The Effects of a Powered Knee Orthosis on Gait Kinematics of Children With Knee Extension Deficiency

Inclusion Criteria: * Age 5-19 years of age * Male or female * Able to understand and follow simple directions based on parent report and physician observation during history and physical examination * Able to provide verbal/written assent. * Less than 20 degrees of knee flexion contracture with hip extended in supine position. * Less than 10 degrees of plantar flexion contracture in neutral foot alignment. * A measured foot-thigh angle of -10 to 25 degrees in prone position. * Based on clinical observation of gait pattern, the patient walks with crouch gait. (The exact level of knee extension deficiency, or crouch, will be quantified after inclusion using gait analysis.) * Able to walk at least 10 feet without stopping with or without a walking aid. Exclusion Criteria: * Any neurological, musculoskeletal or cardiorespiratory injury, health condition, or diagnosis other than cerebral palsy, muscular dystrophy, spina bifida, or incomplete spinal cord injury that would affect the ability to walk as directed for short periods of time. * A history of a seizure in the past year.