Abstract
INTRODUCTION: Baseball pitchers have the highest volume of throws of all baseball players. These large volumes of throwing may lead to injury of the throwing shoulder. Each pitcher has their particular throwing style and arm position they prefer, called arm slot. PURPOSE: Primary aim was to compare the differences in shoulder abduction angle, lateral trunk lean, and shoulder proximal force, in each arm slot. Secondary aim was to provide evidence for defining ranges for each arm slot and bring about information of a new variable, arm slot angle. METHODS: Motion capture (240 Hz) of fourteen (14) pitchers throwing off an artificial dirt mound in a lab. Data analyzed were shoulder abduction angle, lateral trunk lean, and shoulder proximal force. RESULTS: No statistical significance found comparing shoulder abduction angle or shoulder proximal force (P > 0.05) between arm slot groups. Lateral trunk lean however was significantly different (P < 0.05) between arm slot groups. DISCUSSION: Present study was one of the first to look at differences in shoulder proximal forces between different arm slots. Limited data to shoulder kinematics and kinetics in literature; however, data has been shown that at ball release there are high amounts of force and torque occurring at the elbow. Further research needed to look closer into the shoulder forces and torques in each arm slot, and to define ranges for each arm slot as far as arm slot angle.