Energetic and cardiovascular responses to treadmill walking and stationary cycling in subjects with incomplete spinal cord injury

Abstract

Study design:Randomized controlled trail.Objectives:To investigate if people with incomplete spinal cord injury (SCI) can perform high-intensity weight-bearing exercise by comparing cardiovascular responses at maximal workloads during stationary cycling and treadmill walking, and to explore mechanical efficiencies at sub-maximal workloads.Setting:Sunnaas Rehabilitation Hospital, Nesoddtangen, Norway.Methods:Fifteen people with incomplete SCI and 15 healthy control subjects performed sub-maximal and maximal exercise tests of both stationary cycling and uphill treadmill walking on separate days. Oxygen uptake (VO 2; l min -1 and ml kg -1 min -1), carbon dioxide production (VCO 2; l min -1), respiratory exchange ratio (RER) and heart rate (HR) were continuously measured throughout the tests.Results:The SCI group showed no significant differences in peak VO 2 (2.42±0.68 l min -1 versus 2.58±0.76 l min -1, P=0.19) or other cardiovascular responses at maximal workloads for stationary cycling as compared with uphill treadmill walking, except for higher RER during the cycle test. The control subjects exhibited a significantly higher peak VO 2 during the treadmill test as compared with the cycle test (P=0.007). Both groups had lower mechanical efficiency when walking as compared with cycling, but the mean difference between cycling and walking was not significantly different between the groups during sub-maximal workloads (P >0.24).Conclusion:Subjects with incomplete SCI were able to perform high-intensity weight-bearing exercise and exhibited similar mechanical efficiencies at sub-maximal workloads as healthy controls. Uphill walking might be a good alternative to weight-bearing exercise for increasing the physical capacity of people with incomplete SCI.