The effects of additional target-flow inspiratory muscle training (TF-IMT) on the performance of the inspiratory muscles, on general exercise capacity, and on psychologic parameters during a pulmonary rehabilitation program (PR) were studied in 40 patients with COPD selected for ventilatory limitation during exercise. The mean age of the patients was 59 years, and the mean FEV1 was approximately 50 percent of predicted. All patients participated in a ten-week PR program. They were randomized to receive either additional TF-IMT (PR + IMT) or not (PR). The TF-IMT was performed by means of a target-flow resistive device; the generated mouth pressure and the duration of inspiration and of the respiratory cycle were imposed. After the training period, maximal inspiratory mouth pressure and EMG-fatigability of the diaphragm were significantly better in the PR + IMT group than in the PR group. Maximal work load and psychologic symptoms increased to the same extent in both groups. The 12-minute walking distance also increased in both groups, but it increased significantly more in the PR + IMT group than in the PR group. We believe that additional TF-IMT during PR in a selected group of patients with COPD who have ventilatory limitation has an extra beneficial effect on the performance of the inspiratory muscles and on exercise performance.
PMID: 1984942 DOI: 10.1378/chest.99.1.128

Conclusion: We can therefore answer all 3 questions aboutinspiratory muscle training in COPD affirmatively: Thereis a theoretical base that justifies the use of such training.The inspiratory muscles retain the ability to respondstructurally and functionally to training. The response totraining is associated with reduction in dyspnea—one ofthe main goals in the management of COPD. The nextquestion that should be asked is whether, and in whichcases, specific inspiratory training can be considered avalid alternative or useful complement to general trainingin respiratory rehabilitation programs. Meanwhile, untilstudies addressing this question are performed, inspiratorymuscle training could be of benefit to patients with COPDwho present dyspnea despite receiving optimal treatmentand who show significant deterioration in the strengthand/or stamina of their inspiratory muscles.
PMID: 16324596 DOI: 10.1016/s1579-2129(06)60291-7

This article provides a critical review of inspiratory muscle training (IMT) in chronic obstructive pulmonary disease (COPD). Although extensive research on IMT has accumulated, its benefits have been debated, primarily because of methodological limitations of studies. Using relevant key words, multiple databases were searched from 1966. Selected studies used PImax (maximal inspiratory pressure) as an outcome variable. Overall, research demonstrated that a standard protocol of 30% or higher for a duration of 20 to 30 minutes per day for 10 to 12 weeks improves dyspnea and inspiratory strength and endurance with either inspiratory resistive or inspiratory threshold training. Regardless of method, IMT protocols for people with COPD and inspiratory muscle weakness and dyspnea are generally safe, feasible, and effective. Patient selectivity and study of subgroups are recommended.
PMID: 17190116 DOI: 10.1891/rtnp-v20i4a005

PURPOSE OF REVIEW: Most patients with significant chronic obstructive pulmonary disease (COPD) have inspiratory and expiratory muscle weakness. In addition, hyperinflation induces functional weakening of the inspiratory muscles, increased elastic load to breathing, and intrinsic positive end expiratory pressure (PEEPi). Therefore, it was rational to expect that patients with COPD would benefit from specific inspiratory or expiratory muscle training (SIMT, SEMT respectively). However, the functional benefits of SIMT have remained equivocal. In recent years, a number of studies have demonstrated that, when training loads are controlled, SIMT results in important functional benefits. The role of SEMT is still unclear.
RECENT FINDINGS: Well-controlled SIMT in patients with COPD leads to relief of dyspnea, during both daily activities and during physical activity. This yields increased exercise tolerance, and thus the capacity to walk, improving health related quality of life. We argue that there is now evidence that SIMT is an important addition to pulmonary rehabilitation programs for patients with COPD. Although two recent studies have shown that SEMT also provides a beneficial effect in patients with COPD, this does not appear to be supplementary to the effect to SIMT.
SUMMARY: Inspiratory and expiratory muscles can be specifically trained yielding improvements in both strength and endurance. The improvement in inspiratory muscle performance is associated with an improvement in the sensation of dyspnea, exercise tolerance, and quality of life. When the expiratory muscles are specifically trained, a significant increase in exercise performance has also been shown. However, there is probably no additional benefit in combining SEMT with SIMT.
PMID: 15699786 DOI: 10.1097/01.mcp.0000152999.18959.8a

Background Cystic fibrosis is the most common life-limiting genetic condition in Caucasians and the life-expectancy of those newly diagnosed is increasing. Inspiratory muscle training may be a way of improving the lung function and quality of life of people with cystic fibrosis. Hence there is a need to establish whether this intervention is beneficial.
Objectives To determine the effect of inspiratory muscle training on health-related quality of life, pulmonary function and exercise tolerance.
Search methods We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials register comprising of references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings.
Date of most recent search: 08 July 2013.
Selection criteria Randomised or quasi-randomised clinical controlled trials comparing different inspiratory muscle training regimens with each other or a control in people with cystic fibrosis.
Data collection and analysis Three review authors independently applied the inclusion and exclusion criteria to publications and assessed the quality of the included studies.
Main results Fourteen studies were identified. Of these eight studies with 180 participants met the review inclusion criteria. There was wide variation in the quality of the included studies. Data were not published in sufficient detail or with sufficiently similar outcome measures in these studies to perform meta-analyses.
Authors' conclusions We have not found any evidence to suggest that this treatment is either beneficial or not. We would advise that practitioners evaluate on a case-by-case basis whether or not to employ this therapy. We recommend that future studies make more use of health-related quality of life and exercise tolerance measures; and that there is an agreement upon a single standard measure of classifying the clinical status of the participants.
DOI: 10.1002/14651858.CD006112.pub3.