Psychosocial predictors of adolescent girls' physical activity and dietary behaviours after completing the Go Girls! group-based mentoring program

Abstract

The current study applied the theory of planned behaviour to test social cognitions (i.e., affective and instrumental attitudes, subjective norms, self-regulatory efficacy, and intentions) targeted within a group-based mentoring program as predictors of both physical activity and dietary behaviour (separately) 7 weeks after participants completed the program. Data were collected from 237 participants at the end of, and 7 weeks after, completing the program. Multilevel structural equation modelling was used to assess both psychosocial (measured at the end of the program) and behavioural variables (i.e., diet and physical activity; measured 7 weeks after completing the program) among program participants. Analyses revealed that 36.5% and 31.2% of the variance in post-program physical activity and dietary behaviour was explained by affective and instrumental attitudes, self-regulatory efficacy, and intentions. Intentions mediated the effects of self-regulatory efficacy, affective and instrumental attitudes on physical activity behaviour. Similarly, in relation to dietary behaviour, intentions mediated the effects of self-regulatory efficacy, affective and instrumental attitudes. In conclusion, the results of this study provide insight into psychological factors that predict adolescent girls’ health-enhancing physical activity and dietary behaviours after they have left a group-based mentoring program.