Surface EMGdi Evaluate the Efficacy of Pulmonary Rehabilitation in Patients With COPD: a Multi Center Prospective Study

The patients with COPD will participate in a rehabilitation program for 52 weeks. Participants in the proposed study will be randomly programmed into one of four intervention groups: 1. Neither cycle training nor inspiratory muscle training. 2. Cycle training program alone (performing on calibrated stationary cycle ergometer). 3. Inspiratory muscle training alone (performing on threshold loading device). 4. Combined cycle training and inspiratory muscle training(performing on calibrated stationary cycle ergometer and threshold loading device).