COPD presents not only respiratory symtoms but also vascular or muscle dysfunction. Exercise limitation is observed in COPD. Especially, decreased exercise performance related to vascular and fatique in quadriceps muscle. Exercise training is important for aerobic performance increasing. Generally results show exercise training with both lower limb. Increaed arterial stiffness and fatigue are observed in COPD. One leg exercise training result is not enough to highlight these parameters. Three types single leg exercise intervantion will be applied. Exercise capacity, muscle strength, lung function, electromyography, lactate and quality of life will be measured.