Biomechanical changes in gait before and after fatigue in unilateral transtibial amputees

Fatigue can exacerbate gait abnormalities in unilateral transtibial amputees (TTA), but specific changes in walking patterns and compensatory strategies under fatigue remain unclear. This study aimed to investigate gait alterations in unilateral TTA following a fatigue-inducing protocol.

Ten male unilateral TTA and ten age-matched able-bodied controls underwent three-dimensional gait analysis at self-selected speed under non-fatigued and fatigued conditions. Spatiotemporal parameters, joint kinematics, and ground reaction forces were measured. Two-way ANOVA was used for statistical comparisons.

Within the TTA group, the residual limb demonstrated a shorter stance phase (62.3 ± 2.4% vs. 65.1 ± 1.4%) and single support (34.7 ± 1.9% vs. 37.1 ± 2.8%), but greater step length (38.27 ± 2.49% vs. 35.76 ± 1.92%), peak hip flexion(35.0 ± 5.6° vs. 28.6 ± 3.0°) and knee flexion(67.3 ± 7.2° vs. 56.4 ± 5.6°) than the intact limb. Fatigue further increased step length (37.42 ± 2.41% vs. 36.61 ± 2.63%) and hip flexion (33.2 ± 5.3° vs. 30.5 ± 5.3°), while reducing hip extension (10.9 ± 4.8° vs. 12.8 ± 4.2°) and hip horizontal range of motion (17.5 ± 6.0° vs. 19.5 ± 6.6°). Compared to controls, TTA group had longer stride time (1.15 ± 0.04s vs. 1.08 ± 0.08s) and greater hip horizontal range of motion (18.5 ± 6.4° vs. 12.5 ± 3.0°), but lower cadence (105.1 ± 4.1 steps/min vs. 111.6 ± 8.1 steps/min).

Fatigue amplifies pre-existing gait asymmetries in unilateral TTA and elicits compensatory strategies, including increased reliance on the intact limb and greater proximal joint mobility. Targeted interventions to enhance residual limb function and hip flexor strength and endurance may help reduce fatigue-related asymmetry and fall risk.