Why? The Science of Athletics

304 WHY? - THE SCIENCE OF ATHLETICS been projected and perspective error was eliminated by setting up the camera at a considerable distance and using a telephoto lens. The sight line was perpendicular to · the line of flight, and the camera located midway to the central point of flight. Velocity was measured from distances, and times 'and distances were scaled from the film by measuring the projected image and multiplying the measurements by a multiplier. Definite proof was obtained that the flight of the shot can be represented by mechanical formulae, and the force applied to the shot was also computed, an important point since it is to this force and the speed of its action that the acceleration of the shot is due. Taking F as Force, , D as distance through which the force acts, M as DIAGRAM F mass of the shot, and V Humerus to represent the velocity at which the shot leaves the athlete's hand, we find the law of physics, which explains the action to be : FD =-!MV 2 • Or the same result may be obtained by using Newton's law of accele-· rated motion, ignoring wind resistance, F = Ma. Here, the secret of why shot putting records are not greater is found in a certain human inefficiency, because the lever arrangement of the elbow joint is weak and the insertion of the triceps muscle is acute (see Diagram F), and secondly, by reason of the difficulty of exerting force upon an object that is moving away from. the body. Great strength which is not rapid in action is not of much use, but the speed of the extension of the forearm and the drive from the legs are matters of major import– ance.