Introduction – Classification in Paralympic sport aims to create a competitive and fair environment by reducing the impact of impairment on the ability to perform sport-specific activities. In wheelchair tennis (WT), current classification criteria largely rely on expert opinion rather than empirical evidence, particularly regarding trunk function. This study investigated the relationship between upper-body strength (arm, trunk) and wheelchair mobility performance in elite WT players to attain evidence-informed classification. Methods – Fifty-one WT players (men, women, and quad division) were assessed during standardized field tests and match play. Upper-body strength was measured using isometric arm and trunk-related force tests, while mobility performance was quantified using inertial sensors, capturing speed, acceleration, and rotational metrics. Associations between strength and mobility performance outcomes were assessed using Pearson/Spearman correlations. Differences between classification-based trunk function groups (0, 1, 2) were explored using T-tests and effect sizes. Results – Correlations between strength and mobility performance were modest (r = 0.26–0.62). Push and pull forces showed the highest associations with sprint and rotational performance (push up to r = 0.54; pull up to r = 0.62). Comparisons between trunk function groups revealed substantial differences, particularly in acceleration and rotation, with large effect sizes (ES = 1.18–2.43) between athletes with full vs. minimal trunk control. Discussion – Trunk function plays a critical role in WT mobility and is underrepresented in the current classification system. Future classification systems should include functional measures that reflect the impact of impairment on sport-specific activities. Particular attention should be given to dynamic trunk movements during acceleration and rotation to ensure a more evidence-based and functionally relevant approach.

Objective This cross-sectional study examined associations between wheelchair sprint and anaerobic power (measured in the lab) and wheelchair mobility performance (measured in the field) among two groups of wheelchair tennis players. Additionally, construct validity was assessed for both lab and field tests. Design Nine amateur and nine elite wheelchair tennis players performed a Sprint and Wingate test on a wheelchair ergometer in the lab and a Sprint, Illinois, and Spider test in the field, with inertial measurement units on their wheelchairs. Associations were assessed using regression analyses, and construct validity was assessed with an independent t test (elite vs. amateur). Results The strongest associations were observed between lab outcomes and field sprint power (R2 > 90%), followed by peak linear velocity and test duration (R2 = 77%-85%), while peak rotational velocity showed the lowest associations with lab outcomes (R2 = 69%-80%). The elite group outperformed the amateur group on all test outcomes. Conclusions Despite differences in lab- and field-testing methodologies (e.g., trunk influence, linear/rotational components), the strong associations indicate overlap in measured constructs. Field testing offers valuable insight into practical performance, whereas lab testing enables in-depth biomechanical and physiological analyses. All tests effectively discriminate between elite and amateur wheelchair tennis players.