Respiratory muscle training for patients with chronic obstructive pulmonary disease.

The purpose of this article is to describe respiratory muscle training techniques and the effectiveness of this training in patients with chronic obstructive pulmonary disease (COPD). The respiratory muscles can be strengthened, but the benefit of stronger respiratory muscles in patients with COPD is not clear. Maximal sustained voluntary ventilation, inspiratory resistive breathing, and threshold loading are the three most commonly used techniques for improving the endurance of the inspiratory muscles in patients with COPD. Recent studies using inspiratory resistive breathing with targeted devices or threshold trainers have shown more consistent increases in inspiratory muscle function and exercise tolerance than studies using other techniques. Endurance exercise involving the extremities improves inspiratory muscle endurance in younger individuals with cystic fibrosis but not in older persons with COPD. Recommendations are outlined regarding the techniques to use for respiratory muscle training and which patient populations may benefit from these techniques.