Increasing error at targeted phase of gait facilitates motor adaptation for improving crouch gait in children with cerebral palsy.

The purpose of this study was to determine whether applying a targeted downward perturbation force at the pelvis during walking would facilitate motor adaptation for improving crouch gait in children with cerebral palsy (CP). Twelve children with CP who walk with crouch gait participated in a one-visit study consisting of treadmill walking with three force conditions, i.e., early-stance, mid-stance, and constant. Each session consisted of 1 min of walking with no force (baseline), 7 min with force (adaptation), and 2 min with no force (postadaptation). For the early-stance and mid-stance conditions, a downward force was applied starting at either the early-stance phase or the mid-stance phase for 250 ms, respectively. For the constant condition, a downward force was applied throughout the whole gait cycle. Kinematics from both legs and electromyography (EMG) from muscles of the more affected leg were recorded. Participants showed a significant decrease in peak knee flexion (i.e., an improved crouch gait pattern) of the more affected leg during the stance phase in the late postadaptation periods (P = 0.04) for the mid-stance condition, but showed no significant changes for the constant and early-stance conditions (P > 0.05). These findings suggest that applying a targeted downward pulling force during the mid-stance phase, compared with a constant condition, may facilitate motor adaptation for improving crouch gait in children with CP, whereas applying a force during the early-stance phase may also be less effective. Results from this study may be used to develop new intervention approaches to improve crouch gait in children with CP through error-based motor adaptation.NEW & NOTEWORTHY Crouch gait is one of the most frequently observed gait abnormalities in children with cerebral palsy (CP). These findings suggest that applying a targeted downward pulling force during the mid-stance phase, compared with a constant condition, may facilitate motor adaptation for improving crouch gait in children with CP, whereas applying a force during the early-stance may be less effective. These findings may be used to develop new interventions to improve crouch gait in children with CP.