Relationship between Shoulder Kinetics and Arm Slot in Collegiate Baseball Pitchers

Abstract Baseball pitchers experience significant physical demands throughout the throwing motion, and upper extremity injuries remain common across all levels of play. Thus, it was our purpose to examine the relationship between arm slot determinants and shoulder loading in National Collegiate Athletic Association Division I pitchers during in-game performance. A total of 309 pitchers were included. Fastball pitches within the middle 80% of pitch velocities were included in the analysis. Time-series associations between shoulder rotational torque and resultant force with arm slot determinants were assessed with one-dimensional Statistical Parametric Mapping regressions. Linear regressions were conducted between arm slot and shoulder rotational torque and resultant force. A maximum shoulder resultant force was significantly associated with shoulder elevation from 96 to 100% of the pitch (p=0.017; R=0.20, R 2=0.04). Shoulder elevation was associated with a maximum shoulder resultant force in Division I pitchers during in-game environments. These findings highlight the importance of upper-arm placement at ball release in understanding shoulder kinematics during high-velocity throwing. This information may be useful for clinicians when evaluating shoulder stress, as higher shoulder torques and peak humeral loading have been linked to increased injury risk in pitchers. Incorporating shoulder elevation into routine monitoring may provide a practical means of evaluating shoulder loading without requiring mechanical changes.