Individuals with Chronic Obstructive Pulmonary Disease (COPD) present with respiratory muscle dysfunction, characterized by reduced diaphragmatic contractility and mobility due to pulmonary hyperinflation, oxidative stress, and systemic inflammation. Effective assessment of diaphragmatic function is crucial for monitoring progress in pulmonary rehabilitation programs. This study aims to evaluate diaphragmatic function and mobility in COPD patients undergoing pulmonary rehabilitation with inspiratory muscle training, using ultrasound, and to identify associations between diaphragmatic dysfunction and clinical symptoms such as dyspnea and fatigue. A randomized clinical trial will be conducted to investigate the impact of rehabilitation on diaphragmatic function, correlating it with pulmonary function and physical performance.