Hybrid HIIT-FES Cycling for Spinal Cord Injury

Project Summary/Abstract Obesity and metabolic syndrome (obesity, dyslipidemia, hyperglycemia, hypertension) are epidemic in the spinal cord injured (SCI) population. A recent study assessing the body composition and metabolic syndrome rates of 72 motor complete chronic SCI individuals revealed an obesity rate of over 90% and a metabolic syndrome rate of 60%. These results are significantly higher than in the general population. As such individuals with SCI typically have systemic inflammation and an accelerated trajectory towards cardiometabolic disease, and early mortality. Although the accelerated trajectory is multi-factorial, substantial evidence implicates sedentary behavior and low physical activity levels as significant contributing factors. Exercise strategies for individuals with SCI have included upper body arm crank exercise (ACE), functional electrical stimulation leg cycling exercise (FES-LCE), or a combination of the two (FES Hybrid Exercise). These modalities have yielded modest improvements in physical fitness and cardiometabolic risk profiles in individuals with SCI. FES-LCE reportedly increased lean-to-fat mass ratio, enhanced peripheral blood flow and vasoreactivity, and increased bone mass in the paralyzed legs. In addition, FES-LCE improves metabolic function as evidenced by increased glucose disposal. There is evidence that high-intensity interval training exercise can increase muscle mass and improve cardiovascular fitness with considerably less time commitment than non-interval activities. However, given many individuals with SCI respond poorly to the onset of training a primer exercise program for the extremely deconditioned muscles is recommended for optimal results. The investigators intend to investigate the optimization of benefits by using a novel hybrid FES cycling protocol (FES legs cycling plus voluntary arms cycling) combined with high intensity interval training (HIIT) and preceded by a preparatory muscle strengthening program called "peripheral remodeling intermittent muscular exercise (PRIME) to prepare the deconditioned muscles for the more intense exercise in the hybrid HIIT-FES cycling program. The investigators hypothesize that individuals in the PRIME + hybrid HIIT-FES cycling program will demonstrate significantly greater cardiometabolic health and functional benefits than the control group receiving standard of care range of motion exercises.