Range of Motion and Muscle Stiffness Differences in Junior Tennis Players with and without a History of Shoulder Pain.

Background: Due to its significant unilateral predominance, tennis can provoke functional and morphological asymmetries that develop over time and may result in undesired morphological alterations.

Hypothesis/purpose: The goals of this study were a) to assess glenohumeral range of motion and muscular stiffness in young tennis players with and without a history of shoulder pain and b) to examine interlimb asymmetries in these variables in both groups. It was hypothesized that players with a history of shoulder pain would show a reduced glenohumeral internal rotation (IR) and total arc of motion (TAM) and increased stiffness in internal rotator muscles compared to those without shoulder pain.

Study design: Cross-sectional observational study.

Methods: Twenty-five participants participated in the study (11 with a history of shoulder pain and 14 without pain). Participants performed stiffness measurements on muscles involved in the main tennis stroke motions alongside range of motion examinations on the dominant (D) and non-dominant (ND) extremities including IR, external shoulder rotation (ER), and TAM. A two-way mixed-design ANOVA analyzed group and limb effects, with effect sizes classified as small, medium, or large. Significant effects were further examined using Bonferroni post hoc tests.

Results: There were significant differences between the shoulder pain and no shoulder pain group in the D IR (-3.1º, 6.43%, p = 0.048; effect size [ES] = 0.58) and D TAM (-6.1º, 3.01%, p = 0.024; ES = 0.66). Moreover, significant differences were found between the D and ND extremities in IR in both groups (-9.2º, 14.94%, p < 0.001; ES = -1.72) and TAM in the shoulder pain group (-5.6º, 2,77%, p = 0.038; ES = 0.61). Stiffness measurements showed no significant differences between groups or extremities.

Conclusions: Significantly lower values of D IR and TAM and higher IR asymmetries in the shoulder pain group suggest that a deficit in these parameters could be associated with shoulder pain history in junior competitors.

Level of evidence: 2.