Estimation of Pathological Gait Asymmetry of Lower-Limb Prosthetic Users at High and Low Walking Speeds

Gait asymmetry provides a quantitative indication of differences between the right and left lower kinematic chain during a walking. The asymmetry during the pathological gait of subjects wearing prostheses or orthoses may vary according to walking speeds. This work presents the differences in the asymmetry of affected and unaffected lower limbs in pathological gait at high and low speeds validated in subjects with pros-theses and lower limb orthoses. Two datasets were used, the first recorded 18 subjects wearing prostheses after above-knee amputation (recorded with 3D cameras) between speeds 0.4 and 1.4 m/s, and the second recorded a pathological gait simulation on 5 healthy subjects wearing KAFO orthoses (recorded with inertial sensors) at speeds 1.8 and 3.1 m/s. Temporal Asymmetry and Normalized Cross-Correlation (CCnorm) methods were used to estimate asymmetry. Additionally, a statistical study was performed to evaluate whether there were significant differences between high-speed and low-speed asymmetry values. The results allow us to conclude that the asymmetry between the affected and unaffected limb at high speed tends to present more significant asymmetry than at low speed. However, these differences were not statistically significant (p< 0.05 ). Nevertheless, the experimental results may support future clinical applications based on lower limb rehabilitation.