Active for Life Year 5: A cluster randomised controlled trial of a primary school-based intervention to increase levels of physical activity, decrease sedentary behaviour and improve diet

Lead investigator
Professor Debbie Lawlor, University of Bristol

Low levels of physical activity, high levels of sedentary behaviour and low levels of fruit and vegetable consumption are common in children and are associated with adverse health outcomes. This affects normal healthy growth and development in children and means that children are now more likely to be overweight or obese. Children who have healthy levels of activity and intake of fruit and vegetables are more likely to have healthy levels of these behaviours as adults, which means that the health benefits of getting children to be more active, less sedentary and eat more fruit and vegetables last throughout life.

A number of studies, mostly conducted in the US, have shown that school-based interventions where children are taught about healthy diets and physical activity are effective in improving behaviours in childhood. However, there have been problems with these studies. Firstly, they have not measured long-term effects beyond the end of the intervention. Secondly, previous studies have relied on children or their parents reporting how active the children are on an average day, rather than objectively measuring this. Lastly, to date only three studies have been conducted in the UK. These were conducted some time ago and had important methodological weaknesses. It is not clear that interventions that are effective in the US or other countries will be here.

Aims & objectives
To evaluate a school-based intervention that aims to increase levels of physical activity, decrease sedentary behaviour and increase consumption of fruit and vegetables in school children.
Study design

School-based, cluster randomised controlled trial targeting school children in year 5 (age 9-10 years). All state junior/primary schools in the area covered by Bristol City and North Somerset Council were invited to participate; special schools were excluded. Sixty eligible schools were recruited and randomised to intervention arm or control arm. Schools randomised to the intervention (N=30; approximately 1000 children) received the intervention immediately and those randomised to control (N=30; approximately 10) were offered the intervention after completion of the two follow-up assessments.

The intervention comprised:

  • Training for classroom teachers;
  • Provision of 16 lesson-plans and teaching materials, including pictures, CDs and journals;
  • Provision of 10 parental-child interaction homework activities;
  • Information in the school newsletters about the importance of increasing physical activity, reducing sedentary behaviour and improving diet;
  • Written information for parents on how to encourage their children to eat healthily and be active.


Outcomes were assessed at baseline (prior to starting the intervention), one year later (at the end of the intervention) and two years later (to assess any long term impact).

At each stage of assessment the following data were gathered from the children:

  • Accelerometer assessment of physical activity and sedentary behaviour;
  • Weight, height and waist circumference;
  • Questionnaire assessment of diet, physical activity and sedentary behaviour.


Information on costs was also collected, and a cost consequence analysis is being used to undertake an economic evaluation from a societal perspective. Resources will be valued as reported by researchers, teachers and parents, and using routine data sources.

Data from focus groups, and interviews with pupils, parents, teachers and head teachers is being used to increase understanding of how/why the intervention is/isn’t shown to have an effect and how it is integrated into normal school activity.

Further information & publications
Start date
April 2011
End date
May 2015
Trial register number