Strength of Dynamic Stabilizers of the Elbow in Professional Baseball Pitchers Decreases during Baseball Season

Objectives: Injuries to the ulnar collateral ligament (UCL) are one of the most common and severe incurred by pitchers. Baseball pitchers of all ages and levels have seen an increase in the diagnosis of these injuries. Tears of the UCL are caused by high valgus forces at the elbow of which the UCL is the primary restraint. Biomechanical studies have demonstrated that baseball pitchers either approach or exceed the maximum tensile strength of the UCL while throwing. Valgus force is additionally resisted by the flexor pronator (FP) muscles: flexor carpi ulnaris (FCU), flexor digitorum superficialis (FDS), and pronator teres (PT), which act as secondary stabilizers. The importance of these secondary stabilizers has not been clearly demonstrated. The goal of this study was to monitor the strength changes in the secondary stabilizers of the elbow over the course of the baseball season and to attempt to correlate any of those changes to observed UCL injuries.