DISCUSSION
quadriceps femoris muscle CSA, muscle gain, peripheral muscle, hypoxia, Peripheral muscle fatigue, muscle dysfunction, nonhypoxemic COPD, COPD
HYPOXIA, COPD
To the best of our knowledge, this is the first study to investigate the impact of an exercise training intervention with and without supplemental oxygen on independently assessed end points of functional and structural peripheral muscle adaptations in patients with nonhypoxemic COPD. The innovative assessment of the quadriceps femoris muscle CSA by MRI provides new insights into the training adaptations during pulmonary rehabilitation. In this population, limb muscle dysfunction and the related interindividual variability in the effects of exercise training on skeletal muscles are not yet fully understood. The main results of this investigation suggest the following interpretations:Peripheral functional and structural training adaptations are highly variable in this population.Supplemental oxygen increases the impact of exercise training on peak work rate and skeletal muscle mass.Peripheral muscle fatigue and hypoxia during exercise may affect the training response on muscle gain.Exercise-induced intermittent hypoxia might be a determinant to further investigate regarding its association with limb muscle dysfunction in COPD.