Scaption and Rotational Strength Deficits in Collegiate Baseball Athletes With Medial Ulnar Collateral Ligament Injury: A Matched Cross-Sectional Study

Abstract

Context: Medial ulnar collateral ligament (MUCL) injuries requiring surgery continue to rise among collegiate baseball players. Whereas external rotation (ER) and internal rotation (IR) strength have been identified as modifiable risk factors, no study has examined isometric scaption (SCAP) strength in an MUCL-injured collegiate baseball population against a matched uninjured cohort, and no studies have normalized these strength data to body mass.

Objective: To determine whether differences exist in normalized isometric SCAP, ER, and IR strength between MUCL-injured and matched uninjured college baseball players.

Design: Cross-sectional study.

Setting: Physical therapy clinic and athletic training room.

Patients or other participants: A total of 70 collegiate baseball players participated in this study (35 MUCL injured, 35 uninjured). Injured baseball players were matched by position, throwing arm, total years of baseball participation, year in school, and age at enrollment for players without an MUCL injury. Medial ulnar collateral ligament-injured data were retrieved from a single surgeon database, and we recruited the uninjured group from 2 National Collegiate Athletic Association Divisions I and III baseball programs.

Main outcome measures: Bilateral isometric SCAP, ER, and IR strength normalized to body mass (N/kg).

Results: Uninjured baseball players demonstrated more body mass-normalized SCAP, ER, and IR strength on the throwing (mean difference = 0.30 N/kg, 0.34 N/kg, and 0.68 N/kg, respectively) and nonthrowing (mean difference = 0.36 N/kg, 0.32 N/kg, and 0.58 N/kg, respectively) arms when compared with players with an MUCL injury (P value range < .001 to .01) after controlling for body mass index and level of competition.

Conclusions: Our results demonstrate that MUCL-injured baseball players present with less body mass-normalized SCAP, ER, and IR strength compared with a matched uninjured cohort. Body mass-normalized SCAP, ER, and IR strength should be considered as a variable of interest in player screening for injured athletes returning to sport and uninjured athletes with the goal of reducing future injury risk.

Keywords: medial elbow; normalized shoulder strength; overhead athlete.