Weakening of the Active Muscle Restraint Against Valgus Loading During Repeated Baseball Pitching: Direct Evidence of Fatigue in Dynamic Valgus Stabilizers of the Elbow Joint in Collegiate Baseball Pitchers

This study investigates how repeated baseball pitching affects the dynamic stabilizers of the elbow joint, specifically examining whether muscular varus strength diminishes with increased pitch count. The authors found that while the valgus load remained constant throughout the innings, the varus strength of collegiate pitchers significantly decreased after the fourth and seventh innings, suggesting a growing reliance on the ulnar collateral ligament to manage valgus stress as fatigue sets in.