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 kilogrammeter. 



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 difference 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 published 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 column 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 published 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. 



