Prevalence of Glenohumeral Internal Rotation Deficit and Sex Differences in Range of Motion of Adolescent Volleyball Players: A Case-Control Study.

Shoulder range of motion (ROM) adaptation is common observed among volleyball players, but studies on the shoulder joint function of adolescent athletes are lacking. This study aimed to clarify the prevalence of glenohumeral internal rotation deficit (GIRD) among adolescent players and differences in ROM based on sex. A questionnaire survey and ROM measurements of the shoulder joint and trunk using a plastic goniometer were conducted on 123 volleyball players (63 males and 60 females; mean age, 15.8 years). The prevalence of GIRD was investigated for internal rotation differences of >10° and total rotation motion of <5°. Questionnaire items and ROM were compared between GIRD and non-GIRD patients, and sex differences in ROM were also presented. Of the participants, 38.2% (n = 47/123) had GIRD. The GIRD group showed a decrease in external rotation on the dominant side ( p = 0.003, 1 - beta = 0.84), but this was not associated with a history of shoulder injury. Sex differences in shoulder ROM showed hypomobility in males and hypermobility in females. However, there was no association between shoulder injury and GIRD among adolescent players. There are sex differences in ROM, which should be considered in future studies.