The results of this study indicated that the quadriplegics sustained a significantly
lower relative HR and VO2 during the SR compared to the paraplegics (Table II). Lakomy et al ll reported that the relative V02 during a simulated 5 km wheelchair race on the treadmill was approximately 90% in two quadriplegic wheelchair athletes. This was substantially higher than the average value of 76% that they observed in 10 paraplegic wheelchair athletes. The reasons for this discrepancy between the two studies are at present unclear, and further research on a larger group of subjects is needed to confirm
this observation. Van Loan et al7 reported that the peak cardiac output during arm cranking exercise was significantly lower inquadriplegics when compared to paraplegics and able bodied subjects. However, no significant differences were observed among these groups for the (a-v)02 diff during peak exercise. Whether the significantly lower relative V02 during the SR observed in the quadriplegics in the current study was due to reduced blood perfusion to the exercising muscle as a result of their lower cardiac output also needs to be investigated.