Summary of Presentation at the american academy of orthopedic surgeons
March 10, 2009, New Orleans, LA

Shoulder Posterior Capsular Contracture in Youth Baseball Players: It can be Improved by Stretching

1261 male baseball players are evaluated for shoulder posterior capsular contracture. Contracture and injury prevalence are correlated to exposure to throwing. Success with stretching is documented.

Overhead throwing can cause contracture of the shoulder posterior-inferior glenohumeral ligament which can lead to injuries such as SLAP tears. We show that instruction on stretching can favorably alter progression of posterior contractures.

1261 male baseball players ages 7-15 completed a questionnaire and shoulder exam. Measurements of rotation of both shoulders were made with the subjects in the supine position with the scapula stabilized. Glenohumeral Internal Rotation Deficit (GIRD) was calculated. Pitch type and player position, among other variables, were recorded. The prospective cohort was 175 players who were examined twice, usually about a year apart. Players with excessive GIRD (exGIRD) were given stretching instruction, and the control group was those without exGIRD who were not given instruction. Change in GIRD as a result of this intervention was documented.
14.9% reported pain in the throwing arm. 26.8% reported that they threw a curveball, 6.4% threw a slider. 20.7% had exGIRD. Pitchers had nearly twice the rate of exGIRD as fielders, but only 13% more than catchers. Of the prospective cohort, 56 were identified as having exGIRD, and were instructed to stretch. 94.5% of them had a lower (healthier) GIRD at the second exam. 65.0% of the control group of 119 players with normal or no GIRD who were not instructed to stretch showed increase of the GIRD.

Discussion and Conclusion:
Excessive GIRD is associated with overhead throwing and can predispose to injury. This study shows that pitching and catching are both strongly associated with contracture development and arm pain. A prospective, controlled cohort subgroup documents improvement in GIRD in 94.5% of players instructed on proper stretches, as well as the natural evolution of increasing GIRD in overhead throwers who do not stretch. Teaching players to stretch the posterior shoulder capsule can decrease contracture and lessen reports of arm pain in youth baseball players.