Abstract: Capio CM, Sit CH, Abernethy B. Physical activity measurement using MTI (Actigraph) among children with cerebral palsy.Objective: To investigate the validity of MTI accelerometer as a physical activity (PA) measurement instrument for children with cerebral palsy (CP).Design: Participants were classified within Gross Motor Function Classification System I to III and took part in 2 activity sessions: (1) a structured activity protocol with increasing intensities and (2) a free play session. Concurrent measurements of activity counts, heart rate, and observed physical activity were performed.Setting: Data were collected on normal school days in special schools within the participants' 30-minute break period.Participants: Convenience sample of children with CP (N=31; 17 girls, 14 boys...