30 



METABOLISM DURING WALKING. 



MEASUREMENT OF THE STEP-LIFT. 



With each step in walking, the body is raised to a greater or less ; 

 degree in a vertical direction, and this becomes an appreciable factor 

 in the amount of work which is done. In the previous research in this 

 Laboratory on the muscular work of walking, a dual record of these 

 movements was obtained by means of a work-adder wheel, the spring 

 pointer introduced by Professor Carl Tigerstedt, 1 and a kymograph 

 record. The same method of measurement was used in this research 

 (see fig. 7), except that the cord leading to the work-adder wheel was 

 not attached directly to the subject. Instead, a light wooden fork was 

 employed, which was 2 meters long and pivoted at one end, while the 

 prongs were held closely at the subject's shoulders by elastic webbing. 



Fio. 7. Step-lift recorder. 



T, cord fastened to fork at back of subject 

 (see fig. 1, p. 19); A, spring providing 

 tension on cord T; B, recording wheel 

 revolved by the friction of cord T; C, 

 laminated spring-steel pawl to prevent 

 back-lash; D, pen for tracing record; E, 

 signal magnet and pointer for recording 

 time. 



(See S, fig. 1, p. 19.) The cord T (figs. 1 and 7) from the work-adder 

 wheel was fastened to this fork at a point directly behind the subject's 

 neck. Although this attachment was not so near the center of gravity 

 of the body as it might be, the results obtained with it were very positive 

 and showed such slight movements as shifting the weight of the body 

 from one foot to the other a movement scarcely noticeable to the 

 observer while it was less affected by the relative position of the 

 subject on the treadmill. The work-adder wheel was directly con- 



1 C. Tigerstedt, Skand. Archiv f. Physiol., 1913, 30, p. 299. See special application of this 

 pointer under the conditions of this research in Benedict and Murschhauser, Carnegie Inst. 

 Wash. Pub. No. 231, 1915, p. 39. 



