Scapular Dyskinesis, Glenohumeral Internal Rotation, and Pectoralis Minor Length in Male Elite Tennis Players

Scapular dyskinesis (SD) is prevalent among overhead athletes and may contribute to shoulder dysfunction. Internal rotation (IR) asymmetry and pectoralis minor shortening have been described as factors associated with SD in tennis players.

The aim of this study was to identify the prevalence and distribution of scapular dyskinesis (SD) grades in male elite tennis players and to investigate their association with glenohumeral rotational range of motion and pectoralis minor length (PML).

Cross-sectional study.

Forty-three elite male tennis players aged 14-24 years were recruited through posted advertisements at the university, and those who volunteered and met the inclusion and exclusion criteria were enrolled in the study. Scapular dyskinesis was assessed using a standardized visual observation method and classified as normal, subtle, or obvious. Bilateral passive shoulder internal rotation (IR), external rotation (ER), and total rotational motion (TROM) were measured. PML (height-normalized pectoralis minor index [PMI]), and lateral scapular slide test (LSST) distances were recorded. Data were analyzed using one-way ANOVA with Bonferroni post hoc tests, and paired t-tests were used for side-to-side comparisons. Statistical significance was set at p < 0.05.

SD appeared in 70.9% of shoulders (dominant: 79.1%; non-dominant: 62.8%), with a significant difference in grade distribution between sides (p < 0.001). Higher SD grades were associated with reduced IR (dominant: F = 13.55, p < 0.001; non-dominant: F = 18.23, p < 0.001) and decreased TROM (dominant: F = 4.86, p = 0.013; non-dominant: F = 6.57, p = 0.003). The obvious SD group showed the lowest IR values in both shoulders, with significant differences compared to the normal and subtle groups, and demonstrated the shortest PML and shorter PML (dominant: F = 19.63; non-dominant: F = 19.43, p < 0.001).

Elite male tennis players commonly demonstrate SD, with higher dyskinesis grades associated with reduced IR, decreased TROM, and shorter PML. However, these findings reflect associations rather than causal relationships. The coexistence of SD and IR asymmetry should be considered during clinical assessment of overhead athletes.

3.