The study is a randomized controlled trial in patients with stable COPD. The participants are divided into two groups. Patients in the inspiratory muscle training (IMT) group take part in a complex pulmonary rehabilitation program containing breathing exercises, bicycle ergometer conditionings, relaxations, strength and endurance trainings completed by inspiratory muscle training. The members of the IMT group use the POWERbreathe Medic device. The control group perform the complex pulmonary rehabilitation program without IMT. The program is divided into 3 weeks inpatient period and 3 weeks home period. Before, between and after the 3 weeks period all subjects are measured. 60 patients are planned to take part in the investigation. The inspiratory muscle strength is measured by POWERbreathe K1 device. Balance is assessed by functional balance tests: Timed Up and Go Test, Four Square Step Test, Modified Functional Reach Test, Modified Lateral Reach Test, Stand Up Test. Body Sway is measured by HR Mat VersaTek System. The diameter of the diaphragm muscle is assessed by B-mode ultrasound examination using Zonare Z. One Ultrasound System. Arterial stiffness parameters measured by Arteriograph.
