Scapular dyskinesis with preserved structure and function in largely asymptomatic junior elite tennis players: a 2D video and multimodal cross-sectional study.

backgroundScapular dyskinesis is prevalent in overhead athletes, yet whether it reflects early pathology or physiological adaptation in largely asymptomatic adolescent tennis players remains unclear. In an unselected cohort of junior elite tennis players, we first established scapular dyskinesis prevalence and then examined its relationships with clinical scores, ultrasonographic integrity, shoulder-line tilt, and age. We tested whether shoulder-line tilt displacement during arm elevation differs from zero (the shoulder line moving from a resting obliquity toward level), whether it relates to clinical scores and age, and whether dyskinesis coexists with normal ultrasonographic structure and preserved function rather than structural or functional impairment.

methodsWe retrospectively analyzed 20 male junior elite tennis players (mean age 16.0 ± 1.7 years) who underwent bilateral range-of-motion assessment, ultrasonography, the American Shoulder and Elbow Surgeons (ASES) and Constant-Murley (CMS) questionnaires, and posterior two-dimensional video analysis. Two orthopedic surgeons classified scapular dyskinesis by consensus using the Kibler system; shoulder-line tilt angles were quantified by markerless pose estimation. We compared dominant with non-dominant range of motion and related tilt displacement to clinical scores and age.

resultsScapular dyskinesis was present in 65%, predominantly Type I; all 20 athletes had normal rotator cuff integrity on ultrasonography. The dyskinesis subgroup had mean ASES and CMS scores of 99.2 and 98.6, and the groups did not differ in clinical or range-of-motion variables; CMS scores were equivalent, though ASES equivalence was inconclusive given a ceiling effect. Shoulder-line tilt decreased from a resting obliquity toward level at peak elevation, and age correlated strongly and negatively with this tilt displacement.

conclusionsIn this single-program, male-only cohort of largely asymptomatic adolescent elite tennis players, scapular dyskinesis with normal ultrasonography and preserved function is compatible with a physiological adaptation, suggesting an adaptive window; the findings are not generalizable to female athletes, adults, or other sports. Because dyskinesis is linked to future injury risk, long-term follow-up is warranted, interpreted alongside structural and functional status.