Two-Year Effectiveness of a Controlled Trial With Physically Active Lessons on Behavioral Indicators of School Children

Purpose: In this study, we evaluated the effectiveness of two years of an intervention with physically active lessons on indicators of sedentary behavior and physical activity measured objectively in elementary school children. Methods: A controlled clinical trial with cluster sampling was carried out in 2018 and 2019, with four classes of children in the 2nd year of elementary school. The intervention group classes received dynamic activities linked to the pedagogical content (n = 34) for 2 years. The indicators of sedentary behavior and physical activities were evaluated using ActivPal and ActiGraph GT3X accelerometers during the school shift. Crude and adjusted models of Generalized Estimation Equations with Bonferroni's post hoc were used to identify the differences between the groups (three evaluations in 2018 and two evaluations in 2019). Results: There was a reduction in stationary behavior (p = .01) and an increase in light physical activity (p = .044) during the two years. In the first year there were reductions in standing time (p = .044) and number of transitions (p ≤ .001), and an increase in walking time (p = .017). However, in the second year, the mean differences in percentage points were smaller than in the first year. No differences were found for sitting time as well as for moderate and vigorous physical activity. We observed a large effect size for all variables. Conclusions: The introduction of physically active lessons in the classroom reduced time in stationary behavior and increased time in light physical activity. However, the effects on behavior observed in the first year were not maintained in the second year of intervention.