How is observed (de)motivating teaching associated with student motivation and device-based physical activity during physical education?

Previous Self-Determination Theory (SDT) research has highlighted the impact of physical education (PE) teachers’ (de)motivating styles on students’ motivation, in-class moderate-to-vigorous physical activity (MVPA), and sedentary behaviour. However, most studies relied on questionnaires to assess PE teachers’ (de)motivating styles, and the few that used observations focused primarily on one specific (de)motivating style in relation to motivational outcomes, overlooking behavioural outcomes. This study advances SDT-based research by examining associations between PE teachers’ observed (de)motivating styles (i.e. four styles, eight approaches, and 43 behaviours), students’ motivation (i.e. intrinsic motivation, identified regulation, introjected regulation, external regulation, and amotivation), and students’ device-based in-class MVPA and sedentary behaviour. A total of 79 secondary school PE teachers and 885 students participated. One PE lesson per teacher was recorded and (de)motivating styles were rated using the Situation-in-School Physical Education-Coder (SIS-PE-Coder). Students completed an online questionnaire to assess their motivation and wore Actigraph accelerometers to measure in-class MVPA and sedentary behaviour. Linear mixed-effects models, controlling for the lesson topic, and students’ sex and age, revealed that PE teachers’ observed attuning approach related positively and demanding and abandoning approaches related negatively to students’ intrinsic motivation. The demanding approach also related positively to students’ introjected regulation. Notably, the demanding approach showed a dual pathway, negatively relating to intrinsic motivation but positively relating to in-class MVPA. In turn, intrinsic motivation was positively related to in-class MVPA. By relying on observations, the findings suggest that PE teachers can optimize student motivation by being more attuning and less demanding and abandoning.