Frictional and Kinetic Factors in the Work of Sprint Running

If one divides the energy equivalent of the total excess oxygen consumed as a result of a short sprint at top speed by the number of seconds occupied in the run, one finds1 (after correcting for the start and the pull up) (cf. Sargent, 1926) that the rate of energy expenditure while running at a maximum speed is about 13 horse power for an average man. From measurements on isolated muscles (Hill, 1926) as well as from calculations made by Furusawa, Hill and Parkinson (1927) on sprinters, it may be concluded that about 40 per cent of this energy was expended during the sprint in the “initial” or anaerobic phase of muscle contraction, the remainder representing the inefficiency of recovery. The present paper is concerned with the disposition of this initial energy which is being expended at a rate of about 5.2 horse power? The conclusions reached and the problems involved are illustrated in the following diagram :