[Evaluation of habitual physical activity of children during clinical and epidemiological trials]

This synthesis presents the principles of action, advantages and disadvantages of five categories of methods (calorimetry, heart rate monitors, actimetry, observation, questionnaire) utilised to assess habitual physical activity (HPA) of children in clinical practice settings and/or at the time of epidemiological follow-up or management. The aggregation of a set of criteria related to the validity/reliability, ease of administration, ethics, cost and objectives should guide the choice of one method over another. The use of methods recognised as high-standard references (i.e. calorimetry, double-labelled water, direct observation) is limited in public health due to their cost. Heart rate monitors are associated with some discomfort for children, and furthermore, there are questionable due to distortions with regard to the telemetric signal. Actimetry, especially the use of accelerometers, seems to be a balanced approach. Although its use is well-suited to individual diagnosis and clinical research, its relative complexity limits its potential interest and use for epidemiology or for disseminating health messages. Thus, despite the difficulties associated with their use among children (bias related to misunderstanding, impressions and beliefs, socially acceptable response and cognitive/memory limitations), self-administered reporting methods can be useful for large-scale studies and may help in taking into account the perceptual dimension of physical activity and the child's health status.