Few Canadian children are meeting physical activity (PA) guidelines for optimal growth and health. There is little information describing the patterns of PA among Canadian youth, so it is difficult to determine where the deficits occur. The purpose of this study was to identify subgroups of youth and windows of time characterized by low PA and high sedentary behaviour. We conducted a cross-sectional study of 626 youth (aged 10-15 years) in 2 Canadian provinces. The primary exposure variables included geographic setting (rural vs. urban), sex, and days of the week (weekend days vs. weekdays). The primary outcome measures were minutes of light PA, moderate to vigorous physical activity (MVPA), and sedentary behavior, assessed with accelerometry. Compared with weekdays, MVPA was ∼30% lower on weekend days (55.8 ± 23.0 min vs. 38.7 ± 26.7 min; p < 0.001), whereas light PA was ∼15% higher. Significantly more youth achieved an average of >60 min of MVPA on weekdays than on weekend days (46% vs. 22%; p < 0.001). Sex-specific differences in MVPA were more pronounced on weekdays than on weekend days (∼13 vs ∼8 min per day; p < 0.01). Youth in rural settings achieved ∼9 fewer minutes of MVPA daily than youth in urban settings (p < 0.001). In youth 10 to 15 years of age, daily MVPA is lower and light PA is higher on weekend days than on weekdays. Girls and students living in rural areas were particularly vulnerable to low levels of MVPA.

Lower levels of physical activity are associated with childhood obesity. School physical education (PE) policies have been identified as critical to improve child and adolescent physical activity levels but there has been little evaluation of such policies. In the province of Manitoba, Canada, the government implemented a mandatory PE policy in secondary schools designed to increase the daily physical activity levels of adolescents. The objective of this study was to examine the longitudinal changes in and the factors associated with the physical activity trajectories of adolescents in Manitoba during their tenure as secondary school students in the context of this school PE policy. The results found, despite the PE policy, a grade-related decline in the physical activity trajectories of adolescents; however, the decline in physical activity was attenuated among adolescents with low and moderate baseline physical activity compared to adolescents with high baseline physical activity and among adolescents who attended schools in neighbourhoods of low compared to high socioeconomic status. There are several possible explanations for these findings, including the influence of the PE policy on the PA patterns of adolescent subpopulations that tend to be at higher risk for inactivity in both childhood and adult life.

BackgroundThe purpose of this paper is to examine the impact of a province-wide physical education (PE) policy on secondary school students’ moderate to vigorous physical activity (MVPA).Methods Policy: In fall 2008, Manitoba expanded a policy requiring a PE credit for students in grades 11 and 12 for the first time in Canada. The PE curriculum requires grades 11 and 12 students to complete a minimum of 55 h (50% of course hours) of MVPA (e.g., ≥30 min/day of MVPA on ≥5 days a week) during a 5-month semester to achieve the course credit. Study Designs: A natural experimental study was designed using two sub-studies: 1) quasi-experimental controlled pre-post analysis of self-reported MVPA data obtained from census data in intervention and comparison [Prince Edward Island (PEI)] provinces in 2008 (n = 33,619 in Manitoba and n = 2258 in PEI) and 2012 (n = 41,169 in Manitoba and n = 4942 in PEI); and, 2) annual objectively measured MVPA in cohorts of secondary students in intervention (n = 447) and comparison (Alberta; n = 224) provinces over 4 years (2008 to 2012). Analysis: In Study 1, two logistic regressions were conducted to model the odds that students accumulated: i) ≥30 min/day of MVPA, and ii) met Canada's national recommendation of ≥60 min/day of MVPA, in Manitoba versus PEI after adjusting for grade, sex, and BMI. In Study 2, a mixed effects model was used to assess students’ minutes of MVPA per day per semester in Manitoba and Alberta, adjusting for age, sex, BMI, school location and school SES.ResultsIn Study 1, no significant differences were observed in students achieving ≥30 (OR:1.13, 95% CI:0.92, 1.39) or ≥60 min/day of MVPA (OR:0.92, 95% CI: 0.78, 1.07) from baseline to follow-up between Manitoba and PEI. In Study 2, no significant policy effect on students’ MVPA trajectories from baseline to last follow-up were observed between Manitoba and Alberta overall (−1.52, 95% CI:-3.47, 0.42), or by covariates.ConclusionsThe Manitoba policy mandating PE in grades 11 and 12 had no effect on student MVPA overall or by key student or school characteristics. However, the effect of the PE policy may be underestimated due to the use of a nonrandomized research design and lack of data assessing the extent of policy implementation across schools. Nevertheless, findings can provide evidence about policy features that may improve the PE policy in Manitoba and inform future PE policies in other jurisdictions.