Relationship between physical characteristics and physiological responses during maximal arm cranking in paraplegics.

The purpose of this study was to elucidate the main physical factor(s) affecting cardiorespiratory responses during maximal arm cranking exercise in patients with paraplegia. Peak oxygen uptake (peak Vo2), peak pulmonary ventilation (peak VE) and peak heart rate (peak HR) were measured during maximal arm cranking exercise in 28 Japanese male patients. A cluster analysis was applied to the data for peak Vo2, peak HR and peak VE, and then the subjects were classified into four groups (A, B, C and D). Group A showed high peak VE and peak HR and low peak Vo2, Group B low peak Vo2 and high values for other parameters, Group C the greatest physiological values for all measurements among the groups and, in contrast, Group D showed low peak Vo2 and the lowest peak VE and peak HR among the groups. The subjects in Group C had low level of spinal cord injury and were sports participants. On the other hand, duration since injury was not related to the cardiorespiratory responses during maximal arm cranking. These findings indicate that the effects on these responses of years since injury are subordinate to those of the level of spinal cord injury and training.

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.