Short Walking Exercise Leads to Gait Changes and Muscle Fatigue in Children With Cerebral Palsy Who Walk With Jump Gait

OBJECTIVE The aim of this study was to evaluate kinematic changes and muscle fatigue in jump gait during a walking exercise and the relationship between kinematic changes and muscle fatigue and strength. DESIGN This preliminary study included 10 children with cerebral palsy who walk with jump gait. Hip and knee maximal isometric muscle strength were measured using a dynamometer. Then, lower-limb kinematics and electromyography were collected while children walked continuously for 6 min at their self-selected speed. Electromyography median frequency and lower-limb joint angles were compared between the first and the sixth minutes of the walking exercise using t test and Wilcoxon rank test. The relationship between kinematic changes and muscle strength and changes in electromyography median frequency were assessed using correlation analyses. RESULTS During stance, maximal knee flexion significantly increased at the sixth minute (P = 0.01) and was associated with knee extensor muscle weakness (ρ = -0.504, P = 0.03). Muscle fatigue was observed only in the gluteus medius muscle (P = 0.01). CONCLUSIONS Children with cerebral palsy who walked with jump gait and who had knee extensor weakness were more prone to an increase in knee flexion during a continuous walk. The fatigue in the gluteus medius muscle suggests that physical intervention should target the endurance of this muscle to improve jump gait.