Role of social support on physical activity in adolescent girls
Background: Adolescent girls are insufficiently active to achieve health benefits. As a result they have been targeted as a priority group for increasing physical activity levels. However, physical activity interventions for this population have had limited effect. A better understanding of the correlates of physical activity in adolescent girls may better inform intervention design. Social support describes interactions, resources, and assistance from others to influence physical activity behaviour. Social support has been linked to physical activity in adolescent girls and could be a modifiable correlate of physical activity. This thesis aimed to identify: (1) if there is a positive association between social support and physical activity in adolescent girls, and if so, (2) explore the potential pathways through which social support influences behaviour. Method: Firstly, a systematic review and meta-analysis was conducted to explore the role of different providers (e.g. parents/friends) and types of social support (e.g. emotional/instrumental) on adolescent girls’ physical activity, providing effect size estimations for different combinations of associations. Secondly, an analysis of an 8- week school based physical activity intervention for adolescent girls was conducted. This involved a mediation analysis to examine: (1) if self-efficacy mediated associations between social support and physical activity at baseline; and (2) if social support or self-efficacy mediated the effectiveness of the intervention. Finally, a qualitative study using constructivist grounded theory was conducted to investigate the mechanisms through which social support influences physical activity behaviour through conducting individual interviews with adolescent girls (n = 18). Results: The systematic review and meta-analysis identified small but significant positive associations between social support and physical activity in adolescent girls. Similar magnitudes were identified for parent and friend support effect sizes. The mediation analysis found that self-efficacy mediated the relationship between social support and physical activity, however, social support did not mediate the effectiveness of a physical activity intervention for adolescent girls. The results of the grounded theory study suggest that social support can influence adolescent girls’ physical activity through enjoyment, self-efficacy, overcoming barriers to physical activity, motivation, and performance improvements, as well as enabling physical activity. Conclusions: Whilst only small significant associations between social support and physical activity in adolescent girls were identified, social support may also indirectly influence physical activity through enjoyment, self-efficacy, overcoming barriers, motivation, performance improvements and enabling physical activity. There may be promise in targeting these constructs through social support behaviour change strategies in physical activity interventions for adolescent girls.