384 THE HUMAN MOTOR 



295. Walking on the Level Summary. Taylor's results, for the 

 carrying of loads, represent the maximum results obtainable 

 with the average workman namely, a total distance traversed 

 per working day of 26 km. (13 under load and 13 empty handed) 

 a load of about 42 kg. and an average speed of walking of 3 km. 

 per hour, resulting in an average expenditure of 2 J million metre- 

 kilogrammes per diem equivalent (vide the table in para. 289) to 

 a total dynamic expenditure of 1348 great calories. Hence the 

 expenditure per kilogramme of body weight per hour is approxi- 

 mately : 



1348 

 ,=53^4 = = < * great calories. 



This figure represents practically the highest co-efficient of 

 utilization of muscular energy. ( l ) It is important to note that 

 such a muscular output has no injurious effects on the physio- 

 logical condition of the subjects. Certainly the rate of the pulse 

 increased from 30% to 50% above its normal value, but this is 

 not followed by any abnormal effects unless the subject is pre- 

 disposed to any functional weakness of the heart. The duration 

 of the systole increases by 20% or 25%, while the diastole dimin- 

 ishes in duration by one-third or even a half. The ratio between 



them may reach 1-5 (vide 143). The respirations also increase, 



O 



from the normal rate of 16 per minute in repose to as much as 

 25 per minute. The " vital capacity " decreases with increase 

 of load, though not in any regular proportion. The temperature 

 of the body also varies slightly by a quarter or half of a degree 

 centigrade. Lastly, as we have previously seen ( 144), and, as 

 Zuntz has observed, walking exercise strengthens the muscles 

 of the arms, as has been observed by Mosso's ergograph, also the 

 " personal equation " is slightly reduced, i.e., the subject re- 

 sponds more quickly to stimuli. 



The conditions of normal industrial work are only adequately 

 to be met by increasing the speed of walking, by restricting the 

 load to a maximum of 45 kilogrammes and by providing numerous, 

 though short, intervals of rest. Taylor's selected workmen were 

 able to carry 58 tons per diem with a speed of walking which was 

 probably about 5 kilometres per hour, the total work done being 

 approximately 3 million metre-kilogrammes. ( 2 ) 



296. The Ascending Walk. In ascending a stair the work done 

 by the muscles is the product of the weight and the height, and 

 we can, for an approximate result, neglect the horizontal com- 

 ponent of the motion. 



( x ) Since the expenditure of energy at rest is 1^ great calories, the total 

 expenditure is 1'5 -f- '75 = 2- 25 great calories. 



( 2 ) Publication of the Revue de Mitalluvgie, p. 330, 1907. 



