COPD patients experiment a peripheral muscle dysfunction which impact their exercise tolerance and health-related quality of life. The capillary to fiber interface is reduced and impact the exercise capacity of the patients. While the muscle capillary creation in response to exercise training is blunted in COPD patients, the maturation of the neo-capillaries could also be blunted and contribute to the impaired aniogionenesis in patients. Because the capillary maturation is a sensitive and dynamic process, only different modalities of exercise training and multiple time-points of measures would allow to capture this microvascular adaptation.

Aim of the study : Compare the muscle capillary maturation in response to training at 5 and 10 weeks, in sedentary healthy subject trained at the intensity of the ventilatory threshold (60-65% of VO2max), versus :- COPD patients trained at a similar intensity (60-65% of VO2max)- COPD patients trained at a similar absolute intensity (90% of VO2max).

Inclusion Criteria:

• COPD patients :
• FEV1<80%pred.
• non exacerbation during the past 4 weeks
• no oxygen therapy, -

Healthy subjects:

• <150min/week of moderate-to-vigorous physical activity,
• Voorrips score <9

Exclusion Criteria:

• Unstable comorbidity
• Long term oxygen therapy or ventilation
• Rehabilitation program during the past 12 months
• nutritional supplementation during the past 4 weeks
• allopurinol or N-acetylcystein during the past 4 weeks
• long corticosteroid treatment during the past 6 months
• hyperreactivity to xylocain
• anticoagulant or platelet aggregation inhibitors treatment
• participation to an other research study-pregnancy or impossibility to provide informed consent, ...