ABSTRACT
Physical activity (PA) in young children (i.e., age ≤ 10 years) differs to older children due to biological, physiological and neuromuscular factors, and cognitive immaturity. From birth, the acquisition of motor development is the cornerstone for future PA and this process follows a developmental continuum. Young children cannot report their PA, and different assessment methods are required for each stage of motor development. Measurement methods need to consider the spontaneous and sporadic nature of young children’s activity patterns, which reflect intrinsic developmental traits and extrinsic influences including the child’s family and environment. Objective (direct observation), device-based measures (accelerometers, wearable activity trackers) and proxy/subjective (questionnaires) methods are available; however, there is currently no single criterion measurement method that is valid, reliable and practical for measuring PA in population studies. Combination measurement methodology appears to be the best current approach to determine the epidemiology of PA among children from birth to age ten years.
