Ten Years of ‘Flying the Flag’: An Overview and Retrospective Consideration of the Active School Flag Physical Activity Initiative for Children—Design, Development & Evaluation

Whole-school physical activity (PA) promotion programmes are recommended to increase youth PA. Evaluation of programmes is essential to ensure practice is guided by evidence. This paper evaluates the Active School Flag (ASF), a whole-school PA promotion programme in Ireland, using the Reach, Effectiveness, Adoption, Implementation, and Maintenance (RE-AIM) framework. ASF was evaluated across three levels—(1) administration, (2) application, (3) outcomes—using a mixed-methods case study design. Existing data sources were reviewed, the programme coordinator was interviewed, and a pilot study was conducted to investigate impact on 3rd and 5th class students (3 schools, n = 126 students, age range 8–12 years). In-school Moderate to Vigorous Physical Activity (MVPA; by accelerometery), motivation for PA (BREQ), PA self-efficacy (PASES), school affect and peer social support (Kidscreen27) were measured pre-programme (0 months), post-programme (8 months), and at retention (12 months). Teacher perceptions of classroom behaviour (CBAST) were also measured pre- and post-programme. ASF has been successful in engaging 46% of primary schools nationally. Students’ in-school moderate–vigorous PA increased in all pilot-study schools from pre-programme to retention (η(2) = 0.68–0.84). ASF programme design facilitates implementation fidelity, adoption and maintenance through buy in from schools and government stakeholders. ASF presents as an effective PA promotion programme in the short-to-medium term for primary schools. This RE-AIM evaluation provides evidence of ASF effectiveness, alongside valuable findings that could support programme improvement, and inform future similar programmes.