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Background: In response to conflicting findings for activity levels across sociodemographic groups, this study examined differences in adolescents’ in-school, out-of-school, and weekend physical activity (PA) by sociodemographic subgroups using representative US data. Methods: Data were obtained from the Family Life, Activity, Sun, Health, and Eating study. Multiple regression models compared in-school, out-of-school, and weekend PA by gender and race/ethnicity, and examined potential modification of associations by grade (middle vs high school) and socioeconomic status (lower vs higher). Results: Final analytic sample was 1413 adolescents (Mean age = 14.5 y, 51.3% female, 64.5% white). Compared with whites, in-school PA was significantly higher among blacks and those classified as other race/ethnicity for middle school (69.8 and 71.0, respectively, vs 66.4 min/d), and among Hispanics for high school (52.7 vs 48.4 min/d). Hispanics’ (vs whites’) out-of-school PA was significantly lower for middle school (63.7 vs 66.6 min/d), but higher for high school (54.0 vs 51.8 min/d). In-school PA was significantly higher among adolescents of lower (vs higher) socioeconomic status among males and Hispanics (all Ps < .05). Conclusions: The relation of race/ethnicity with PA varies by grade and time of day/week. Socioeconomic status findings contradict previously reported findings. Efforts to increase PA based on sociodemographic disparities should consider potential interaction effects.
Johnson and Pettee Gabriel completed this work while at the School of Public Health in Austin, University of Texas Health Science Center at Houston, Austin, TX, USA. Johnson is now with the Center for Child Health, Behavior, and Development, Seattle Children's Research Institute, Seattle, WA, USA. Pettee Gabriel is now with the Department of Epidemiology, School of Public Health, University of Alabama at Birmingham, AL, USA. Ranjit and Springer are with the Department of Health Promotion and Behavioral Sciences, School of Public Health in Austin, University of Texas Health Science Center at Houston, Austin, TX, USA. Kohl is with the Department of Epidemiology, Human Genetics & Environmental Sciences, School of Public Health in Austin, University of Texas Health Science Center at Houston, Austin, TX, USA; and the Department of Kinesiology and Health Education, University of Texas at Austin, Austin, TX, USA.