Purpose: This study aimed to describe cardiorespiratory, quadriceps oxygenation, and muscle fatigue responses during a one-legged quadriceps isokinetic endurance exercise in chronic obstructive pulmonary disease (COPD) and control subjects.
Methods: Fourteen patients with COPD and 14 control subjects performed a cardiopulmonary cycling exercise test to exhaustion to assess peak oxygen consumption (V˙O2peak), minute ventilation (V˙Epeak), and heart rate (HRpeak). They also performed a quadriceps isokinetic endurance exercise consisting in 30 maximal knee extensions at 90°·s with continuous monitoring of expired gases, cardiac output, and oxygenation of the quadriceps by near-infrared spectroscopy.