Continuous Walking Alters Gait Patterns In Individuals With Lower Limb Amputation

PURPOSE: To investigate the changes in gait kinematics and muscle activation during an extended period of continuous walking in people with lower limb amputation (LLA). METHODS: Ten participants (4F/6M, 54.0 ± 13.4 years, 82.4 ± 13.8 kg, 173.8 ± 13.5 cm, 16.7 ± 15.1 years post amputation) with unilateral LLA (3 Transtibial/7 Transfemoral) walked on an instrumented treadmill at a self-selected speed continuously for 15 minutes. Eight reflective clusters were attached to the participant’s thorax, sacrum, bilateral thighs, bilateral calves, and bilateral forefeet. kinematic data were reduced to 100 points to represent 0-99% of the gait cycle from heel strike to ipsilateral heel strike, with 60% representing toe-off. Heel strike was defined as the point when vertical ground reaction forces exceeded 20 N. Average waveforms were calculated for the gait cycle with 90% confidence intervals to compare the first 5 minutes and the final 5 minutes of walking. Areas when the confidence intervals did not overlap for 3 or more consecutive points were considered statistically significant. Mean differences (MD) were calculated for all significant differences. RESULTS: Participants walked an average of 0.68 ± 0.21 m/s. In the final 5 minutes, participants exhibited greater hip rotation (MD = 6.78°) in the amputated side during mid-stance compared to the first 5 minutes. Increased trunk flexion was observed on the amputated side in the early stance (MD = 14.11°) and swing phase (MD = 16.15°) during the final 5 minutes. Hip flexion also decreased (MD = 13.08°) during stance on the amputated side in the final 5 minutes. Participants showed higher ipsilateral trunk lateral flexion (MD = 1.34°) on the intact side in the loading response in the first 5 minutes compared to the final 5 minutes. CONCLUSIONS: Fifteen minutes of walking led to changes in gait kinematics in people with LLA. Changes are mostly proximal at the hip and trunk, which suggests that extended periods of walking lead to compensatory behavior and may increase the risk of lower back pain and hip osteoarthritis in individuals with LLA. Future research should explore if improved muscle strength on the amputated limb improves function during gait.