Title: A cluster randomised controlled trial of a Peer-Led physical Activity iNtervention for Adolescent girls (PLAN-A)
Funder: Department of Health and Social Care

Abstract: Design: Two-arm cluster-randomised controlled trial to evaluate the effectiveness and cost-effectiveness of the PLAN-A intervention. Setting: State secondary schools with Year 9 girls (aged 13-14) in greater Bristol. Target population: Girls in Year 9. School is the unit of randomisation with 20 secondary schools and 1400 pupils recruited. Randomisation will be performed by an independent statistician; 10 schools allocated to the PLAN-A intervention and 10 schools to usual care control. Intervention: The intervention comprises: (a) peer-nomination, (b) peer-supporter training and (c) peer-diffusion. Year 9 girls nominate by questionnaire, the girls in their year who are: good listeners, leaders, trustworthy and respected. The 18% most nominated girls are invited to be peer-supporters, and attend a two-day course (with top up training 5 weeks later) to develop the knowledge and confidence to promote physical activity to their peers. Training is held off-site by external trainers who attend 3 day’s training. Outcomes: Outcomes will be assessed at two time points: baseline (Yr 8 Autumn term) and follow-up (Yr 9 Autumn term, 5-6 months post-intervention). Accelerometer-assessed minutes of moderate-to-vigorous physical activity (MVPA) on weekdays is the primary outcome. The following will be secondary outcomes: (a) Mean weekend minutes of MVPA, (b) Mean weekday sedentary minutes, (c) Mean weekend sedentary minutes, (d) Self-esteem. We will measure potential mediators of any intervention effect, aligned with the intervention’s theoretical basis. Resource use, including intervention materials, venue costs, trainer and pupil time, expenses and administration costs will be collected. Process evaluation: Process evaluation will examine: (a) intervention implementation and fidelity (training observations, questionnaires & interviews with trainers), (b) intervention reciept by pupils (questionnaires & focus groups with peer-supporters & non-peer supporters) and (c) intervention sustainability and roll out (interviews with school contacts & public health commissioners). Sample size: The target between-arm difference is 10 minutes of weekday MVPA (i.e., 50 minutes per week) and the 95% CI from the feasibility study suggests that this is achievable. However, recognising that smaller intervention effects may also lead to meaningful differences in health at a population level, the sample size is calculated to detect a 6-minute difference in weekday MVPA. Based on a cluster size of 70, intra-class correlation and standard deviation of weekday MVPA of 0.01 and 20 minutes respectively, 5% two-sided alpha, 90% power and inflation for 30% loss to follow up we will recruit 20 schools and 1400 pupils. Analysis: Analysis and presentation of results will adhere to CONSORT, the analysis plan will be agreed by the TSC, and registered with ISCTRN before data collection. The primary analysis will be examined on an Intention-to-Treat basis without imputation. To take account of the hierarchical data, multivariable mixed effects linear regression will estimate difference in the primary outcome for intervention vs. control, adjusting for baseline outcome scores and randomisation variables (eg. area). In a secondary analysis, we will further adjust for variables that are imbalanced at baseline. Similar analyses will be repeated for secondary outcomes. Sensitivity analyses will assess any effect of missing data using imputation methods.

Lay abstract: Being physically active is good for young people’s physical and mental health but few adolescent girls are active enough to get these benefits and teenage girls face many barriers to being active. Most programs that run in schools to increase adolescents’ physical activity do not work, but few good quality studies have been tried in the UK and new, novel approaches are needed. During adolescence, friends’ opinions and activity levels become very influential on young people’s own physical activity choices and motivations. If we can harness the power of peers to increase adolescent girls’ activity, this could be a new way to inspire girls to become and stay active. Whilst peers are a well known source of influence on girls’ activty few good quality studies have tested peer-led interventions. We have worked for 2 years developing PLAN-A, a Peer-Led physical Activity interveNtion for Adolescent (Year 8; 12-13 years) girls. PLAN-A involved Year 8 girls completing a peer-nomination questionnaire to identify girls in their year who could shape the opinions of their friends (who they trust, resepct, are good listeners & leaders). The 18% most nominated girls are invited to be a peer-supporter who attend a 2-day training course outside of school, run by female trainers with expertise in physical activity or youth work, to learn about girls’ activity, identify the people skills needed as a peer-supporter and to support their close friends to be active. Peer-supporters return to school and informally sow the seeds to inspire or encourage their friends to be or keep active. We have shown (in a study funded by NIHR) that PLAN-A can be delivered, is acceptable to schools, pupils and parents and could increase girls actvity levels compared to girls in schools that did not get the intervention. We would now like to do a large study to test whether PLAN-A can increase the activity of girls in Year 9. We will recruit 20 schools and select them by random to either get the PLAN-A intervention (10 schools, 700 girls) or not, and be comparator schools (10 schools, 700 girls). We will measure girls’ activity levels using a device called an accelerometer which records how many minutes of moderate-to-vigorous physical activity participants do each day over a 7-day period before schools are chosen to be intervention or comparator (start of Year 9) and again 1 year later (at the start of Year 10). We will measure the cost of running the intervention to test if the intervention is good value for money. We will do interviews and group discussions with the peer-supporters, pupils, and trainers to find out what worked and what could be changed about the project and will interview school teachers and public health experts to see how best to run the project beyond the research and in real world settings. We will develop a local advisory group including teachers, public health experts, health improvement officers, physical activity and sport charities. The group will help shape the project, how we work with schools and ensure that the project is acceptable to young people. At the end of the project we will give the results to schools, hold an event to present our findings to local and national healthcare decision makers and also publish our findings in academic journals. The majority of the funds that we need for this project are for staff to manage the trial and equipment.

Research activity codes: 3.1 PRIMARY PREVENTION INTERVENTIONS TO MODIFY BEHAVIOURS OR PROMOTE WELL-BEING
Health categories: CANCER AND NEOPLASMS;CARDIOVASCULAR;METABOLIC AND ENDOCRINE;ORAL AND GASTROINTESTINAL;STROKE