It is now well established that respiratory rehabilitation, including a program of exercise reconditioning, increases tolerance to exercise and improve the quality of life. Besides the classical type of endurance exercises stimulating the cardio-respiratory system, it is suggested to add resistance exercises. Several studies have reported the benefit of this strategy but the link with intracellular molecular pathways has not been described; moreover, it is unknown whether the existence of an initial muscular atrophy influences the gain in muscle strength/mass.