A school-level randomized preliminary study of in-classroom physical activity breaks among fifth graders.

In-classroom physical activity breaks (IcPABs) are a pragmatic strategy to reduce sedentary time and promote movement during instructional lessons. However, evidence from primary schools operating within a high-stakes examination-focused education system, where academic achievement in national assessments is prioritized in classroom instruction is limited from low- and middle-income countries. This study aimed to examine the preliminary effects and feasibility of a teacher-led, in-classroom physical activity break intervention on school-time movement behaviors, academic performance, and selected health-related outcomes among Sri Lankan fifth-grade students. 220 students from two government primary schools in Sri Lanka (mean age = 9.48 years ± 0.5, 61% male) were randomly assigned to (1) an intervention group (n = 100): attending thrice-a-day, 5-min IcPAB for 12 weeks; and (2) a control group (n = 120). Pre- and post-intervention assessments were conducted for academic achievement (standardized tests), movement behaviors (ActiGraph Gt3X), body-mass-index (anthropometric data), aerobic fitness (20m shuttle run test), and perceived stress (PSQ8-11). Generalized Linear Mixed Models were used for statistical analyses at exploratory level. Feasibility was evaluated using teacher logs, classroom observations and process evaluation records. Significant group-by-time effects were observed for reading performance (82.2 ± 13.9 to 88.0 ± 12.9 vs 76.7 ± 10.5 to 77.6 ± 13.0 in controls), MVPA (27.2 ± 9.4 to 44.3 ± 9.9 vs 31.1 ± 8.4 to 24.3 ± 9.4), step count (5609 ± 1019 to 7769 ± 1339 vs 7998 ± 1023 to 3942 ± 1046), and sedentary school time (1490.7 ± 53.1 to 1475.4 ± 59.4 vs 1485.0 ± 22.9 to 1655.1 ± 40.8). The study fidelity assessment confirmed 1 to 4 times daily activity implementation. The process evaluation indicated satisfactory participant engagement and smooth implementation, suggesting the study was conducted as intended. This school level randomized preliminary study observed improvements in reading performance, while effects on mathematics and health-related outcomes were limited. However, in-classroom physical activity breaks were feasible to implement in an academically intensive Sri Lankan primary school context and were associated with favorable changes in school-time movement behaviors. Yet larger multi-school trials are expected to confirm these findings.