Asymmetry of the Trunk and Lower Extremity Joint Frontal Plane Kinematics During Single-Leg Standing and Squat in Paralympic Athletes With Upper Limb Deficiency Compared With Intact Athletes

OBJECTIVE: To compare trunk and lower extremity asymmetries in frontal and sagittal kinematics between athletes with upper limb deficiency (ULD) and intact athletes during bilateral-leg standing (BLST), single-leg standing (SLST), and single-leg squat (SLSQ). DESIGN: Cross-sectional study. METHODS: Eleven elite Paralympic athletes with ULD and 11 elite intact athletes performed BLST, SLST, and SLSQ. Angles of the trunk, pelvis, hip, knee, and ankle were recorded using fixed cameras in the frontal and sagittal planes. Kinematic asymmetries between groups as well as the relationship between loss of mass relative to body mass (LM%) and ipsilateral trunk tilt were analyzed. RESULTS: Paralympic athletes exhibited greater ipsilateral trunk tilt during ULD side SLSQ (∆ = 7.1°, P = .02, d = 1.26) compared with intact athletes, but not during intact-side SLSQ. No significant correlation was found between LM% and bilateral angle differences in the frontal plane among Paralympic athletes ( P>.05, .06 ≤ | r| ≤ .27). CONCLUSION: Athletes with ULD compensated for missing body mass by tilting their trunk over their support leg when performing SLSQ only on the ULD side. The amount of trunk tilt did not seem to depend on the amount of missing mass. JOSPT Open 2025;3(2):146-153. Epub 5 November 2024. doi:10.2519/josptopen.2024.0074