Autonomy supportive environments and mastery as basic factors to motivate physical activity in children: a controlled laboratory study

44 children were assigned to low (1 toy) or high (3 toys) choice groups. Children completed 60 min sessions with access to traditional active toys on one visit and exergame versions of the same active toys on another visit.Choice had a greater effect on increasing girls' (146%) than boys' (23%) activity time and on girls' (230%) than boys' (minus 24%) activity intensity. When provided choice, girls' activity time and intensity were no longer lower than boys' activity time and intensity. The combination of choice and mastery by providing access to 3 exergames produced greater increases in physical activity time (1 toy 22.5 min, 3 toys 41.4 min) than choice alone via access to 3 traditional games (1 toy 13.6 min, 3 toys 19.5 min). Energy expenditure was 83% greater when engaging in traditional games than exergames.Boys and girls differ in their behavioral responses to autonomy supportive environments. By providing girls with greater autonomy they can be motivated to engage in physical activity equal to boys. An environment that provides both autonomy and mastery is most efficacious at increasing physical activity time. Though children play exergames 87% longer than traditional games, the rate of energy expenditure is 83% lower for exergames than traditional indoor versions of the same games.Engaging in adequate physical activity is considered an essential component for the maintenance of weight loss and provides many other health benefits for children [1]. However, many children do not engage in adequate physical activity to receive all of its health benefits [2]. Unfortunately, treatment programs based on a number of behavioural change models and applied in a number of settings have not demonstrated efficacy for promoting sustained increases in youth physical activity after cessation of the program [3]. The development of more effective behavioural interventions for increasing youth physical activity depends on improving our understanding of basic factors that influe