Our team proposes to determine if TES has an effect on muscle structure or function in children wit mild to moderate spastic cerebral palsy. Directly measuring cross-sectional area and metabolic output of treated and untreated muscle groups in the same child will give clinicians information about the effect of TES on muscle structure. Isometric strength measurement and estimates of recruitment will yield information about the fuction of treated and untreated muscles. Understanding the relative contributions of muscl and neural influences on any strength increases will assist in designing the most efficient methods of improving strength for children with cerebral palsy. Measures of hypertonia will provide information about the influence (if any) of TES on spasticity as well as help us understand if spasticity influences the effect of TES on strength or muscle structure and function. Measurement of Health Locus of Control will provide information on the influence of health beliefs on adherence to a long term electrical stimulation protocol in children with cererbral palsy.