EXPERIMENTS WITH HORIZONTAL WALKING. 



119 



from 2.73 calories (E. D. B.) to 3.75 calories (H. R. R.). The gradual 

 increase in the heat-output on the basis of body-weight is consistent 

 throughout practically all the tests for all of the subjects. There is 

 but one exception, i. e., with E. D. B. for 60 to 65 meters per minute, 

 when the heat-output was higher than that with the succeeding speed 

 of 65 to 70 meters per minute. It may be recalled that the series of 

 experiments with a speed of 60 to 65 meters per minute was the first 

 series with this subject. 



TABLE 28. Average oxygen consumption and heat-output for subjects walking on a level 



at speeds between 85 and 100 meters per minute. 



The increase for the heat per kilogram of body-weight for each in- 

 crease of 5 meters in speed is not uniform, either for the different sub- 

 jects or for the different speeds. Such changes as 2 per cent for J. H. G. 

 in passing from a speed of 50 to 55 meters per minute to 55 to 60 meters 

 per minute, and 9 per cent for H. R. R. in passing from a speed of 60 to 

 65 meters to 65 to 70 meters per minute, are noted. In the majority 

 of cases the variation ranges from 5 to 10 per cent for each increase of 

 5 meters in speed. It may be stated from the data available in the 

 table that the heat-output per kilogram of body-weight for all ordinary 

 speeds of walking, such as might be taken as a "constitutional" by a 



