The purpose of this study is to investigate the efficacy of an education outside the classroom (EOtC) intervention on adolescents' physical activity, school motivation, academic achievement, and wellbeing. The study will also investigate which pedagogical and didactical elements of EOtC are important to achieve more physical activity, school motivation, and wellbeing.

Globally, many children and adolescents are insufficiently physically active which increases the prevalence of non-communicable diseases and poor mental health over the lifecourse. Schools are an important setting to promote physical activity (PA) as children and adolescents spend a large proportion of their waking hours in this setting. The MOVEOUT study aims to increase school-based PA and wellbeing trough implementing regular practice of education outside the classroom (EOtC) during school hours. In EOtC, teachers relocate teaching and learning activities to places and settings outside the school building, e.g., urban and green space, societal institutions, and private companies, in agreement with curricular aims, content and obligations. The aim of EOtC is to promote pupils' learning and wellbeing through practical activities and the use of body and senses in authentic situations. Cross-sectional studies suggest that practice of EOtC is positively associated with more moderate-to-vigorous PA for boys, and more and light-intensity PA for girls. Quasi-experimental studies further demonstrate a positive effect of regular practice of EOtC on school motivation and wellbeing, without compromising academic performance. However, no studies have investigated the effect of EOtC on PA, school motivation, or wellbeing in a randomised controlled design. Furthermore, the specific pedagogical and didactical elements in EOtC sessions that promote PA, school motivation, and wellbeing have not been researched. Therefore, the aim of MOVEOUT is to study the effect on adolescents' PA, school motivation, and wellbeing and the mechanisms of EOtC that might promote PA, school motivation, and wellbeing in a randomised controlled design.

Compared to previous studies, the MOVEOUT study provides a methodologically improved and more robust evaluation. This study investigates the efficacy, mechanisms, and mediating effects of an EOtC intervention, The TEACHOUT Intervention[1], in a cluster randomised waitlist controlled trial with 15 intervention schools and 15 control schools. Schools will be required to have one or more classes grade 4-10 (pupils aged 10-16). The study will investigate which pedagogical and didactical elements of EOtC that are important to achieve more PA, school motivation, and wellbeing for 1) all adolescents, 2) adolescents at risk of becoming overweight, and 3) boys and girls separately. MOVEOUT will provide solid evidence of the effect of EOtC and supplement theory on EOtC pedagogy and didactics, which is needed in practice and policy to inform the already ongoing scale-up of EOtC, for instance in Northern European countries. The study is conducted in partnership between the applying institutions and the participating schools through all phases.

Inclusion Criteria

• Non-special need municipal primary and lower secondary school classes grade 4-10.
• Classes not involved in other school development or research projects.
• Participants for whom parents or legal guardians have provided written informed consent.
• Outcome data at baseline (for PA at least one time point; either winter or spring)

Exclusion Criteria

• Classes not able to comply with the following will be excluded from per-protocol analysis, but will be included in the intention-to-treat analysis: intervention group classes should have a school-year average of >150 min of weekly EOtC and the control group classes should have a school-year average of <=150 min of weekly EOtC.
• Pupils with significant health problems as judged by the investigators based on parents or legal guardians report of child health status will be excluded from the analysis.

Anonymised participant-level data can be made available upon reasonable request to the PI such as e.g. verification of the research results. To comply with the European General Data Protection Regulation, and to accommodate article 10 of the Danish Act on Data Protection anonymised participant-level data will be made available on the Open Science Framework five years after the main publication of this study.

Anonymised participant-level data will be made available on the Open Science Framework five years after the main publication of this study.

Statistical plan, study protocol and analytical code will be made available in the osf folder upon acceptance of first preregistered manuscript.

Data can be made available upon reasonable request to the PI such as e.g. verification of the research results.