Upper-Limb asymmetry in wheelchair para-athletes: a comparative analysis across sports disciplines

BACKGROUND: Wheelchair use has increased globally, with many individuals relying on wheelchairs not only for mobility but also for participation in sport. However, upper-limb (UL) asymmetries are common among wheelchair athletes and may contribute to overuse injuries. Limited evidence exists regarding how asymmetry differs among athletes in para-sports who use wheelchairs to compete. This study aimed to compare UL asymmetry levels among wheelchair para-athletes across different sports disciplines through an exploratory analysis.

METHODS: A cross-sectional study was conducted with 30 wheelchair para-athletes (27 men, 3 women; 18-40 years) competing in six disciplines: powerlifting, wheelchair rugby, table tennis, wheelchair basketball, boccia, and wheelchair handball. Muscle strength and range of motion (ROM) were assessed using a validated portable dynamometer/inclinometer across seven UL movements. Asymmetry was calculated as the percentage difference between dominant and non-dominant limbs, with values ≥15% classified as asymmetric.

RESULTS: Wheelchair handball (10%), basketball (12%), and powerlifting (10%) demonstrated predominantly symmetric profiles, whereas table tennis (17%), boccia (30%), and wheelchair rugby (26%) exhibited greater asymmetry. Significant differences between symmetric and asymmetric groups were observed in strength (shoulder abduction, flexion, extension, and internal rotation; p  < 0.05) and ROM (shoulder abduction, adduction, and flexion; p  < 0.05), with higher values recorded in the asymmetric group.

CONCLUSION: UL asymmetry indices ranged from 10% to 30% across disciplines, with table tennis, boccia, and rugby surpassing the 15% threshold. These differences in shoulder strength and ROM suggest that unilateral technical demands and impairment level are key determinants of musculoskeletal adaptation in wheelchair sport.