The Spinal Cord Injury Move More (SCIMM) study: benefits of breaking up prolonged sedentary time on heart disease risk in people with spinal cord injury

INTERVENTION: Current interventions as of 10/11/2017: This is a randomised crossover design with two trial conditions that each last 5.5 hours with a minimum washout of at least 6 days between each condition. The study will test the heart disease risk marker responses to the two conditions below. A researcher who is not involved in participant recruitment and intervention will create a randomization list using the block randomization method (software: Research Randomizer, https://www.randomizer.org). This list will be provided to the study investigators. The investigator responsible for enrolment will remain blinded to the intervention allocations until 48 hours prior to the first main trial for each participant. The trial conditions are: 1. Uninterrupted sitting (SIT): participants will remain seated uninterrupted at a desk during the 5.5 hour trial period 2. Sitting + activity breaks (SIT‐ACT): participants will perform 2 min of moderate‐intensity arm crank exercise every 20 min during the 5.5 hour day with the first bout taking place 20 min after breakfast. The moderate‐intensity exercise in the SIT‐ACT condition will be performed at a Rating of Perceived Exertion of 13 (somewhat hard). During the inactive periods the volunteers will carry out desk‐based activities on a computer, read, talk, or watch DVDs. Before and during the trial, the researchers will measure each participant’s levels of blood sugar and cholesterol after eating, insulin levels and blood pressure. There is no follow‐up. Previous interventions: This is a randomised crossover design with three trial conditions that each last 7 hours with a minimum washout of at least 6 days between each condition. The study will test the heart disease risk marker responses to the three conditions below. A researcher who is not involved in participant recruitment and intervention will create a randomization list using the block randomization method (software: Research Randomizer, https://www.randomizer.org). This list wi CONDITION: Spinal cord injury ; Injury, Occupational Diseases, Poisoning ; Injury of spinal cord, level unspecified PRIMARY OUTCOME: Current primary outcome measures as of 10/11/2017:; Postprandial plasma glucose concentration incremental area under the curve, measured with a benchtop analyser from whole blood samples collected at baseline and then regularly during each of the two trial conditions; ; Previous primary outcome measures:; Postprandial plasma glucose concentration incremental area under the curve, measured spectrophotometrically from venous blood samples collected at baseline and then hourly during each of the three trial conditions SECONDARY OUTCOME: Current secondary outcome measures as of 10/11/2017:; 1. Incremental area under the curve for postprandial triglycerides, measured with a benchtop analyser from whole blood samples collected at baseline and then regularly during each of the two trial conditions; 2. Incremental area under the curve for HDL, with a benchtop analyser from plasma collected at baseline and then regularly during each of the two trial conditions; 3. Incremental area under the curve for insulin, measured using an enzyme immunoassay from plasma samples collected at baseline and then regularly during each of the two trial conditions; 4. Systolic and diastolic blood pressure, measured using an automated oscillatory blood pressure monitor at baseline and then regularly during each trial; ; Previous secondary outcome measures:; 1. Incremental area under the curve for postprandial triglycerides, measured spectrophotometrically from venous blood samples collected at baseline and then hourly during each of the three trial conditions; 2. Incremental area under the curve for HDL, measured spectrophotometrically from venous blood samples collected at baseline and then hourly during each of the three trial conditions; 3. Incremental area under the curve for insulin, measured using an enzyme immunoassay from venous blood samples collected at baseline and then hourly during each of the three trial conditions; 4. Total area under the curve for IL‐6, measured using an enzyme immunoassay from venous blood samples collected at baseline and then hourly during each of the three trial conditions; 5. Systolic and diastolic blood pressure, measured using an automated oscillatory blood pressure monitor at baseline and then hourly during each trial INCLUSION CRITERIA: Current inclusion criteria as of 10/11/2017: 1. Male and female 2. Aged 18‐60 years 3. Not highly active: engaging in less than <300 min per week of moderate‐to‐vigorous physical activity 4. Have a chronic spinal cord injury (=1 year since injury) 5. Injured at Thoracic level 6 to Sacral Level 5 (mild to low level paraplegia). These individuals have intact sympathetic innervation to the heart and resting blood pressure is typically normal Previous INCLUSION CRITERIA: 1. Male 2. Aged 18‐50 years 3. Physically inactive: engaging in less than <150 min per week of moderate‐to‐vigorous physical activity 4. Have a chronic spinal cord injury (=1 year since injury) 5. Injured at Thoracic level 6 to Sacral Level 5 (mild to low level paraplegia). These individuals have intact sympathetic innervation to the heart and resting blood pressure is typically normal