person with that of another. Our 
 experience in this Laboratory points to no relationship between the pulse- 
 rate of two individuals, although the records for a single individual are 
 frequently surprisingly proportional to the metabohsm. 
 
 COMPARISON OF THE METABOLISM IN THE LYING AND SITTING POSITIONS. 
 
 Although observations were made of the metabohsm of subject II 
 in the post-absorptive condition for both the sitting and the lying posi- 
 tions, unfortimately the studies of the metabohsm in the lying position 
 were made some three weeks later than those of the metabohsm in the 
 sitting position, hence a comparison of the results is not free from criti- 
 cism. If, however, we compare the average values found for the 
 metabohsm in the lying position on April 18, 1914 (see table 7), with 
 the average of the values for the metabohsm in the sitting position 
 obtained on March 26 and 27 and April 3, 1914 (see table 8), we find a 
 percentage increase in the carbon-dioxide output with the subject sit- 
 ting over that with the subject in the lying position of 4.7 per cent, in 
 the oxygen consumption of 7.4 per cent, in the heat production of 7.2 
 per cent, and in the pulse-rate of 7.0 per cent. According to these incom- 
 plete data, therefore, the increase in the metabohsm with the subject 
 sitting over that with the subject in the lying position is approximately 
 7 per cent.^ We may also note here the agreement between the incre- 
 ment in the pulse-rate and that of the total metabohsm. 
 
 iBenedict, Carnegie Inst. Wash. Pub. 203, 1915, p. 351. 
 
 ^See, also, Emmes and Riche, Am. Journ. Physiol., 1911, 27, p. 406. 
 
70 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 METABOLISM IN VARIOUS STANDING POSITIONS. 
 
 With subject I no attempt was made to vary the character of the 
 standmg experiment, but with subject II numerous observations were 
 made both with and without food and with the subject standing in 
 various positions. A large majority of the experiments, i. e., 53 experi- 
 ments, were made when the subject was standing quietly in a relaxed 
 position. Eight experiments were made with the subject standing in a 
 relaxed position, but resting the hands upon a staff. Eight experiments 
 were made with the subject leaning against a support, and finally 10 
 experiments were carried out with the man standing in the position 
 of "attention." Since later we noted that there was considerable 
 extraneous muscular activity incidental to walking at a rapid rate, 
 which consisted for the most part of vigorous arm-motion, two experi- 
 ments were made on May 11 and 15 in which the post-absorptive 
 metaboHsm was measured with the subject standing still but moving 
 his arms vigorously, simulating as nearly as possible the movement of 
 the arms in rapid walking. 
 
 The results of the standing experiments with the subject in the post- 
 absorptive condition will first be considered and are given in table 10. 
 Since our interest is chiefly with the total heat-output, we may properly 
 compare the metaboUsm in the various standing positions upon this 
 basis. 
 
 When the subject stood in a relaxed position, his heat output varied 
 from the very low value of 1.12 calories to 1.40 calories per minute, the 
 average value being 1.25 calories per minute. When he stood in a 
 relaxed position, but with his hands resting upon a staff, the average 
 heat-output was essentially the same as in the first position, namely, 
 1.26 calories per minute; but when he leaned against a support there 
 was a perceptible diminution in the heat-output, which then averaged 
 but 1.18 calories per minute. It is, however, somewhat irregular to 
 compare an average value for the relaxed position obtained from 26 
 experiments with the average values for other positions obtained from 
 only 3 experiments; the sHght changes in the metabohc level shown by 
 these averages are therefore probably without significance. Essen- 
 tially the same may be said of a comparison of the values obtained for 
 the relaxed position with those obtained for the position of attention 
 when the heat output increased only to 1.30 calories. Our general 
 impression was that this subject did not maintain, to any great degree, 
 a rigid position of "attention." From the foregoing comparison it is 
 clear that the experimental evidence does not warrant the deduction 
 that there is a measurable difference in the metabohsm for any of the 
 various standing positions in which the metabolism was studied, such 
 as standing in a relaxed position, with the hands on a staff, with the 
 subject leaning against a support, or standing in the position of 
 "attention." 
 
DISCUSSION OF RESULTS. 
 
 71 
 
 When instead of the muscular repose of these standing positions the 
 subject swings his arms vigorously, as would be done in rapid walking, 
 we note a great increase in the metabohsm. Unfortunately there is 
 not a particularly satisfactory agreement in the values obtained for the 
 two experiments under these conditions, for on May 11 the heat-output 
 per minute was 2.53 calories, or essentially 100 per cent greater than 
 when the subject stood quietly, while on May 15 the metabohsm was 
 3.13 calories or approximately 150 per cent greater than the metab- 
 ohsm of the subject when standing at rest. 
 
 Table 10. — Metabolism of subject II standing in different positions in experiments without food. 
 
 [Values per minute.] 
 
 Date. 
 
 
 1 
 
 S o 
 
 P4 
 
 Date. 
 
 1 
 
 
 
 
 
 1 
 
 1 
 
 1914 
 Standing, relaxed: 
 
 Mar. 20 
 
 31 
 
 Apr. 1 
 
 6........ 
 
 7 
 
 8 
 
 9 
 
 10 
 
 14 
 
 15 
 
 16 
 
 17 
 
 21 
 
 22 
 
 23 
 
 24 
 
 25 
 
 27 
 
 28 
 
 May 5 
 
 10 
 
 11 
 
 12 
 
 13 
 
 14 
 
 Average 
 
 ex. 
 218 
 209 
 213 
 218 
 r214 
 1198 
 204 
 202 
 212 
 223 
 214 
 
 214 
 205 
 207 
 208 
 198 
 192 
 217 
 221 
 229 
 215 
 259 
 226 
 213 
 209 
 
 c.c. 
 275 
 260 
 266 
 246 
 257 
 236 
 265 
 228 
 257 
 245 
 252 
 258 
 265 
 242 
 251 
 252 
 
 264 
 245 
 274 
 277 
 246 
 278 
 293 
 257 
 257 
 
 cats. 
 
 1.32 
 
 1.25 
 
 1.28 
 
 1.21 
 
 1.24 
 
 1.14 
 
 1.26 
 
 1.12 
 
 1.24 
 
 1.21 
 
 1.23 
 
 1.251 
 
 1.28 
 
 1.18 
 
 1.21 
 
 1.22 
 
 1.15 
 
 1.24 
 
 1.20 
 
 1.32 
 
 1.34 
 
 1.20 
 
 1.38 
 
 1.40 
 
 1.24 
 
 1.24 
 
 71 
 71 
 75 
 74 
 82 
 90 
 
 82 
 78 
 94 
 74 
 90 
 85 
 78 
 84 
 74 
 82 
 79 
 77 
 82 
 83 
 74 
 85 
 82 
 79 
 80 
 
 1914 
 Standing, staff: 
 
 Mar. 24 
 
 26 
 
 Apr. 3 
 
 Average 
 
 Standing, support: 
 
 Mar. 24 
 
 26 
 
 31 
 
 Average 
 
 Standing, attention: 
 
 Mar. 25 
 
 27 
 
 31 
 
 Average 
 
 Standing, swinging 
 arms ■? 
 
 May 11 
 
 15 
 
 c.c. 
 217 
 223 
 
 224 
 
 c.c. 
 250 
 253 
 278 
 
 cats. 
 1.22 
 1.24 
 1.34 
 
 82 
 80 
 
 77 
 
 221 
 
 260 
 
 1.26 
 
 80 
 
 196 
 201 
 214 
 
 256 
 238 
 239 
 
 1.22 
 1.15 
 
 1.17 
 
 79 
 79 
 
 77 
 
 204 
 
 244 
 
 1.18 
 
 78 
 
 206 
 219 
 233 
 
 265 
 272 
 272 
 
 1.27 
 1.31 
 1.33 
 
 72 
 71 
 75 
 
 219 
 
 270 
 
 1.30 
 
 73 
 
 455 
 554 
 
 516 
 643 
 
 2.53 
 3.13 
 
 
 214 
 
 258 
 
 1.25 
 
 80 
 
 ^The average respiratory quotient of 0.83 is assumed in computing heat-output on this day. 
 ^he subject stood swinging his hands and arms as vigorously as in the most rapid walking. 
 
 In the subsequent computations several basal values may be em- 
 ployed. The most obvious are those obtained with the subject in the 
 lying position and, as has aheady been seen, we have the results of two 
 series of measurements which were made with an interval of approxi- 
 mately two years. We have also used the value obtained with the 
 subject in the standing position. With subject I, three periods with 
 
74 
 
 ENBBGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 of "attention." All of these values were obtained after a heavy meal, 
 with the diet uncontrolled. Recognizing again the probable influence 
 of the preceding meal upon the individual values, we see, nevertheless, 
 that the evidence points towards a practically constant metabolism 
 independent of the variations in the standing position under approxi- 
 mately similar conditions. 
 
 Tablb 12. — Metabolism of svbjecl II standing in digereni positions after a heavy meal. 
 
 [Values per minute.] 
 
 Date and conditions 
 of experiments. 
 
 f 
 
 1 
 
 1^ 
 II 
 
 M-2. 
 
 1 
 f 
 
 Date and conditions 
 of experiments. 
 
 1 
 
 r 
 
 6 
 
 IS 
 II 
 
 1 
 
 1914 
 Diet uncontrolled : 
 Standing, relaxed: 
 
 Mar. 16 
 
 19 
 
 20 
 
 21 
 
 31 
 
 Apr. 1 
 
 3 
 
 Average 
 
 Standing, staff: 
 
 Mar. 24 
 
 26 
 
 30 
 
 Average 
 
 Standing, support: 
 
 Mar. 24 
 
 26 
 
 28 
 
 Average 
 
 Standing, attention : 
 
 Mar. 21 
 
 25 
 
 27 
 
 31 
 
 Average 
 
 Average of all 
 periods 
 
 c.c. 
 261 
 247 
 274 
 275 
 277 
 283 
 244 
 
 c.c. 
 319 
 303 
 318 
 355 
 345 
 319 
 293 
 
 cats. 
 1.54 
 1.46 
 1.55 
 1.70 
 1.66 
 1.57 
 1.42 
 
 86 
 87 
 96 
 89 
 86 
 81 
 
 1914 
 Diet controlled : 
 Standing, relaxed : 
 Protein — 
 
 Apr. 6 
 
 7 
 
 8 
 
 23 
 
 24 
 
 Average .... 
 
 Carbohydrate — 
 
 Apr. 9 
 
 10 
 
 14 
 
 15 
 
 25 
 
 27 
 
 Average 
 
 Fat- 
 Apr. 16 
 
 17 
 
 21 
 
 22 
 
 Average .... 
 
 c.c. 
 241 
 217 
 230 
 223 
 219 
 
 c.c. 
 296 
 289 
 275 
 254 
 299 
 
 caZs. 
 1.43 
 1.37 
 1.33 
 1.24 
 1.41 
 
 81 
 94 
 
 226 
 
 283 
 
 1.36 
 
 88 
 
 266 
 
 322 
 
 1.56 
 
 88 
 
 245 
 264 
 242 
 267 
 274 
 294 
 
 295 
 301 
 295 
 277 
 324 
 326 
 
 1.43 
 1.47 
 1.42 
 1.38 
 1.58 
 1.61 
 
 76 
 86 
 90 
 83 
 83 
 75 
 
 289 
 274 
 318 
 
 356 
 317 
 339 
 
 1.71 
 1.55 
 1.69 
 
 95 
 94 
 95 
 
 294 
 
 337 
 
 1.65 
 
 95 
 
 254 
 254 
 280 
 
 301 
 289 
 314 
 
 1.46 
 1.42 
 1.54 
 
 92 
 93 
 
 85 
 
 264 
 
 303 
 
 1.48 
 
 82 
 
 239 
 231 
 220 
 227 
 
 292 
 281 
 301 
 299 
 
 1.41 
 1.36 
 1.42 
 1.42 
 
 98 
 99 
 91 
 93 
 
 263 
 
 301 
 
 1.47 
 
 90 
 
 270 
 292 
 294 
 265 
 
 295 
 309 
 298 
 326 
 
 1.46 
 1.54 
 1.50 
 1.57 
 
 94 
 95 
 95 
 89 
 
 229 
 
 293 
 
 1.40 
 
 95 
 
 280 
 
 307 
 
 1.52 
 
 93 
 
 274 
 
 317 
 
 1.55 
 
 91 
 
 During the observations made with the specially controlled diets, the 
 subject stood in the relaxed position, without leaning upon a staff or 
 against a support. These show an average value of 1.36 calories for 
 the protein diet, 1.48 calories for the carbohydrate diet, and 1.40 
 calories for the fat diet, values not strikingly unlike those found on the 
 days with an uncontrolled diet. We may then with propriety average 
 
DISCUSSION OF RESULTS. 75 
 
 the results obtained for the four groups of experiments in the relaxed 
 position, i. e., one group with an uncontrolled diet and three with con- 
 trolled diets, and state that after the midday meal our subject showed 
 with considerable constancy an average heat-output of 1.45 calories 
 per minute. 
 
 From the values obtained in the experiments with the subject stand- 
 ing after a heavy meal, basal values were computed for use in calculat- 
 ing the increment due to walking under the same conditions of diet. 
 Considering first the results obtained with an uncontrolled diet, we 
 averaged the values determined with the subject standing in the four 
 positions, i. e., relaxed and unsupported, relaxed with the hands resting 
 upon a staff, relaxed and leaning against a support, and the position of 
 "attention." The averages found were 274 c.c. for the carbon-dioxide 
 production, 317 c.c. for the oxygen consumption, and 1.55 calories for 
 the heat-output. These averages were used for basal values in calculat- 
 ing the increase in the metaboUsm due to walking for all of the experi- 
 ments following a heavy meal with an uncontrolled diet. 
 
 The average value found on the days with a diet rich in protein, 
 namely, 1.36 calories, was used as a base-line for the walking experi- 
 ments on May 5 and 10, as the standing metabolism was not determined 
 on those days after the protein meal. A heavy protein meal was also 
 taken on April 6, 7, 23, and 24, and both the standing metabolism and 
 the metaboUsm during walking were determined. The standing values 
 for the individual days were therefore used as the basal values for com- 
 puting the increment due to walking. 
 
 The average value for the carbohydrate days was not used as a basal 
 value for any of the walking experiments. For the walking experi- 
 ments following the midday meal on May 4, 6, and 11, an average of 
 the values obtained on April 25 and 27, i. e., 1.59 calories, was used as 
 a base-line in the computations, as the diets were considered to be more 
 nearly comparable on those days. As has previously been stated, this 
 basal" value was also used for the walking experiment following the 
 carbohydrate breakfast on April 29. For the experiments on April 9, 
 10, 14, 15, 25, and 27, the standing metabolism determined for that 
 day was used as a basal value for the respective walking experiments 
 which were subsequently made on that day. 
 
 On days when the diet was excessively rich in fat, the standing 
 metabolism was always determined before the walking experiment and 
 the values found were used as base-Unes for the individual days, no use 
 being made of the average value. 
 
 Conclusions Regarding Influence op Food upon the Standing Metabolism. 
 
 The average value for the metaboUsm in the standing experiments 
 without food, as shown in table 10, was approximately 1.25 calories. 
 After the light morning meal, the metaboUsm was 1.43 calories (see 
 
76 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 table 11) and after the heavy noon meal 1.45 calories. There was, 
 therefore, an average increment of approximately 0.2 calorie or 16 per 
 cent, due to the ingestion of the food. This value is strikingly m agree- 
 ment with that found with subject I, and we may accordingly state 
 that the basal metaboUsm of both subjects used in the research was 
 increased approximately 16 per cent by the ingestion of the kinds and 
 amounts of food consumed. This has an important bearing upon the 
 subsequent calculations, for it is obviously impossible to make an intelli- 
 gent comparison of the standing values obtained with individuals in the 
 post-absorptive condition with those obtained after the ingestion of food. 
 Finally, it should not be forgotten that a part, at least, of the incre- 
 ment ascribed here to the ingestion of food, particularly after the noon 
 meal, may be due to a shght after-effect of the muscular activity of 
 walking in the forenoon experimental periods. On the other hand, 
 there is such a close agreement between the increment in the metabolism 
 after the Hght meal, which was invariably taken before the morning 
 walking periods, and the increment in the metabolism after the midday 
 meal, that it would imply that the influence of the morning work must 
 have been extremely small. 
 
 METABOLISM DURING WALKING. 
 
 The preliminary study of the mechanics of position incidental to 
 walking was obviously only for the purpose of throwing light upon the 
 various mechanical processes involved in walking and the metabolism 
 essential thereto. The primary purpose of the research was to study 
 the actual metabolism during the motion of forward progression. 
 
 WALKING EXPERIMENTS WITH SUBJECT I. 
 
 The first series of walking experiments was made by Dr. Tigerstedt 
 with subject I in the month of December 1913. These experiments 
 were all carried out under practically the same conditions, — that is, 
 following two or three periods when the subject stood in a relaxed 
 position during which time the basal standing metaboUsm was meas- 
 ured. The body-weight of the subject was a practically constant 
 factor, as it did not alter materially throughout the month. An 
 attempt was made to maintain an essentially constant speed of the 
 treadmill, the rate averaging not far from 76 meters per minute. In a 
 few of the experiments, the speed was lowered to about 65 meters per 
 minute, but in no instance did it exceed 80 meters per minute. Under 
 these conditions we may consider that the study was based upon a 
 constant speed and that accordingly all values are strictly comparable 
 so far as the velocity is concerned. The walking experiments con- 
 sisted of two or three and occasionally fo\ir periods per day. On two 
 days walking experiments were made after the ingestion of food. 
 
DISCUSSION OF RESULTS. 77 
 
 The results of all of the walking experiments with subject I are given 
 in abstract in table 13. Inasmuch as the experience of previous 
 investigators has shown that the variations in velocity play an impor- 
 tant r61e in the total energy transformations, we have recorded here 
 the distance per minute which the subject walked and have likewise 
 computed the number of horizontal kilogrammeters by multiplying 
 the distance per minute by the body-weight. From the kymograph 
 records it was possible to find the average height to which the body was 
 raised at each step by obtaining the average height of each recorded 
 movement; by multiplying this average height by the number of steps, 
 the total distance that the body was moved in a vertical direction could 
 be computed with reasonable accuracy, thus giving a component 
 for the analysis of the various factors involved in walking. The 
 measurements of the distance that the body was elevated per minute 
 are recorded in column d. 
 
 The total heat-output was calculated from the gaseous exchange not 
 only for the walking periods but also for the standing periods preceding 
 the walking; these values are recorded in column e. The increase due 
 to walking was obtained by difference and the energy required to move 
 1 kilogram 1 meter in a forward direction, i. e., 1 horizontal kilo- 
 grammeter, is recorded in gram-calories in column g. These latter 
 values are obviously the most important result of this study. 
 
 EXPERIMENTS WITHOUT FOOD. 
 
 Considering first the values without food, it will be seen that the 
 heat-output per horizontal kilogrammeter varies from a minimum of 
 0.446 gram-calorie to a maximum of 0.637 gram-calorie, but the large 
 majority of the values lie close to the average value of 0.507 gram- 
 calorie. A general inspection of these results shows indications of a 
 periodicity or rhythm in the efiiciency of this subject in walking. Thus, 
 low values are found on December 2 and 3, which are followed by a 
 group of high values continuing until December 22, while the last 
 three experimental days that the subject was without food give dis- 
 tinctly lower values than those found in the preceding group. There 
 is not, however, sufficient regularity in this rhythm to indicate the 
 effect of training of the subject or in the use of the treadmill. To be 
 sure, the first value, that of November 29, is considerably higher than 
 the average and it is probably fair to assume that the high value of 
 0.637 gram-calorie found on December 15 was more or less accidental. 
 On the other hand, we see no reason why these values should be rejected 
 and the figures are sufficiently numerous to make it immaterial whether 
 or not these or any other particular values are discarded so far as the 
 influence upon the general average is concerned. While it may appear 
 that the low values found on the last three days would imply the effect 
 of training, it should be stated at the outset that this subject was a 
 
78 
 
 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 Table 13. — Increase in heat-output during walking in experiments with subject I. 
 [Observations made by Dr. Carl Tigerstedt.] 
 
 
 Date and condi- 
 tions of experi- 
 ments. 
 
 (o) 
 
 Body- 
 weight 
 with 
 clothing. 
 
 (6) 
 
 Distanof 
 
 per 
 minute. 
 
 (c) 
 
 , Horizonta] 
 kilogram- 
 meters. 
 (0X6). 
 
 (d) 
 
 Raising 
 of body 
 
 per 
 minute. 
 
 Heat-output (computed). 
 
 
 (e) 
 1 Total, 
 per 
 
 Increase over standing. 
 
 
 (/) 
 Total. 
 
 (0) 
 Per horizontal, 
 kilogrammeter 
 
 
 
 
 
 
 
 minute. 
 
 
 (f^c). 
 
 
 1913 
 
 
 
 
 
 
 
 
 
 Without food. 
 
 
 
 
 
 
 
 
 
 Nov. 29: 
 
 kUos. 
 
 meters. 
 
 
 meters. 
 
 cals. 
 
 cals. 
 
 gm.'cal. 
 
 
 Standing*. . . 
 
 
 75:1^ 
 
 
 
 1.35 
 
 
 
 
 Walking 
 
 72.50 
 
 5345 
 
 3!l5 
 
 4.41 
 
 3!66 
 
 0.562 
 
 
 Dec. 1: 
 
 
 
 
 
 
 
 
 
 Standing 
 
 
 
 
 
 1.34 
 
 
 
 
 Walking 
 
 72! 60 
 
 76!o 
 
 6^518 
 
 3!26 
 
 4.10 
 
 2.76 
 
 !5o6 
 
 
 
 
 76.6 
 
 5,661 
 
 3.36 
 
 4.35 
 
 3.01 
 
 .641 
 
 
 Dec. 2: 
 
 
 
 
 
 
 
 
 
 Standing 
 
 
 
 
 
 1.37 
 
 
 
 
 Walking 
 
 73.12 
 
 76.2 
 
 si 572 
 
 3.26 
 
 4.03 
 
 2.66 
 
 .477 
 
 
 
 
 76.8 
 
 5,616 
 
 4.62 
 
 4.10 
 
 2.73 
 
 .486 
 
 
 Dec. 3: 
 
 
 
 
 
 
 
 
 
 Standing . . . . 
 
 
 
 
 
 1.30 
 
 
 
 
 Walking. . . . 
 
 72.80 
 
 76.6 
 
 5,569 
 
 3.57 
 
 4.07 
 
 2^77 
 
 .497 
 
 
 
 
 77.2 
 
 5,620 
 
 3.62 
 
 4.07 
 
 2.77 
 
 .493 
 
 
 
 
 77.5 
 
 5,642 
 
 3.68 
 
 4.19 
 
 2.89 
 
 .512 
 
 
 Dec. 4: 
 
 
 
 
 
 
 
 
 
 Standing 
 
 
 
 
 
 1.28 
 
 
 
 
 Walking 
 
 73.61 
 
 77!7 
 
 5^673 
 
 3.41 
 
 4.19 
 
 2191 
 
 isis 
 
 
 
 
 77.7 
 
 5,673 
 
 3.68 
 
 4.22 
 
 2.94 
 
 .618 
 
 
 
 
 78.2 
 
 6,709 
 
 3.67 
 
 4.14 
 
 2.86 
 
 .501 
 
 
 Dec. 5:» 
 
 
 
 
 
 
 
 
 
 Standing .... 
 
 
 
 
 
 1.67 
 
 
 
 
 Walking. . . . 
 
 72! 51 
 
 ■Ts!?!^ 
 
 5, 489 
 
 3!57 
 
 4.43 
 
 2.86 
 
 .521 
 
 
 
 
 78.2 
 
 5,670 
 
 4.10 
 
 4.50 
 
 2.93 
 
 .517 
 
 
 
 
 79.0 
 
 5,728 
 
 4.10 
 
 4.68 
 
 3.11 
 
 .543 
 
 
 Dec. 8: 
 
 
 
 
 
 
 
 
 
 Standing .... 
 
 
 
 
 
 1.29 
 
 
 
 
 Walking 
 
 72.33 
 
 76.5 
 
 5, '533 
 
 3!52 
 
 4.02 
 
 2.73 
 
 !493 
 
 
 
 
 78.6 
 
 5,685 
 
 3.78 
 
 4.29 
 
 3.00 
 
 .528 
 
 
 
 
 79.3 
 
 6,736 
 
 4.04 
 
 4.27 
 
 2.98 
 
 .520 
 
 
 
 
 79.7 
 
 5,766 
 
 4.16 
 
 4.39 
 
 3.10 
 
 .538 
 
 
 Dec. 15: 
 
 
 
 
 
 
 
 
 
 Standing .... 
 
 
 
 
 
 1.32 
 
 
 
 
 Walking.... 
 
 72.10 
 
 74.2" 
 
 5,'356 
 
 3.68 
 
 4.73 
 
 siii 
 
 .637 
 
 
 
 
 75.6' 
 
 6,451 
 
 3.83 
 
 4.33 
 
 3.01 
 
 .562 
 
 
 
 
 76.3 
 
 6,601 
 
 3.94 
 
 4.24 
 
 2.92 
 
 .631 
 
 
 
 
 76.3 
 
 5,501 
 
 3.99 
 
 4.20 
 
 2.88 
 
 .624 
 
 
 Dec. 16: 
 
 
 
 
 
 
 
 
 
 Standing .... 
 
 
 .... 
 
 
 
 1.37 
 
 
 
 
 Walking 
 
 72.05 
 
 75.1 
 
 5,'4ii 
 
 3.89 
 
 4.30 
 
 2.93 
 
 .541 
 
 
 
 
 76.7 
 
 5,526 
 
 3.99 
 
 4.18 
 
 2.81 
 
 .509 
 
 
 
 
 77.6 
 
 6,591 
 
 4.20 
 
 3.91 
 
 2.54 
 
 .454 
 
 
 Dec. 17: 
 
 
 
 
 
 
 
 
 
 Standing 
 
 
 
 
 
 1.31 
 
 
 
 
 Walking 
 
 72.82 
 
 76.6" 
 
 5,'462 
 
 3. '73 
 
 3.99 
 
 2.68 
 
 .491 
 
 
 
 
 76.4 
 
 6,563 
 
 3.89 
 
 4.12 
 
 2.81 
 
 .605 
 
 
 
 
 78.1 
 
 5,687 
 
 4.16 
 
 4.20 
 
 2.89 
 
 .508 
 
 
 
 
 78.6 
 
 5,724 
 
 4.16 
 
 4.33 
 
 3.02 
 
 .628 
 
 ^Computed from the average elevation of the body per step aa obtained from the kvmoeraDh 
 records and the steps per minute. See table 3 for information regarding number of steps 
 'Usually three periods with the subject standing preceded the walking experiment 
 '"No sleep but much alcohol" on the night preceding the experiment of Dec. 5. 
 
DISCUSSION OF RESULTS. 
 
 79 
 
 Table 13. 
 
 -Increase in heat output during walking in experiments with subject I — Continued. 
 [Observations made by Dr. Carl Tigerstedt.] 
 
 Date and condi- 
 tions of experi- 
 
 (a) 
 
 Body- 
 weight 
 
 (6) (c) (d) 
 
 Distance Horizontal Raising 
 kilogram- of bodv 
 
 Heat-output (computed). 
 
 
 Increase over standing. 
 
 
 
 ments. 
 
 with 
 
 per 
 
 meters. 
 
 per 
 
 minute. 
 
 (e) 
 
 (.f) 
 
 to) 
 
 
 clothing. 
 
 minute. 
 
 (aX6). 
 
 Total 
 
 
 Per horizontal 
 
 
 
 
 
 
 per 
 
 Total. 
 
 kilogrammeter. 
 
 
 
 
 
 
 minute. 
 
 
 (/-^c). 
 
 1913 
 
 
 
 
 
 
 
 
 Without food — 
 
 
 
 
 
 
 
 
 Continued. 
 
 
 
 
 
 
 
 
 Dec. 18: 
 
 kilos. 
 
 meters. 
 
 
 meters. 
 
 cals. 
 
 cals. 
 
 gm.-cal. 
 
 Standing.... 
 
 
 
 
 
 1.29 
 
 
 
 Walking 
 
 74! 76 
 
 75.'3^ 
 
 5,629 
 
 3.52 
 
 3.98 
 
 2.&9 
 
 A78 
 
 
 
 76.4 
 
 5,712 
 
 3.68 
 
 4.09 
 
 2.80 
 
 .490 
 
 
 
 76.7 
 
 5,734 
 
 3.68 
 
 4.19 
 
 2.90 
 
 .506 
 
 
 
 76.9 
 
 5,749 
 
 3.73 
 
 4.22 
 
 2.93 
 
 .510 
 
 Dec. 19: 
 
 
 
 
 
 
 
 
 Standing 
 
 
 
 
 
 1.36 
 
 
 
 Walking 
 
 74.17 
 
 76.1' 
 
 5,644 
 
 3.83 
 
 4.29 
 
 2.93 
 
 .519 
 
 
 
 77.9 
 
 5,778 
 
 3.99 
 
 4.23 
 
 2.87 
 
 .497 
 
 
 
 78.3 
 
 5,808 
 
 4.10 
 
 4.26 
 
 2.90 
 
 .499 
 
 
 
 78.7 
 
 5,837 
 
 4.20 
 
 4.26 
 
 2.90 
 
 .497 
 
 Dec. 20: 
 
 
 
 
 
 
 
 
 Standing 
 
 
 
 
 
 1.31 
 
 
 
 Walking 
 
 74.31 
 
 76.2 
 
 5,662 
 
 3.68 
 
 4.00 
 
 2.69 
 
 A75 
 
 
 
 77.7 
 
 5,774 
 
 4.04 
 
 4.28 
 
 2.97 
 
 .514 
 
 
 
 78.6 
 
 5,841 
 
 4.20 
 
 4.43 
 
 3.12 
 
 .534 
 
 
 
 78.9 
 
 5,863 
 
 4.25 
 
 4.48 
 
 3.17 
 
 .541 
 
 Deo. 22: 
 
 
 
 
 
 
 
 
 Standing 
 
 
 
 
 
 21.34 
 
 
 
 Walking 
 
 73! 77 
 
 76!3 . 
 65.9'^ 
 
 5^629 
 
 4!67 
 
 4.21 
 
 2!87 
 
 .510 
 
 
 
 4,861 
 
 3.17 
 
 3.76 
 
 2.42 
 
 .498 
 
 
 
 77.4 
 
 5,710 
 
 4.28 
 
 4.23 
 
 2.89 
 
 .506 
 
 
 
 67.51/ 
 
 4,979 
 
 3.41 
 
 3.74 
 
 2.40 
 
 .482 
 
 Deo. 23: 
 
 
 
 
 
 
 
 
 Standing 
 
 
 
 
 
 n.34 
 
 
 
 Walking 
 
 73! 76 
 
 75!9 
 
 5^698 
 
 3.97 
 
 4.03 
 
 2.69 
 
 .481 
 
 
 
 66.4 »/ 
 
 4,897 
 
 3.07 
 
 3.55 
 
 2.21 
 
 .451 
 
 
 
 76.9 
 
 5,671 
 
 4.08 
 
 4.14 
 
 2.80 
 
 .494 
 
 
 
 66.4'' 
 
 4,897 
 
 3.30 
 
 3.66 
 
 2.32 
 
 .474 
 
 Deo. 27: 
 
 
 
 
 
 
 
 
 Standing 
 
 
 
 
 
 n.34 
 
 
 
 Walking 
 
 72! 96 
 
 78 ^4 
 
 5,720 
 
 i.m 
 
 4.07 
 
 2.73 
 
 .'477 
 
 
 
 65.2^ 
 
 4,757 
 
 3.02 
 
 3.46 
 
 2.12 
 
 .446 
 
 
 
 78.6 
 
 5,735 
 
 4.13 
 
 4.07 
 
 2.73 
 
 .476 
 
 Average. . . 
 With food. 
 
 
 65.1^ 
 
 4,750 
 
 3.02 
 
 3.48 
 
 2.14 
 
 .451 
 
 73.10 
 
 75.9 
 
 
 3.78 
 
 
 2.81 
 
 .507 
 
 
 
 
 
 
 
 
 Nov. 26: 
 
 
 
 
 
 
 
 
 Standing .... 
 
 
 
 
 
 1.61 
 
 
 
 Walking 
 
 73] 30 
 
 75] 3 
 
 5^519 
 
 3.57 
 
 5.03 
 
 3.42 
 
 !626 
 
 Deo. 9: 
 
 
 
 
 
 
 
 
 Standing 
 
 
 
 
 
 1.61 
 
 
 
 Walking 
 
 72 [33 
 
 76!6 
 
 6^497 
 
 3.68 
 
 4.61 
 
 3.60 
 
 !546 
 
 
 
 78.3 
 
 5,663 
 
 3.89 
 
 4.39 
 
 2.78 
 
 .491 
 
 
 
 79.1 
 
 5,721 
 
 4.04 
 
 4.33 
 
 2.72 
 
 .475 
 
 ■^Computed from the average elevation of the body per step as obtained from the kymograph 
 records and the steps per minute. See table 3 for information regarding number of steps. 
 'Average of "standing" values obtained in experiments without food, Nov. 29-Dec. 20. 
 
80 ENERGY TKANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 trained athlete, and although not particularly careful of himself, when 
 out of training, he was nevertheless in reasonably good condition. The 
 fact that alcohoUc excesses preceded the experiment on December 5 
 shows, of itself, that the subject was not in strict training. Indeed, it 
 was impossible for us to control him outside of the Laboratory. 
 
 In considering the values without food, it is of interest to note the 
 variations in the standing metabolism in their relation to the total 
 increase due to walking. While we find from the values given in table 
 6 that the average heat-output for this man without food was 1.34 
 calories per minute, it will be seen here that the variations ranged from 
 1.28 calories per minute on December 4 to 1.57 calories on December 5. 
 The latter date was the day following the alcohoUc excesses and it may 
 be noted that this increase in the basal metaboUsm continued through- 
 out the walking periods, as the three highest values for the heat-output 
 during walking were found on this day. On the other hand, when the 
 high basal metabohsm is deducted, the gram-calories per horizontal 
 kUogrammeter are essentially the same as the average value. 
 
 EXPERIMENTS WITH FOOD. 
 
 On the two days in which experiments were made with subject I 
 after the ingestion of food, the standing or basal metaboUsm was per- 
 ceptibly higher than in the experiments without food. The total 
 metaboUsm during walking was likewise higher in all of the experi- 
 mental periods. On the other hand, when the standing or basal metab- 
 oUsm is deducted, we find that the gram-calories per horizontal kilo- 
 grammeter were, in the second experiment, quite within the normal 
 Umits. We can find no explanation for the high value obtained on the 
 first day. The fact that the high basal metaboUsm due to food per- 
 sisted through the walking period is of special interest, as it shows that 
 the muscular activity incidental to the amount and rate of walking in 
 these experiments resulted in a metaboUsm which was superimposed 
 upon the increased metaboUsm due to the ingestion of food. In 
 general, we may say that when this subject walked on a level plane, 
 the energy required over and above maintenance to move 1 kilogram 
 over a distance of 1 meter, i. e., 1 horizontal kUogrammeter, was in 
 round numbers 0.5 gram-calorie. The correlation between these 
 results and those obtained with subject II and the earUer observations 
 of Benedict and Cathcart may properly be deferred until the discussion 
 of the experiments with subject II. 
 
 ENERGY REQUIRED FOR THE ELEVATION OF THE BODY. 
 
 In walking at the average speed of 75.9 meters per minute, we find, 
 from the records obtained with Dr. Tigerstedt's tracing pointer and 
 by counting the number of steps, that the total distance per minute that 
 the subject raised his body in a vertical direction amounted, on the 
 average, to 3.78 meters per minute. With an average body-weight of 
 
DISCUSSION OF BESULTS. 81 
 
 73.1 kilograms, this would correspond to a work equivalent of 276.32 
 kilogrammeters or 0.65 large calorie per minute. Since the total 
 increase over the standing metabolism due to walking averaged 2.81 
 large calories per minute, it is seen that approximately 23 per cent of the 
 energy required for the work of forward progression was employed in 
 raising the body in a vertical direction. 
 
 These experiments give no data regarding the amount of energy 
 required to lower the body after being raised at each step. Various 
 assumptions are found for this in the Uterature, ranging from one- 
 quarter to three-quarters of the work done in the elevation of the body, 
 but it is obviously out of place to attempt such gross interpretations 
 of the results. 
 
 In conclusion, then, we may say that when walking in a horizontal 
 direction at the rate of 76 meters per minute, a man with a body-weight of 
 73 kilograms produces 2.81 calories per minute above his standing basal 
 metabohsm, of which 0.65 calorie or 23 per cent is required to raise the 
 body through a distance of approximately 4 meters per minute. It is 
 thus apparent at the outset that a very important factor in the energy 
 consumption while walking in a horizontal direction may be the type of 
 step employed. Unfortunately our observations were not made upon a 
 sufficient number of persons to permit a complete discussion of this point. 
 
 WALKING EXPERIMENTS WITH SUBJECT II. 
 
 Subject II, who was a professional athlete, though not in continuous 
 training, had exercised excessively in bicycle riding and had been the 
 subject in Cathcart's research on the muscular work of bicycle riding. 
 He had done a considerable amount of walking when in training, but 
 was not an especially weU-trained walker and certainly could not be 
 classed as a professional pedestrian. On the other hand, he performed 
 all of the tests on the treadmill at even the highest speeds with perfect 
 ease and was at no time unduly distressed. 
 
 The walking experiments with this subject covered a period of 
 approamately two months, i. e., from March 16 to May 15, 1914. 
 About 40 per cent of the experiments were made without food; the 
 remainder of the experiments followed either the breakfast or the mid- 
 day meal, the diet in some cases being controlled. The speed of rota- 
 tion of the treadmill varied during the experiments without food from 
 56.0 meters per minute to 146.8 meters per minute and in a few experi- 
 ments, with the subject running, it increased to 148.7 meters per 
 minute. The greater part of the experiments were made with a speed 
 between 56.0 and 93.3 meters per minute. 
 
 In computing the energy per horizontal kilogrammeter, we have the 
 same problem to consider that was met with in the case of subject I, 
 namely, the selection of a suitable base-Une. As the tests with sub- 
 ject II were more varied than those with the first subject, at least 
 
82 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 three base-lines are possible, if not indeed permissible. These are, (1) 
 the average resting value with the subject standing in a relaxed posi- 
 tion, without su'pport, which was obtained in 25 experimental days from 
 March 20 to May 14, 1914, this value being 1.25 calories per minute; 
 (2) the average resting, lying value of 51 experiments in 1911-12 by 
 Benedict and Cathcart, this being 1.17 calories per minute, referred to 
 here as lying value I; and (3) the resting lying basal value found as an 
 average of four experimental periods on April 18, 1914, namely, 1.11 
 calories per minute, referred to here as lying value II. The subject in 
 all these experiments was without food. 
 
 EXPERIMENTS WITHOUT FOOD. 
 
 All of the experiments without food for subject II have been brought 
 together in table 14 and are arranged chronologically, the only dis- 
 turbance in this order being for the experiment on May 13. The change 
 in position for the experiment of May 13 was made to bring the results 
 more nearly in the order of the increasing velocity of walking. The 
 heat-output per horizontal kilogrammeter for each experiment has been 
 computed in gram calories on the three base-Unes previously cited. 
 The results using a basal value obtained with the subject standing in a 
 relaxed position are given in column g; those with an average basal 
 value obtained by Benedict and Cathcart in their experiments between 
 December 7, 1911, and April 16, 1912 (lying value I), are given in col- 
 umn h; and those with a basal value obtained from the special experi- 
 ment made by Mr. L. E. Emmes on April 18, 1914 (lying value II), 
 are given in column i. Inasmuch as the values for the subject standing 
 relaxed were determined specifically for this research, and hence in 
 this particular, at least, are more appropriate than the other basal 
 values used, we shaU lay great stress in our discussion upon the incre- 
 ments computed from this base-line. 
 
 A general inspection of the values in column g shows that there is 
 a tendency towards constancy until May 4, at which time the rate of 
 walking first exceeded 100 meters per minute. Considering the 
 experiments when the speed was below 100 meters per minute, we 
 find 57 periods with speeds ranging from 56 to 93.3 meters inclusive, 
 the average speed being 71.5 meters per minute and the energy require- 
 ment for one horizontal kilogrammeter averaging 0.493 gram-calorie. 
 An inspection of the table shows considerable variation above and 
 below these average figures in isolated cases as, for instance, on April 
 15, when in one period the heat output per horizontal kilogrammeter 
 was 0.603 gram-calorie. On the other hand the value of 0.555 gram- 
 calorie is exceeded but six times and the individual values fall below 
 0,45 gram-calorie likewise only six times out of the 57 periods. It is 
 thus clear that the value 0.493 gram-calorie is distinctly representative 
 of the heat requirements for moving 1 kilogram 1 meter at speeds 
 ranging from 56 to 93.3 meters per minute. 
 
DISCUSSION OF BESULTS. 
 
 83 
 
 Table 14. — Increase in 
 
 heat-output during walking 
 
 in experiments mth subject II ivithmUfood. 
 
 
 to) 
 
 (b) 
 
 to) 
 
 to) 
 
 Heat-output toomputed). 
 
 to) 
 
 Total 
 
 per 
 
 minute. 
 
 (/) 
 
 Increase 
 
 above 
 
 standing 
 
 relaxed. 
 
 Increase per kilogram- 
 
 Date and condi- 
 tions of experi- 
 ments. 
 
 Body- 
 weight 
 with 
 cloth- 
 ing. 
 
 Dis- 
 tance 
 per 
 minute. 
 
 Horizon- 
 tal kilo- 
 gram- 
 meters 
 
 toXft). 
 
 Raising 
 of body 
 
 per 
 minute. 
 
 meter (gram-calorie.) 
 
 to) 
 Above 
 standing 
 relaxed 
 
 to) 
 
 Above 
 lying. 
 
 (i) 
 
 Above 
 lying, 
 
 
 
 
 
 
 
 
 (/-i-c). 
 
 I. 
 
 II. 
 
 1914 
 
 
 
 
 
 
 
 
 
 
 Standing, re- 
 
 kUos. 
 
 meters. 
 
 
 meters. 
 
 cals. 
 
 cals. 
 
 gm.-cal. 
 
 gm.-cal. 
 
 gm.-cal. 
 
 laxed» 
 
 
 
 
 
 1.25 
 
 
 
 
 
 Lying, P 
 
 
 
 
 
 1.17 
 
 
 
 
 
 Lying, IP 
 
 
 
 
 
 1.11 
 
 
 
 
 
 Walking: 
 
 
 
 
 
 
 
 
 
 
 Mar. 20.. 
 
 72.4 
 
 (*) 
 
 
 2.61 
 
 3.48 
 
 2.23 
 
 
 
 
 24.. 
 
 72.0 
 
 60.6 
 
 4,363 
 
 1.09 
 
 3.74 
 
 2.49 
 
 0.571 
 
 o!689 
 
 o!663 
 
 25.. 
 
 72.6 
 
 60.6 
 
 4,363 
 
 1.77 
 
 3.40 
 
 2.16 
 
 .493 
 
 .611 
 
 .626 
 
 26.. 
 
 72.0 
 
 62.7 
 
 4,514 
 
 3.09 
 
 3.42 
 
 2.17 
 
 .481 
 
 .498 
 
 .612 
 
 27.. 
 
 72.0 
 
 57.6 
 
 4,147 
 
 2.09 
 
 3.16 
 
 1.90 
 
 .468 
 
 .477 
 
 .492 
 
 31.. 
 
 72.0 
 
 57.2 
 
 4,118 
 
 2.01 
 
 3.27 
 
 2.02 
 
 .491 
 
 .510 
 
 .626 
 
 Apr. 1.. 
 
 72.0 
 
 59.3 
 
 4,269 
 
 2.22 
 
 3.36 
 
 2.11 
 
 .494 
 
 .513 
 
 .527 
 
 3.. 
 
 72.0 
 
 76.2 
 
 5,486 
 
 2.38 
 
 4.39 
 
 3.14 
 
 .572 
 
 .587 
 
 .598 
 
 6.. 
 
 72.0 
 
 57.8 
 
 4,161 
 
 1.78 
 
 3.32 
 
 2.07 
 
 .498 
 
 .517 
 
 .631 
 
 
 
 56.8 
 
 4,090 
 
 1.83 
 
 3.26 
 
 2.00 
 
 .489 
 
 .609 
 
 .623 
 
 
 
 56.0 
 
 4,032 
 
 1.91 
 
 3.20 
 
 1.95 
 
 .484 
 
 .603 
 
 .618 
 
 7.. 
 
 72.0 
 
 59.6 
 
 4,291 
 
 1.98 
 
 3.63 
 
 2.28 
 
 .631 
 
 .650 
 
 .664 
 
 
 
 58.2 
 
 4,190 
 
 1.95 
 
 3.19 
 
 1.94 
 
 .463 
 
 .482 
 
 .496 
 
 8.. 
 
 72.0 
 
 76.1 
 
 5,479 
 
 3.01 
 
 4.45 
 
 3.20 
 
 .584 
 
 .699 
 
 .610 
 
 
 
 77.6 
 
 5,587 
 
 2.81 
 
 3.97 
 
 2.72 
 
 .487 
 
 .501 
 
 .612 
 
 
 
 78.3 
 
 6,637 
 
 2.85 
 
 3.89 
 
 2.64 
 
 .468 
 
 .483 
 
 .493 
 
 9.. 
 
 72.0 
 
 59.3 
 
 4,269 
 
 1.92 
 
 3.40 
 
 2.15 
 
 .604 
 
 .622 
 
 .536 
 
 
 
 58.8 
 
 4,233 
 
 2.05 
 
 3.20 
 
 1.95 
 
 .461 
 
 .480 
 
 .494 
 
 
 
 59.0 
 
 4,248 
 
 1.98 
 
 3.36 
 
 2.11 
 
 .497 
 
 .516 
 
 .530 
 
 10.. 
 
 72.0 
 
 77.3 
 
 5,566 
 
 2.77 
 
 4.09 
 
 2.84 
 
 .610 
 
 .525 
 
 .636 
 
 
 
 78.9 
 
 5,681 
 
 3.21 
 
 4.09 
 
 2.84 
 
 .500 
 
 .614 
 
 .525 
 
 14.. 
 
 71.9 
 
 61.7 
 
 4,436 
 
 2.45 
 
 3.43 
 
 2.18 
 
 .491 
 
 .609 
 
 .523 
 
 
 
 62.1 
 
 4,465 
 
 2.34 
 
 3.28 
 
 2.03 
 
 .456 
 
 .473 
 
 .486 
 
 
 
 62.4 
 
 4,487 
 
 2.37 
 
 3.26 
 
 2.01 
 
 .448 
 
 .466 
 
 .479 
 
 15.. 
 
 71.5 
 
 77.2 
 
 5,520 
 
 3.33 
 
 4.58 
 
 3.33 
 
 .603 
 
 .618 
 
 .629 
 
 
 
 79.4 
 
 5,677 
 
 3.52 
 
 4.02 
 
 2.77 
 
 .488 
 
 .502 
 
 .613 
 
 
 
 80.2 
 
 5,734 
 
 3.49 
 
 4.04 
 
 2.79 
 
 .487 
 
 .501 
 
 .611 
 
 16.. 
 
 71.5 
 
 61.9 
 
 4,426 
 
 2.38 
 
 3.16 
 
 1.91 
 
 .432 
 
 .460 
 
 .463 
 
 
 
 62.3 
 
 4,454 
 
 2.37 
 
 3.22 
 
 1.97 
 
 .442 
 
 .460 
 
 .474 
 
 
 
 61.8 
 
 4,419 
 
 2.20 
 
 3.21 
 
 1.96 
 
 .444 
 
 .462 
 
 .475 
 
 17.. 
 
 71.5 
 
 76.6 
 
 6,477 
 
 3.36 
 
 4.36 
 
 3.11 
 
 .568 
 
 .582 
 
 .593 
 
 
 
 78.1 
 
 5,584 
 
 3.45 
 
 3.94 
 
 2.69 
 
 .482 
 
 .496 
 
 .507 
 
 
 
 79.3 
 
 6,670 
 
 3.80 
 
 4.14 
 
 -2.89 
 
 .510 
 
 .624 
 
 .634 
 
 21.. 
 
 70.5 
 
 60.8 
 
 4,287 
 
 2.32 
 
 3.13 
 
 1.88 
 
 .439 
 
 .467 
 
 .471 
 
 22.. 
 
 70.5 
 
 76.8 
 
 5,415 
 
 3.33 
 
 3.91 
 
 2.66 
 
 .491 
 
 .506 
 
 .617 
 
 
 
 78.6 
 
 6,642 
 
 3.44 
 
 3.97 
 
 2.72 
 
 .491 
 
 .505 
 
 .616 
 
 
 
 79.2 
 
 6,684 
 
 3.42 
 
 3.94 
 
 2.69 
 
 .482 
 
 .496 
 
 .607 
 
 23.. 
 
 — _ ^ — 
 
 70.6 
 
 61.1 
 
 {') 
 
 4,308 
 
 2.53 
 2.46 
 
 3.27 
 3.17 
 
 2.02 
 1.92 
 
 .469 
 
 .487 
 
 .501 
 
 3ee table 91, Bene- 
 
 'Average of periods "standing, relaxed" as shown in table 10, p. 71. 
 'Average of results with this subject from Dec. 7, 1911 to Apr. 16, 1912. 
 diet and Cathcart, Carnegie Inst. Wash. Pub. 187, 1913, p. 78.) 
 'Determined during four periods of an experiment on Apr. 18, 1914, the subject being without 
 
 food. 
 
 ^Probably at the rate of about 67 meters per minute. 
 'Probably at the rate of about 61 meters per minute. 
 
84 
 
 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 Table 14 — Increase in heat-output during walking in experiments with subject II 
 without /ood—Continued. 
 
 
 (a) 
 
 (6) 
 
 (c) 
 
 (d) 
 
 Heat-output (computed). 
 
 (e) 
 
 Total 
 
 per 
 
 minute 
 
 (/) 
 
 Increase 
 
 above 
 
 standing 
 
 relaxed. 
 
 Increase per kUogram- 
 
 Date and condi- 
 tions of experi- 
 ments. 
 
 Body- 
 weight 
 with 
 cloth- 
 ing. 
 
 Dis- 
 tance 
 per 
 minute 
 
 Horizon- 
 tal kilo- 
 gram- 
 meters 
 (aXb). 
 
 Raising 
 of body 
 
 per 
 minute 
 
 meter (gram-calorie). 
 
 (ff) 
 Above 
 standing 
 relaxed 
 
 (A) 
 Above 
 lying, 
 
 (i) 
 
 Above 
 lying, 
 
 
 
 
 
 
 
 
 C/+C). 
 
 I. 
 
 II. 
 
 1914 
 
 
 
 
 
 
 
 
 
 
 Walking — 
 
 
 
 
 
 
 
 
 
 
 Continued ; 
 
 kilos. 
 
 meters. 
 
 
 meters. 
 
 cats. 
 
 cats. 
 
 gm.-cal. 
 
 gm.-cal. 
 
 gm.-cal. 
 
 Apr. 24.. 
 
 70.5 
 
 76.4 
 
 5,386 
 
 3.60 
 
 3.79 
 
 2.54 
 
 .472 
 
 .486 
 
 .498 
 
 
 
 78.4 
 
 5,527 
 
 3.69 
 
 3.94 
 
 2.69 
 
 .487 
 
 .501 
 
 .512 
 
 25.. 
 
 69.9 
 
 63.0 
 
 4,404 
 
 2.65 
 
 3.21 
 
 1.96 
 
 .445 
 
 .463 
 
 • .477 
 
 
 
 64.0 
 
 4,474 
 
 2.69 
 
 3.30 
 
 2.05 
 
 .458 
 
 .476 
 
 .489 
 
 27.. 
 
 70.5 
 
 73.5 
 
 5,182 
 
 3.25 
 
 3.77 
 
 2.52 
 
 .486 
 
 .502 
 
 .513 
 
 
 
 78.1 
 
 5,506 
 
 3.64 
 
 3.97 
 
 2.72 
 
 .494 
 
 .509 
 
 .519 . 
 
 28.. 
 
 70.5 
 
 78.2 
 
 5,513 
 
 3.41 
 
 4.04 
 
 2.79 
 
 .506 
 
 .521 
 
 .531 
 
 
 
 79.8 
 
 5,626 
 
 3.60 
 
 3.99 
 
 2.74 
 
 .487 
 
 .501 
 
 .512 
 
 
 
 80.0 
 
 5,640 
 
 3.53 
 
 4.06 
 
 2.81 
 
 .498 
 
 .512 
 
 .523 
 
 
 
 80.7 
 
 5,689 
 
 3.80 
 
 4.12 
 
 2.87 
 
 .504 
 
 .519 
 
 .529 
 
 
 
 80.4 
 
 5,668 
 
 3.33 
 
 4.40 
 
 3.15 
 
 .556 
 
 .570 
 
 .580 
 
 
 
 80.2 
 
 5,654 
 
 3.67 
 
 4.07 
 
 2.82 
 
 .499 
 
 .513 
 
 .524 
 
 
 
 80.2 
 
 5,654 
 
 3.80 
 
 4.14 
 
 2.89 
 
 .511 
 
 .525 
 
 .536 
 
 
 
 80.4 
 
 5,668 
 
 3.46 
 
 4.09 
 
 2.84 
 
 .501 
 
 .515 
 
 .526 
 
 May 13.. 
 
 71.5 
 
 82.6 
 
 5,906 
 
 3.76 
 
 4.13 
 
 2.88 
 
 .488 
 
 .501 
 
 .511 
 
 
 
 89.7 
 
 6,414 
 
 4.51 
 
 4.50 
 
 3.25 
 
 .507 
 
 .519 
 
 .529 
 
 
 
 80.1 
 
 5,727 
 
 3.29 
 
 3.94 
 
 2.69 
 
 .470 
 
 .484 
 
 .494 
 
 
 
 76.6 
 
 5,477 
 
 2.84 
 
 3.75 
 
 2.50 
 
 .456 
 
 .471 
 
 .482 
 
 
 
 93.3 
 
 6,671 
 
 5.25 
 
 4.72 
 
 3.47 
 
 .520 
 
 .532 
 
 .541 
 
 
 
 91.9 
 
 6,571 
 
 5.15 
 
 4.67 
 
 3.42 
 
 .520 
 
 .533 
 
 .542 
 
 4.. 
 
 71.7 
 
 114.5 
 
 8,210 
 
 6.43 
 
 6.71 
 
 5.46 
 
 .665 
 
 .675 
 
 .682 
 
 
 
 109.1 
 
 7,823 
 
 6.16 
 
 5.79 
 
 4.54 
 
 .580 
 
 .591 
 
 .598 
 
 
 
 102.0 
 
 7,313 
 
 5.88 
 
 5.42 
 
 4.17 
 
 .570 
 
 .581 
 
 .589 
 
 5.. 
 
 71.7 
 
 106.0 
 
 7,601 
 
 4,86 
 
 5.54 
 
 4.29 
 
 .564 
 
 .575 
 
 .583 
 
 
 
 102.6 
 
 7,356 
 
 5.82 
 
 5.33 
 
 4.08 
 
 .555 
 
 .566 
 
 .574 
 
 
 
 103.6 
 
 7,428 
 
 6.06 
 
 5.51 
 
 4.26 
 
 .574 
 
 .584 
 
 .592 
 
 6.. 
 
 71.7 
 
 140.7 
 
 10,088 
 
 9.76 
 
 10.23 
 
 8.98 
 
 .890 
 
 .898 
 
 .904 
 
 
 
 139.6 
 
 10,009 
 
 8.90 
 
 10.38 
 
 9.13 
 
 .912 
 
 .920 
 
 .926 
 
 
 
 142.9 
 
 10,246 
 
 8.79 
 
 10.91 
 
 9.66 
 
 .943 
 
 .951 
 
 .956 
 
 10.. 
 
 72.3 
 
 145.5 
 
 10,519 
 
 5.37 
 
 10.99 
 
 9.74 
 
 .926 
 
 .934 
 
 .939 
 
 
 
 146.8 
 
 10,613 
 
 5.81 
 
 11.68 
 
 10.43 
 
 .983 
 
 .990 
 
 .996 
 
 
 
 146.6 
 
 10,598 
 
 8.02 
 
 11.00 
 
 9.75 
 
 .920 
 
 .928 
 
 .933 
 
 Running: 
 
 
 
 
 
 
 
 
 
 
 May 11.. 
 
 72.0 
 
 146.6 
 
 10,554 
 
 13.45 
 
 9.47 
 
 8.22 
 
 .779 
 
 .786 
 
 .792 
 
 
 
 146.7 
 
 10,562 
 
 13.89 
 
 9.57 
 
 8.32 
 
 .788 
 
 .795 
 
 .801 
 
 
 
 148.3 
 
 10,677 
 
 14.80 
 
 9.69 
 
 8.44 
 
 .790 
 
 .798 
 
 .804 
 
 12.. 
 
 72.0 
 
 147.1 
 
 10,591 
 
 15.40 
 
 10.80 
 
 9.55 
 
 .902 
 
 .909 
 
 .915 
 
 
 
 148.4 
 
 10,684 
 
 14.09 
 
 9.19 
 
 7.94 
 
 .743 
 
 .751 
 
 .756 
 
 
 
 148.1 
 
 10,663 
 
 15.40 
 
 9.80 
 
 8.55 
 
 .802 
 
 .809 
 
 .815 
 
 
 
 148.1 
 
 10,663 
 
 14.74 
 
 9.97 
 
 8.72 
 
 .818 
 
 .825 
 
 .831 
 
 
 
 148.7 
 
 10,706 
 
 15.37 
 
 10.06 
 
 8.81 
 
 .823 
 
 .830 
 
 .836 
 
 Walking: 
 
 
 
 
 
 
 
 
 
 
 May 14.. 
 
 71.5 
 
 146.4 
 
 10,467 
 
 7.59 
 
 11.23 
 
 9.98 
 
 .953 
 
 .961 
 
 .967 
 
 Running: 
 
 
 
 
 
 
 
 
 
 
 May 14.. 
 
 
 146.5 
 
 10,474 
 
 15.44 
 
 11.13 
 
 9.88 
 
 .943 
 
 .951 
 
 .957 
 
 
 
 147.2 
 
 10,524 
 
 12.47 
 
 9.15 
 
 7.90 
 
 .751 
 
 .758 
 
 .764 
 
 
 
 147.6 
 
 10,553 
 
 12.34 
 
 9.26 
 
 8.01 
 
 .759 
 
 .767 
 
 .772 
 
 
 
 148.1 
 
 10,588 
 
 11.09 
 
 9.66 
 
 8.41 
 
 .794 
 
 .802 
 
 .808 
 
 15.. 
 
 71.0 
 
 144.7 
 
 10,273 
 
 12.48 
 
 9.64 
 
 8.39 
 
 .817 
 
 .824 
 
 .830 
 
 
 
 148.4 
 
 10,536 
 
 12.14 
 
 9.67 
 
 8.42 
 
 .799 
 
 .807 
 
 .812 
 
 
 
 147.7 
 
 10,486 
 
 13.13 
 
 9.47 
 
 8.22 
 
 .784 
 
 .792 
 
 .797 
 
DISCUSSION OF RESULTS. 85 
 
 In two of the walking experiments without food, those of April 6 
 and 7, we were able to obtain electrocardiograms of the pulse of this 
 subject and the results are recordedintable4 (pp. 54 and 55). In previous 
 researches a striking uniformity has been found in the changes of the 
 metaboUsm and the pulse-rate, amounting at times to a distinct 
 percentage relationship between them. Such a uniformity was noted 
 by Benedict and Cathcart in their study of a bicycle rider when the 
 metaboUsm and pulse-rate during riding were compared with the 
 values obtained in the lying or sitting position. In this research, on 
 the contrary, the pulse-rate in the experiments of April 6 and 7 showed 
 a distinct lowering when the subject changed from the standing posi- 
 tion to walking, particularly in the experiment on April 7, notwith- 
 standing the fact that the total metaboUsm during walking increased 
 from 100 to 200 per cent above the basal metaboUsm of standing. 
 This lowering of the pulse-rate was so positive that it is difl&cult to 
 beUeve that any error was made in the measurements. Furthermore, 
 in the fourth period of the experiment on April 7, we find that the pulse- 
 rate with the subject standing after walking increased materially over 
 that during walking. The evidence thus impUes that when standing 
 still upon the treadmill, this subject had a much higher pulse-rate than 
 when he was walking at a slow speed. These records are entirely 
 contrary to our previous experience but the lowered pulse-rate during 
 walking has been confirmed by Professor H. Monmouth Smith, of the 
 Laboratory staff, in similar experiments with three other subjects, thus 
 estabUshing the fact. Further experimenting is now in progress and 
 the results will be incorporated in a subsequent report. 
 
 Influence of Velocity. 
 
 On all days subsequent to May 4, with the single exception of May 
 13, the speed of walking exceeded 100 meters per minute. At this 
 higher speed there was a distinctly higher energy requirement per 
 horizontal kilogrammeter. Thus, we have six periods when the rate 
 of walking was from 102 to 114.5 meters per minute and averaged 106.3 
 meters per minute. At this speed the average heat-output per hori- 
 zontal kilogrammeter was 0.585 gram-calorie, a material increase over 
 0.493 gram-calorie, the average heat-output for the lower speed. A 
 further grouping of the experiments is permissible when the speed 
 ranged from 139.6 to 148.7 meters per minute, as with this higher 
 speed a considerable increase is shown in the heat requirement per unit 
 of work. Some of the experiments in this group show that when the 
 subject ran instead of walked, the heat-output per horizontal kilo- 
 grammeter was lowered, although the rate of progression was prac- 
 tically the same; accordingly we may not advantageously draw average 
 values. In the two walking experiments on May 6 and 10 the speed 
 averaged 143.7 meters per minute and the heat per horizontal kilo- 
 grammeter 0.929 gram-calorie. In the first period of the experiment 
 
86 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 of May 14 the subject walked at the rate of 146.4 meters per minute, 
 with a heat-output of 0.953 gram-calorie per horizontal kilogrammeter. 
 
 In the four following periods the subject ran, although the speed 
 per minute was approximately the same as that in the walking period. 
 Nevertheless, the average heat-output per unit of work was materially 
 less, i. e., 0.812 gram-calorie. 
 
 It is thus apparent that the velocity had a very considerable influ- 
 ence upon the heat per unit of work when the subject was walking. 
 This confirms the earlier contention of Durig and his associates that the 
 heat required to move 1 kilogram 1 meter increases with the speed. 
 Furthermore, the method of progression, i. e., walking or running, had 
 likewise a very considerable influence on the heat per unit of work. 
 Both of these factors require subsequent elaboration. 
 
 Comparison of the Heat peh Unit of Work as Computed fbom Difpehent Base-linhb. 
 
 The last three columns of table 14 permit the comparison of the heat 
 per unit of work, i. e., per horizontal kilogranuneter, as computed 
 from the three base-hnes. Instead of using the individual values in 
 table 14, however, this comparison can better be made by using only 
 the average figures for the several groups presented in the foregoing 
 discussion on the influence of velocity. To find exactly the differ- 
 ences due to the selection of the base-line, we have therefore brought 
 together in table 15 a general average for all of the experiments without 
 food, both walking and running. The walking experiments are 
 divided into three groups, according to the speed at which the subject 
 walked. Thus we have 57 periods when the subject walked at a slow 
 rate ranging from 56 to 93.3 meters and averaging 71.5 meters, 6 periods 
 with a medium speed averaging 106.3 meters per minute, and 7 periods 
 with a high speed averaging 144.1 meters per minute. During the 
 running experiments, the speed averaged 147.5 meters per minute. 
 The values showing the heat-output per unit of work done, using the 
 Benedict and Cathcart basal value (lying I), are given in column 6, 
 those for which the basal value of April 18, 1914, was employed (lying II) 
 in column c, and those calculated from the basal value found with the 
 subject standing in the relaxed position are given in column d. 
 
 With the large amounts of heat involved in the walking experiments 
 the relatively sUght differences appearing in these three base-Unes 
 should not have a very great effect. It is obvious, moreover, that the 
 greater the amount of work done in walking, the less will be the per- 
 centage change due to the selection of the base-line. Thus we note that 
 the heat per unit of work done at the slow speed is lower when the 
 standing basal value is employed than it is when the lying value II 
 (that of April 18, 1914) is used, the difference between the two averages 
 being approximately 6 per cent. With the increase in the work 
 involved in walking at the moderate speed, the difference due to the 
 selection of the basal value becomes considerably less, i. e., 3 per cent, 
 
DISCUSSION OF RESULTS. 
 
 87 
 
 and finally with the large heat production incidental to walking at the 
 rate of 144.1 meters per minute, the difference between the calculations 
 with the two base-Unes becomes approximately only 1 .5 per cent. This 
 small difference likewise holds in the running experiments. The values 
 computed from the Benedict and Cathcart base-line show the same 
 general characteristics, although the difference between the two results 
 is smaller than with the basal value of April 18, 1914. 
 
 It thus appears that as the total amount of work increases it becomes 
 less important which of the three base-lines is used. For slow and 
 moderate speeds a possible difference of 3 to 6 per cent in the average 
 value of the heat per unit of work may be expected, while with the 
 highest speed this difference decreases to from 1 to 1.5 per cent. The 
 
 Table 16. — Comparison of heat-output during walking and running as referred to basal values 
 for the lying and standing positions. 
 
 [Experiments with subject II without food.] 
 
 Number of 
 periods. 
 
 Average 
 distance 
 
 per 
 minute 
 (meters) 
 
 (a) 
 
 Heat (computed) per hori- 
 zontal kilogrammeter 
 (gram-calorie). 
 
 Above 
 lying I' 
 
 Above 
 lying 11' 
 
 (0 
 
 Above 
 
 standing 
 
 relaxed' 
 
 (d) 
 
 Walking: 
 
 57 
 
 6 
 
 7 
 
 Running : 
 
 15 
 
 71.5 
 106.3 
 144.1 
 
 147.5 
 
 0.509 
 .595 
 .940 
 
 .814 
 
 0.521 
 .603 
 .946 
 
 .819 
 
 0.493 
 .585 
 .932 
 
 .806 
 
 'See table 14, p. 83, for explanation of basal values used. 
 
 importance of the selection of a basal value is therefore greatest when 
 the amount of walking to be performed is smallest, i. e., when the sub- 
 ject is walking at moderate speed. This is somewhat unfortunate, for 
 a large proportion of walking for exercise, for the carrying of burdens, 
 and in marching is usually done at a moderate speed. Since, however, 
 the basal values obtained with the subject standing in the relaxed 
 position were daily and accurately determined, and since there is such 
 a high degree of constancy in the standing relaxed values, we consider 
 that they may be properly used as the basal values for these compu- 
 tations. The figures obtained per unit of work on this basis may there- 
 fore be considered to represent the increased metaboUsm necessary to 
 move 1 kilogram 1 meter in a horizontal direction. 
 
 EXPERIMENTS WITH FOOD. 
 
 A large number of experiments following the ingestion of food were 
 made with subject II. The results of all these experiments are pre- 
 sented in table 16, the data being grouped arbitrarily according to the 
 preceding meal and especially according to the character of the diet. 
 
88 
 
 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 Table 16. — Increase in heat-oiUpvt during walking in experiments with, subject II 
 
 with food. 
 
 
 
 (a) 
 
 (6) 
 
 (c) 
 
 (d) 
 
 Heat-output (computed). 
 
 
 
 Increase over 
 
 
 
 Body 
 
 weigh 
 
 with 
 
 
 Horizon- 
 tal kilo- 
 gram- 
 
 
 
 standing. 
 
 Diet and date. 
 
 Condition. 
 
 t ^^^ 
 tance 
 
 Raising 
 of body 
 
 (e) 
 
 (/) 
 
 (0) 
 Per 
 
 
 
 cloth- 
 
 per 
 
 meters 
 
 per 
 
 Total 
 
 
 horizon- 
 
 
 
 ing. 
 
 minute. 
 
 (0X6). 
 
 minute. 
 
 per 
 minute. 
 
 Total. 
 
 tal kilo- 
 gram- 
 meter 
 
 1914 
 
 
 
 
 
 
 
 
 
 Breakfast. 
 
 
 kUos 
 
 meters. 
 
 
 meters. 
 
 cats. 
 
 caXs. 
 
 gm.-cal. 
 
 Not controlled: 
 
 Standing'. . 
 
 
 
 
 
 '1.43 
 
 
 
 Mar. 16 . . 
 
 Walking... 
 
 iiA 
 
 I Vi.Z 
 
 5^379 
 
 2^88 
 
 3.92 
 
 2.49 
 
 0.463 
 
 18.. 
 
 ....do 
 
 72. < 
 
 I 76.0 
 78.0 
 
 5,502 
 5,647 
 
 3.34 
 3.62 
 
 4.06 
 4.09 
 
 2.63 
 2.66 
 
 .478 
 .471 
 
 
 
 19.. 
 
 ....do 
 
 72.-: 
 72.^ 
 72.^ 
 
 t 74.9 
 
 y 57.9 
 
 1 57.9 
 
 57.5 
 
 5,423 
 4,192 
 4,192 
 4,163 
 
 3.16 
 3.11 
 2.74 
 S.61 
 
 4.21 
 3.74 
 3.40 
 3.74 
 
 2.78 
 2.31 
 1.97 
 2.31 
 
 .513 
 .551 
 .470 
 .555 
 
 21. . 
 
 do 
 
 23.. 
 
 ....do 
 
 
 
 28.. 
 
 ....do 
 
 72. ( 
 
 ) 59.4 
 
 4,277 
 
 2.52 
 
 t 3.48 
 
 2.05 
 
 .479 
 
 30. . 
 
 ....do 
 
 72. ( 
 72. ( 
 
 ) 58.5 
 ) 55.1 
 
 4,212 
 3,967 
 
 2.26 
 1.91 
 
 3.65 
 3.23 
 
 2.22 
 1.80 
 
 .527 
 .454- 
 
 Apr. 4.. 
 
 ....do 
 
 
 
 
 56.8 
 
 4,090 
 
 1.98 
 
 3.07 
 
 1.64 
 
 .401 
 
 
 
 
 56.2 
 
 4,046 
 
 1.87 
 
 3.24 
 
 1.81 
 
 .447 
 
 Controlled : 
 
 
 
 
 
 
 
 
 
 Carbohydrate 
 
 
 
 
 
 
 
 
 
 Apr. 29. . 
 
 Standing^. . 
 
 
 
 
 
 n.59 
 
 
 
 
 Walking... 
 
 76.5 
 
 ) 76.9 
 
 5^452 
 
 sies 
 
 4.31 
 
 2!72 
 
 .499 
 
 
 
 
 
 78.2 
 
 5,544 
 
 3.56 
 
 4.26 
 
 2.67 
 
 .482 
 
 
 
 
 
 79.5 
 
 5,637 
 
 3.52 
 
 4.20 
 
 2.61 
 
 .463 
 
 
 
 
 
 80.9 
 
 5,736 
 
 3.74 
 
 4.07 
 
 2.48 
 
 .432 
 
 
 
 
 
 81.1 
 
 5,750 
 
 3.76 
 
 4.09 
 
 2.50 
 
 .435 
 
 
 
 
 
 80.9 
 
 5,736 
 
 3.29 
 
 3.87 
 
 2.28 
 
 .397 
 
 
 
 
 
 81.0 
 
 5,743 
 
 3.73 
 
 4.10 
 
 2.51 
 
 .437 
 
 
 
 
 
 81.1 
 
 5,750 
 
 3.69 
 
 3.98 
 
 2.39 
 
 .416 
 
 Lunch. 
 
 
 
 
 
 
 
 
 
 Not controlled: 
 
 Standing'. . 
 
 
 
 
 
 n.55 
 
 
 
 Mar. 16. . 
 
 Walkine... 
 
 72^ 
 
 t 75!3 
 
 5,452 
 
 3.17 
 
 3.99 
 
 2.44 
 
 !448 
 
 18.. 
 
 ....do 
 
 72.' 
 
 t 76.3 
 
 5,524 
 
 3.75 
 
 4.02 
 
 2.47 
 
 .447 
 
 19.. 
 
 ....do 
 
 72.' 
 
 t 74.9 
 
 5,423 
 
 3.55 
 
 4.09 
 
 2.54 
 
 .468 
 
 20.. 
 
 ....do 
 
 72.' 
 
 t 52.7 
 
 3,815 
 
 2.39 
 
 3.16 
 
 1.61 
 
 .422 
 
 21.. 
 
 ....do 
 
 72.' 
 72. ( 
 72. ( 
 72. ( 
 
 t 52.8 
 ) 62.7 
 ) 61.1 
 ) 60.7 
 
 3,823 
 4,514 
 4,399 
 4,370 
 4,219 
 
 2.59 
 
 .81 
 
 1.50 
 
 2.30 
 
 3.40 
 3.99 
 3.64 
 3.67 
 
 1.85 
 2.44 
 2.09 
 2.12 
 
 .484 
 .541 
 .475 
 .485 
 
 24. . 
 
 do 
 
 25.. 
 
 do 
 
 26.. 
 
 do 
 
 27.. 
 
 ....do 
 
 72. ( 
 
 ) 58.6 
 
 2.15 
 
 3.62 
 
 2.07 
 
 .491 
 
 28.. 
 
 ....do 
 
 72. ( 
 
 ) 59.3 
 
 4,270 
 
 2.12 
 
 3.81 
 
 2.26 
 
 .529 
 
 30.. 
 
 ....do 
 
 72. ( 
 
 ) 58.5 
 
 4,212 
 
 2.40 
 
 3.59 
 
 2.04 
 
 .484 
 
 
 
 
 57.3 
 
 4,126 
 
 2.24 
 
 3.53 
 
 1.98 
 
 .480 
 
 31.. 
 
 ....do 
 
 72!( 
 
 ) 57.7 
 
 4,154 
 
 1.72 
 
 3.53 
 
 1.98 
 
 .477 
 
 Apr. 3 . . 
 
 ....do 
 
 72. ( 
 
 ) 57.0 
 
 4,104 
 
 2.02 
 
 3.44 
 
 1.89 
 
 .461 
 
 
 
 
 77.0 
 
 5,544 
 
 2.84 
 
 4.68 
 
 3.13 
 
 .565 
 
 
 
 
 78.9 
 
 5,681 
 
 3.38 
 
 4.47 
 
 2.92 
 
 .514 
 
 4.. 
 
 ....do 
 
 72!( 
 
 ) 54.4 
 
 3,917 
 4,183 
 
 2.05 
 
 3.51 
 
 1.96 
 
 .500 
 
 
 
 
 58.1 
 
 2.21 
 
 3.74 
 
 2.19 
 
 !524 
 
 'Average of all periods with subject standing after a light meal (breakfast). See table 11, p. 72. 
 
 'Standing, relaxed. Average of values obtained with similar diet on Apr. 25 and Apr. 27. See 
 table 12, p. 74. 
 
 ^Average of results obtained for all positions standing after lunch, diet not controlled. See 
 table 12, p. 74. 
 
DISCUSSION OF RESULTS. 
 
 89 
 
 Table 16. — Increase in heat^ouljmt during walking in experiments with subject II 
 with food — Continued . 
 
 
 
 (a) 
 
 (b) 
 
 (c) 
 
 (d) 
 
 Heat-output (computed). 
 
 
 Increase over 
 
 
 
 Body- 
 weight 
 with 
 
 
 Horizon- 
 tal kilo- 
 gram- 
 
 
 
 standing. 
 
 Diet and date. 
 
 Condition. 
 
 Dis- 
 tance 
 
 Raising 
 of body 
 
 (e) 
 
 (/) 
 
 (ff) 
 Per 
 
 
 
 doth- 
 ing. 
 
 per 
 minute. 
 
 meters 
 (aXh). 
 
 per 
 minute. 
 
 Total 
 
 per 
 minute. 
 
 Total. 
 
 horizon- 
 tal kilo- 
 gram- 
 meter 
 (/-^c). 
 
 1914 
 
 
 
 
 
 
 
 
 
 Lunch — Cont'd. 
 
 
 
 
 
 
 
 
 
 Gontrolled: 
 
 
 
 
 
 
 
 
 
 Protein: 
 
 
 kilos. 
 
 meters. 
 
 
 meters. 
 
 cats. 
 
 cats. 
 
 gm.-cal. 
 
 Apr. 6., 
 
 Standing. . 
 
 
 
 
 
 1.43 
 
 
 
 
 Walking... 
 
 72.6' 
 
 57.5 
 
 4,140 
 
 2^21 
 
 3.54 
 
 2;ii 
 
 isib 
 
 
 
 
 57.2 
 
 4,118 
 
 1.94 
 
 3.51 
 
 2.08 
 
 .505 
 
 
 
 
 56.3 
 
 4,054 
 
 1.81 
 
 3.46 
 
 2.03 
 
 .501 
 
 7.. 
 
 Standing. . 
 
 
 
 
 
 1.37 
 
 
 
 
 Walking... 
 
 72^0 
 
 58.8 
 
 4^234 
 
 i!78 
 
 3.59 
 
 2^22 
 
 .524 
 
 
 
 
 58.7 
 
 4,226 
 
 1.83 
 
 3.77 
 
 2.40 
 
 .568 
 
 
 
 
 56.9 
 
 4,097 
 
 1.82 
 
 3.41 
 
 2.04 
 
 .498 
 
 8.. 
 
 Standing . . 
 
 
 
 
 
 1.33 
 
 
 
 
 Walking... 
 
 72.0 
 
 76^9 
 
 5^536 
 
 2.50 
 
 4.28 
 
 2.95 
 
 .533 
 
 
 
 
 78.0 
 
 5,616 
 
 3.01 
 
 4.38 
 
 3.05 
 
 .543 
 
 
 
 
 79.2 
 
 5,702 
 
 2.70 
 
 4.46 
 
 3.13 
 
 .549 
 
 23.. 
 
 Standing. . 
 
 
 
 
 
 1.24 
 
 
 
 
 Walking... 
 
 70!5 
 
 6i.2 
 
 4^315 
 
 2.74 
 
 3.55 
 
 2.31 
 
 .535 
 
 
 
 
 61.6 
 
 4,343 
 
 2.57 
 
 3.44 
 
 2.20 
 
 .507 
 
 
 
 
 61.6 
 
 4,343 
 
 2.48 
 
 3.45 
 
 2.21 
 
 .509 
 
 
 
 
 61.7 
 
 4,350 
 
 2.63 
 
 3.45 
 
 2.21 
 
 .508 
 
 24.. 
 
 Standing . . 
 
 
 
 
 
 1.41 
 
 
 
 
 Walking... 
 
 70.5 
 
 77!o 
 
 5,428 
 
 3.74 
 
 4.05 
 
 2.64 
 
 .486 
 
 
 
 
 78.8 
 
 5,555 
 
 3.88 
 
 4.11 
 
 2.70 
 
 .486 
 
 
 
 
 80.0 
 
 5,640 
 
 3.84 
 
 4.26 
 
 2,85 
 
 .505 
 
 
 
 
 80.0 
 
 5,640 
 
 3.88 
 
 4.24 
 
 2.83 
 
 .502 
 
 May 5 . . 
 
 Standing^. . 
 
 
 
 
 
 11,36 
 
 
 
 
 Walking... 
 
 71 !7 
 
 112.6 
 
 8^073 
 
 7'69 
 
 6.34 
 
 4.98 
 
 .617 
 
 
 
 
 113.7 
 
 8,152 
 
 7.83 
 
 6.43 
 
 5.07 
 
 .622 
 
 
 
 
 106.0 
 
 7,600 
 
 6.40 
 
 5.89 
 
 4.53 
 
 .596 
 
 
 
 
 111.3 
 
 7,980 
 
 7.76 
 
 6.31 
 
 4.95 
 
 .620 
 
 May 10.. 
 
 Standing'. . 
 
 
 
 
 
 n.36 
 
 
 
 
 Walking... 
 
 72!3 
 
 146.5 
 
 10,592 
 
 7.83 
 
 11.05 
 
 9.69 
 
 .915 
 
 
 
 
 146.9 
 
 10,621 
 
 8.28 
 
 11.07 
 
 9.71 
 
 .914 
 
 Carbohydrate: 
 
 
 
 
 
 
 1.43 
 
 
 
 Apr. 9 . . 
 
 Standing . . 
 
 
 
 
 
 
 
 
 Walking . . . 
 
 72.0 
 
 59.4 
 
 4i277 
 
 i!95 
 
 3.48 
 
 2.05 
 
 .479 
 
 
 
 
 59.0 
 
 4,248 
 
 1.94 
 
 3.43 
 
 2.00 
 
 .471 
 
 
 
 
 58.8 
 
 4,234 
 
 1.94 
 
 3.53 
 
 2.10 
 
 .496 
 
 Apr. 10.. 
 
 Standing. . 
 
 
 
 
 
 1.47 
 
 
 
 
 Walking.. 
 
 72!o 
 
 78.0 
 
 5,616 
 
 3.01 
 
 4.70 
 
 3.23 
 
 .575 
 
 
 
 
 79.1 
 
 5,695 
 
 3.17 
 
 4.59 
 
 3.12 
 
 ,548 
 
 
 
 
 79.7 
 
 5,738 
 
 3.35 
 
 4.37 
 
 2.90 
 
 .505 
 
 14. 
 
 Standing . 
 
 
 
 
 
 1.42 
 
 
 
 
 Walking.. 
 
 7i!9 
 
 6i!2 
 
 4,400 
 
 2!38 
 
 3.40 
 
 i.98 
 
 .450 
 
 
 
 
 62.0 
 
 4,458 
 
 2.20 
 
 3.54 
 
 2.12 
 
 .476 
 
 
 
 
 62.2 
 
 4,472 
 
 2.27 
 
 3.47 
 
 2.05 
 
 .458 
 
 15. 
 
 Standing . 
 
 
 
 
 
 1.38 
 
 
 
 
 Walking . . 
 
 . 71.6 
 
 78!2 
 
 5^591 
 
 3!88 
 
 4.52 
 
 3.14 
 
 .562 
 
 
 
 
 80.1 
 
 5,727 
 
 3.72 
 
 4.41 
 
 3.03 
 
 .529 
 
 
 
 
 80.6 
 
 5,763 
 
 3.88 
 
 4.63 
 
 3.25 
 
 .564 
 
 I ^ . 
 
 iStandingi relaxed; average obtained on 6 days with protein diet (table 12). 
 
90 
 
 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 Table 16. — Increase in heat-output during walking in experiments mth subject II 
 vnth food — Continued. 
 
 
 
 (a) 
 
 (fc) 
 
 (c) 
 
 (d) 
 
 Heat-output (computed). 
 
 
 Increase over 
 
 
 
 
 
 
 
 
 standing. 
 
 Diet and date. 
 
 Condition. 
 
 Body- 
 weight 
 with 
 
 Dis- 
 tance 
 
 Horizon- 
 tal kilo- 
 gram- 
 
 Raising 
 of body 
 
 (e) 
 Total 
 
 
 
 (/) 
 
 (g) 
 
 Per 
 
 
 
 cloth- 
 ing. 
 
 per 
 niinute 
 
 meters 
 (oXfc). 
 
 per 
 minute 
 
 per 
 minute 
 
 Total. 
 
 horizon- 
 tal kUo- 
 gram- 
 meter 
 (f^c). 
 
 1914 
 
 
 
 
 
 
 
 
 
 Lunch — Cont'd. 
 
 
 
 
 
 
 
 
 
 Carbohydrate — 
 
 
 
 
 
 
 
 
 
 cont'd. 
 
 
 kUoa. 
 
 meters. 
 
 
 meters. 
 
 cats. 
 
 coils. 
 
 gm.-cal. 
 
 Apr, 25.. 
 
 Standing. . 
 
 
 
 
 
 1.58 
 
 
 
 
 Walkine.. 
 
 69.9 
 
 63.1 
 
 4^411 
 
 2.88 
 
 3.52 
 
 1.94 
 
 .'446 
 
 
 
 
 63.8 
 
 4,460 
 
 2.70 
 
 3.53 
 
 1.95 
 
 .437 
 
 
 
 
 63.7 
 
 4,453 
 
 2.85 
 
 3.49 
 
 1.91 
 
 .429 
 
 
 
 
 63.3 
 
 4,425 
 
 2.64 
 
 3.34 
 
 1.76 
 
 .398 
 
 27.. 
 
 Standing. . 
 
 
 
 
 
 1.61 
 
 
 
 
 Walking... 
 
 Tois 
 
 77.5 
 
 5,464 
 
 3.60 
 
 4.30 
 
 2.69 
 
 .492 ' 
 
 
 
 .... 
 
 78.9 
 
 5,562 
 
 3.56 
 
 4.02 
 
 2.41 
 
 .433 
 
 
 
 .... 
 
 79.8 
 
 5,626 
 
 3.88 
 
 4.24 
 
 2.63 
 
 .467 
 
 
 
 
 80.2 
 
 5,654 
 
 3.74 
 
 4.04 
 
 2.43 
 
 .430 
 
 May 4 . . 
 
 Standing^ . 
 
 
 
 
 
 '1.59 
 
 
 
 
 Walking... 
 
 7i;7 
 
 lis 14 
 
 sjisi 
 
 6!84 
 
 6.59 
 
 5.66 
 
 .615 
 
 
 
 
 112.3 
 
 8,052 
 
 7.88 
 
 6.46 
 
 4.87 
 
 .605 
 
 
 
 
 110.3 
 
 7,909 
 
 7.41 
 
 6.10 
 
 4.51 
 
 .570 
 
 6.. 
 
 Standing^ . 
 
 
 
 
 
 '1.59 
 
 
 
 
 Walking... 
 
 7i!7 
 
 143.6 
 
 10,253 
 
 7!82 
 
 10.73 
 
 9!i4 
 
 !89i 
 
 11.. 
 
 Standing!. 
 
 
 
 
 
 '1.59 
 
 
 
 
 Running. . . 
 
 72.0 
 
 148.7 
 
 10,706 
 
 13^95 
 
 9.50 
 
 7.91 
 
 !739 
 
 Fat; 
 
 
 
 
 
 
 
 
 
 Apr. 16.. 
 
 Standing . . 
 
 
 
 
 
 1.41 
 
 
 
 
 Walking... 
 
 71.5 
 
 61.6 
 
 4^405 
 
 2.49 
 
 3.35 
 
 1.94 
 
 .440 
 
 
 
 
 62.3 
 
 4,455 
 
 2.48 
 
 3.15 
 
 1.74 
 
 .391 
 
 
 
 
 62.2 
 
 4,447 
 
 2.24 
 
 3.43 
 
 2.02 
 
 .454 
 
 
 
 
 61.9 
 
 4,426 
 
 2.21 
 
 3.42 
 
 2.01 
 
 .454 
 
 17.. 
 
 Standing. . 
 
 
 
 
 
 1.36 
 
 
 
 
 Walking... 
 
 n.'s 
 
 77.6 
 
 5^548 
 
 3.96 
 
 4.06 
 
 2.76 
 
 .487 
 
 
 
 
 79.5 
 
 5,684 
 
 3.78 
 
 4.27 
 
 2.91 
 
 .512 
 
 
 
 
 80.0 
 
 5,720 
 
 3.85 
 
 4.56 
 
 3.20 
 
 .559 
 
 
 
 
 80.0 
 
 5,720 
 
 3.67 
 
 4.15 
 
 2.79 
 
 .488 
 
 21.. 
 
 Standing. . 
 
 
 
 
 
 1.42 
 
 
 
 
 Walking... 
 
 70.5 
 
 60 !4 
 
 4; 258 
 
 2.45 
 
 3.33 
 
 1.91 
 
 .449 
 
 
 
 
 60.6 
 
 4,272 
 
 2.56 
 
 3.43 
 
 2.01 
 
 .471 
 
 
 
 
 60.5 
 
 4,265 
 
 2.34 
 
 3.44 
 
 2.02 
 
 .474 
 
 
 
 
 60.5 
 
 4,265 
 
 2.23 
 
 3.43 
 
 2.01 
 
 .471 
 
 22.. 
 
 Standing. . 
 
 
 
 
 
 1.42 
 
 
 
 
 Walking... 
 
 70.5 
 
 77.3 
 
 5, '456 
 
 3.86 
 
 4.07 
 
 2.65 
 
 .486 
 
 
 
 
 78.7 
 
 5,548 
 
 3.86 
 
 4.24 
 
 2.82 
 
 .508 
 
 
 
 
 79.5 
 
 5,604 
 
 3.92 
 
 4.25 
 
 2.83 
 
 .505 
 
 
 
 
 
 79.7 
 
 5,619 
 
 3.84 
 
 4.18 
 
 2.76 
 
 .491 
 
 'Standing, relaxed. 
 
 Average of 
 
 values 
 
 obtained 
 
 with .sim 
 
 lar diet on Apr. 25 and 
 
 Apr. 27. 
 
 See table 12, p. 74. 
 
 
 
 
 
 
 
 
 
DISCUSSION OF RESULTS. 91 
 
 As we have already seen from the discussion in an earlier section/ 
 the metabolism in the standing relaxed position after the ingestion of 
 food was considerably greater than that obtained when the subject was 
 without food, this being due to the katabolic stimuh of the foodstuffs. 
 Of most importance, however, is the question whether the increment due 
 to walking is superimposed upon the increased katabohsm due to food 
 or whether this increment is lessened by the fact that the body is 
 previously stimulated to a greater katabolic activity. With a view to 
 studying the influence of variations in the intensity of the pre-walking 
 stimulation, certain of the diets were so controlled as to consist in 
 large part of one of the three principal food constituents, i. e., protein, 
 fat, or carbohydrate. With the experimental conditions and the impos- 
 sibility of controlling the subject's diet while he was outside of the 
 laboratory, it was impracticable to make a thorough study of this par- 
 ticular phase of the problem. Our data do not therefore present a 
 conclusive statement as to the influence of the special protein, fat, or 
 carbohydrate diets, but merely contribute to the interesting question 
 as to whether or not the increase in the katabohsm following the inges- 
 tion of food persists during increased muscular activity or if there be a 
 summation effect under these conditions. 
 
 Since we have seen not only from the work of previous investigators, 
 but from tables 14 and 15, that there is a marked influence upon the 
 heat per unit of work as the result of an increase in velocity, particu- 
 larly when the velocity is above 95 meters per minute, it seems prefer- 
 able to consider the data presented in table 16 from this point of view. 
 As in the experiments with this subject when no food was taken, here 
 again we find that in the greater number of the experiments the speed 
 varied from 52.7 to 81.1 meters per minute, there being but 7 periods at 
 speeds ranging from 106 to 113.7 meters per minute, and but 4 periods 
 with a speed over 140 meters per minute. 
 
 Considering first the experiments at the lower speed, we find that 
 91 periods are available for study. The average velocity diu-ing these 
 periods was 68.2 meters per minute and the heat per unit of work done, 
 i. e., per horizontal kilogrammeter, was 0.486 gram-calorie. It will be 
 seen from the table that the standing basal value for the total heat- 
 output per minute in the experiments with food ranged from 1.24 to 
 1.61 calories per minute, averaging considerably above those obtained 
 when the subject was standing in the post-absorptive condition. On 
 the other hand, since the average value per unit of work done in 57 
 periods without food was 0.493 gram-calorie and the average of 91 
 periods with food was 0.486 gram-calorie, it is clear that the increase 
 over the basal metabolism was the same in both instances; in other 
 words, the increment due to the work of forward progression was 
 
 'See p. 75. 
 
92 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 constant, irrespective of whether the subject was with or without food, 
 this being true for subject II with the rate of speed varying from 52.7 
 to 93.3 meters per minute. 
 
 At moderate speeds above 100, we have seven periods with food in 
 which the velocity varied from 106 to 113.7 meters per minute, the 
 average speed being 111.4 meters per minute, and the average output of 
 heat per unit of work done 0.606 gram-calorie. Certain difficulties 
 appear when an attempt is made to compare the results of these 
 periods with food with periods without food. First, the speed per 
 minute without food was 106.3 meters and that with food 111.4 meters, 
 this being a perceptible increase. Second, but few periods are available 
 for comparison either with or without food, there being but 7 for the 
 former and 6 for the latter. If we make such a comparison, however, 
 we find that with food the heat per unit of work is 0.606 gram-calorie, 
 while that without food was only 0.585 gram-calorie. It is probably 
 not possible to attribute this increase in the heat-output per unit of 
 work solely to the increase of 5 per cent in the speed, and we can only 
 state that with speeds averaging 111.4 meters per minute the increase 
 in the heat per horizontal kilogrammeter with food is perceptibly 
 greater than that with food at a speed of 68.2 meters per minute. 
 
 The comparison becomes even more difficult when we consider the 
 experiments with the highest speeds, namely, those of 140 meters per 
 minute and over. Here we have but 4 periods with food, with the 
 speed ranging from 143 to 148.7 meters per minute and an average 
 speed of 146.3 meters per minute. The comparison is still further 
 comphcated by the fact that in one of these four periods the subject 
 was running. The average heat-output per unit of work done for the 
 three walking periods was 0.907 gram-calorie and the value found for 
 the one period with the subject running was 0.739 gram-calorie, a 
 value much less than that obtained with the subject walking. 
 
 We may thus say that all of the observations made after the taking 
 of food are completely in accord with those made when no food was 
 taken, i. e., an increase in the energy per unit of work done as the speed 
 increased and a considerably less energy per unit of work done when 
 the subject was running as compared with that when he was walking. 
 An analysis of the processes of running and walking and the character 
 of the steps is necessary to interpret these differences intelhgently.^ 
 
 Electrocardiograms of the pulse-rate were obtained in a few of the 
 experiments following the ingestion of food, namely, those of April 4, 
 6, and 7.^ These records show the same discrepancy between the pulse- 
 rate and the metabolism as was found in the experiments without food.* 
 
 'See p. 98. *See table 4, pp. 54 and 55. 'See p. 85. 
 
DISCUSSION OF RESULTS. 
 
 93 
 
 INFLUENCE OF THE CHARACTER OF DIET ON THE HEAT-OUTPUT PER UNIT 
 
 OF WORK. 
 
 While from the general observations of the metabolism with and 
 without food the inference was properly drawn that there was no 
 material increase in the heat-output per unit of work in the food 
 periods, nevertheless certain of the experiments permit a more detailed 
 examination of this point since a reasonably satisfactory grouping of 
 the results may be made upon the basis of the character of the diet. 
 The experimental plan as originally outlined called for a series of 
 walking experiments at each of the three standard speeds with diets 
 containing a preponderance of each of the three principal nutrients. 
 
 The average figures representing fhe heat per unit of work with the 
 three diets and the three speeds are collected in table 17. In this table 
 the average speed for the different groups is given, as the speed per 
 minute, especially with the low speed, was not exactly the same for the 
 three diets. Only the walking experiments are considered in this 
 connection, none of the running experiments being included. 
 
 Table 17 — Influen:: jj charader of diet on the fieat-output per horizontal kilogranvmeter during 
 walking experiments with subject II. 
 
 Character of diet. 
 
 Low speed. 
 
 Moderate speed. 
 
 High speed. 
 
 Meters. 
 
 Gm.-eal. 
 
 Meters. 
 
 Gm.-oal. 
 
 Meters. 
 
 Gm.-cal. 
 
 Carbohydrate 
 
 Protein 
 
 73.2 
 67.1 
 70.1 
 
 0.471 
 .516 
 
 .478 
 
 112.0 
 110.9 
 
 0.597 
 .614 
 
 143.0 
 146.7 
 
 0.891 
 .915 
 
 Fat . .■ 
 
 
 Aside from the generally increasing value of the heat per unit of 
 work as the speed increases, which is clearly shown in table 17, we 
 note, in comparing the values obtained with the different diets, a dis- 
 tinctly higher, although not striking, increase in the heat per unit of 
 work with the protein diet as compared with the carbohydrate diet, 
 this increase being approximately 9 per cent at the low speed and 3 per 
 cent at the moderate and high speeds. With the fat diet the com- 
 parison was made only with the low speed, and we find that the heat- 
 output per unit of work was essentially the same as that with the car- 
 bohydrate diet and measurably less than was obtained with the protein 
 diet. The general impression derived from the comparison of all the 
 experiments with subjects I stnd II was that the heat per unit of work 
 was practically independent of the taking of food. It appears from the 
 foregoing discussion, however, that this conclusion should be slightly 
 modified when diets containing large quantities of protein are con- 
 sidered, for the data in table 17 indicate that with such a diet a slightly 
 higher heat-output per unit of work may be expected. 
 
94 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 INFLUENCE OF FATIGUE UPON THE HEAT-OUTPUT PEE UNIT OF WORK. 
 
 Many of our experiments were made with a sufficient number of con- 
 secutive walking periods to permit a study of the heat per unit of work 
 done under conditions of accumulated work. The average length of 
 the walking period was 14 minutes. The distance traveled in a period 
 in the prolonged walking experiments varied from 800 to 1,200 meters, 
 and the subject walked not only diu-ing the experimental periods, when 
 the gaseous metaboUsm was being measured, but also between these 
 periods. When, therefore, the experiment consisted of four or more 
 experimental periods, it will be seen that the continuous walking would 
 amount frequently to several kilometers, thus providing conditions for 
 studying the effect of fatigue. In relatively few of these experiments, 
 however, was there substantial evidence of extreme fatigue. 
 
 The results of the observations in which there were four or more 
 periods of continuous walking are brought together in table 18. The 
 data given show the total distance walked by the subject prior to the 
 beginning of each experimental period^ and both the distance walked 
 per minute and the heat-output per unit of work performed during the 
 period. On two days, April 28 and 29, 1914, there were eight walking 
 periods; the total distance traversed each day in continuous walking 
 was approximately 23 kilometers. Throughout both experiments the 
 distance per minute remained essentially constant at about 80 meters; 
 we thus have ideal conditions for studying the influence of fatigue 
 resulting from continuous walking. On April 28, when the subject was 
 without food, there was no essential difference in the unit of work done 
 as the experiment progressed, although there were variations from 
 period to period. On the next day, a similar experiment was made 
 after food had been taken. The average heat per unit of work done 
 on this day was considerably less than that on April 28 and a general 
 tendency was also shown for the heat per unit of work done to decrease 
 as the work progressed. Inspection of the values found for another 
 experiment of 6 periods on May 13, when the subject was without food, 
 shows more or less fluctuation in the values obtained for the heat per 
 unit of work done, but there is no uniformity in the changes and, 
 indeed, the values are somewhat greater in the last periods than in the 
 earlier periods. With the experiments having only four periods, in 
 which the total distance walked prior to the last period ranged from 
 8 to 12 kilometers, we find that on certain days there was a tendency 
 for the heat per unit of work to decrease as the walking progressed and 
 on other days to increase, but in the majority of the experiments there 
 was no regularity in the variations. 
 
 From the data given in table 18, we may conclude that there may be 
 noticeable differences in the absolute heat per unit of work done on 
 different days, a point particularly brought out in the experiments of 
 
 'For total distance walked, aee table 4, pp. 56 to 60. 
 
DISCUSSION OF RESULTS. 
 
 95 
 
 April 28 and April 29. Nevertheless, there is no definitely uniform 
 influence of prolonged walking upon the efficiency for horizontal 
 movement shown by this subject and the heat per unit of work after he 
 had walked 20 kilometers is as liable to be lower than the initial value 
 as it is to be higher. In other words, in this series of experiments, the 
 measured metabolism agrees perfectly with the subjective impression 
 that there was not a sufficient degree of fatigue to affect the comfort 
 
 Table 18. — Heat-outpiU per unit of work during prolonged walking in experiments with subject II . 
 
 
 Distance walked. 
 
 Heat 
 
 
 Distance walked. 
 
 Heat 
 
 
 
 
 (com- 
 puted) 
 
 
 
 
 (com- 
 puted) 
 
 
 
 
 
 
 
 Date. 
 
 Total to 
 
 Per 
 
 per hori- 
 zontal 
 
 Datel 
 
 Total to 
 
 Per 
 
 per hori- 
 zontal 
 
 
 beginning 
 
 minute 
 during 
 period. 
 
 kilo- 
 
 
 beginning 
 
 minute 
 during 
 period. 
 
 kilo- 
 
 
 of period.' 
 
 gram- 
 meter.' 
 
 
 of period.' 
 
 gram- 
 meter.* 
 
 1914 
 
 
 
 
 1914 
 
 
 
 
 Without food: 
 
 meters. 
 
 meters. 
 
 gm.-cal. 
 
 With food: 
 
 meters. 
 
 meters. 
 
 gm.-cal. 
 
 Apr. 28. . . 
 
 382 
 
 78.2 
 
 0.506 
 
 Apr. 29.. 
 
 650 
 
 76.9 
 
 0.499 
 
 
 3,322 
 
 79.8 
 
 .487 
 
 
 3,519 
 
 78.2 
 
 .482 
 
 
 6,316 
 
 80.0 
 
 .498 
 
 
 6,585 
 
 79.5 
 
 .463 
 
 
 9,538 
 
 80.7 
 
 .504 
 
 
 9,699 
 
 80.9 
 
 .432 
 
 
 13,062 
 
 80.4 
 
 .556 
 
 
 12,615 
 
 81.1 
 
 .435 
 
 
 16,416 
 
 80.2 
 
 .499 
 
 
 15,547 
 
 80.9 
 
 .397 
 
 
 19,033 
 
 80.2 
 
 .511 
 
 
 18,662 
 
 81.0 
 
 .437 
 
 
 22,479 
 
 80.4 
 
 .501 
 
 
 21,676 
 
 81.1 
 
 .416 
 
 May 13... 
 
 521 
 
 82.6 
 
 .488 
 
 Apr. 22.. 
 
 368 
 
 77.3 
 
 .486 
 
 
 3,993 
 
 89.7 
 
 .507 
 
 
 3,452 
 
 78.7 
 
 .508 
 
 
 7,737 
 
 80.1 
 
 .470 
 
 
 7,067 
 
 79.5 
 
 .505 
 
 
 11,391 
 
 76.6 
 
 .456 
 
 
 10,345 
 
 79.7 
 
 .491 
 
 
 16,413 
 
 93.3 
 
 .520 
 
 Apr. 23.. 
 
 348 
 
 61.2 
 
 .535 
 
 
 20,527 
 
 91.9 
 
 .520 
 
 
 2,723 
 
 61.6 
 
 .507 
 
 With food: 
 
 
 
 
 
 5,512 
 
 61.6 
 
 .509 
 
 Apr. 16... 
 
 303 
 
 61.6 
 
 .440 
 
 
 7,976 
 
 61.7 
 
 .508 
 
 
 2,557 
 
 62.3 
 
 .391 
 
 Apr. 24.. 
 
 354 
 
 77.0 
 
 .486 
 
 
 5,901 
 
 62.2 
 
 .454 
 
 
 2,879 
 
 78.8 
 
 .486 
 
 
 9,424 
 
 61.9 
 
 .454 
 
 
 5,541 
 
 80.0 
 
 .505 
 
 Apr. 17..-. 
 
 507 
 
 77.6 
 
 .487 
 
 
 8,295 
 
 80.0 
 
 .502 
 
 
 3,945 
 
 79.5 
 
 .512 
 
 Apr. 25.. 
 
 323 
 
 63.1 
 
 .440 
 
 
 7,572 
 
 80.0 
 
 .559 
 
 
 2,330 
 
 63.8 
 
 .437 
 
 
 12,266 
 
 80.0 
 
 .488 
 
 
 5,122 
 
 63.7 
 
 .429 
 
 Apr. 21... 
 
 307 
 
 60.4 
 
 .449 
 
 
 8,125 
 
 63.3 
 
 .398 
 
 
 2,658 
 
 60.6 
 
 .471 
 
 Apr. 27. . 
 
 372 
 
 77.5 
 
 .492 
 
 
 5,374 
 
 60.5 
 
 .474 
 
 
 2,905 
 
 78.9 
 
 .433 
 
 
 8,615 
 
 60.5 
 
 .471 
 
 
 5,693 
 9,366 
 
 79.8 
 80.2 
 
 .467 
 .430 
 
 'For total distance walked, see table 4, pp. 56 to 60. 
 'Calculated for each period from the increment above values obtained with the subject standing 
 relaxed. See tables 14 and 16, pp. 83 and 88. 
 
 of the subject or his metaboUsm and that at the speed used throughout 
 these tests, namely, 80 meters per minute, walking may be done for 
 many kilometers without affecting the efficiency of the body for loco- 
 motion in a forward direction. 
 
 The stamina of the subject and his capacity for excessive work was 
 severely tested in the earlier research on prolonged bicycle riding, in 
 
96 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 which it was demonstrated that this subject had ridden the equivalent of 
 100 miles over average roads on an empty stomach; but in this research 
 it was impracticable to carry out prolonged endurance tests at high 
 rates of speed. Indeed, at the highest speed, i. e., 140 kilometers per 
 minute, it is very certain that the subject would have run instead of 
 walked, as distances as great as 20 or more kilometers are rarely covered 
 rapidly by walking, but usually by running. On the other hand, a 
 speed of 80 meters per minute represents an average rapidity of motion 
 when long-distance walking is to be done and hence the values obtained 
 at this speed have a much greater practical use than would values 
 secured with the subject walking at a higher speed. 
 
 COMPARISON OF THE HEAT-OUTPUT PER UNIT OF WORK DURING RUNNING 
 WITH THAT OBTAINED DURING WALKING. 
 
 The striking difference between the heat per unit of work observed 
 when the subject was running and that obtained when he was walking 
 has already been noted in table 15 (see p. 87), the figures showing that 
 considerably less energy per unit of work was required for moving the 
 body forward in running than in walking under the experimental 
 conditions. The values obtained when the subject was moving 
 forward at the rate of approximately 144 meters per minute give the 
 only data for a direct comparison, no running experiments being made 
 at the lower rates of walking. At this speed, the value computed for 
 walking (using the standing basal value) is 0.932 gram-calorie and for 
 running 0.806 gram-calorie. That these are not accidental figures 
 is shown by the fact that the first value is the average of 7 reasonably 
 agreeing periods and the second value is the average of 15 well agreeing 
 periods; in other words, we deal here with a positive difference of 
 approximately 15 per cent. It thus becomes important to analyze, 
 if possible, the mechanical movements incidental to walking, and par- 
 ticularly rapid walking, to find the reason for this discrepancy. 
 
 TraveUng at the speed of 144 meters per minute, the ordinary 
 individual without load generally runs rather than walks. On the 
 other hand, in transporting heavy material as, for example, nuhtary 
 accouterments and trappings, running would be wholly impracticable 
 and walking must be resorted to. It has been noted, especially in 
 observations of professional walkers, that in rapid walking there is 
 commonly very great extraneous arm movement, the arms being 
 violently swung back and forth with each step. In the belief that this 
 unusual extraneous muscular movement results in a large energy 
 transformation which does not directly contribute to the forward pro- 
 gression, the study previously referred to was made in which the energy 
 requirement of subject II was observed while he stood and swung his 
 arms violently as in rapid walking. These values have already been 
 discussed in connection with the standing resting values,^ when it was 
 
 'See table 10 and p. 71. 
 
DISCUSSION OF RESULTS. 
 
 97 
 
 found that in one experiment the heat-output per minute was 2.53 
 calories and in the other 3.13 calories per minute, or an average heat- 
 output of 2.83 calories per minute as compared with 1.25 calories per 
 minute, the average of the basal values obtained with the subject 
 standing relaxed. It will therefore be seen that when the arms were 
 swung violently, the metaboUsm was increased 126 per cent. 
 
 It is accordingly important for us to eUminate, if possible, the influ- 
 ence of this extraneous arm motion. To this end we have computed in 
 table 19 the heat-output per unit of work during rapid walking, using 
 
 Table 19. — Increase in heat-output during fast walking in experiments with subject II. 
 [Basal value, standing swinging arms.'] 
 
 Date. 
 
 Body- 
 weight 
 with 
 clothing. 
 
 Distance 
 
 per 
 minute. 
 
 Heat-output (computed). 
 
 Total 
 
 per 
 
 minute. 
 
 Increase due to walking. 
 
 Total. 
 
 Per horizontal 
 kilogrammeter. 
 
 1914 
 Without food: 
 
 May 6 
 
 10.... 
 
 14.... 
 
 Average 
 
 With food: 
 
 Protein — 
 
 May 10 
 
 Carbohydrate — 
 May 6 
 
 Average 
 
 kilos. 
 71.7 
 
 72.3 
 
 7i]5 
 
 meters. 
 140.7 
 139.6 
 142.9 
 145.5 
 146.8 
 146.6 
 146.4 
 
 cais. 
 10.23 
 10.38 
 10.91 
 10.99 
 11.68 
 11.00 
 11.23 
 
 cals. 
 7.40 
 7.55 
 8.08 
 8.16 
 8.85 
 8.17 
 8.40 
 
 gm.-cal. 
 
 0.734 
 .754 
 .789 
 .776 
 .834 
 .771 
 .803 
 
 
 
 
 
 .780 
 
 72,3 
 71.7 
 
 146.5 
 146.9 
 
 143.0 
 
 11.05 
 11.07 
 
 10.73 
 
 8.11 
 8.13 
 
 7.56 
 
 .766 
 .765 
 
 .737 
 
 
 
 
 
 .756 
 
 'The subject stood without food swinging his arms violently as in the most rapid walking. 
 (See table 10, p. 71.) In computing the results for walking without food, the average value 
 (2.83 cals.) is used; for walking with food the increment (2.83 — 1.25 = 1.58 cals.) due to swinging 
 the arms is added to the value obtained for "standing, relaxed" with the respective diets. 
 
 2.83 calories as the base-line, i. e., the average value found with the 
 subject standing and swinging his arms violently. Under these condi- 
 tions we find a marked depression in the heat-output per unit of work as 
 compared with that computed with a base-Une obtained with the sub- 
 ject standing in a relaxed position. In the experiments without food, 
 this averaged with the high speeds, 0.932 gram-calorie,^ but with the 
 new basal value, it averages 0.780 gram-calorie. This value compares 
 favorably with the value of 0.806 gram-calorie^ found in the 15 periods 
 with the subject running, being some 3 per cent less. 
 
 >See table 15, p. 87. 
 
DISCUSSION OF RESULTS. 99 
 
 At the low speed the subject walked 69.3 meters per minute, and took 
 108.2 steps per minute, the average length of the step being 64.0 cm. 
 With an increase in speed we note an increase not only in the number of 
 steps per minute, but likewise in the length of the step, the number 
 of steps per minute for the fast walking being 152.4 and the length of 
 the step 94.8 cm. When we consider the height to which the body was 
 raised, we find that the average height per minute was greatly increased 
 as the speed increased, that obtained at the medium rate being more 
 than twice the value secured with the low speed, i. e., an increase from 
 2.88 meters to 6.69 meters. When the average values obtained at the 
 medium and fast speeds are compared, we find that although the 
 average distance walked per minute increased from 109.0 meters to 
 144.5 meters and the number of steps taken per minute from 130.9 
 to 152.4, the increment in the distance over which the body was raised 
 was but 1.21 meters. 
 
 Of special interest in this connection is the extraordinary influence of 
 the change in locomotion from fast walking to running. The increase 
 in the speed was inconsiderable, being but 3.1 meters per minute. We 
 find, however, that in running the average height to which the body was 
 lifted increased from 7.90 meters to 13.76 meters per minute and the 
 average number of steps from 152.4 _to 181.9 per minute, the latter 
 increment not being at all in proportion to the former. On the other 
 hand, the length of the step was decreased in running from 94.8 cm. 
 to 81.1 cm. It is thus apparent that in running the steps were taken 
 much more rapidly and considerably shortened and that the body was 
 raised to a much higher point at each step. 
 
 In any analysis of the mechanics of forward progression, therefore, 
 we should bear in mind the fact that in running the body is actually 
 lifted to nearly twice the height that it is raised during walking. This 
 would of itself involve mechanical work not directly contributory to the 
 work of forward progression and we should therefore expect to find, on 
 this basis alone, that the work of walking would be much more economi- 
 cally done than the work of running. On the other hand, it has been 
 pointed out in connection with the fast walking experiments that the 
 subjects involuntarily, or possibly as the result of previous training, did 
 an excessive amount of muscular work with the arms which likewise 
 was not contributory to the motion of forward progression. If, how- 
 ever in comparing the values for the heat output per unit of work done 
 in walking and running, we use as a base-Une the value obtained with 
 the subject standing and swinging his arms vigorously, we find that the 
 advantage stiU lies with the walking rather than with the running. 
 Thus, while the heat-output per unit of work with the subject running 
 without food is 0.806 gram-calorie with the standing relaxed base-line, 
 when we use the base-line obtained with the subject swinging his arms 
 the value becomes 0.780 gram-calorie for the 7 periods without food and 
 
100 ENERGY TRANSFORMATIONS DURING HORIZONTAL WALKING. 
 
 0.756 gram-calorie for the three periods with food, with an average 
 value of approximately 0.768 gram-calorie. While these experiments 
 are relatively few in number, it is quite possible that the apparent lower 
 value obtained for walking as compared with running, after deducting 
 the standing active base-line, may be explained by the fact that the 
 body is elevated nearly twice as' much when running as when walking 
 and that to cover the same distance about 20 per cent more steps were 
 needed. In the motion of forward progression we have therefore to 
 take into account, first, the extraneous muscular activities not directly 
 contributory to the work of forward progression, chief among these 
 being the extraneous muscular movements of the arms in rapid walking 
 which require the expenditure of a considerable amount of energy. 
 Second, the type of step or the gait plays an important r61e, since in 
 raising the body work is performed, requiring an expenditure of energy. 
 When the body is raised approximately 14 meters per minute during 
 running, it may be readily computed that with a man weighing 70 
 kilograms, this would be equivalent to raising 980 kilograms one meter 
 in one minute corresponding to over 2.2 large calories. Any tjrpe of 
 locomotion, therefore*, which minimizes the raising of the body is the 
 most economical. As a natural outcome of the study it will be seen 
 that it would be desirable for athletes and others interested in the work 
 of forward progression to develop a gait which will eliminate these two 
 apparently unnecessary and extraneous factors, each of which requires 
 the expenditure of a considerable amount of energy which is not 
 directly contributory to the motion of forward progression. 
 
 Nutrition Laboratory of the 
 
 Carnegie Institution of Washington. 
 Boston, Massachusetts, June 19, 1915.