Self-reported physical activity levels during a segmented school day in a large multiethnic sample of high school students.

The school day provides youth several opportunistic time periods to be active. How active youth are during these time periods or whether they engage in physical activity across multiple time periods is not well established. A cross-sectional sample of 12-18-year-old students (n=3471) were recruited from low socioeconomic status high schools within South Auckland, New Zealand. Participants reported their physical activity during lunchtime, morning recess, and after school, as well as their level of active transportation to and from school. For each physical activity opportunity participants were dichotomised as being either "more active" or "less active". Height, weight, and waist circumference measurements were also collected for each participant. Data were analysed using binary logistic regression to understand demographic associations and with kappa coefficient calculations to examine level of association in participation levels between different time periods. The percentage of students considered 'more active' depended on the physical activity variable of interest (after-school, 56.3%; active transportation, 58.1%; morning recess, 26.4%; lunchtime recess, 32.4%). Only 11.1% of participants were classified as 'more active' across all four physical activity opportunities. Substantial agreement (kappa=.68) was only observed in participation levels at lunchtime and morning recess. At-risk groups for lower physical activity were female students, senior students, and students of Asian/Other descent. During a school day multiple opportunistic time periods exist for youth to be active, yet a large proportion of students are not as active as they could be with few youth engaging in physical activity across various segments of the school day.