Understanding adolescents' physical activity levels and underpinning contextual factors is crucial for health promotion. This cross-sectional study, using 24-hour time use diaries and sociodemographic variables from the Longitudinal Study of Australian Children, addressed gaps in understanding of physical activity in the before-school segment (the time between waking up and commencing classes). The study examined a) adolescents' time spent in before-school physical activity, focusing on location and shared presence, and b) sociodemographic correlates of before-school physical activity. Completed diaries by 12-13 year-olds (n = 3,201) revealed that adolescents reported an average of 10.8 minutes of daily before-school physical activity (average segment length: 114 min), mostly classified as active transport (5.7 min). Most before-school physical activity occurred in a location other than home or school (6.1 min) and with peers (6.1 min). Notably, 51% of boys and 60% of girls did not report any before-school physical activity. Through two-part regression, we found that boys, adolescents from single-parent households, and those with longer before-school segments are more likely to report before-school physical activity compared to their counterparts. Before-school initiatives should promote active transport and diverse opportunities in other settings. Research into barriers and facilitators may inform more inclusive and effective promotion strategies, including school-based initiatives.
Keywords: Adolescence; before-school; physical activity; time-use.