Submitted to: American Journal of Preventive Medicine
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/1/2005
Publication Date: 5/1/2005
Citation: Jago, R., Anderson, C., Baranowski, T., Watson, K. 2005. Adolescent patterns of physical activity differences by gender, day, and time of day. American Journal of Preventive Medicine. 28(5):447-452. Interpretive Summary: In this study we assessed the physical activity levels of 81 eight-grade adolescents for four days (Thursday – Sunday) using an accelerometer. Participants also completed a diary for each assessment day. The data were analyzed to examine the amount of activity in which the participants engaged and whether there were differences by day, time of day or gender. The results showed that participants engaged in an average of 18.6 minutes of moderate to vigorous physical activity per day, which is less than the Surgeon Generals recommendation. Boys were more active than girls in the afternoon period (3pm – 7pm) on every day except Sunday. Boys spent more time watching TV, playing computer games and sports while girls spent more time in personal care. Results suggest that strategies to reduce time spent in personal care, watching TV and playing computer games may result in increased physical activity.
Technical Abstract: More information about the physical activity of adolescents is needed. This study used objective measurement to investigate differences in activity patterns related to gender, body mass index (BMI), day, and time of day. Eighth-grade adolescents (37 boys, 44 girls) wore the Manufacturing Technologies Inc. (MTI) accelerometer for 4 days and kept a previous-day physical activity recall diary in the fall of 2002. Minutes per hour in sedentary, light, and moderate/vigorous activity, as recorded by the MTI, and in nine activity categories, as recorded by the diary, were calculated for three time periods (6:00 am to 2:59 pm, 3:00 pm to 6:59 pm, 7:00 pm to midnight) on each day (Thursday through Sunday). The results show that doubly multivariate analysis of variance revealed significant gender by day by time differences in sedentary (p =0.005) and moderate/vigorous (p <0.001) activity, but no significant BMI interactions. Except on Sunday, boys were less sedentary and more active than girls during the late afternoon period. Significant gender by category (p <0.001) and day by category (p <0.001) interactions were also found in the log data. Boys spent more time engaged in TV/electronics and sports, while girls spent more time in personal care. Three activity categories (sports, social interaction, active transportation) stayed at consistent levels across days, while others varied widely by day of the week. Our study concluded that except on Sunday, consistent gender differences were found in activity levels, especially for the late afternoon period. Significant increases in sitting, TV/electronic games, and chores were seen for weekend days. Results support strategies to reduce sitting and electronic recreation, which may increase physical activity.