Studies suggest that inspiratory muscle training (IMT) improves respiratory muscle function and exercise tolerance. However effects were modest and this is probably because of the moderate training load. Increased intensity of IMT and IMT combined with general exercise (GET) may optimize effects. This study aims to compare the effects of IMT with that of GET and the combination of IMT and GET in 144 patients with moderate to very severe chronic obstructive pulmonary disease. Subjects will be randomly assigned to one of 4 groups: IMT with inspiratory pressure loads progressing from 25% to 50% of maximal inspiratory pressure (PImax), IMT with a sham inspiratory pressure load, GET with a cycle ergometer, and the combination of IMT with pressure loads progressing from 25% to 50% of PImax and GET with a cycle ergometer. Patients will train for 4 months and the following will be measured at baseline and after each month of training: (1) respiratory muscle strength as measured with PImax and maximal expiratory pressure, (2) respiratory muscle endurance as measured by the endurance time for breathing against an inspiratory pressure load equal to 66% of PImax, (3) exercise tolerance as measured by the 12 minute distance walk, and (4) patients' confidence in their ability to perform physical exertion as measured by perceived self-efficacy. Additionally, the following will be measured at baseline and after 4 months of training: (1) exercise capacity as measured by an incremental exercise test on cycle ergometry, (2) pulmonary impairment, (3) patients' perceptions of symptoms, (4) patients' perception of functional impairment, and (5) patients' report of affective moods. Demographic data and nutritional status will be assessed at baseline and patients' perception of the intervention will be assessed after 4 months of training with a semistructured interview. Compliance with the intervention and daily symptoms will be reported on a weekly log. Data will be analyzed with descriptive statistics and repeated measures analysis of variance.
