The purpose of this study is to determine whether nervous system alterations and motor drive failure can contribute to muscle weakness in COPD during voluntary movement. If necessary, we will look after the role of nocturnal hypoxia in these alterations.

COPD is a common disease that induces many systemic repercussions. Among these, peripheral muscle dysfunction is particularly deleterious because it leads to the decreases of the level of activity and the quality of life for patients. Movement involves activation of many structures, from the instructor, i.e. the brain, to the effector, i.e. the muscle. Netherless, the studies which have described peripheral muscle dysfunction have been focused on the muscle, so they have proposed a reducing vision of the phenomenon. Other studies have reported cerebral alterations in COPD, like cognitive disturbance, increase of the neuronal conduction time, and decrease of the white matter density, and were associated with chronic hypoxemia. Such alterations are consistent with the existence of a decrease of the central motor drive during voluntary movement in COPD patients. Therefore the study will aim to determine precisely which mechanisms are involved in peripheral muscle dysfunction in copd.

Inclusion Criteria:

• COPD Patients at stage 2 and 3
• Healthy sedentary subjects

Exclusion Criteria:

• Epilepsy, pace-maker, nervous disorders

Two groups of COPD patients and one group with healthy sedentary subjects