Energy expenditure and physical activity in relation to fitness in children.

Physical activity is accepted as one of the major prerequisites for normal growth and development of children and adolescents. Other desired outcomes include psychological well-being and the potential development of positive attitudes and habits as a foundation for an active lifestyle in adulthood. In addition the increasing evidence for the physiological health benefits of physical activity in adulthood, particularly in relation to coronary heart disease (CHD) has stimulated interest in investigating the childhood antecedents of adult health. However, rigorous evaluation of the role of childhood physical activity and fitness has been hampered by a combination of methodological and conceptual constraints. First, there is a discernible feeling that children are less active and fit today than in the past. While intuitively plausible, this assumption has been difficult to validate because of difficulties in obtaining detailed, accurate and objective information on habitual patterns of energy expenditure and physical activity. Second, there has been a lack of consensus about how fitness and its components should be defined and tested. For example, major emphasis has been placed on cardiorespiratory fitness in children while the potential health and fitness benefits of regular low-to-moderate intensity physical activity have been largely overshadowed. Therefore, while physical activity and physical fitness are obviously related, their relative importance to shortand long-term health status remains to be established.