Patterns of age-related change in physical activity during the transition from elementary to high school

This study was designed: 1) to describe patterns of age-related change in total and moderate-to-vigorous physical activity (MVPA) in children as they transitioned from elementary school to high school, and 2) to determine if those patterns differed across demographic sub-groups formed on the basis of gender, race/ethnicity, parent education (socioeconomic status), and urbanicity. A cohort of children (analysis sample, N = 951) was comprised of students drawn from two public school districts in South Carolina. Physical activity was measured by accelerometry on at least two and up to five occasions between 2010 and 2017. Growth curve analyses were performed to describe the pattern of age-related change in the physical activity variables for the full sample and for demographic sub-groups. A relatively steep age-related decline in total physical activity was observed in children before age 14, with a slower rate after that age. Physical activity was lower in girls than boys, and the age-related rate of decline was steeper in girls. Physical activity patterns did not differ across race/ethnicity groups, but children of parents with less education were more active than children of parents with more education. Children living in rural areas participated in less MVPA than children living in urban settings, and this difference increased with increasing age. These findings indicate that children experience a particularly steep decrease in physical activity as they transition from elementary to middle school, and this trend is particularly prominent in girls, children living in rural areas, and children of parents with college education.