Action 3:30R: protocol for a cluster randomised feasibility study of a revised teaching assistant-led extracurricular physical activity intervention for 8 to 10 year olds

Background: Approximately half of seven-year-old children do not meet physical activity (PA) recommendations. Interventions targeting primary school children’s afterschool discretionary time could increase PA. Teaching assistants (TAs) are a school resource and could be trained to deliver after-school PA programmes. Building on earlier work, this paper describes the protocol for a cluster randomised feasibility study of a teaching assistant led after-school intervention aimed at increasing PA levels of year 4 and 5 children (8-10 years old).

Methods: Phase 1 – Pre-baseline: 12 schools will be recruited. In all schools, self-reported PA will be measured in all consenting year 3 and 4 children. In four schools, pupils will additionally wear a waist-worn Actigraph accelerometer for seven days.
Phase 2 – Baseline: Schools will be randomised to one of two enhanced recruitment strategies being tested for children; 1) a club briefing, 2) the briefing plus a taster Action 3:30 session. Up to 30 children per school will be able to attend Action 3:30 sessions and will provide baseline data on height, weight, psychosocial variables and accelerometer-measured PA.
Phase 3 – Intervention and follow up: Schools randomised into intervention or control arm. Intervention schools (n = 6) will receive a 15-week after-school programme when children are in years 4 and 5, run by TAs who have attended a 25-hour Action 3:30 training programme. Control schools (n = 6) will continue with normal practice. Follow up measures will be a repeat of baseline measures at the end of the 15 week intervention.
Phase 4 – Process evaluation: session attendance, perceived enjoyment and perceived exertion will be assessed during the intervention, as well as the economic impact on schools. Post-study qualitative assessments with TAs, school contacts, and pupils will identify how the programme could be refined. Accelerometer-determined minutes of moderate-to-vigorous physical activity (MVPA) per day will be calculated as this is likely to be the primary outcome in a future definitive trial.

Discussion: The Action 3:30 cluster randomised feasibility trial will assess the public health potential of this intervention approach and provide the information necessary to progress to a definitive cluster randomised controlled trial.

Trial registration: ISCRTN 32920. Registered 01/12/2016
Key words: children, physical activity, intervention, teaching assistant, feasibility trial