THE LAWS OF ENERGETIC EXPENDITURE 167 



Angle (vide fig. 134) - 20 +20 



Additional Oxygen 212 cc. 344 cc. 360 cc. 



The position of the muscles (the power) on the lever which 

 receives the load and the number of muscles which take part in 

 the same static effort, modify the expenditure, but, all things 

 being equal, the latter is proportional to the static load and the 

 duration of the action. This is generally written : 



D = K x P (1 +r), 



D e being the nett expenditure of the static effort (in excess of 

 the expenditure in repose), and K, a co-efficient of proportion. ( x ) 



113. Dynamic Contraction : Work. - If a load be displaced, the 

 work of the muscles can either be motive or resistant. If D 

 be the dynamic expenditure, it will be relative to the static effort 

 D, and to the work accomplished T. Chauveau gave the 

 equation : 



D, = D, + T. 



the quantities being expressed in Calories, for instance. 



He also found that the expenditure equivalent to T comprises 

 the value (P X h), of the mechanical work (a weight lifted to a 

 height or lowered from a height h) and the value of the friction R, 

 which oppose the movement of the muscles. It also includes a 

 fraction V, equivalent to the expenditure in starting the action. 

 The equation will therefore be : 



D d = D, + T = D, + Ph + R + V. 



The term R, which is equal to the passive resistances, is assumed 

 to be included both in the static contraction D, and also in V. 

 This term R therefore figures twice in the expenditure D^, and 

 remains to be known in D<? and in V. The exact values to be con- 

 sidered will be : 



D^ = (D, R) +Ph + R + (V R). 

 or : 



D rf = D, + Ph + V R. 



This is Chauveau's ( 2 ) formula, giving the analysis of expendi- 

 ture for a work Ph. 



All these values can be expressed in calories, or litres of 

 oxygen, or in kilogrammetres. 



114. A Proof of Chauveau's Formula. Reduced thus to four 

 terms, Chauveau's formula cannot be shown experimentally, 



(*) The results of Bernstein and Poher, who obtained a more rapid 

 increase of the expenditure in static effort (Pfluger's Archiv., vol. xcv., 

 p. 146, 1903) should be accepted with reserve. 



() A. Chauveau (Comptes Rendus Sciences, 1902, vol. cxxxiv., p. 1266). 



