Objective: The aim of this study was to determine whether the relationship between impaired pulmonary function and level of spinal cord injury would relate to lower maximal ventilation during exercise (Vemax) and hence reduced aerobic capacity.
Design: Pulmonary function and maximal aerobic capacity (V˙O2max) were assessed as measured by maximal oxygen uptake in 20 men with complete spinal cord injury (C5–T11). Static and dynamic lung volumes (forced vital capacity, forced expiratory volume in 1 sec, and maximum voluntary ventilation) were measured by spirometry. V˙O2max and Vemax were measured during a graded maximal exercise test on an arm crank ergometer.
Results: Level of injury was inversely correlated with measures of pulmonary function, Vemax and V˙O2max. On the basis of the correlations, the authors constructed a path analysis to test whether level of injury indirectly (via pulmonary function and/or Vemax) or directly reduced V˙O2max. Akaike information criteria indicated that the strongest effect of level of injury on V˙O2max was via reduced Vemax.
Conclusions: Respiratory capacity does influence exercise capacity in the population with spinal cord injury and may play an important role in delimiting aerobic exercise capacity.