Effects of physically active lessons and physically active breaks on cognitive development and academic performance of schoolchildren: protocol for a cluster randomized clinical trial

Movement is crucial for health, but it has declined due to increased sedentary behavior, which is associated with physical and mental health problems in children and adolescents. School-based interventions have shown positive effects on behavior, academic performance, and cognitive development. However, further research is needed, particularly in middle- and low-income countries such as Brazil, which presents contextual characteristics different from those in countries where most studies have been conducted. Understanding these processes and comparing them with other existing projects is essential to inform potential public policies. The present study aims to methodologically describe a five-year cluster-randomized clinical trial of physically active classroom interventions designed to promote improvements in cognitive and academic outcomes. This is a cluster randomized clinical trial, called the ERGUER/Aracaju Project, conducted in public schools in Aracaju/SE with 1st-grade elementary school students followed over five years (2022–2026). The interventions are carried out by classroom teachers twice a week. Physically active lessons (PAL) are carried out through school content with methodologies that involve movement, while physically active breaks (PAB) have no school content and consist of exercises lasting an average of five minutes to interrupt sedentary behavior and promote moderate to vigorous movement. A total of six schools is participating in the project: two in PAL condition, two in PAB condition, and two in control condition. The primary outcome is cognitive development assessed through computerized tests that check executive functions and academic performance assessed by teachers’ grades and national and state exams. Secondary outcomes, such as anthropometry, physical activity level and sedentary behavior, eating habits, sleepiness, quality of life, and perception of school are also measured. We expect to provide information that expands the current knowledge in the field by offering a perspective on the potential long-term effects of classroom-based physical activity strategies, particularly in the context of outside high-income countries. Brazilian Clinical Trials Registry (REBEC trial: RBR-10zxwdrh, retrospectively registered on 2025-01-09, https://ensaiosclinicos.gov.br/rg/RBR-10zxwdrh ).