The purpose of this research study is to learn more about the usefulness of a physical therapy treatment that combines robot-assisted walking with electrical impulses that help to make muscles contract. This treatment is intended for children with cerebral palsy. Up to eleven children with cerebral palsy will receive up to 18 treatments and will have several evaluations before and after treatment.

Inclusion Criteria:

• GMFCS II, III, or IV cerebral palsy
• 5-12 years of age
• meet safety criteria for robotic gait training (<300 lbs, intact skin, femoral length 21-47 cm, ability to follow simple instructions)
• meet safety criteria for functional electrical stimulation (voluntary hip and knee muscle contraction, intact skin)

Exclusion Criteria:

• planned major intervention during study period
• contractures that interfere with upright stance
• history of non-traumatic long bone fracture or clinically significant osteoporosis
• significant concurrent illness
• significant condition not typically associated with cerebral palsy