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 exercise training induce a physiological angiogenesis, we have recently observed that there was a blunted muscle angiogenesis after training in COPD patients. This could be the consequence a an inadequate training duration or intensity. Aim of the study: Compare the muscle micro-vascular response to training (capillary-to-fiber ratio) 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).