Perceptions of active and inactive prototypes are associated with objective measures of physical activity in adolescents

The benefits of physical activity are known, but the proportion of adolescents meeting daily activity guidelines remains low. Physical activity interventions based on psychological behavioural models can be more effective than programmes which are not underpinned by theory, so exploring behavioural constructs to target is important. The Theory of Planned Behaviour, which assumes reasoned intentions explain actions, is a useful framework for predicting activity, but it leaves variance unexplained. The Prototype Willingness Model, which proposes a second pathway in which perceptions of social images, or prototypes, explain actions via behavioural willingness, may account for the more impulsive decisions that adolescents are inclined to make in social situations. We aimed to determine whether variables in the social reactive pathway of the Prototype Willingness Model explain variance in an objective measure of daily activity, over and above the reasoned action path. Participants aged 12-13 (n= 205) from three schools were invited to complete measures of constructs in the Prototype Willingness Model and to wear an accelerometer for the next seven days to measure physical activity. Overall, 126 students (65 males) participated. Hierarchical regression showed that intention, attitudes and subjective norms explained 12.8% of variance in activity. Prototype perceptions and willingness explained an additional 13.1% of variance. Participants’ perceived similarity to active prototypes, and unfavourable perceptions of inactive prototypes, significantly predicted activity in the full model. Boys were significantly more active than girls, t(124) = 6.11, p <.001 but there were no significant differences between sexes on any of the psychological variables. Results indicate that variance in adolescent physical activity is explained by constructs associated with the Prototype Willingness Model over and above reasoned action variables linked to the Theory of Planned Behaviour. These findings highlight the importance of targeting prototype perceptions to encourage physical activity in this age group