Gait electromyography in normal and spastic children, with special reference to quadriceps femoris and hamstring muscles.

Telemetered gait electromyography was used to investigate gait patterns and the phasic behavior of the quadriceps femoris and medial hamstring muscles in 26 normal children and 32 children with spastic cerebral palsy. The average child with spastic cerebral palsy was found to have a shorter stance phase than the normal, but the cadence, while more variable, was nearly the same as normal. The spastic muscles typically exhibited prolonged phasic activity or a dysphasic pattern. Most of the patients with spastic hamstrings also had spastic quadriceps, suggesting that over-weakening the hamstrings may produce an unwanted genu recurvatum or hyperextended knee gait. Care must be taken to balance hamstring spasticity with quadriceps spasticity. A final result with slight knee flexion is preferable to hyperextension.