Purpose: The purpose of this study was to assess the cardiorespiratory responses during arm exercise with and without concurrent electrical stimulation-induced leg cycling in people with paraplegia.
Methods: On separate days, 10 subjects with spinal cord injuries (T5-T12) performed either arm cranking (ACE), or simultaneous arm cranking + electrical stimulation-induced leg cycling (ACE+ES-LCE) graded exercise tests. Results: During submaximal, steady-state exercise, ACE+ES-LCE elicited significantly higher O2, (by 0.25-0.28 L[middle dot]min-1), stroke volume (by 13 mL), and eBTPS (by 9.4 L[middle dot]min-1) compared with ACE alone. In contrast, there were no significant differences of submaximal HR, cardiac output, or power output between the exercise modes. At maximal exercise, ACE+ES-LCE elicited significantly higher O2 (by 0.23 L[middle dot]min-1) compared with ACE alone, but there were no differences in power output, HR, or eBTPS.
Conclusions: These results demonstrate that during submaximal or maximal exercise there was a greater metabolic stress elicited during ACE+ES-LCE compared with during ACE alone. The higher stroke volume observed during submaximal ACE+ES-LCE, in the absence of any difference in HR, implied a reduced venous pooling and higher cardiac volume loading during ACE+ES-LCE. These results suggest that training incorporating ACE+ES-LCE may be more effective in improving aerobic fitness in people with paraplegia than ACE alone.