Factors limiting maximal oxygen uptake in exertional monoparesis.

Strength and maximal oxygen uptake (VO2max) for each leg were compared in a trained multiple sclerosis (MS) patient with exertional left monoparesis. Left quadriceps strength and left leg VO2max were 22% and 30% lower, respectively, compared to the right (control) leg. Because the same O2 delivery system served each leg during exercise, VO2max of the paretic leg was not limited by cardiorespiratory factors but rather by strength and/or muscle oxidative capacity. However, training with monoparesis likely enhanced O2 extraction and aerobic work capacity of the right leg.