Athletes involved in repetitive overhead shoulder rotation demonstrate increased external rotation and decreased internal rotation range of motion. Deficits in internal rotation have been linked to the development of shoulder pathology. The purpose of this study is to determine if a posterior shoulder stretch program is effective in increasing dominant arm internal rotation and horizontal adduction range of motion in overhead athletes identified as having reduced mobility and posterior shoulder tightness. Thirty-seven overhead athletes in volleyball, swimming and tennis, with internal rotation range of motion deficits greater than or equal to 15°, were randomised into intervention or control groups. The intervention group performed the “sleeper stretch” daily for eight weeks while the control group performed usual activities. Independent t-tests determined whether internal rotation and horizontal adduction range of motion differences between groups were significant and two-way repeated measures analysis of variance tests measured the rate of shoulder range of motion change. Reported shoulder pain and function were also obtained at each evaluation. Significant differences were found between the intervention and control groups' internal rotation and horizontal adduction range of motion at eight weeks (p<0.001 and p=0.003 respectively) compared to baseline (zero weeks) (p=0.19 and p=0.82 respectively). Significant changes in internal rotation were detected in the intervention group at four weeks (p<0.001) with further adaptations noted at eight weeks. Horizontal adduction improved at a slower rate demonstrating significant changes at eight weeks (p=0.003). Reported shoulder pain and functional ability (p=0.002) were different between the study groups at eight weeks. Overhead, collegiate-level athletes with an internal rotation deficit greater than or equal to 15° are able to significantly increase internal rotation and horizontal adduction range of motion by performing a posterior shoulder stretch exercise for eight weeks.
