The effects of posterior shoulder stretch on rotator cuff strength ratio in adolescent baseball players with scapular dyskinesis: A randomized controlled trial

BACKGROUND: Posterior shoulder tightness (PST) has been identified as an important factor that causes scapular dyskinesis. Therefore, rehabilitation programs should focus on an intervention involving a posterior shoulder stretch combined with a scapular stabilization exercise (PSSE). However, few studies have investigated the effects of PSSE on rotator cuff (RC) muscle strength in overhead athletes with scapular dyskinesis. OBJECTIVE: To determine the effects of PSSE on RC muscle strength, dynamic control ratio (DCR), range of motion (ROM), and pain. METHODS: Twenty-four adolescent baseball players with scapular dyskinesis were randomly allocated to one of two groups which trained for 6-weeks. Group I performed PSSE while group II performed same exercises but without stretching (SSE). The isokinetic peak moment/body weight (PM/BW) of concentric and eccentric external rotation (ERc and ERe) and concentric and eccentric internal rotation (IRc and IRe), the DCR (ERe/IRc and IRe/ERc), ROM, and pain were measured in pre- and post-intervention. RESULTS: A time-by-group interaction effect was observed for the concentric and eccentric ER, the DCR, and the ROM only the PSSE group. CONCLUSIONS: PSSE intervention is a more effective program than SSE for improving RC muscle strength and balance, particularly in terms of its ER component and the associated DCR.