Comparative Analysis of Anatomical and Pathological Glenohumeral Internal Rotation Deficit Among Volleyball Players: A Cross-Sectional Study.

Background: Glenohumeral internal rotation deficit (GIRD) has been widely researched in a variety of overhead sports, most notably baseball players. While some research involving volleyball players has been conducted, there is still a considerable gap in the current understanding of this topic. Volleyball play frequently results in obvious disparities in the range of motion between the dominant and non-dominant arms, notably in internal rotation, external rotation and total range of motion of the shoulder joint. GIRD has been associated with increased injury risk and shoulder strength deficits. However, distinguishing between anatomical GIRD (aGIRD) - a normal adaptation in overhead athletes and pathological GIRD (pGIRD) which is linked to injury and impaired performance - offers critical insight into how different subtypes may contribute to shoulder dysfunction. Purpose: The purpose of this study was to analyze the prevalence of anatomical and pathological GIRD sub-types in volleyball players and examine their association with gender, court position, weekly practice time, and experience. Study Design: Cross-sectional study. Methods: One hundred-seventy professional and semi-professional volleyball players, 91 female and 79 male, participated in the study (Age: 24.45 ± 3.24). One hundred thirty-seven participants (80.6%) reported being right hand dominant. Thirty-three participants (19.4%) reported being left hand dominant. A universal goniometer was utilized to measure the internal rotation (IR) range of motion (ROM) and external rotation (ER) ROM of the dominant and non-dominant arms, and the total range of motion (TROM) was calculated. Chi-square tests were conducted to examine associations between GIRD classification (aGIRD, pGIRD, absent GIRD) and categorical variables. Results: A significantly higher prevalence of glenohumeral internal rotation deficit was observed in this study when compared to previous studies, accounting for 89.4% (152) of the total. Of those found to have glenohumeral internal rotation deficit 80 individuals (52.6%) had pGIRD and 72 individuals (37.4%) had aGIRD. There were associations between GIRD type and experience (p = 0.001), weekly practice time (p = 0.002), gender (p < 0.001), and court position (p = 0.001). Athletes with more experience, higher practice time, and who were male were more likely to present with pGIRD. pGIRD was also more prevalent among middle and outside hitters, while aGIRD and normal GIRD were more common among setters and middle blockers. Conclusion: These data suggest that a significant majority of volleyball players exhibit GIRD, with pGIRD being more prevalent among those affected. Factors such as experience, weekly practice time, gender, and court playing position were found to be significantly associated with the type of GIRD, highlighting the complex relationship between player characteristics and shoulder mobility adaptations in volleyball athletes. Level of Evidence: 3.