The long-term goals of this research are to quantify patient-specific changes in neuromuscular control in order to optimize treatment planning and improve mobility for individuals with cerebral palsy (CP). As a first step, the aims of this proposal are to evaluate neuromuscular control before and after one of the most common treatments for individuals with CP, orthopaedic surgery. The investigators will evaluate if patient-specific measures of neuromuscular control, based upon the framework of muscle synergies, can predict improvements in walking ability after surgery. Further, investigators will determine whether neuromuscular control changes after surgery and if these changes contribute to improvements in movement. To achieve these goal the investigators will implement and test new tools to quantify neuromuscular control which integrate clinical gait analysis and two computational techniques: synergy analysis and dynamic musculoskeletal simulation. This research will provide the foundation to use measures of altered neuromuscular control to inform treatment planning, develop alternative treatments, and improve mobility in CP and other neurologic disorders.