Reflections from process evaluations of school-based physical activity interventions targeting adolescents: GoActive: A process evaluation of a complex, multi-site RCT

Background: GoActive is a multicomponent school-based physical activity intervention targeting Year 9 students (13-14yrs). The impact of the 12-week intervention on objectively measured MVPA at 10-month follow-up is being tested in an ongoing cluster randomised controlled trial with 16 schools. A mixed methods process evaluation investigated variations in the implementation across schools and evaluated process indicators including reach, recruitment, dose, intervention fidelity, context and sustainability.

Methods: This mixed-methods process evaluation was guided by the MRC guidance for conducting process evaluations of complex interventions. Participants´ experiences and process indicators were assessed through direct observation, purposively sampled semi-structured individual and focus group interviews, website analytics, and questionnaires (delivered to all key groups within the intervention: students, teachers, older adolescent mentors, and local authority-funded funded facilitators). Quantitative data were collected by questionnaire in both the control and intervention arms of the study. Data was analysed thematically, integrating results through a matrix, leading to overall mixed methods synthesis of findings.

Results: All eligible Year 9 students were exposed to the intervention (reach); 88% consented to the evaluation. Preliminary results show variations in implementation between schools, and within schools. For example, engagement with mentor-ship components of the intervention, and form teacher engagement with the intervention varied. Students expressed positive associations with the intervention, but modifications to the mentor component, and teacher engagement had a significant impact on student experience and receptiveness of the intervention. Barriers expressed by all participants included the timing of implementation within the school year, lack of school resourcing, and delegation of organising GoActive sessions. Further mixed-methods analyses will explore dose, implementation quality, and fidelity of the intervention, with careful attention to the school context.

Conclusion: This approach to process evaluation demonstrates a comprehensive, integrated assessment of the implementation and processes of a complex physical activity intervention within a cluster randomised controlled trial. Our results will allow us to re-appraise the program's conceptual base, understand trial results, as well as inform and optimise the program for post-trial sustainability and potential roll out. Furthermore, the mixed-methods approach can be applied to, and adapted for use in other complex intervention trials.