On the efficiency of muscular work

In a paper communicated to the Royal Society in 1913, Prof. J. S. Macdonald published a series of observations upon the heat production of persons performing certain known quantities of work upon a bicycle ergometer. In that paper, and again in a more recent publication, Prof. Macdonald has outlined certain methods of interpreting his results, which are of much importance; these I shall discuss in the latter half of this communication, but, before doing so, it will be interesting to examine some purely numerical questions to which Macdonald’s paper gave rise. In a note on Macdonald’s earlier paper, Messrs. Glazebrook and Dye have published a formula descriptive of Macdonald’s numerical results. This formula is H =a +b M + W/α +β M, (1) where H = heat production in calories, M = body mass in kilogrammes, W = work equivalent in calories,a, b, α , andβ are constants.