Date of Award


Document Type

Campus Access Dissertation




Clinical-Community Psychology

First Advisor

Dawn Wilson


A major health concern, especially among underserved adolescents is minimal engagement of physical activity. Furthermore, girls engage in fewer minutes per day of physical activity (PA) than boys. Social cognitive theory (SCT) suggests that behavior is influenced by cognitive and interpersonal factors such as self-efficacy (SE) and social support (SS), respectively. Parents can offer SS to their adolescents in the form of emotional (e.g. encouragement) and/or instrumental SS (e.g. buying exercise equipment). Past studies have indicated that parent SS and adolescent SE for overcoming barriers to PA have been positively associated with PA. Some suggest that SE may act as a mediator between parental SS and adolescent PA. Moreover, past studies have demonstrated sex differences in the role of SE as a mediator between SS and PA.

The current study aimed to expand on past research by examining whether SE mediates the relationship between parental SS and adolescent PA, and whether these effects were stronger in adolescent boys as compared to adolescent girls. Baseline data was collected from 1,421 sixth graders in South Carolina. Measures for emotional SS, instrumental SS, and SE for overcoming barriers were incorporated into the present study. The outcome variable, moderate-to-vigorous physical activity (MVPA) was assessed via 7-day estimates using accelerometry. Separate mediation models were analyzed across sex (one for boys, one for girls) on PA measures. Adolescent SE was hypothesized to mediate the effect of SS on PA, and boys were predicted to show a stronger effect than girls. SE mediated the relationship between emotional SS and PA; and mediated between instrumental SS and PA. There was no significant difference in mediated effects across boys and girls when either instrumental or emotional SS was the predictor. Findings from this study demonstrate that SE for overcoming barriers may help explain why different types of SS are related to increases in adolescent PA. This research also illustrates that perhaps SE works as a mediator between parent SS and adolescent PA similarly between boys and girls. SE for overcoming barriers may work as a mediator between parent SS and adolescent PA similarly between boys and girls.


© 2011, Michelle Segal Peterson