STUDY PROTOCOL Open Access Integrating physical activity into the primary school curriculum: rationale and study protocol for the “Thinking while Moving in English” cluster randomized controlled trial Myrto F. Mavilidi 1* , David R. Lubans 1 , Philip J. Morgan 1 , Andrew Miller 2 , Narelle Eather 1 , Frini Karayanidis 3 , Chris Lonsdale 4 , Michael Noetel 4 , Kylie Shaw 2 and Nicholas Riley 1 Abstract Background: The current and declining physical activity levels of children is a global concern. Integrating physical activity into the school curriculum may be an effective way not only to improve children’s physical activity levels but also enhance educational outcomes. Given the recent national focus in Australia on improving the literacy levels of children in primary school, and an increasing proportion of time spent on explicitly teaching these skills, integrating physical activity into English could be a viable strategy to improve literacy levels and physical activity at the same time. The aim of this study is to evaluate the impact of the ‘Thinking While Moving in English’ (TWM-E) program on children’s physical activity, on-task behavior in the classroom, academic achievement, and executive function. Methods: Grade 3–4 children from 10 public schools in New South Wales, Australia will be randomly allocated to intervention (n = 5) or control (n = 5) groups. All teachers will receive 1-day workshop of registered professional learning and a TWM-E equipment pack (e.g., chalk, lettered bean bags). Intervention schools will be asked to adapt their English lessons to embed movement-based learning in their daily program for three 40-min lessons per week, over a six-week period. The primary outcome is children’s physical activity levels across the school day (measured using accelerometry). Secondary outcomes are children’s on-task behavior during English lessons, academic achievement in English, and executive function. A detailed process evaluation will be undertaken including questionnaires, fidelity checks, and teacher and student interviews. Discussion: The TWM-E program has the potential to improve primary school children’s physical activity levels, along with academic outcomes (on-task behavior, cognition, and academic achievement), and provide stakeholders with exemplar lessons and guidelines which illustrate how to teach English to children whilst they are moving. Trial registration: Australian and New Zealand Clinical trial Register ACTRN12618001009202 Date registered: 15/06/2018 retrospectively registered. Keywords: Physical activity, Primary schools, English, On-task behavior, Cognitive function, Randomized controlled trial © The Author(s). 2019 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. * Correspondence: Myrto.Mavilidi@newcastle.edu.au 1 Priority Research Centre for Physical Activity and Nutrition, University of Newcastle, Callaghan NSW 2308, Australia Full list of author information is available at the end of the article Mavilidi et al. BMC Public Health (2019) 19:379 https://doi.org/10.1186/s12889-019-6635-2