The influence of a home-based exercise intervention on human health indices in individuals with chronic spinal cord injury (HOMEX-SCI): study protocol for a randomised controlled trial

Background: Spinal cord injury (SCI) creates a complex pathology that can lead to an increase in sedentary behaviours and deleterious changes in body composition. Consequently, individuals with SCI are at increased risk of developing cardiovascular disease and type-2 diabetes mellitus. While the role of physical activity on the reduction of chronic disease risk is well documented in non-disabled individuals the evidence is less conclusive for persons with SCI. The aim of this methodological paper is to outline the design of a study that will assess the role of a home-based exercise intervention on biomarkers of metabolic and cardiovascular health in persons with SCI: the HOMEX-SCI study. Methods/design: Eligible participants will be inactive (physical activity level <= 1.60) individuals, with a chronic (more than 1 year) spinal cord lesion between the second thoracic and the fifth lumbar vertebrae, and aged between 18 and 65 years. Following baseline laboratory testing and lifestyle monitoring, participants will be randomly allocated to a control (CON) group or a 6-week home-based exercise intervention (INT) group. The INT consists of 45 minutes of moderate-intensity (60-65 % peak oxygen uptake) arm-crank exercise four times per week. Participants assigned to the CON group will be asked to maintain their normal lifestyle. The main outcomes of this study (biomarkers of metabolic and cardiovascular health) are obtained from venous blood samples, collected in the fasted and postprandial state. Eight other measurement categories will be assessed: (1) body composition, (2) physical activity, (3) energy intake, (4) measures of health and wellbeing, (5) resting metabolic rate, heart rate and blood pressure, (6) aerobic capacity, (7) immune function, and (8) adipose tissue gene expression. Discussion: This study will explore the feasibility of home-based moderate-intensity exercise and ascertain its impact on metabolic and cardiovascular health in comparison to a lifestyle maintenance CON group. Findings from this study may help to inform new evidence-based physical activity guidelines and also help to elucidate the physiological mechanisms whereby exercise might exert beneficial effects in persons with chronic SCI. The results will also act as a scientific platform for further intervention studies in other diverse and at-risk populations.