Why? The Science of Athletics

274 WHY?-THE SCIENCE OF ATHLETICS Speed Leading to Projection Speed in the actions leading up to the projection of a missile is, however, a factor of major importance. What was said in the last chapter regarding the influence the speed at which the pole vaulter and the long jumper approaches the take-off has upon his subsequenf performance in vaulting or jumping must obviously hold good where the javelin thrower is con– cerned, provided he masters the technique of passing from the approach run to the throwing position without any break in the smooth rhythm of his progression. In the case of the Shot Put the initial impulse'" is generated by the swing of the left leg (right-handed shot– putter), the falling forward of the body, and the powerful drive from the right leg, when the body is just crossing its forward point of balance, as shown by F. R. Webster in Fig. 95, Plate 2 I. The more powerful the forward drive can be made, commensurate with proper balance in the putting sta11ce, the greater will be the speed acquired, and therefore less units of impulse will be needed for a put of a given distance, or, conversely, the greater the speed of the glide the more units of impulse a man will have available for his use in the delivery of the projectile. Where Hammer and Discus Throwers are concerned it is the turning mov~ment within the throwing cir_cle which generates the initial velocity of body movement, which will subsequently be converted into the propulsive force of the throwing action. But neither in running, gliding nor turning can a man generate ·the force for a velocity of projection of I 20 ft. per second; there must be other contributory factors. Let us try to discover what those factors are. Perhaps the analogy of a huntsman cracking his whip will best illustrate the point, for when he does so no very great momentum is generated by the swinging of the crop, but when the loosely swinging lash is arrested with a sudden jerk a wave of impulse flows along it and there is a loud report as tke energy reaches the silk cord at the