MAN AS A SOURCE OF MECHANICAL POWER

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