Exploring the effectiveness of a school-based physical activity policy in British Columbia, Canada: a mixed-methods observational study.

The Daily Physical Activity (DPA) policy in British Columbia requires elementary schools to help students achieve 30 min of physical activity during instructional and noninstructional time on school days. The purpose of this study was to determine how elementary teachers implement the DPA policy, and examine differences in children's light physical activity (LPA) and moderate-to-vigorous physical activity (MVPA) at school, based on how the teacher implemented the DPA policy during the school day (provision of DPA during instructional time or only noninstructional time). In this observational mixed-methods study, 12 teachers were interviewed on their implementation approaches. Teachers provided DPA opportunities during instructional time (i.e., prescriptive implementers, n = 9) or relied on students to be active during noninstructional times (i.e., nonprescriptive, n = 3). Next, 10 students from each interviewed teacher's classroom were randomly selected to wear accelerometers for one school week. Hierarchical linear modeling was used to examine the contribution of teacher's implementation strategy on student's activity levels. t-Tests examined differences in students' activity levels between implementation groups. Teacher's DPA implementation strategy accounted for a significant proportion of variance in student's activity throughout the school day (p's < .05). The prescriptive group (n = 88) was more active (LPA and MVPA) and spent a greater proportion of their school days in MVPA during instructional time than the nonprescriptive group (n = 23). Heterogeneity in policy implementation creates variations in policy effectiveness. Students provided with opportunities to be active during instructional time may accumulate more MVPA compared with those who are not given these opportunities. Registration: Not applicable.