Center of mass movement and energy transfer during walking in children with cerebral palsy.

OBJECTIVE To gain insight into the mechanical inefficiencies of gait patterns used by children with spastic diplegia by analysis of center of mass (COM) movement and energy recovery. DESIGN Prospective study using between-group measures to analyze differences between children with cerebral palsy (CP) and age-matched controls without CP. SETTING Assessments were performed in a gait laboratory. PARTICIPANTS Fifteen children with spastic diplegia and 6 age-matched controls without CP with a mean age of 9.7 years. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Gait data assessed included temporal-distance factors, COM vertical excursion, work done on the COM, and the percentage of energy transferred and relative phase between the potential and kinetic energy. RESULTS Children with CP had a 33% smaller energy recovery factor than the controls (P<.001). They also had 60% greater COM vertical excursion (P<.02) and a poorer phasic relation between potential and kinetic energies (P<.02), both of which contributed to greater mechanical work performed (P<.003). CONCLUSIONS Compared with the age-matched controls without CP, the children with CP were mechanically less efficient in their gait. Interventions that promote heel contact and roll over and greater knee stability to better utilize the kinetic energy of push-off could improve walking efficiency.