 After giving informed consent, patients will be randomized on admission into usual care or usual care plus resistance training. Patients will be followed-up using the clinical pathway for COPD 10 days. After one month patients will attend the outpatient clinic for a follow-up visit. Besides the measurement prescribed in the clinical path for COPD including arterial blood gas measures, lung function, functional investigation of the patients, patients will undergo muscle strength measures and venous blood will be drawn for the analysis of systemic inflammatory and growth factors. Half of the patients will receive a resistance training program. At the end of the hospital admission, a needle biopsy of the vastus lateralis muscle will be obtained. 