Aerobic performance capacity in paraplegic subjects

To determine adaptation to prolonged exercise in paraplegics, maximal O₂ uptake ( \(\dot V_{O_{2max} } \) ) and lactate threshold (LT) were evaluated during an arm cranking exercise in nine patients (P) and nine able-bodied (AB) subjects. Mean \(\dot V_{O_{2max} } \) averaged 25.1 and 31.6 ml · min⁻¹ · kg⁻¹ in P and AB groups respectively. \(\dot V_{O_{2max} } \) in P was found to be directly related to the level of spinal injury: the higher the lesion the lower the uptake. Lactate threshold expressed as a percentage of \(\dot V_{O_{2max} } \) was higher in P (59%) than in AB (43%), and close to that observed in armtrained athletes. Since training has less effect on \(\dot V_{O_{2max} } \) in paraplegics than in able-bodied subjects, attributable to a deficiency in the circulatory adaptation of paraplegics to exercise, the observed differences between AB and P in lactate threshold and submaximal exercise indicate that the possible effect of training in paraplegics is located at the level of intracellular chemistry, with a diminution in glycogenolysis (higher LT) and a higher rate of lipid utilization (lower RQ).