Feedback of triceps surae EMG in gait of children with cerebral palsy: a controlled study.

Children with spastic hemiplegia secondary to cerebral palsy show disrupted patterns of work and power in gait. A computer-assisted feedback system was used to deliver EMG feedback from the triceps surae muscle group to walking subjects in conjunction with amplitude and timing targets for muscle relaxation and activation. Biofeedback of triceps surae muscle activity during gait was compared with physical therapy (PT) in a two-period crossover design, with intervening biomechanical gait analyses to assess the effects of each type of treatment. Kinematic and kinetic gait variables were affected differently by each type of treatment. Stride length and velocity were positively affected by the biofeedback protocol. Positive work done by the affected ankle increased through PT, but gait symmetry was negatively affected, such that the stance phase was prolonged, and peak ankle power at push-off was not improved. In contrast, the biofeedback treatment improved gait symmetry, and was associated with greater ankle power for push-off, as well as increases in total positive work at the hip and ankle. It is concluded that the feedback protocol might be an effective adjunct to physical therapy in hemiplegic children.