Level of competition influences overhead athletes' shoulder internal rotation range of motion in the side-lying position.

Background: A common impairment present in overhead athletes is decreased internal rotation (IR) range of motion (ROM). The supine position has typically been utilized for measuring IR ROM, but a side-lying position has demonstrated better reliability. There is, however, a paucity of reported values for this side-lying position in overhead athletes, as well as any impact on IR ROM across levels of athletic competition. Hypotheses for this study were: (1) dominant shoulder IR ROM would significantly decrease as level of competition increased; (2) dominant and nondominant IR ROM would be significantly different between the 2 positions, with the side-lying position yielding the least amount of IR ROM; and (3) the dominant shoulder would have significantly less IR ROM than the nondominant shoulder for both positions. Methods: Two measurements of passive IR ROM on the dominant and nondominant shoulder were gathered in a side-lying and supine position in 176 National Collegiate Athletic Association Division I (DI), III, and recreational overhead athletes. Results: The dominant shoulder mean IR ROM values for the side-lying and supine positions were 40.0° ± 10.1° and 54.5° ± 11.6°, respectively; paired Conclusion: The side-lying position yielded significantly smaller IR ROM values compared to the supine position. The average IR ROM for the side-lying position for the dominant and nondominant shoulder in asymptomatic overhead athletes was 40° and 53°, respectively. National Collegiate Athletic Association DI athletes had a significantly smaller dominant-shoulder side-lying IR ROM value of 35°.