Ankle muscle activity during gait in children with cerebral palsy and equinovarus deformity.

Temporal electromyographic (EMG) characteristics of lower limb muscles during gait of spastic hemiplegic and diplegic children with cerebral palsy are described. All subjects were referred for presurgical evaluation of equinovarus deformity. The data indicated both similar and discriminating phasic EMG characteristics between groups of patients. All children displayed premature triceps surae activity beginning in swing phase of gait and continuing through stance. Tibialis posterior, normally active during stance, was also active during swing phase of gait. However, some patients displayed cocontraction of triceps surae and tibialis anterior during stance, together with hamstring muscle activity within normal limits. The remainder of the patients displayed a prolonged duration of hamstring activity. How this gait analysis contributed to presurgical decisions for equinovarus gait is discussed and compared with data from postsurgical gait analysis.