Background: Physical activity declines during childhood and determinants of this decline are
poorly understood. The purpose of this prospective study was to examine modifiable …

PURPOSE: The objectives of this study were to describe longitudinal trends in adolescent
physical activity in a sample of US adolescents and to assess the effect of multiple …

PURPOSE: To determine the annual rate at which physical activity changes in girls during
middle school using both objective and self-report measures of physical activity. METHODS …

Objective To identify factors associated with changes in physical activity in adolescent girls
at risk for sedentary lifestyles and obesity. Design A cohort study was performed with 201 …

BACKGROUND: Several reviews have summarized the research on correlates of older
children's and adolescents' physical activity behaviors, but none have been published on …

BACKGROUND: Declining levels of physical activity in the population at large may be
responsible in part for the rising rates of childhood obesity. Studies to date, however, have …

Declining levels of physical activity probably contribute to the increasing prevalence of
overweight in US youth. In this study, the authors examined cross-sectional and longitudinal …

Background: Low levels of physical activity and high levels of sedentary behavior during
adolescence are a cause for concern. Sociodemographic, developmental, environmental …

CONTEXT: Data are available on correlates of physical activity in children and adolescents,
less is known about the determinants of change. This review aims to systematically review …

BACKGROUND: It is unclear to what extent factors affecting energy balance contribute to the
development of body fatness in youth. The objective of the current study was to describe the …