Despite the benefits of classroom physical activity breaks on student health and academic outcomes, more research is needed to understand what factors may be associated with classroom physical activity break implementation, to bolster buy-in from school stakeholders and increase implementation. This quantitative study examined frequency of classroom physical activity break implementation in relation to (1) objectively measured teachers' physical activity and sedentary behaviors, (2) confidence for leading classroom physical activity breaks, (3) social norms (perceptions of other teachers' classroom physical activity break implementation), and (4) teacher- and school-level demographics. In total, 153 classroom teachers in 20 elementary and middle schools completed a survey including classroom physical activity break frequency, confidence, and social norms, one item each, dichotomized (1 = "most/all the time" OR "agree/strongly agree"). Accelerometry assessed total activity and daytime sedentary behavior. Analyses included multilevel binary logistic regression. Teachers were 90% female, 68% White, and 55% in elementary schools. Odds of implementing classroom physical activity breaks were lower among middle school teachers, 14 times greater among those with greater confidence, and over 17 times greater when teachers perceived others frequently implementing classroom physical activity breaks. Teacher activity was not associated with classroom physical activity break implementation. Future interventions to increase classroom physical activity break implementation should focus on increasing teachers' confidence to lead classroom physical activity breaks and creating more buy-in from classroom teachers to enhance each school's culture of health. By enhancing teacher confidence and social norms for implementing classroom physical activity breaks, we may increase school-based physical activity opportunities.
Keywords: classroom physical activity breaks; classroom teachers; confidence; physical activity; school health; social norms.