Mech. of Pitching

A baseball pitcher throws a baseball across the plate and the batter hits it to center field, and elderly man pitches horseshoes, a young person spikes a volleyball, student practices driving a golf ball while a college athlete practices punting a football. Once more, as is the case with pushing and pulling, a widely diverse set of activities has a common denominator. Each of these activities involves sequential movement of the body segments resulting in the production of a summated velocity at the end of the chain of segments used. The path produced by the end point of this chain of segments is curvilinear in nature. Sequential segmental motions are most frequently used to produce high velocities in external objects. Depending on the objective of the skill, speed, accuracy, distance, or some combination, modifications in the sequential pattern may be involved, larger or smaller ranges of motion might be used, and longer of shorter lever lengths may be chosen. Regardless of the modifications, the basic nature of the sequential throwing, striking or kicking pattern remains the same.

Broer was the first to call attention to the similarity of movement patterns used in seemingly dissimilar activities such as the baseball pitch, the badminton clear, and the tennis serve. Objective evidence of such similarities between throwing and striking activities within each of the three major upper-extremity patterns; overarm, sidearm and underarm. The representative activities from these categories across throwing patterns also showed great similarity in the muscular action of the lower extremity. Atwater distinguished between the overarm and sidearm throwing patterns in terms of the direction in which the trunk laterally flexed. When lateral flexion occurred away from the throwing arm, and overarm pattern was used; lateral flexion toward the throwing arm indicated a sidearm pattern. The underarm patter is distinguished by motion predominantly in a sagittal plane with the hand below the waist. Each pattern involves a preparatory movement referred to as a backswing, or windup, followed by the establishment of a base of support prior to the initiation of the force phase and ending in the follow-through. The base of support in the direction of the force application; forward and backward is a distinguishing feature of skill level. It has been well documented that more highly skilled individuals have longer strides. Once the base has been established, the more proximal segments begin the force application phase while the more distal segments complete the backswing.