Patients in both groups receive training 3 days/week for 3 months. Initial treadmill velocity is 18 meters/minute; velocity is increased in increments of 6 meters/minute until the maximum speed is achieved at which each patient exhibits the best locomotor capability at full weight bearing. Patients are trained with the minimal weight support assistance necessary for effective limb progression without excessive knee flexion or hyperextension. Polypropylene ankle-foot orthosis is allowed.