Why? The Science of Athletics

SOME MORE MATHEMATICS FOR ATHLETES 273 co-ordinated, and perfectly timed progressive action cul– minating in the maximum explosive effort, which may best be likened to a "jerk". Concentrated Explosive Effort Professor A. V. Hill has pointed out, in this connection, that "even with the high gearing ratio with which they work, no human muscles are capable, in a simple movement, of producing a velocity com– parable with that with which a cricket-ball is projected" . .Now a cricket ball has been thrown more than r 3/4 times as far as a javelin and nearly 2 3/4 times as far as a discus, but a cricket ball comes readily to the hand, weighs approximately 5 rj2 ozs., and must always travel with an even centre of gravity, since it has all points of its circumference equidistant from its centre. On the other hand a javelin weighs r lb. 12 r/4 ozs. and is 8ft. 6 ins. in length; while a full sized discus weighs 4 2/5lb., and has a circular dimension of 8 s/8 ins., with a thickness through the exact centre of not less than r 3/4 ins. These missiles, therefore, are subject to forces reacting through their shape to make them unstable in flight. But when a cricket ball, having all the advantages just enumerated, is thrown to a distance of 150 yards, which is approximately the world's record, the energy of its projection, according to Professor Hill's calculations, is about 75 ft.-lbs., that is to say, there is a velocity of projection of r 20 ft. per second, or 8o miles per hour. If you compare the cricket ball throwing record of about 450ft. with the javelin record of 251 ft. 6 ins. and the discus record of approximately 172 ft., you will see the tremendous forces the athletes concerned must have employed, in comparison with the cricket ball thrower. Let us consider, for a moment, what are the contribu– tary factors l~ading up to the production of maximum performance in throwing. We will ignore such questions as training, co-ordination of muscular effort and the crucial angles of delivery, since these matters have been dealt with in detail already. s