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.