STUDY PROTOCOL Open Access The effect of home-based low-volume, high-intensity interval training on cardiorespiratory fitness, body composition and cardiometabolic health in women of normal body mass and those with overweight or obesity: protocol for a randomized controlled trial Emmanuel Frimpong 1 , Chloe Dafkin 1 , Janine Donaldson 2 , Aletta Maria Esterhuyse Millen 3 and Rebecca Mary Meiring 1,4* Abstract Background: There is a high prevalence of women in South Africa with overweight and obesity which is associated with an increased risk of cardiometabolic disorders. Perceived barriers such as lack of time and motivation reduce engagement in beneficial activity behaviours for health. High-intensity interval training (HIIT) is a time-efficient and effective way to improve cardiometabolic risk profile regardless of a loss in body mass or change in body composition. This randomized controlled trial aims to determine the effects on cardiorespiratory fitness, body composition and cardiometabolic health and feasibility of a home-based 14-week HIIT program in women with overweight/obesity or normal body mass. Methods: One hundred and twenty women (18–40 years old) with a body mass index between 20 and 35 kg/m 2 , will be stratified according to their BMI (normal, BMI 20–24.9 kg/m 2 ; or high BMI ≥25 kg/m 2 ) and randomized into a HIIT exercising group (HIIT) or a non-exercising control group (CON). HIIT participants will perform exercises for 11 min/session six times per week for a period of 14 weeks. The 2 × 4 HIIT protocol will require a work phase of own- body weight exercise lasting 2 minutes (85% VO 2 peak), repeated four times and separated by a one-minute active rest phase (65% VO 2 peak). CON participants will be asked to maintain their normal habitual lifestyle. Outcomes of cardiorespiratory fitness, body composition, echocardiography, central blood pressure, arterial stiffness and biomarkers of cardiometabolic health will be measured before and after the 14-week intervention. Every 4 weeks during the intervention, an objective estimation of compliance to the study protocol will be assessed by measuring participant physical activity over 7 days using an Actigraph GT3X accelerometer. (Continued on next page) © 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: rebecca.meiring@auckland.ac.nz 1 Movement Physiology Research Laboratory, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa 4 Department of Exercise Sciences, Faculty of Science, The University of Auckland, Building 907-228, Suiter Street, Newmarket, Auckland 1023, New Zealand Full list of author information is available at the end of the article Frimpong et al. BMC Sports Science, Medicine and Rehabilitation (2019) 11:39 https://doi.org/10.1186/s13102-019-0152-6