Electromyographic evaluation of the sound and involved side during gait of spastic hemiplegic children with cerebral palsy.

The purpose of this study was to investigate the surface electromyogram (EMG) of the lower limbs of hemiplegic children with spastic cerebral palsy during gait. The EMG of seven muscles was analyzed for 17 children (5-12 years old). The EMG of the involved side was decreased for the examined shank muscles and increased for the hamstrings, during certain phases of the gait cycle, compared with the sound side. The rectus femoris of the involved side showed prolonged activation during the swing phase. The enhanced activation of the hamstrings may be beneficial/compensatory, preventing knee hyperextension. The presence of equinus foot obstructs the foot clearance and hence the prolonged rectus femoris EMG activity during the swing phase may contribute to shorten the lower limb by flexing the hip. Possible compensatory mechanisms of the proximal muscles of the involved lower limb that can be measured with instrumented gait analysis should be taken into account before the decision for a specific treatment.