The measurement of physical activity in children

Abstract

There is a need to measure physical activity in children accurately, as low levels of activity may be related to risk factors for acquired diseases. The cost of observational studies may be prohibitive in epidemiological or large-scale studies where the use of questionnaires may be more appropriate. While information on non-planned activities may be difficult to capture, questionnaires in children can provide data on sedentary activities, the energy expended in regular activities, and method of transport to and from school. Heart-rate monitoring is an indirect objective measure of physical activity and present-day monitors can store data for a number of days. Accelerometry is an objective and reliable method for assessment of activity and inactivity, and can be used over representative time periods with minimal discomfort to individuals. The advent of small activity monitors has led to a major improvement in the ability to monitor children's activity.