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Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
Timeline of the “MEXA-SE” intervention study. Note: PA: Physical activity; SB: Sedentary behaviour; *In-school monitoring comprised observations of physical education classes and school recess.