Shot Put: Throw Mechanics

The shot put is a track and field event that involves throwing a heavy metal ball called a shot as far as possible using only one arm in a pushing motion, what is called putting. The shot put athlete (or shot-putter) needs strength, but must also be quick and coordinated in order to create momentum and maximum force during the throwing motion. The shot-putter begins at the back of a marked circle that is 7 ft (2.1 m) in diameter. The shot-putter faces away from the throwing direction while positioning the shot against the shoulder and under the chin. In two quick steps, the shot-putter turns, moves quickly to the front of the circle while launching the shot by thrusting the arm forward.

The throw mechanics of the shot put involve primarily four factors. Projection speed (v) is measured from the point the shot-putter releases the shot; projection angle θ is the angle between the horizontal and the initial shot direction, range (R) is the horizontal distance from the release of the shot to where it lands; and height difference (h) is the distance from the ground to the vertical release point.

The projection speed (v) is the most important of these factors. It is determined by the magnitude and direction of the forces applied to the shot and by the distance over which these forces act.

The optimum projection angle θ for achieving maximum horizontal range (R) depends on the size, strength, and throwing technique of each particular athlete. The optimum projection angle usually ranges from 26 to 38°. The projection speed (v) and the launch height (h) are dependent on the projection angle. Experiments have shown that the projection speed generated by an athlete steadily decreases with increasing projection angle. The decrease in projection speed with the increase in projection angle is the result of two factors.

As the projection angle increases, the shot-putter must expend a greater effort to overcome the weight of the shot, and so less effort is available to accelerate the shot (or produce the projection speed). The muscular and skeletal systems of the human body is better able to exert forces in the horizontal direction than in the vertical direction.

In the end, the release height of the shot put is determined by the athlete's body position at the moment of release. If all other factors are equal, the athlete who attains a position in which the throwing arm, trunk, and legs are fully extended at the instant of release will achieve greater distances than the athlete who is in a less-desirable position.

see also Shotput; Skeletal muscle.