["Journal of School Health, Volume 96, Issue 8, August 2026. ", "\nABSTRACT\n\nBackground\nRecess can be beneficial for enhancing physical activity levels, but evidence on broader developmental outcomes remains mixed.\n\nMethods\nA randomized controlled trial (21 Dutch primary schools, N = 1154 children, mean age = 9.0 years) evaluated a one‐year recess intervention. Physical activity behavior was measured using accelerometers and observation. Motor skills were assessed with the Athletic Skills Track, and social–emotional functioning through teacher‐ and self‐reports and observations. Implementation fidelity was monitored.\n\nResults\nNo significant intervention effects were found on physical activity behavior or social–emotional functioning. Motor skills improved for both groups, with greater gains in the control group. Implementation fidelity did not significantly affect results.\n\nImplications for School Health Policy, Practice, and Equity\nImplementing standardized intervention programs may not necessarily produce the intended outcomes, possibly requiring more context‐specific strategies. Schools may benefit from practical tools to effectively promote children's physically active play at the playground, considering school‐ and population‐specific characteristics.\n\nConclusions\nThis study refines the evidence on recess‐based interventions. The larger gains in motor skills observed in the control group suggest that interventions do not necessarily affect practice as intended, highlighting the importance of considering contextual and methodological factors to better understand what works, for whom, and under which conditions.\n"]