 Moreover, FEV1 appears not to be a predictor of mortality in COPD patients. Pulmonary hyperinflation has been related with adaptation in diaphragm muscle maintaining the muscles capacity to generate power whilst reducing its displacement. The importance of the diaphragm in lung mechanics associated with hyperinflation has been the subject of frequent discussion owing to widespread use of lung volume reducing surgery which results in increased movement range of the diaphragm muscle. However, to date, the relationship between diaphragm mobility and functional capacity in COPD patients remains unknown. 