Race/ethnic variations in school-year versus summer differences in adolescent physical activity.

Children and adolescents gain more weight in the summer than the school year, and there are race/ethnic differences in this pattern. Youth physical activity is lower in the summer, and the main aim of the present study was to examine race/ethnic and sex differences in adolescent physical activity, sedentary behavior, and related variables, comparing the school-year and summer. Adolescents aged 11-17 years were recruited from lower-income areas of five states in 2017-2018, and n = 207 completed surveys in both the school-year and summer: 56 African Americans, 30 American Indians, 21 Asian/Pacific Islanders, 49 Latinos, and 51 White, non-Hispanics. Of these, n = 150 also had accelerometer data. Objectively-measured physical activity was lower in the summer, especially among American Indian, Asian/Pacific Islander, and Latino subgroups. Reported screen time was substantially higher in the summer (p < .04), with the biggest increase among African Americans. Reported enjoyment of physical activity was generally lower in the summer (p < .02), which could help explain reduced physical activity. Which race/ethnic groups were at higher risk in the summer varied for physical activity and screen time, so interventions should be tailored for each group. Improved strategies to increase physical activity in the summer, especially among higher-risk groups, could contribute to youth obesity control.