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.

Inclusion Criteria:

• COPD diagnosis with stage II-IV (GOLD),
• Stable clinical condition (no exacerbation or hospital admission in the last four weeks preceding the study)
• Absence of other disease that may potentially contribute to dyspnea (heart disease, congestive heart failure, neuromuscular diseases, severe postural changes)

Exclusion Criteria:

• BMI> 30 kg / m2
• Musculoskeletal limitations
• Use of oxygen therapy
• Extreme discomfort during the procedure application