Pitcher Aging Affects Throwing Shoulder Biomechanics and Proprioception: The Italian Experience

Introduction: Baseball is a sport increasingly practiced in Italy. The pitcher is at risk from repetitive stress on the dominant upper arm. Because of this, pitchers train far more on the dominant arm leading to asymptomatic biomechanical changes. The purpose of this study was to compare shoulder intra/extra rotational power and shoulder motor skill in young and senior athletes. Methods: Twenty right-hand healthy pitchers playing for at least four years were recruited : Group A (12±2yrs) and Group B (24±1yrs). Subjects with a history of shoulder dislocation, shoulder surgery or structural injuries to the shoulder complex were excluded from the study. Isokinetic tests (IT) were performed to evaluate intra/extra rotational power, and shoulder motor skill test (SMST) to evaluate proprioception. Results: Performing IT, we have found in both groups a significant higher external rotation compared to internal rotation in the throwing shoulder (TS), while in the contralateral shoulder (CS) the balance was preserved ( p<0.003). In Group A, SMST was 4±2 points (TS) and 4±1 points (CS), p=n.s. In Group B, SMST was 9±1 points (TS) and 4±2 points (CS), p