Relationship of physical activity and fitness in youth

The purpose of this article is to present an overview of the research devoted to the relationships of physical activity and physical fitness in children. Results are summarised of (1) training studies on aerobic power and muscle strength, (2) intervention studies aiming on the benefits of extra, more intensive physical education using the school environment and (3) longitudinal studies contrasting physically active and inactive children in retrospect. The training studies show always-significant improvements in physical fitness in both sexes and regardless of biological maturation. The physical education intervention studies are not reliable or- do not reveal significant and beneficial effects on physical fitness. The positive effects from the longitudinal studies are not conclusive, because self -selection may have caused the differences in physical fitness. The general lack of physical activity in youth needs strategies to promote physical activity. (C) 2001 Editions scientifiques et medicales Elsevier SAS.