Assessment of physical activity among primary school aged children: the Children's Leisure Activities Study (CLASS)

Overweight and obesity rates among children in Australia have increased twofold in the last decade. Physical activity is thought to play an important role in the prevention and treatment of childhood obesity. Children's physical activity data in Australia are incomplete and mainly based on parental proxy reports. One of the reasons for the lack of children's physical activity prevalence data in Australia is the difficulties of measurement. The aim of this study was to develop and examine a reliable, valid and feasible method for assessing physical activity among primary school aged children. A total of 112 grade 5 and 6 children and their parents were recruited from four state primary schools in the eastern and western suburbs of Melbourne. The test-retest reliability of a parental proxy physical activity questionnaire and a children's self report physical activity questionnaire was assessed. The criterion validity of the questionnaires was assessed using accelerometry. Findings suggest that the self report and proxy report questionnaires provided reliable measures of the type, frequency and duration of children's physical activity behaviour. Overall, the criterion validity of the questionnaires was poor. Although accelerometry as an objective measure shows promise, it does not provide the important physical activity behavioural and contextual information that is critical for the development of strategies to promote physical activity among children. We recommend that a combination of self report or proxy and objective measurement (using accelerometry or even pedometry) appears to be the current 'best buy' in the assessment of children's physical activity behaviour.<br />