Hemodynamic responses of quadriplegics to maximal arm-cranking and FNS leg cycling exercise

The purpose of this study was to compare maximal central hemodynamic responses of spinal-cord-injured quadriplegic subjects to voluntary arm-crank exercise (ACE) and to electrically induced leg cycling exercise. Six C6-C7 quadriplegic men performed graded exercises to maximum with both an arm-crank ergometer and a leg-cycle ergometer, utilizing functional neuromuscular stimulation (FNS) of paralyzed leg musculature. Both exercise modes produced a V-dot O/sub 2/ peak of approximately 1 l/min, with peak power outputs for the arm and leg exercises of 38 and 11 W, respectively. Compared with voluntary ACE, FNS cycling elicited a significantly higher mean cardiac output, stroke volume, and mean arterial blood pressure, and significantly lower mean heart rate and rate-pressure product. While maximal FNS cycling is mechanically less efficient than ACE, it appears to produce a more desirable hemodynamic response pattern, i.e. greater venous return and cardiac volume-load with less myocardial stress. Thus, FNS leg cycling may be more effective than ACE for aerobic cardiovascular training of quadriplegics.<>