 This study aimed to evaluate the acute effect of PLB technique on diaphragmatic mobility, the kinematics of the thoracoabdominal complex analysis of lung volumes and exercise tolerance in patients with Chronic Obstructive Pulmonary Disease COPD. This is a study randomized cross-over clinical trial and blind, in subjects with Chronic Obstructive Pulmonary Disease COPD according to criteria of the Global Initiative for Chronic Obstructive Lung Disease GOLD FEV1 FVC 0.7 and FEV1 80 predicted selected at the Clinical Hospital of the Federal University of Pernambuco UFPE and Otavio de Freitas General Hospital HGOF. The investigators recruited 13 patients COPD according to previous sample calculation aged between 40 and 80 years, of both sexes. The first day was held evaluation of lung function, respiratory muscle strength, body composition, dyspnea index and functional capacity. On the second day was held evaluation of thoracoabdominal complex kinematics by plethysmography Optoelectronics OEP with Quiet Breathing QB or pursed-lips breathing PLB. Lung volumes with 2 minutes with QB and 6 minutes PLB or only 6 minutes by QB as randomization were observed. Before and after performing the requested breathing pattern diaphragmatic mobility was observed by Ultrasonography US and requested the patient an Inspiratory Capacity maneuver IC. The evaluator who performed the ultrasound was blinded as to the beginning of the breathing pattern of order performed by the patient. 