Condition category
Not Specified
Date applied
Date assigned
Last edited
Prospectively registered
Overall trial status
Recruitment status
No longer recruiting

Plain English Summary

Background and study aims
Being physically active is good for children’s health. Few adolescent girls are active enough to get these health benefits and teenage girls face lots of barriers to being physically active. Research shows that most school-based programs to increase adolescents' physical activity do not work, but few high quality studies have been tried in the UK. A peer-led program called PLAN-A has been developed in which adolescent girls inspire their peers to take part in more physical activity. Preliminary work has shown that PLAN-A has the potential to help adolescent girls to be more physically active.
This study aims to examine whether girls who take part in the PLAN-A program in 10 intervention schools obtain more moderate to vigorous intensity physical activity (MVPA) a year after the baseline assessment has been made than girls in 10 comparison schools. It also assesses how much the program costs and conducts qualitative research to understand how the program was received by schools and pupils and if it could be improved or adapted before using widely.

Who can participate?
Year 9 girls in participating schools.

What does the study involve?
The study is based on a feasibility trial in which a peer-led physical activity intervention for 13-14 year old girls was developed. The study is conducted in 20 schools, ten of which receive the intervention. In these schools, peer supporters are trained by experts in physical activity and youth work. Ten schools are “comparison schools” and do not do the peer-training. Schools are allocated to intervention or comparison at random.
Year 9 girls in all twenty schools are asked to provide information at two times: before the schools are chosen to be project or comparison schools, and 1 year after the first measurements. Participants’ physical activity levels are measured using activity monitors and their motivation for being active using questionnaires. The cost of delivering the intervention is also assessed. Interviews and group discussions with peer-supporters, pupils, school staff, trainers and public health commissioners are used to find out what was successful and what could be changed in future.

What are the possible benefits and risks of participating?
The benefits of participation for peer-supporters include an increased awareness of physical activity and the health benefits of being more active, improved teamwork, communication, empathy and problem solving skills, and a potential increase in physical activity levels due to the ideas and knowledge gained during the training and intervention period. The benefits of participation for Year 9 girls who are not peer-supporters include being encouraged to be more active from their peers, greater exposure to new ideas about how to incorporate physical activity into their day-to-day life, and the potential health benefits this holds. Schools benefit by having a number of their pupils attending a training course which may increase their skills, confidence and leadership abilities. Additionally, physical activity levels throughout the Year 9 female cohort may be increased.
The potential risks to participants are minimal. Peer-supporters may face instances of bullying/teasing, but we ensure reporting procedures are in place to minimise such instances and effectively deal with any that do arise. Non-peer-supporters may feel pressured to be active, but the training that peer-supporters receive covers empathy and effective communication.

Where is the study run from?
University of Bristol (UK)

When is the study starting and how long is it expected to run for?
May 2018 to January 2021

Who is funding the study?
National Institute for Health Research (Public Health Research Programme) (UK)

Who is the main contact?
Prof Russ Jago (scientific)

Trial website

Contact information



Primary contact

Prof Russ Jago


Contact details

Centre for Exercise
Nutrition and Health Sciences
School for Policy Studies
University of Bristol
8 Priory Road
United Kingdom
+ 44 (0)117 9546603

Additional identifiers

EudraCT number number

Protocol/serial number

PHR 17/50/01

Study information

Scientific title

A cluster randomised controlled trial of a Peer-Led physical Activity iNtervention for Adolescent girls (PLAN-A)



Study hypothesis

The hypothesis is that girls in the intervention arm will engage in more minutes of weekday MVPA at time 1 than girls in the comparison arm. We also hypothesise that there will be secondary effects on Weekend MVPA as well as both Weekday and Weekend sedentary time.

Ethics approval

School for Policy Studies Ethics Committee University of Bristol, 24/05/2018, ref: SPSREC17-18.C22

Study design

Cluster randomised controlled trial

Primary study design


Secondary study design

Cluster randomised trial

Trial setting


Trial type


Patient information sheet

Not available in web format, please use the contact details below to request a patient information


Physical activity


Ten schools are chosen at random to run the peer-training project and ten schools are comparison schools and do not do the peer-training.
1. Peer-nomination:
Peer-supporters are identified by peer nomination in which consenting Year 9 girls identify, by questionnaire, the female peers they perceive to be influential. The highest scoring 18% (those with most nominations) are invited to be peer-supporters, with the aim of ensuring that ≥15% take on this role
2. Peer-supporter training:
Peer-supporters attend a two-day course to develop the skills, knowledge and confidence to promote physical activity amongst their peers. Training is held off-site and led by external peer-supporter educators who themselves have attended a training programme. The peer-supporter training is informed by our developmental work with Year 9 girls, is interactive and address issues central to girls’ PA, including: PA benefits, active choices, developing an active identity, being active with friends, sedentary behaviour, communicating with confidence, empathy and supporting motivation. The content is grounded in self-determination theory to build the girls’ perceived autonomy, competence and sense of social support, both for being a peer-supporter and to promote physical activity. Peer-supporters are encouraged to keep these concepts in mind when having conversations with their peers.
3. 10-week informal health message peer-diffusion component:
Peer-supporters informally promote messages about increasing physical activity amongst their peers for 10 weeks. At the mid-point of the intervention peer-supporters attend a 1 day off-site top-up session to revisit core messages, share successes and collaboratively resolve problems.
Year 9 girls in all twenty schools are asked to provide information at two times: before the schools are chosen to be project or comparison schools and 1 year after the first measurements.

Intervention type



Drug names

Primary outcome measure

Accelerometer determined mean minutes of Weekday MVPA at T1 (baseline + 1 year)

Secondary outcome measures

1. Accelerometer determined mean minutes of Weekend MVPA at T1 (baseline + 1 year)
2. Accelerometer determined mean minutes of Weekday sedentary time at T1 (baseline + 1 year)
3. Accelerometer determined mean minutes of Weekend sedentary time at T1 (baseline + 1 year)
4. Cost-effectiveness of the PLAN-A intervention from a public-sector perspective

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

Year 9 girls in participating schools

Participant type


Age group




Target number of participants


Total final enrolment


Participant exclusion criteria

No participant exclusion criteria

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

University of Bristol
Centre for Exercise, Nutrition and Health Sciences, School for Policy Studies, 8 Priory Road
United Kingdom

Sponsor information


University of Bristol

Sponsor details

Research and Enterprise Development
3rd Floor
Senate House
Tyndall Avenue
United Kingdom

Sponsor type




Funder type


Funder name

NIHR Public Health Research Programme - (REF PHR 17/50/01)

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

We plan to publish up to four study papers. 1) study protocol paper; 2) main trial (cost and cost effectiveness) paper; 3) process evaluation paper; and 4) mediation paper.

1. 2020 non-peer-reviewed Statistical Analysis Plan in (added 17/02/2020)
2. 2020 non-peer-reviewed Health Economics Analysis Plan in (added 17/02/2020)

IPD sharing statement:
In line with the NIHR research contract, anonymised data from this study will be made available to other researchers. This will be done using the University of Bristol’s Research Data Repository.

Intention to publish date


Participant level data

Stored in repository

Basic results (scientific)

Publication list

2019 protocol in (added 13/01/2020)

Publication citations

Additional files

Editorial Notes

02/12/2020: The overall trial end date was changed from 31/12/2020 to 31/01/2021. 17/02/2020: The Statistical Analysis and Health Economics Analysis plans have been added to the publication and dissemination plan. 13/01/2020: Publication reference added. 11/03/2019: The total final enrolment number has been added. 19/02/2019: Recruitment end date was changed from 31/01/2019 to 08/02/2019