2 METABOLISM DURING WALKING. 



ideal for periods of 24 hours. During rest experiments the agreement 

 has been shown to obtain for periods as short as one hour. The agree- 

 ment in the short periods has not, however, been thus far demonstrated 

 under conditions of excessive muscular work with accompanying 

 alterations in body-temperature and the possibility of over- ventilation 

 of the lungs, as well as possibilities of special metabolic cleavages, 

 such as lactic acid. 



In the research here projected it was definitely planned to conduct 

 the experiments ultimately in a respiration chamber provided with 

 calorimetric features. Since special stress was to be laid upon the 

 measurements of ventilation of the lungs, body-temperature, heart- 

 rate, and physiological factors other than the metabolism, it was 

 deemed wisest first to carry out a series of experiments in which the 

 subject walked upon a treadmill in the laboratory and was thus much 

 more accessible than he would be when walking upon a treadmill in 

 a respiration chamber. It is this series of experiments that is reported 

 in this publication. The calorimeter for carrying out the work experi- 

 ments planned has actually been constructed in the Nutrition Labora- 

 tory and thoroughly tested as to its capacity for measuring large 

 amounts of heat as well as respiratory products. At the moment 

 of writing it has not been used for experiments with men on the 

 treadmill. 



It is hoped that when full information is obtained of some of the 

 fundamental requirements of the human body during periods of 

 muscular exercise, scientists will be in a better position to consider 

 the question from the standpoint of industrial efficiency, and that 

 in the end it may be possible to state whether or not a laborer should 

 be able to perform a given amount of work with a greater efficiency 

 than is commonly done, that is, with less cost to the body economy. 

 If such evidence is positive, the problem of training the laborer and 

 determining in what way the energy is wasted will be the next and 

 most obvious step, and the suggestions and criticisms of Frederick 

 W. Taylor 1 would have the added support of physiological science. 

 Mention should also be made here of the very clever mechanical 

 devices of Amar, 2 who has already attacked the problem of efficiency 

 in various kinds of work. 



The results of two researches 3 made by this Laboratory as a part of 

 the original plan have already appeared. The following pages present 

 the results of further study which has been applied more especially 

 to the work of grade walking. As a necessary accompaniment of a 

 study of grade walking, observations were made with the subject 



1 Taylor, The principles of scientific management, New York, 1911. 



2 Amar, Le motour humain, Paris, 1914. 



3 Benedict and Cathcart, Carnegie Inst. Wash. Pub. No. 187, 1913; Benedict and Mursch- 

 hauser, Carnegie Inst. Wash. Pub. No. 231, 1915. 



