An Investigation into the Effectiveness of School-based Physical Activity Interventions for Adolescent Girls

Background Regular engagement in physical activity (PA) provides children and young people with numerous physical, psychological and social health benefits. PA levels decline during adolescence and girls are less active than boys. Schools have been suggested as a promising location to target adolescent girls’ PA behaviours. Recently, numerous researchers have incorporated peer-led approaches into PA intervention designs. However, little is known about the feasibility, acceptability and effectiveness of these approaches. The overarching aims of the research programme were to investigate the effectiveness of school-based PA interventions for adolescent girls and assess the feasibility, acceptability and effectiveness of a novel school-based peer-led PA intervention to improve the PA levels and reduce the sedentary time (ST) of adolescent girls. Methods This programme of work included four studies. Study 1 was a systematic review and meta-analysis of the literature to assess the effectiveness of previous school-based interventions for adolescent girls. Study 2 was an exploration study, which assessed girls’ thoughts and perceptions of current school PA practices. Study 3 incorporated the design of a novel three-tier peer-led school PA intervention, with a mentoring component, as part of the Girls’ Peer Activity (G-PACT) project. University students (Mentors) delivered a series of leadership and PA educational sessions to a group of adolescent PA Leaders who disseminated this information to their Peers and encouraged them to engage in more PA. The G-PACT intervention was underpinned 7 by Social Cognitive Theory and Self-Determination Theory. This study evaluated the effectiveness of the G-PACT intervention on adolescent girls’ PA levels and ST. Study 4 was a feasibility and acceptability assessment of the G-PACT intervention in the secondary school setting utilising a qualitative approach. Results Study 1 established that school-based interventions for adolescent girls have a small but positive impact on girls’ PA levels. Interventions underpinned by theory and multi-component in nature were more effective. Study 2 provided an insight into girls’ school PA experiences, highlighting their enjoyment of PA with friends and the importance of choice over activities. Study 3 demonstrated that the G-PACT intervention with a fitness class-based after-school club was effective increasing girls’ PA levels. Study 4 indicated that the link between Mentors and Leaders in the G-PACT intervention was feasible and acceptable. However, the link between Leaders and their Peers requires refinement to improve the communication processes. Conclusion Schools are a promising setting to promote PA among this population, but past interventions only have a small positive impact on girls’ PA levels. Engaging with adolescent girls and listening to their needs is crucial to inform the development of complex interventions in a school setting. Novel interventions such as the G-PACT intervention should be encouraged as they show promise in increasing adolescent girls’ PA levels, and this innovative intervention approach warrants piloting before consideration on a larger scale.