Interview topic guide.

Background Roughly 70% of UK adolescents are insufficiently physically active, while secondary education reform is needed to improve adolescent wellbeing and 21 st -century skill-building. One potential strategy to help address these areas is physically active learning (PAL), where movement is integrated into curricular lessons. In the UK, studies have largely focussed on primary schools; little is known about PAL in UK secondary schools. This study aimed to explore, using mixed-methods, UK secondary school teachers’ acceptability of PAL, and their delivery preferences, perceived implementation barriers and facilitators. Methods Cross-sectional data were collected from UK secondary teachers via online survey (N = 75). In addition to descriptive statistics, Mann-Whitney U tests were conducted to examine differences by gender and school types (urban/rural, state-funded/independent), and Kruskal-Wallis tests for differences by subject. Qualitative data on teachers’ current teaching practice, PAL acceptability, and perceived barriers and facilitators, collected through open survey questions (N = 63), and online teacher interviews (N = 7), were analysed using the framework method. Results Using a scale of 1.0 (strong disagreement) to 5.0 (strong agreement), participants liked the concept of PAL (median 4.0, IQR 4.0,5.0) and would use PAL if it was school policy (median 4.0, IQR 3.5,5.0). Female participants were more certain that PAL should be implemented than male ( U = 361.5, p = 0.04). Languages teachers found PAL appropriate for their subject more than humanities and social science teachers ( U = 6, p = 0.01). Four main themes were generated: (1) ‘It’s time for a change’; (2) ‘PAL seems like common sense’; (3) ‘Is PAL realistic in secondary schools?’ and (4) ‘Recommendations for implementation’, highlighting a collaborative approach. Conclusions UK secondary teachers largely felt that PAL is a logical and enjoyable tool to contribute to education system improvement and can benefit pupils’ wellbeing and learning, ...