Man as a Source of Mechanical Power

Abstract It is deduced from the published literature that the usable external power output of the body is limited in the following manner for the reasons stated : (1) In single movements (of duration less than 1 sec) to less than 6 h.p. ; by the intrinsic power production of muscle, and by the difficulty of coupling a large mass of muscle to a suitably matched load. (2)In brief bouts of exercise (0-1—5 min) to 2—0-5 h.p. ; by the availability in the muscles of stores of chemical substances that can yield energy by hydrolysis (3)In steady-state work (5 min to 150 min or moro) to 0-5-0-4 h.p. ; by the ability of the body to absorb and transport oxygen. (4)In long-term work, lasting all day, to perhaps 0-2 h.p. ; by wear and tear of muscles, the need to eat, etc. All these figures refer to champion athletes ; ordinary healthy individuals can produce less than 70-80 per cent as much power