Mech. of Pitching
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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. The purpose of the backswing is the place the segments in a favorable position for the force phase.
For the overarm pattern, this kind of throw is characterized by rotation at the shoulder joint. In the backswing or preparatory, phase the abducted arm rotates laterally, and in the forward, or force, phase the arm rotates medially. Some elbow extensions, wrist flexion and spinal rotation occur in the force phase. These movements are accompanied by ration of the thigh. An immature pattern may be identified as using fewer segments, working more simultaneously rather than sequentially, and involving a more limited range of motion. Overhand patter applied in baseball pitch using forward force phase is characterized by medial rotation of the arm, elbow extension, spinal rotation, and medial rotation of the pelvis at the contralateral hip joint. Underarm patters consist of a forward movement of the extended arm in the sagittal plane, usually starting from a position of hyperextension and ending in a forward reach. The basic joint action of the arm if flexion. The actions of the wrist, spine and pelvis are the same as those observed in the overarm pattern. In a sidearm pattern the basic movement is medial rotation of the pelvis on the opposite hip with the arm usually in an abducted position. The arm is moved forward in a horizontal plane because of the pelvic action and spinal rotation. The spine also laterally flexes toward the throwing arm. The range of the upper-extremity movement many also be enlarged by the addition of horizontal abduction at the shoulder. The elbow is maintained in extension or is extended from a slightly flexed position, depending on the nature of the skill in question for example batting throwing a basketball for distance or tennis forehand drive. Wrist flexion may also be part of the action in some techniques.
Anatomical principles are very important when it comes to throwing. To ignore this principle of sequential motion is to risk injury because sequential motion can generate extremely high velocities, as well as impart high braking forces. Muscles contract more forcefully if they are first put on a stretch, provided they are not overstretched. This principle suggests the function of the windup in pitching and if the preliminary movements in other sport skills. Unnecessary movements and tensions in the performance