 Objective: The investigators studied the effects of respiratory muscle stretching in an 8-week pulmonary rehabilitation program. Methods: This was a simple-blind parallel controlled trial, conducted an out-patient clinic. Twenty six patients with COPD mean age 68 6 y, percent of predicted FEV1 47 16 were randomized to either respiratory muscle stretching group plus exercise training RMS, and exercise training group Sham, in an 8-week exercise program that had 3 sessions per week. The investigators measured inspiratory and expiratory muscle strength by maximal inspiratory and expiratory pressure - PIM and PEM, exercise capacity by 6-minute walk distance, dyspnea and quality of life. 