Physical Literacy through Active plaY and environmental affordances in outdoor kindergarten settings: a multidimensional approach to Unveiling Potential (PLAY UP) - study protocol for a cluster-randomised trial.

introductionOutdoor active play is essential for children's health, well-being and holistic development. However, there is a lack of high-quality evidence on effective sustainable and scalable interventions that leverage outdoor play and environmental affordances to promote physical literacy, including motor competence, physical activity, engagement and motivation for movement in early childhood. In particular, limited research has examined how outdoor kindergarten environments can be intentionally used and optimised to support diverse forms of active play through social and other potential affordances, nor how educators can be supported to facilitate such processes. The PLAY UP project aims to address this gap by investigating how a co-created, affordance-based intervention, developed in collaboration with children and supported by educator training, can enhance preschool children's engagement in active play and multidimensional development in outdoor kindergarten settings. METHODS AND ANALYSIS: This study describes the protocol of a cluster-randomised trial to be conducted in Portugal, involving three kindergartens and up to 215 preschool children, their educators and parents. The protocol includes an initial pilot phase (approximately 75 children from one kindergarten) to assess feasibility, acceptability and implementation procedures, followed by a main study phase with intervention and wait-list control clusters. The intervention comprises 15 sessions delivered in outdoor kindergarten settings. PLAY UP adopts a multidimensional and multimethod approach combining quantitative and qualitative methods. Outcomes related to physical literacy, including physical activity, motor competence, engagement, enjoyment and motivation for movement, are assessed using questionnaires, standardised tasks, accelerometry, Global Positioning System-based positioning technologies and systematic observations, complemented by interviews. Data will be analysed using cluster-aware statistical models and integrative mixed-methods approaches. ETHICS AND DISSEMINATION: This study has been approved by the Ethics Committee of the University of Évora (Ref. #24101). Written informed consent was obtained from parents or legal guardians, and all data will be handled confidentially in accordance with ethical and data protection standards. Study findings will be disseminated through open-access peer-reviewed publications, scientific conferences and knowledge-transfer activities targeting education professionals and relevant stakeholders. TRIAL REGISTRATION NUMBER: NCT07355179.