Effect of inspiratory muscle training (IMT) on static and dynamic respiratory muscle function in patients with COPD

Abstract

We investigated the effects of IMT on respiratory muscle function and changes in respiratory pressure swings (Pes, Pga and Pdi), and diaphragm activation (EMGdi) during a constant work rate loaded breathing task before and after IMT. Twenty patients with COPD were randomized into an intervention group (IMT ≥50%PImax) or a control group (IMT ≤10%PImax). Measurements of dynamic muscle function were performed during the final minute of the baseline loaded breathing test and again at post-isotime. The IMT group achieved larger improvements in muscle function. Patients were able to breathe deeper and generate higher inspiratory flows during the breathing task as illustrated by higher work/breath and power/breath (Table 1). This resulted in more EMGdi activation while pressure swings were not significantly different. Larger reductions in inspiratory effort and dyspnea scores in the IMT group, did not reach statistical significance. Improved endurance breathing time after IMT is accompanied by improved dynamic respiratory muscle performance during the loaded breathing task.