152 



METABOLISM DURING WALKING. 



They note that the energy cost of "marking time" was with the three 

 greatest loads (16, 21, and 26 kg.) higher than that for slow marching 

 at 62.5 yards (57.2 meters) per minute, and with a load of 11 kg., 

 "marking time" called for almost identically the same energy-output 

 as a slow march of 57.14 meters per minute. A most significant dis- 

 cussion of "marking time" is presented by Cathcart and Orr. 1 



The energy requirement for "marking time" is considerably larger 

 than one would anticipate and shows that unnecessary and extraneous 

 movements might easily lead to considerable differences in the metab- 

 olism measurements with muscular work of a moderate degree of 

 intensity. Benedict and Murschhauser 2 have called attention to this 

 in some measurements in which their subject stood and swung his 

 arms and hands as in fast walking, with the result that there was an 

 increase of 126 per cent over his quiet standing metabolism. 



STEPS AND STEP-LIFT DURING HORIZONTAL WALKING. 



As was stated in an earlier section (p. 33), a record was kept of the 

 number of steps the subject took in walking, and measurements were 

 frequently made of the height to which the subject lifted his body as a 

 result of the heel-and-toe action in walking. These records are given 

 in detail in tables 29 to 33. The daily averages are summarized 

 according to the speed of walking in table 41, in which the average 

 length of step is also included. It is believed that the number of steps 

 taken is accurately known, and therefore the average length of step is 

 without appreciable error. This can not be so fully claimed, however, 

 for the height of the step-lift, as will be shown later. (See p. 155.) 



TABLE 41. Number of steps and height of step-lift in walking on a level. (Values per minute.) 



'Cathcart and Orr, loc. cit., p. 54. 



'Benedict and Murschhauser, Carnegie Inst. Wash. Pub. No. 231, 1915, pp. 71 and 97. 



