Additional Information:• NOTICE: this is the author's version of a work that was accepted for publication in Preventive Medicine. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published
AbstractObjective: Physical education (PE) programs aim to promote physical activity (PA) and reach most school-aged youth. However, PA levels within PE lessons are often low. In this clusterrandomized controlled trial, we examine the effects of three self-determination theory-based motivational strategies on PA and sedentary behavior, as well as their hypothesized antecedents during PE lessons.Methods: Data were collected in Sydney, Australia (October -December 2011). After baseline testing, teachers (n = 16) and their classes (n = 288 students; M = 13.6 years, 50.4% male) were randomly assigned to one of four teaching strategy conditions: (1) explaining relevance; (2) providing choice; (3) complete free choice; or (4) usual practice. Teachers then delivered the assigned strategy. Primary outcomes were accelerometer-assessed PA and student motivation during lessons. Secondary outcomes included sedentary behavior, perceptions of teachers' support and psychological needs satisfaction.Results: The 'free choice' intervention increased PA (p < .05). 'Providing choice' and 'free choice' interventions decreased sedentary behavior (p < .05). The interventions did not influence motivation, but students' autonomy increased during both choice-based interventions (p < .05).Conclusions: Promoting choice can produce short-term increases in PA and decreases in sedentary behavior, as well as increased perceived autonomy during PE lessons.