2026 Volume 4 Issue 1 Pages 48-54
Objective: A previous study focused on tennis players highlighted greater muscle thickness on the non-dominant side related to trunk rotation in serves and strokes. However, the influence of experience duration on this side-to-side asymmetry in trunk muscles remains unexplored. This study aimed to compare trunk muscle thickness and cross-sectional area between dominant and non-dominant sides among tennis players, while also investigating correlations with playing experience.
Methods: Eighteen tennis players with at least one year of experience practicing twice weekly participated in this study. Ultrasound sonography was employed to measure the thickness and cross-sectional area of abdominal muscles (rectus abdominis, external oblique, internal oblique, and transversus abdominis) and dorsal muscles (erector spinae and multifidus) on both sides. The morphology between dominant and non-dominant sides was compared using a paired t-test, and the correlation between asymmetry (calculated as non-dominant / dominant side ratio) and sports experience was assessed using Pearson’s correlation.
Results: Tennis players exhibited significantly greater thickness in the non-dominant abdominal muscles. Notably, only the asymmetry in internal oblique thickness showed a positive correlation with playing experience.
Conclusion: This study demonstrated that among the trunk muscles assessed, only the internal oblique showed a significant positive correlation between asymmetry and playing experience. These findings indicate that playing experience is associated with asymmetric adaptation of the internal oblique, a muscle involved in trunk rotation and stabilization. However, since this was a cross-sectional study, causality cannot be determined. Further longitudinal studies are needed to clarify how long-term tennis play contributes to trunk muscle asymmetry.
