Objective: To determine whether a posterior shoulder stretch was effective in increasing internal rotation (IR) and horizontal adduction (HAd) range of motion (ROM) in overhead athletes identified as having reduced mobility.
Design: Randomized controlled trial (parallel design).
Setting: University-based sports medicine clinic.
Participants: Thirty-seven university-level athletes in volleyball, swimming, and tennis, with IR ROM deficits ≥15°, were randomized into intervention or control groups. No subjects withdrew or were lost to follow-up.
Intervention: The intervention group performed the "sleeper stretch" daily for 8 weeks, whereas the control group performed usual activities.
Main outcome measures: Independent t tests determined whether IR and HAd ROM differences between groups were significant at 8 weeks and 2-way repeated-measures analysis of variance tests measured the rate of shoulder ROM change. Subject-reported shoulder pain and function were obtained at each evaluation.
Results: Significant differences were found between the intervention and control groups' IR and HAd ROM at 8 weeks (P < 0.001 and P = 0.003, respectively) compared with baseline (zero weeks) (P = 0.19 and P = 0.82, respectively). Significant improvements in IR were detected in the intervention group at 4 weeks (P < 0.001), whereas HAd demonstrated significant changes only at 8 weeks (P = 0.003). Reported shoulder function (P = 0.002) was different between study groups at 8 weeks.
Conclusion: Overhead, university-level athletes with an IR deficit ≥15° significantly increased their IR and HAd ROM after performing a posterior shoulder stretch for 8 weeks.
Clinical relevance: Effective management of posterior shoulder tightness through stretching may reduce the incidence of shoulder pathology in overhead athletes.