CHoosing Active Role Models to INspire Girls (CHARMING): protocol for a cluster randomised feasibility trial of a school-based, community-linked programme to increase physical activity levels in 9–10-year-old girls

BACKGROUND: In the UK, there is evidence that girls’ physical activity tends to decline to a greater extent than boys as they enter adolescence. ‘Role models’ could play a vital role in inspiring girls to become or remain physically active. The CHARMING Programme is a primary school-based community linked role-model programme, co-developed in 2016, with children, parents, schools and wider stakeholders. It involves different types of physical activity delivered for 1-h each week by a community provider and peer role models (e.g. older girls from secondary schools) joining in with the sessions. The programme ultimately aims to increase and sustain physical activity levels among 9–10-year-old girls. This study aims to assess the feasibility and acceptability of the CHARMING Programme and of evaluating it using a randomised trial. METHODS: This study is a feasibility cluster randomised controlled trial, with embedded process evaluation and health economic evaluation. Approximately 90 Year 5 (i.e. 9–10-year-old) girls will be recruited across six primary schools in Mid-South Wales. Participating schools will be allocated to the programme: control on a 2:1 basis; four intervention schools will run the CHARMING Programme and two will continue with usual practice. A survey and accelerometer will be administered at baseline and repeated at 12 months. Interviews and focus groups will be conducted post-intervention delivery. The primary aim is to assess feasibility of a future randomised trial via the recruitment of schools, participants and role models; randomisation; retention; reach; data collection completion rates; programme adherence; and programme fidelity, views on intervention acceptability and programme barriers and facilitators. Secondary aims are to evaluate established physical activity outcome measures for children plus additional health economic outcomes for inclusion in a future full-scale trial. DISCUSSION: The results of this study will inform decisions on whether and how to proceed to a full-scale evaluation of the effectiveness and cost-effectiveness of the CHARMING Programme to improve or sustain physical activity. TRIAL REGISTRATION: ClinicalTrials.gov ISRCTN36223327. Registered March 29, 2021 SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s40814-021-00961-6.