Associations Between Physiological Characteristics and Physical Performance in Amputee Soccer Players: A Cross-Sectional Study

Background and Objectives: Amputee soccer places exceptional demands on lumbopelvic stability and upper extremity capacity due to unilateral lower limb amputation and forearm crutch use. This cross-sectional study examined associations between core stabilization, core endurance, respiratory muscle strength, isokinetic knee muscle strength, and dominant handgrip strength with physical performance in amputee soccer players, and examined which physiological variables were most strongly associated with performance. Materials and Methods: Fifteen male amputee soccer players (age: 27.4 ± 5.6 years; BMI: 20.8 ± 1.4 kg/m2) competing in the Turkish Amputee Football Super League were included. Core stabilization was assessed by the pressure biofeedback unit (PBU), core endurance by the McGill Core Endurance Battery, respiratory muscle strength by maximal inspiratory and expiratory pressures (MIP and MEP), isokinetic knee muscle strength at 60°/s, 180°/s, and 240°/s using the IsoMed 2000 dynamometer, and dominant handgrip strength by a hydraulic hand dynamometer. Physical performance outcomes were single-leg triple hop test (THT) distance, 10-m sprint time, and Closed Kinetic Chain Upper Extremity Stability Test (CKCUEST) score. Results: PBU score was negatively correlated with THT distance (r = −0.928, p < 0.001) and 10-m sprint time (r = −0.580, p = 0.023). McGill total score was correlated with THT distance (r = 0.561, p = 0.030), and dominant handgrip strength with CKCUEST score (r = 0.634, p = 0.011). No significant associations were found for respiratory muscle strength or isokinetic knee muscle strength. Separate regression models showed that PBU score explained variance in THT distance (R2 = 0.861, p < 0.001) and 10-m sprint time (R2 = 0.336, p = 0.023); McGill total score explained variance in THT distance (R2 = 0.315, p = 0.030). Conclusions: Core stabilization and endurance appear to be primary factors associated with physical performance in amputee soccer and warrant targeted assessment and training.