Why? The Science of Athletics

ATHLETIC TESTS AND MEASUREMENTS OF ABILITY 157 (A-D) in which he still maintains control of the shot. Now force employed over a certain distance is work, but to obtain the maximum effect in shot-putting the work must be done rapidly, wherefore the time factor enters into our calculations and, leaving out the question of the angle of departure of the missile, we find that it is the time-rate which determines the distance to which the shot can be propelled, and so, finally, we reach the conclusion that the "time-rate of work is horsepower". FIG. r6 c D Equally interesting inferences may be drawn in rela– tion to the jumping events, especially the high jump, in which horizontal velocity is converted into vertical spring at the moment of the take-off foot making its final impact upon the ground ; although, of course, there are many other factors concerned in the accomplishment of a per– fect jump, which is consonant with the athlete's ability plus his natural spring. The force which the high jumper exerts as rapidly as possible in the take-off action of the foot from which his spring is made is exerted, probably, over a distance of not more than 12 inches. He uses that power, in relation to his weight, for acceleration through that 12 inches, and the force exerted and the time taken to exert it over that distance determine the height a man can jump. It is by no means unusual for a coach to tell his charges