Measurement of physical activity

With assessment of physical activity becoming more common in physical education and youth sport research, it is critically important that researchers, educators and coaches become knowledgeable about the dierent methods used to measure physical activity in young people. On the surface, measuring physical activity may seem straightforward. Students will obligingly wear a pedometer during a physical education lesson or complete a self-report questionnaire about their participation in organized sport. However, in reality, obtaining valid and reliable assessments of physical activity in children and adolescents is an extremely dicult undertaking. Unlike some other health behaviours, physical activity does not come in handy easyto-measure packages or containers (e.g., packs per day, cans of soft drink); it cannot be placed in a test tube and assayed in the laboratory; and while cardiorespiratory tness is modestly correlated with physical activity in youth, physical activity lacks a precise biological marker. Additionally, physical activity is a remarkably complex behaviour characterized by multiple dimensions and domains. e dimensions of physical activity are well known and include frequency, duration, intensity and type. For young people, the domains of physical activity are numerous and typically comprise in-school physical activity (including recess and physical education), outof-school physical activity (school, club sports and dance), transportation-related physical activity (walking or biking to and from school), and physical activity in specic behavioural settings (e.g., after-school programmes, preschools). Ideally, a physical activity assessment tool would provide valid and reliable measures of all four dimensions of activity behaviour in all of the aforementioned domains. However, due to practical considerations and unresolved methodological issues, no such measurement tool currently exists. us, as the quote above suggests, the selection and application of a physical activity measurement tool will always depend heavily on the specic aims of the investigation and the resources available to the research team