Cross-Sectional Analysis of Sex Differences in Out-of-School Physical Activity Among Elementary School Students

Introduction: Previous literature has shown differences in physical activity time between boys and girls during the school day. However, these studies did not include physical activity time outside of school. This study aims to explore the differences in physical activity time outside of school, during school, and throughout the full day between fourth grade girls and boys. Methods: In a large, suburban school district, 386 fourth grade students wore accelerometers both in school and at home for 1 school week. The students also completed an activity diary for one 24-hour period, in which they provided information on physical activities completed before and after school that lasted longer than 5 minutes. Bivariate analyses of demographic characteristics by sex of students were calculated. Bivariate analyses of average moderate-to-vigorous physical activity minutes in school, out of school, and for the full day by demographic characteristics, including sex, were calculated. Random-intercept models estimated associations of interest between physical activity levels and demographic variables. Results: Girls had significantly fewer minutes of physical activity outside of school, during school, and during the full day than boys. On average, girls accrued 8 less minutes of daily in-school physical activity (19.3 vs 27.1 minutes; p<0.001), 7 less minutes of daily out-of-school physical activity (25.1 vs 31.9 minutes; p<0.001), and 15 less minutes of full-day physical activity (44.5 vs 59.0 minutes; p<0.001) than boys. For both boys and girls, participation in sports was significantly associated with full-day and out-of-school physical activity. Less girls participated in sports than boys (26.4% vs 36.8%). Conclusions: Differences in elementary-aged physical activity may be due to differences in sex norms and activity outside of school. Girls had less physical activity during all periods of the day than boys and less participation in sports and active commuting. Future research could aim to increase physical activity for elementary-aged girls both in and out of school.