Trajectories of Objectively Measured Physical Activity among Secondary Students in Canada in the Context of a Province-Wide Physical Education Policy: A Longitudinal Analysis

Abstract

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.

Trajectories of objectively measured sedentary time among secondary students in Manitoba, Canada in the context of a province-wide physical education policy: A longitudinal analysis

“…This research was conducted as part of a prospective cohort embedded within the Manitoba Increasing Physical Activity in Secondary Students (MIPASS) study evaluating the impact of a province-wide secondary school PE policy on student PA. 18 Introduced in September 2008, the PE policy mandates students accumulate a minimum of 30 minutes of MVPA per day on at least 5 days per week, in or out of classes. 18 Details of the Manitoba secondary school PE policy are described elsewhere.…”

“…18 Details of the Manitoba secondary school PE policy are described elsewhere. 18,19 Data were collected through a two-stage process whereby secondary schools (n = 31) offering grades 9 through 12 with enrolment greater than 100 were randomly selected in blocks to represent the urban and rural geography of Manitoba. 18 In each selected school, a convenience sample of grade 9 or 10 PE classes was recruited.…”

“…18,19 Data were collected through a two-stage process whereby secondary schools (n = 31) offering grades 9 through 12 with enrolment greater than 100 were randomly selected in blocks to represent the urban and rural geography of Manitoba. 18 In each selected school, a convenience sample of grade 9 or 10 PE classes was recruited. All students were subsequently screened to exclude those absent at baseline recruitment, unable to perform regular daily living activities, or living with chronic conditions.…”

“…All students were subsequently screened to exclude those absent at baseline recruitment, unable to perform regular daily living activities, or living with chronic conditions. 18 Prior to study participation, written informed consent was obtained from parents and assent from students. A total of 596 students in grades 9 and 10 were recruited at baseline.…”

“…18 Of these, 533 (89.4%) students returned the accelerometers at baseline and were followed up once a year until 2011 or grade 12, whichever came first. 18 Students not meeting the minimum accelerometer wear-time requirement (n = 65) or with an extreme MVPA measurement (n = 21) at baseline were excluded from the analyses. 18 Therefore, a total of 447 (75.0%) students comprised the final sample.…”