title: Protocol for a feasibility cluster randomised controlled trial of a peer-led school-based intervention to increase the physical activity of adolescent girls (PLAN-A).
abstract: BACKGROUND
  Physical activity levels are low amongst adolescent girls, and this population faces specific barriers to being active. Peer influences on health behaviours are important in adolescence and peer-led interventions might hold promise to change behaviour. This paper describes the protocol for a feasibility cluster randomised controlled trial of Peer-Led physical Activity iNtervention for Adolescent girls (PLAN-A), a peer-led intervention aimed at increasing adolescent girls' physical activity levels.
  
  
  METHODS
  A two-arm cluster randomised feasibility trial will be conducted in six secondary schools (interventionn= 4; controln= 2) with year 8 (12-13 years old) girls. The intervention will operate at a year group level and consist of year 8 girls nominating influential peers within their year group to become peer-supporters. Approximately 15 % of the cohort will receive 3 days of training about physical activity and interpersonal communication skills. Peer-supporters will then informally diffuse messages about physical activity amongst their friends for 10 weeks. Data will be collected at baseline (time 0 (T0)), immediately after the intervention (time 1 (T1)) and 12 months after baseline measures (time 2 (T2)). In this feasibility trial, the primary interest is in the recruitment of schools and participants (both year 8 girls and peer-supporters), delivery and receipt of the intervention, data provision rates and identifying the cost categories for future economic analysis. Physical activity will be assessed using 7-day accelerometry, with the likely primary outcome in a fully-powered trial being daily minutes of moderate-to-vigorous physical activity. Participants will also complete psychosocial questionnaires at each time point: assessing motivation, self-esteem and peer physical activity norms. Data analysis will be largely descriptive and focus on recruitment, attendance and data provision rates. The findings will inform the sample size required for a definitive trial. A detailed process evaluation using qualitative and quantitative methods will be conducted with a variety of stakeholders (i.e. pupils, parents, teachers and peer-supporter trainers) to identify areas of success and necessary improvements prior to proceeding to a definitive trial.
  
  
  CONCLUSIONS
  This paper describes the protocol for the PLAN-A feasibility cluster randomised controlled trial which will provide the information necessary to design a fully-powered trial should PLAN-A demonstrate evidence of promise.
  
  
  BACKGROUND
  ISRCTN12543546.
authors.affiliation: grid.5337.20000000419367603Centre for Exercise, Nutrition & Health Sciences, School for Policy Studies, University of Bristol, Bristol, UK.
authors.forename: Simon J
authors.identifier: 0000-0001-7994-0844
authors.initials: SJ
authors.lastname: Sebire
authors.affiliation: grid.5337.20000000419367603Centre for Exercise, Nutrition & Health Sciences, School for Policy Studies, University of Bristol, Bristol, UK.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Edwards
authors.affiliation: grid.5337.20000000419367603School of Social & Community Medicine, University of Bristol, Bristol, UK.
authors.forename: Rona
authors.initials: R
authors.lastname: Campbell
authors.affiliation: grid.5337.20000000419367603Centre for Exercise, Nutrition & Health Sciences, School for Policy Studies, University of Bristol, Bristol, UK.
authors.forename: Russell
authors.initials: R
authors.lastname: Jago
authors.affiliation: grid.5337.20000000419367603School of Social & Community Medicine, University of Bristol, Bristol, UK.
authors.forename: Ruth
authors.initials: R
authors.lastname: Kipping
authors.affiliation: grid.5337.20000000419367603Centre for Exercise, Nutrition & Health Sciences, School for Policy Studies, University of Bristol, Bristol, UK.
authors.forename: Kathryn
authors.initials: K
authors.lastname: Banfield
authors.affiliation: grid.5337.20000000419367603School of Social & Community Medicine, University of Bristol, Bristol, UK.
authors.forename: Keeley
authors.initials: K
authors.lastname: Tomkinson
authors.affiliation: grid.5337.20000000419367603School of Social & Community Medicine, University of Bristol, Bristol, UK.
authors.forename: Kirsty
authors.initials: K
authors.lastname: Garfield
authors.affiliation: grid.4827.90000000106588800Farr Institute, Swansea University Medical School, Swansea, UK.
authors.forename: Ronan A
authors.initials: RA
authors.lastname: Lyons
authors.affiliation: grid.5337.20000000419367603School of Social & Community Medicine, University of Bristol, Bristol, UK.
authors.forename: Joanne
authors.initials: J
authors.lastname: Simon
authors.affiliation: grid.5337.20000000419367603School of Social & Community Medicine, University of Bristol, Bristol, UK.
authors.forename: Peter S
authors.initials: PS
authors.lastname: Blair
authors.affiliation: grid.5337.20000000419367603School of Social & Community Medicine, University of Bristol, Bristol, UK.
authors.forename: William
authors.initials: W
authors.lastname: Hollingworth
keywords: Adolescent girls; Intervention; Peers; Physical activity; School