The link between physical activity and health is clear. Promoting physical activity can be a cheap and first-line treatment for nearly every chronic disease. However, most clinicians do not apply the same level of surveillance, assessment, and management approach to detect problems with physical activity or sleep in children and adolescents with Cerebral Palsy (CP). Consequently, many children with CP miss out on an important first line of treatment. This article presents an evidence-informed clinical practice guide to help practitioners detect 24-hour activity problems in children with CP. This is a critical step to help them adopt healthy lifestyle behaviours, which will provide long-term health benefits.