Peak oxygen uptake and respiratory function in persons with spinal cord injury

This study investigated the association between peak oxygen uptake (peak VO2) during arm cranking exercise and respiratory function in paraplegics. Fourteen male paraplegics were recruited for the present study. The subjects were grouped according to the level of injury into the HL (Th3-Th8) and LL (Th11-L3) group. Prior to the maximal test, pulmonary function, including vital capacity (VC) and residual volume (RV), was measured in the sitting position. Mean peak VO2 in the LL group (1662 ml.min-1) was significantly greater than that in the HL group (1357 ml.min-1), corresponding to 82% of that in the LL group (P < or = 0.05). In respiratory function, the HL group showed marked restrictive impairment of ventilatory function. That is, VC and RV were significantly lower in the HL group than in the LL group (P < or = 0.05). The reduction in VC and RV is related to the degree of loss of control in respiratory functioning muscle mass. However, there was no clear-cut correlation between respiratory function and peak VO2 expressed as a function of body mass (ml.kg-1.min-1). In addition, a multiple linear regression analysis revealed that RV and VC were not associated with peak VO2 (ml.min-1) in contrast to the importance of body mass. It seems reasonable to conclude from these results that respiratory function is not an important factor in determining peak VO2 in the paraplegic.