GASEOUS METABOLISM DURING WALKING. 547 



unit of work. As previously pointed out, with Squad B there was a 

 sUght decrease in this factor, indicating an increased efficiency. A 

 change in this factor is of such great physiological importance that it is 

 only with considerable reserve that one should draw deductions from it. 

 Remembering that the normal data with Squad B on January 6 had a 

 wide variation and that Squad A on reduced diet have no normal values 

 obtained with them directly for use in such comparison, and that the 

 normal values for Squad B must therefore be employed, it may be con- 

 sidered unjustifiable to draw a definite conclusion that the subjects 

 walked at a greater efficiency on a reduced diet than under normal con- 

 ditions. Nevertheless, the figure of 6 per cent with Squad B is sub- 

 stantiated, at least to a reasonable extent, by the figure of 12.6 per cent 

 with Squad A. It is thus probable that there is a distinct increase in 

 efficiency, even when considering the activity from the standpoint of 

 per unit of work accomplished. 



While a larger group of subjects would be desirable, it is believed 

 that the number of men studied is sufficiently large to average most 

 of the individual variations. The three sets of experiments were made 

 in exact duplicates and the conditions of the series were similar. The 

 results from the three series may therefore be taken as contributory 

 to the whole picture. In considering these results it should be re- 

 membered that in this test the influence of practice was reduced to an 

 almost negligible quantity. Every muscle employed in treadmill 

 walking was employed a hundred fold over in the daily routine of each 

 man. The rate of walking was purposely made moderate to eliminate 

 the question of excessive work, and the periods were brief enough to 

 eliminate the question of fatigue. 



While we believe that the conclusions regarding these experiments 

 show unquestionably an actual saving in energy for the transportation 

 of the body of the individual over a stated distance and distinctly 

 imply, also, that each unit of work is accomplished with a somewhat 

 higher degree of efficiency, the important relationship between this 

 type of work and muscular activities in general should here be empha- 

 sized. Walking is a practiced effort. The experiments were planned 

 for tests with moderate exercise of a well-established and practiced char- 

 acter. But in consideration of the fact that not only is there an abso- 

 lute total saving in energy, but a probability of a slight saving per unit 

 of work, we have every reason to believe that similar increases in 

 efficiency, both total and relative, would be shown with other forms 

 of exercise including, indeed, industrial operations, if the influence of 

 fatigue and excessive work were eliminated. On these two latter 

 points these experiments do not give and were not planned to give aily 

 evidence. Whether the men would show equal efficiency in prolonged 

 walking or heavy-grade walking on a reduced diet as on a normal diet 

 is a question for further study. But the conclusion seems clear to us 



