BIOMECHANICS OF WINDMILL SOFTBALL PITCHING WITH IMPLICATIONS ABOUT INJURY MECHANISMS AT THE SHOULDER AND ELBOW

Underhand pitching has received minimal attention in the sports medici ne literature. This may be due to the perception that, compared with o verhead pitching, the underhand motion creates less stress on the arm, which results in fewer injuries. The purpose of this study was to cal culate kinematic and kinetic parameters for the pitching motion used i n fast pitch softball. Eight female fast pitch softball pitchers were recorded with a four-camera system (200 Hz). The results indicated tha t high forces and torques were experienced at the shoulder and elbow d uring the delivery phase. Peak compressive forces at the elbow and sho ulder equal to 70-98% of body weight were produced. Shoulder extension and abduction torques equal to 9-10% of body weight x height were cal culated. Elbow flexion torque was exerted to control elbow extension a nd initiate elbow flexion. The demand on the biceps labrum complex to simultaneously resist glenohumeral distraction and produce elbow flexi on makes this structure susceptible to overuse injury.