The investigators would like to understand how the physical activity levels and body size of a child with cerebral palsy (CP) in a clinical situations versus out in the community relates to what they want to do in day to day life (participation in life). The investigators believe that what a child really does out in day to day life will predict life participation to a greater degree than what they do in a structured clinical situation (i.e. therapy session with therapist). The investigators think that increased body size with normal growth is related to less physical activity and participation in day to day life for children with cerebral palsy (CP) who can walk. This project will use a novel accelerometer to measure walking activity during day to day life.