330 



REPORTS ON THE STATE OF SCIENCE. ETC. 



Cost of Cycling at Varied Rate and Work. — Report of Committee 

 (Prof. J. S. Macdonald, Chairman ; Dr. F. A. Duffield, Secretary). 

 {Drawn up by the Secretary.) 



The intention in thi? set of experiments was to obtain data covering a greater range 

 of movement than had hitherto been attempted, and consequently the subject of 

 heavier weight and stronger build (J. McH.) was selected to perform the cycling 

 involving additional endurance at these faster rates. The procedure followed in 

 these experiments was precisely the same as that employed in the former work. The 

 subject pedalled on a stationary bicycle with a ropo-brake acting on the hind wheeL 

 The levels of work were approximately 0, -5, 1-0, 1-5, and 2-0 kals. per minute. The 

 new rates of cycling were at 95 and 100 revolutions a minute. Samples of expired 

 air weie collected at 18, 23, and 28 minute intervals respectively after the commence- 

 ment of the cycling, and the mean of the three air analyses is taken and expressed as- 

 kalories per minute. 



5 6 7 6 9 10 II 12 



MET/iBOLISM IN KALS pm 



The fresh data are plotted on the accompanying chart, alongside those of the 

 lower rates of 40, 62, and 84 revolutions a minute, thus providing a series of metabolic 

 values resulting from the performance of varying amounts of work at five different 

 rates of movement. The experimental points obtained from the faster rates — namely, 

 95 and 106 revolutions per minute, lie on two straight lines parallel to one another 

 and to the lines which represent the results of experiments at the slower rates of 40, 

 62, and 84 ; but up to the present the series is not complete, and it may be that 

 when the additional points have been obtained and charted the inclination of the 

 lines may be slightly altered. 



Speaking generally, the conclusions drawn from previous experiments are found 

 applicable to the results obtained with these higher rates of movement. The ' cost 

 of movement ' per se, as distinguishable from the ' cost of work performance,' is 

 represented by a definite distance along the abscissa, which distance increases with 

 the rate, and then with each increment of work the ' cost ' rises along a straight 

 line starting from this point, so that the total cost may be summed as H=<^-!-aK ; 

 for each particular rate of movement ' <p ' being a constant, and ' x ' a, disefficiency 

 coefficient which does not seem to vary in any obvious fashion throughout the whole 

 series of experiments at all rates of movement. 



It is intended to complete the series of experiments on this subject and to include 

 the results in the report next year. 



