Breathing Retraining: From Sick/Victims to Superhumans

Inspiratory Muscle Training References

Inspiratory Muscle Training for Sports (rowing, cycling, and swimming) and COPD, Cystic Fibrosis, Asthma, Bronchiectasis, and other diseases

Rowers sports performance Here are the main references regarding the application of the respiratory training devices (Powerlung, Powerbreathe, UltraBreathe, and Expand-A-Lung) on inspiratory muscle training and sports performance (rowing, cycling, and swimming) and chronic diseases (asthma, COPD, bronchiectasis, cystic fibrosis, diabetes, pre- and postsurgery, chronic heart failure, ischaemic heart disease, stroke, ventilator weaning, and neuromuscular diseases).

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References (Sports Performance)

Riganas CS, Vrabas IS, Christoulas K, Mandroukas K.
Specific inspiratory muscle training does not improve performance or VO2max levels in well trained rowers.
J Sports Med Phys Fitness. 2008 Sep;48(3):285-92.
Ergophysiology Laboratory, Department of Physical Education and Sports Sciences, Thessaloniki, Greece.
... CONCLUSION: In conclusion, six weeks of IMT increases inspiratory muscle strength by approximately 28% in highly trained rowers. However, this increase in inspiratory muscle strength does not appear to improve VO2max, dyspnea sensation during exercise, or rowing performance in well-trained rowers.

Klusiewicz A, Borkowski L, Zdanowicz R, Boros P, Wesołowski S.
The inspiratory muscle training in elite rowers.
J Sports Med Phys Fitness. 2008 Sep;48(3):279-84.
Department of Physiology, Institute of Sport, Warsaw, Poland.
... CONCLUSION: The data obtained corroborate the observations that in well-trained athletes the introduction of the principle of incremental inspiratory resistance allows to improve methodically the inspiratory muscles' strength. Once the essential period of IMT has been completed, the training volume should be reduced in order to secure the attained level of the inspiratory muscles' strength.

Volianitis S, McConnell AK, Koutedakis Y, McNaughton L, Backx K, Jones DA.
Inspiratory muscle training improves rowing performance.
Med Sci Sports Exerc. 2001 May;33(5):803-9.
School of Sport and Exercise Sciences, The University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
... CONCLUSIONS: IMT improves rowing performance on the 6-min all-out effort and the 5000-m trial.

Romer LM, McConnell AK, Jones DA.
Inspiratory muscle fatigue in trained cyclists: effects of inspiratory muscle training.
Med Sci Sports Exerc. 2002 May;34(5):785-92.
Sports Medicine and Human Performance Unit, School of Sport and Exercise Sciences, The University of Birmingham, Edgbaston, Birmingham, UK. romerlm@hotmail.com
... CONCLUSION: These data support existing evidence that there is significant global inspiratory muscle fatigue after sustained heavy endurance exercise. Furthermore, the present study provides new evidence that performance enhancements observed after IMT are accompanied by a decrease in inspiratory muscle fatigue.

Romer LM, McConnell AK, Jones DA.
Effects of inspiratory muscle training on time-trial performance in trained cyclists.
J Sports Sci. 2002 Jul;20(7):547-62.
The Human Performance Laboratory, School of Sport and Exercise Sciences, The University of Birmingham, Edgbaston, UK.
... These results support evidence that specific inspiratory muscle training attenuates the perceptual response to maximal incremental exercise. Furthermore, they provide evidence of performance enhancements in competitive cyclists after inspiratory muscle training.


References (Sports Performance)

Eur J Appl Physiol. 2010 Feb;108(3):505-11. Epub 2009 Oct 16.
Inspiratory muscle training improves 100 and 200 m swimming performance.
Kilding AE, Brown S, McConnell AK.
School of Sport and Recreation, Faculty of Health and Environmental Sciences, AUT University, Auckland, New Zealand.
Inspiratory muscle training (IMT) has been shown to improve time trial performance in competitive athletes across a range of sports. Surprisingly, however, the effect of specific IMT on surface swimming performance remains un-investigated. Similarly, it is not known whether any ergogenic influence of IMT upon swimming performance is confined to specific race distances. To determine the influence of IMT upon swimming performance over 3 competitive distances, 16 competitive club-level swimmers were assigned at random to either an experimental (pressure threshold IMT) or sham IMT placebo control group. Participants performed a series of physiological and performance tests, before and following 6 weeks of IMT, including (1) an incremental swim test to the limit of tolerance to determine lactate, heart rate and perceived exertion responses; (2) standard measures of lung function (forced vital capacity, forced expiratory volume in 1 s, peak expiratory flow) and maximal inspiratory pressure (MIP); and (3) 100, 200 and 400 m swim time trials. Training utilised a hand-held pressure threshold device and consisted of 30 repetitions, twice per day. Relative to control, the IMT group showed the following percentage changes in swim times: 100 m, -1.70% (90% confidence limits, +/-1.4%), 200 m, -1.5% (+/-1.0), and 400 m, 0.6% (+/-1.2). Large effects were observed for MIP and rates of perceived exertion. In conclusion, 6 weeks of IMT has a small positive effect on swimming performance in club-level trained swimmers in events shorter than 400 m.

Eur J Appl Physiol. 2005 Aug;94(5-6):527-40. Epub 2005 Jun 8.
Effects of concurrent inspiratory and expiratory muscle training on respiratory and exercise performance in competitive swimmers.
Wells GD, Plyley M, Thomas S, Goodman L, Duffin J.
Graduate Department of Exercise Sciences, University of Toronto, Toronto, Canada.
The efficiency of the respiratory system presents significant limitations on the body's ability to perform exercise due to the effects of the increased work of breathing, respiratory muscle fatigue, and dyspnoea. Respiratory muscle training is an intervention that may be able to address these limitations, but the impact of respiratory muscle training on exercise performance remains controversial. Therefore, in this study we evaluated the effects of a 12-week (10 sessions week(-1)) concurrent inspiratory and expiratory muscle training (CRMT) program in 34 adolescent competitive swimmers. The CRMT program consisted of 6 weeks during which the experimental group (E, n = 17) performed CRMT and the sham group (S, n = 17) performed sham CRMT, followed by 6 weeks when the E and S groups performed CRMT of differing intensities. CRMT training resulted in a significant improvement in forced inspiratory volume in 1 s (FIV1.0) (P = 0.050) and forced expiratory volume in 1 s (FEV1.0) (P = 0.045) in the E group, which exceeded the S group's results. Significant improvements in pulmonary function, breathing power, and chemoreflex ventilation threshold were observed in both groups, and there was a trend toward an improvement in swimming critical speed after 12 weeks of training (P = 0.08). We concluded that although swim training results in attenuation of the ventilatory response to hypercapnia and in improvements in pulmonary function and sustainable breathing power, supplemental respiratory muscle training has no additional effect except on dynamic pulmonary function variables.

Eur J Appl Physiol. 2008 Aug;103(6):635-46. Epub 2008 May 14.
Pulmonary adaptations to swim and inspiratory muscle training.
Mickleborough TD, Stager JM, Chatham K, Lindley MR, Ionescu AA.
Human Performance Laboratory, Department of Kinesiology, Indiana University, Bloomington, IN 47405, USA.
Because the anomalous respiratory characteristics of competitive swimmers have been suggested to be due to inspiratory muscle work, the respiratory muscle and pulmonary function of 30 competitively trained swimmers was assessed at the beginning and end of an intensive 12-week swim training (ST) program. Swimmers (n = 10) combined ST with either inspiratory muscle training (IMT) set at 80% sustained maximal inspiratory pressure (SMIP) with progressively increased work-rest ratios until task failure for 3-days per week (ST + IMT) or ST with sham-IMT (ST + SHAM-IMT, n = 10), or acted as controls (ST only, ST, n = 10). Measures of respiratory and pulmonary function were assessed at the beginning and end of the 12 week study period. There were no significant differences (P > 0.05) in respiratory and pulmonary function between groups (ST + IMT, ST + SHAM-IMT and ST) at baseline and at the end of the 12 week study period. However, within all groups significant increases (P < 0.05) were observed in a number of respiratory and pulmonary function variables at the end of the 12 week study, such as maximal inspiratory and expiratory pressure, inspiratory power output, forced vital capacity, forced expiratory and inspiratory volume in 1-s, total lung capacity and diffusion capacity of the lung. This study has demonstrated that there are no appreciable differences in terms of respiratory changes between elite swimmers undergoing a competitive ST program and those undergoing respiratory muscle training using the flow-resistive IMT device employed in the present study; as yet, the causal mechanisms involved are undefined.

COPD
J Appl Physiol. 2009 Sep;107(3):971-6. Epub 2009 Apr 2.
Response of the respiratory muscles to rehabilitation in COPD.
Decramer M.
Respiratory Division, University Hospital, University of Leuven, 3000 Leuven, Belgium. Marc.Decramer@uzleuven.be
Abstract
Respiratory rehabilitation is known to improve outcomes in patients with chronic obstructive pulmonary disease (COPD). The question addressed in the present review is whether these beneficial effects are related to improvements in inspiratory muscle function. Respiratory muscle fatigue often did not occur during exercise in patients with COPD, since exercise limitation usually occurred when significant force reserve in the inspiratory muscles was still present. Notwithstanding, a number of observations may provide indirect evidence that respiratory muscle fatigue may occur during exercise. Some evidence is present that, in normal humans, whole body exercise training improved inspiratory muscle endurance, but no studies are available in patients with COPD. Animal studies invariably demonstrated that exercise training increased the number of oxidative fibers and oxidative enzyme activity in inspiratory muscles. These effects, however, were considerably smaller than the effects found on peripheral muscles with similar fiber composition. Clear evidence indicated that inspiratory muscle training (IMT) improved inspiratory muscle function. Two large meta-analyses indicated that, if the training load was properly controlled, IMT alone or combined with general exercise reconditioning improved inspiratory muscle strength and endurance and dyspnea. The combination did not result in greater improvements in functional exercise capacity. Animal studies and one patient study confirmed the occurrence of structural remodeling of the inspiratory muscles in response to IMT. The final question is whether improvements in inspiratory muscle function produced by IMT lead to improved outcomes in COPD. In all five studies in which training load was adequately controlled, a significant reduction of dyspnea during activities of daily living was found. Eight randomized studies examined the effects of the combination. Greater improvements in exercise capacity were only found in three studies, and none showed a greater reduction in dyspnea.

J Cardiopulm Rehabil Prev. 2008 Mar-Apr;28(2):128-41.
Inspiratory muscle training compared with other rehabilitation interventions in chronic obstructive pulmonary disease: a systematic review update.
O'Brien K, Geddes EL, Reid WD, Brooks D, Crowe J.
Department of Physical Therapy, University of Toronto, Toronto, Ontario, Canada. kelly.obrien@utoronto.ca
Abstract
PURPOSE: To determine the effect of inspiratory muscle training (IMT) (alone or combined with exercise and/or pulmonary rehabilitation) and compare with other rehabilitation interventions among adults with chronic obstructive pulmonary disease (COPD).
METHODS: We conducted a systematic review, using Cochrane Collaboration protocol. We included randomized controlled trials, published in English, comparing IMT or combined IMT and exercise/pulmonary rehabilitation with other rehabilitation interventions among adults with COPD. Abstracts were reviewed independently by 2 investigators to determine study eligibility up to December 2005. Data were abstracted and methodological quality of included studies was assessed.
RESULTS: A total of 156 additional articles were retrieved. Two new studies met the inclusion criteria and were included with 16 studies in the original review. Results highlight updated subgroup analyses comparing (1) IMT versus exercise and (2) combined IMT and exercise versus exercise alone. Fourteen meta-analyses were performed for outcomes of inspiratory muscle strength, exercise tolerance, and quality of life. Results showed significant improvements in maximum inspiratory pressure and maximum exercise tidal volume favoring combined IMT and exercise compared with exercise alone.
CONCLUSIONS: Performing a combination of IMT plus exercise may lead to significant improvements in inspiratory muscle strength and one outcome of exercise tolerance for individuals with COPD.

Respir Med. 2008 Dec;102(12):1715-29. Epub 2008 Aug 15.
Inspiratory muscle training in adults with chronic obstructive pulmonary disease: an update of a systematic review.
Geddes EL, O'Brien K, Reid WD, Brooks D, Crowe J.
School of Rehabilitation Science, Institute of Applied Health Science, Room 403, McMaster University, 1400 Main Street West, Hamilton, ON, Canada L8S 1C7. geddesl@mcmaster.ca
The purpose was to update an original systematic review to determine the effect of inspiratory muscle training (IMT) on inspiratory muscle strength and endurance, exercise capacity, dyspnea and quality of life for adults with chronic obstructive pulmonary disease (COPD). The original MEDLINE and CINAHL search to August 2003 was updated to January 2007 and EMBASE was searched from inception to January 2007. Randomized controlled trials, published in English, with adults with stable COPD, comparing IMT to sham IMT or no intervention, low versus high intensity IMT, and different modes of IMT were included. Nineteen of 274 articles in the original search met the inclusion criteria. The updated search revealed 17 additional articles; 6 met the inclusion criteria, all of which compared targeted, threshold or normocapneic hyperventilation IMT to sham IMT. An update of the sub-group analysis comparing IMT versus sham IMT was performed with 10 studies from original review and 6 from the update. Sixteen meta-analyses are reported. Results demonstrated significant improvements in inspiratory muscle strength (PI(max), PI(max) % predicted, peak inspiratory flow rate), inspiratory muscle endurance (RMET, inspiratory threshold loading, MVV), exercise capacity (Ve(max), Borg Score for Respiratory Effort, 6MWT), Transitional Dyspnea Index (focal score, functional impairment, magnitude of task, magnitude of effort), and the Chronic Respiratory Disease Questionnaire (quality of life). Results suggest that targeted, threshold or normocapneic hyperventilation IMT significantly increases inspiratory muscle strength and endurance, improves outcomes of exercise capacity and one measure of quality of life, and decreases dyspnea for adults with stable COPD.

COPD. 2005 Sep;2(3):319-29.
Inspiratory muscle training compared with other rehabilitation interventions in adults with chronic obstructive pulmonary disease: a systematic literature review and meta-analysis.
Crowe J, Reid WD, Geddes EL, O'Brien K, Brooks D.
School of Rehabilitation Science, IAHS-Room 403, McMaster University, 1400 Main Street West, Hamilton, Ontario, Canada. crowej@mcmaster.ca
The purpose of this systematic review was to determine the effect of inspiratory muscle training (IMT) (alone or combined with exercise and/or pulmonary rehabilitation) compared to other rehabilitation interventions such as: exercise, education, other breathing techniques or exercise and/or pulmonary rehabilitation among adults with chronic obstructive pulmonary disease (COPD). A systematic review of the literature on IMT and COPD was conducted according to the Cochrane Collaboration protocol. Inclusion criteria for the review included randomized controlled trials, published in English, comparing IMT or combined IMT and exercise/pulmonary rehabilitation with other rehabilitation interventions such as general exercise, education, other breathing techniques or exercise/pulmonary rehabilitation among adults with COPD. 274 articles were retrieved, and 16 met the inclusion criteria. Seven meta-analyses were performed that compared targeted or threshold IMT to exercise (n = 3) or to education (n = 4). Results showed significant improvements in inspiratory muscle strength and endurance, and in the dyspnea scale on a quality of life measure, for participants in the IMT versus education group. In other instances where meta-analyses could not be performed, a qualitative review was performed. IMT results in improved inspiratory muscle strength and endurance compared to education. Further trials are required to investigate the effect of IMT (or combined IMT) compared to other rehabilitation inventions for outcomes such as dyspnea, exercise tolerance, and quality of life.

Eur Respir J. 2006 Jun;27(6):1119-28.
High-intensity inspiratory muscle training in COPD.
Hill K, Jenkins SC, Philippe DL, Cecins N, Shepherd KL, Green DJ, Hillman DR, Eastwood PR.
Dept of Pulmonary Physiology, Sir Charles Gairdner Hospital, Hospital Avenue, Nedlands, Western Australia, 6009 Australia. peter.eastwood@health.wa.gov.au
The aim of the present study was to investigate the effects of an interval-based high-intensity inspiratory muscle training (H-IMT) programme on inspiratory muscle function, exercise capacity, dyspnoea and health-related quality of life (QoL) in subjects with chronic obstructive pulmonary disease. A double-blind randomised controlled trial was performed. Sixteen subjects (11 males, mean forced expiratory volume in one second (FEV(1)) 37.4+/-12.5%) underwent H-IMT performed at the highest tolerable inspiratory threshold load (increasing to 101% of baseline maximum inspiratory pressure). Seventeen subjects (11 males, mean FEV(1 )36.5+/-11.5%) underwent sham inspiratory muscle training (S-IMT) at 10% of maximum inspiratory pressure. Training took place three times a week for 8 weeks and was fully supervised. Pre- and post-training measurements of lung function, maximum inspiratory pressure, maximum threshold pressure, exercise capacity, dyspnoea and QoL (Chronic Respiratory Disease Questionnaire; CRDQ) were obtained. H-IMT increased maximum inspiratory pressure by 29%, maximum threshold pressure by 56%, 6-min walk distance by 27 m, and improved dyspnoea and fatigue (CRDQ) by 1.4 and 0.9 points per item, respectively. These changes were significantly greater than any seen following S-IMT. In conclusion, high-intensity inspiratory muscle training improves inspiratory muscle function in subjects with moderate-to-severe chronic obstructive pulmonary disease, yielding meaningful reductions in dyspnoea and fatigue.

Am J Respir Crit Care Med. 1999 Aug;160(2):500-7.
Cycle ergometer and inspiratory muscle training in chronic obstructive pulmonary disease.
Larson JL, Covey MK, Wirtz SE, Berry JK, Alex CG, Langbein WE, Edwards L.
University of Illinois at Chicago, Chicago, Illinois, USA. JLLarson@uic.edu
In patients with chronic obstructive pulmonary disease (COPD) the intensity of aerobic training is limited by dyspnea. Improving strength of the inspiratory muscles could enhance aerobic exercise training by reducing exercise-related dyspnea. We examined effects of home-based inspiratory muscle training (IMT) and cycle ergometry training (CET) in 53 patients with moderate to severe COPD (FEV(1)% pred, 50 +/- 17 [mean +/- SD]). Patients were randomly assigned to 4 mo of training in one of four groups: IMT, CET, CET + IMT, or health education (ED). Patients were encouraged to train to the limits of their dyspnea. Inspiratory muscle strength and endurance increased in IMT and CET + IMT groups compared with CET and ED groups (p < 0. 01). Peak oxygen uptake increased and heart rate, minute ventilation, dyspnea, and leg fatigue decreased at submaximal work rates in the CET and CET + IMT groups compared with the IMT and ED groups (p < 0. 01). There were no differences between the CET and CET + IMT groups. Home-based CET produced a physiological training effect and reduced exercise-related symptoms while IMT increased respiratory muscle strength and endurance. The combination of CET and IMT did not produce additional benefits in exercise performance and exercise-related symptoms. This is the first study to demonstrate a physiological training effect with home-based exercise training.

Chest. 2001 Sep;120(3):748-56.
Inspiratory muscle training in patients with COPD: effect on dyspnea, exercise performance, and quality of life.
Sanchez Riera H, Montemayor Rubio T, Ortega Ruiz F, Cejudo Ramos P, Del Castillo Otero D, Elias Hernandez T, Castillo Gomez J.
Pneumology Service, Virgen Del Rocio University Hospital, Sevilla, Spain. ablucil@mx2.redestb.es
OBJECTIVE: The aim of the study was to assess the effect of target-flow inspiratory muscle training (IMT) on respiratory muscle function, exercise performance, dyspnea, and health-related quality of life (HRQL) in patients with COPD.
PATIENTS AND METHODS: Twenty patients with severe COPD were randomly assigned to a training group (group T) or to a control group (group C) following a double-blind procedure. Patients in group T (n = 10) trained with 60 to 70% maximal sustained inspiratory pressure (SIPmax) as a training load, and those in group C (n = 10) received no training. Group T trained at home for 30 min daily, 6 days a week for 6 months.
MEASUREMENTS: The measurements performed included spirometry, SIPmax, inspiratory muscle strength, and exercise capacity, which included maximal oxygen uptake (VO(2)), and minute ventilation (VE). Exercise performance was evaluated by the distance walked in the shuttle walking test (SWT). Changes in dyspnea and HRQL also were measured.
RESULTS: Results showed significant increases in SIPmax, maximal inspiratory pressure, and SWT only in group T (p < 0.003, p < 0.003, and p < 0.001, respectively), with significant differences after 6 months between the two groups (p < 0.003, p < 0.003, and p < 0.05, respectively). The levels of VO(2) and VE did not change in either group. The values for transitional dyspnea index and HRQL improved in group T at 6 months in comparison with group C (p < 0.003 and p < 0.003, respectively).
CONCLUSIONS: We conclude that targeted IMT relieves dyspnea, increases the capacity to walk, and improves HRQL in COPD patients.

Eur Respir J. 1997 Mar;10(3):537-42.
Inspiratory muscle training in chronic airflow limitation: effect on exercise performance.
Lisboa C, Villafranca C, Leiva A, Cruz E, Pertuzo J, Borzone G.
Department of Respiratory Diseases, Catholic University of Chile, Santiago.
The effect of inspiratory muscle training (IMT) on exercise capacity in patients with chronic airflow limitation (CAL) has been debated. The present study was planned to further investigate the effects of IMT on exercise performance. Twenty patients (aged 62+/-1 yrs; forced expiratory volume in one second/forced vital capacity (FEV1/FVC) 36+/-2%) were trained 30 min daily for 6 days a week during 10 weeks, with either 30% (Group 1) or 10% (Group 2) of peak maximal inspiratory pressure (PI,max) as a training load. Exercise performance was evaluated by the distance walked in 6 min (6MWD) and by changes in oxygen consumption (V'O2) and minute ventilation (V'E) during a progressive exercise test. Changes in PI,max and dyspnoea were also measured. Results showed a significant increment in peak PI,max in both groups, whereas dyspnoea and 6MWD improved only in Group 1 (p<0.05 and p<0.01, respectively). No increment in maximal workload or in peak V'O2 was observed in either group. Patients in Group 1, however, showed a reduction in V'E and V'O2 for the same exercise. A correlation between changes in V'E and V'O2 during a workload of 75 kpm x min(-1) was observed in Group 1 (r=0.92; p<0.001). We conclude that inspiratory muscle training using a load of 30% peak maximal inspiratory pressure, improves dyspnoea, increases walking capacity and reduces the metabolic cost of exercise.

Eur Respir J. 1997 Mar;10(3):537-42.
Inspiratory muscle training in chronic airflow limitation: effect on exercise performance.
Lisboa C, Villafranca C, Leiva A, Cruz E, Pertuzo J, Borzone G.
Department of Respiratory Diseases, Catholic University of Chile, Santiago.
The effect of inspiratory muscle training (IMT) on exercise capacity in patients with chronic airflow limitation (CAL) has been debated. The present study was planned to further investigate the effects of IMT on exercise performance. Twenty patients (aged 62+/-1 yrs; forced expiratory volume in one second/forced vital capacity (FEV1/FVC) 36+/-2%) were trained 30 min daily for 6 days a week during 10 weeks, with either 30% (Group 1) or 10% (Group 2) of peak maximal inspiratory pressure (PI,max) as a training load. Exercise performance was evaluated by the distance walked in 6 min (6MWD) and by changes in oxygen consumption (V'O2) and minute ventilation (V'E) during a progressive exercise test. Changes in PI,max and dyspnoea were also measured. Results showed a significant increment in peak PI,max in both groups, whereas dyspnoea and 6MWD improved only in Group 1 (p<0.05 and p<0.01, respectively). No increment in maximal workload or in peak V'O2 was observed in either group. Patients in Group 1, however, showed a reduction in V'E and V'O2 for the same exercise. A correlation between changes in V'E and V'O2 during a workload of 75 kpm x min(-1) was observed in Group 1 (r=0.92; p<0.001). We conclude that inspiratory muscle training using a load of 30% peak maximal inspiratory pressure, improves dyspnoea, increases walking capacity and reduces the metabolic cost of exercise.

Eur Respir J. 2007 Sep;30(3):479-86. Epub 2007 May 15.
Comparison of incremental and constant load tests of inspiratory muscle endurance in COPD.
Hill K, Jenkins SC, Philippe DL, Shepherd KL, Hillman DR, Eastwood PR.
Department of Pulmonary Physiology, Sir Charles Gairdner Hospital, Hospital Avenue, Nedlands, Western Australia, Australia 6009.
The aim of the present study was to determine the relative value of incremental and constant load tests in detecting changes in inspiratory muscle endurance following high-intensity inspiratory muscle training (H-IMT) in chronic obstructive pulmonary disease. In total, 16 subjects (11 males; forced expiratory volume in one second (FEV(1)) 37.4+/-12.5%) underwent H-IMT. In addition, 17 subjects (11 males; FEV(1) 36.5+/-11.5%) underwent sham inspiratory muscle training (S-IMT). Training took place three times a week for 8 weeks. Baseline and post-training measurements were obtained of maximum threshold pressure sustained during an incremental load test (P(th,max)) and time breathing against a constant load (t(lim)). Breathing pattern was unconstrained. H-IMT increased P(th,max) and t(lim) relative to baseline and to any change seen following S-IMT. The effect size for P(th,max) was greater than for t(lim). Post-training tests were accompanied by changes in breathing pattern, including decreased duty cycle, which may have served to decrease inspiratory work and thereby contribute to the increase in P(th,max) and t(lim) in both groups. When assessing inspiratory muscle function in chronic obstructive pulmonary disease via tests in which the pattern of breathing is unconstrained, the current authors recommend incremental load tests be used in preference to constant load tests. However, to attribute changes in these tests to improvements in inspiratory muscle endurance, breathing pattern should be controlled.

Respir Med. 2007 Dec;101(12):2429-36. Epub 2007 Sep 17.
Role of physiotherapy in the management of chronic lung diseases: an overview of systematic reviews.
Garrod R, Lasserson T.
School of Physiotherapy, St. George's, University of London, Faculty of Health and Social Care Sciences, Cranmer Terrace, London SW17 0RE, UK. rgarrod@hscs.sgul.ac.uk
Abstract
Four Cochrane respiratory reviews of relevance to physiotherapeutic practice are discussed in this overview. Physiotherapists aim to improve ventilation for people with respiratory disease, and approach this using a variety of techniques. As such, the reviews chosen for discussion consider a wide range of interventions commonly used by physiotherapists: breathing exercises, bronchopulmonary hygiene techniques and physical training for peripheral and respiratory muscles. The reviews show that breathing exercises may have beneficial effects on health-related quality of life in asthma, and that inspiratory muscle training (IMT) may improve inspiratory muscle strength. However, the clinical relevance of increased respiratory muscle strength per se is unknown, and the longer-term effects of breathing exercises on morbidity have not been considered. One review clearly shows that bronchopulmonary hygiene techniques in chronic obstructive pulmonary disease (COPD) and bronchiectasis increase sputum production. Frequent exacerbation is associated with increased sputum and high bacterial load, suggesting that there may be important therapeutic benefit of improved sputum clearance. Future studies evaluating the long-term effects of bronchopulmonary hygiene techniques on morbidity are recommended. In the third review, the importance of pulmonary rehabilitation in the management of COPD is once again reinforced. Physiotherapists are crucial to the delivery of exercise training programmes, and it is likely that the effects of pulmonary rehabilitation extend to other important outcomes, such as hospital admission and re-admission. On the basis of the evidence provided by these Cochrane reviews, this overview highlights important practice points of relevance to physiotherapy, and recommendations for future studies.

Heart Disease
Eur J Cardiovasc Prev Rehabil. 2004 Dec;11(6):489-96.
Inspiratory muscle training using an incremental endurance test alleviates dyspnea and improves functional status in patients with chronic heart failure.
Laoutaris I, Dritsas A, Brown MD, Manginas A, Alivizatos PA, Cokkinos DV.
Onassis Cardiac Surgery Centre, Athens, Greece. ylaoutaris@yahoo.com
BACKGROUND: The benefits of inspiratory muscle training (IMT) in patients with chronic heart failure (CHF) have been inadequately studied.
DESIGN AND METHODS: Using a prospective, age and sex-matched controlled study, we investigated 35 patients with moderate to severe CHF (NYHA class II-III and left ventricular ejection fraction 24.4+/-1.3% [mean+/-SEM]). An incremental respiratory endurance test using a fixed respiratory workload was provided by software with an electronic mouth pressure manometer interfaced with a computer. The training group (n=20) exercised at 60% of individual sustained maximal inspiratory pressure (SMIP) and the control group (n=15) at 15% of SMIP. All patients exercised three times weekly for 10 weeks. Pulmonary function, exercise capacity, dyspnea and quality of life were assessed, pre- and post-training.
RESULTS: The training group significantly increased both maximum inspiratory pressure (Pimax), (111+/-6.8 versus 83+/-5.7 cmH2O, P<0.001), and SMIP (527822+/-51358 versus 367360+/-41111 cmH2O/sec x 10(-1), P<0.001). Peak VO2 increased after training (17.8+/-1.2 versus 15.4+/-0.9 ml/kg/min, P<0.005), as did the six-minute walking distance (433+/-16 versus 367+/-22 meters, P<0.001). Perceived dyspnea assessed using the Borg scale was reduced for both the treadmill (12.7+/-0.57 versus 14.2+/-0.48, P<0.005) and the walking (9+/-0.48 versus 10.5+/-0.67, P<0.005) exercise tests and the quality of life score was also improved (21.1+/-3.5 versus 25.2+/-4, P<0.01). Resting heart rate was significantly reduced with training (77+/-3.3 versus 80+/-3 beats/min, P<0.05). The control group significantly increased Pimax (86.6+/-6.3 versus 78.4+/-6.9 cmH2O, P<0.05), but decreased SMIP (274972+/-32399 versus 204661+/-37184 cmH2O/sec x 10(1), P<0.005). No other significant effect on exercise capacity, heart rate, dyspnea, or quality of life was observed in this group.
CONCLUSION: Inspiratory muscle training using an incremental endurance test, successfully increases both inspiratory strength and endurance, alleviates dyspnea and improves functional status in CHF.

J Cardiopulm Rehabil Prev. 2009 Sep 22. [Epub ahead of print]
Inspiratory Muscle Training Improves Oxygen Uptake Efficiency Slope in Patients With Chronic Heart Failure.
Stein R, Chiappa GR, Goths H, Dallʼago P, Ribeiro JP.
Exercise Pathophysiology Research Laboratory and Cardiology Division, Hospital de Clinicas de Porto Alegre (Drs Stein, Chiappa, and Ribeiro), School of Physical Therapy, UNILASALLE, Canoas (Mr Goths and Dr Dall'Ago), Department of Physiological Sciences, Fundaooo Faculdade Federal de Cioncias Modicas de Porto Alegre, Porto Alegre (Dr Dall'Ago), and Department of Medicine, Federal University of Rio Grande do Sul, Porto Alegre (Dr Ribeiro), Brazil.
PURPOSE: Inspiratory muscle training (IMT) improves exercise capacity and ventilatory responses to exercise in patients with chronic heart failure (CHF) with inspiratory muscle weakness (IMW). We analyzed the effects of IMT on the oxygen uptake efficiency slope (OUES) in this patient population.
METHODS: Thirty-two CHF patients with IMW (maximal inspiratory pressure [PImax] < 70% of predicted) were randomly assigned to either a 12-week program of IMT (IMT, n = 16) or placebo-IMT (P-IMT, n = 16). PImax and OUES were obtained before and after the intervention.
RESULTS: Inspiratory muscle training resulted in 115% increment in PImax (5.9 +/- 0.9 vs 12.7 +/- 0.9 kPa; P < .001) and in significant improvement in OUES (1,554 +/- 617 to 2,037 +/- 747 mL min O2/L min of minute ventilation; P = .001). There were no significant changes in the P-IMT group. There was a significant association between the changes in PImax and OUES (r = 0.82, P < .01).
CONCLUSION: In CHF patients with IMW, IMT results in a significant increase in OUES.

Clin Rehabil. 2010 Mar;24(3):240-50. Epub 2010 Feb 15.
Respiratory muscle training improves cardiopulmonary function and exercise tolerance in subjects with subacute stroke: a randomized controlled trial.
Sutbeyaz ST, Koseoglu F, Inan L, Coskun O.
Fourth Physical Medicine & Rehabilitation Clinic, Ankara Physical Medicine and Rehabilitation Education and Research Hospital, Ankara, Turkey. serapts@yahoo.com
OBJECTIVE: To determine whether two types of exercise--breathing retraining (BRT) and inspiratory muscle training (IMT)--improve on cardiopulmonary functions and exercise tolerance in patients with stroke.
DESIGN: A randomized controlled trial.
SETTING: Education and research hospital.
SUBJECTS: Forty-five inpatients with stroke (24 men, 21 women) were recruited for the study. The subjects were randomized into three groups: 15 assigned to receive inspiratory muscle training (IMT); 15 assigned to received breathing retraining, diaphragmatic breathing and pursed-lips breathing (BRT); 15 assigned to a control group.
INTERVENTIONS: All study groups participated in a conventional stroke rehabilitation programme. For the same period, the IMT and BRT groups trained daily, six times a week, with each session consisting of one half-hour of training for six weeks.
MAIN MEASURES: Each subject underwent pulmonary function and cardiopulmonary exercise tests. Subjects were also assessed for exertional dyspnoea, stages of motor recovery, ambulation status, activity of daily living and quality of life.
RESULTS: After the training programme, the IMT group had significantly improved forced expiratory volume at 1 second (FEV(1)), forced vital capacity (FVC), vital capacity (VC), forced expiratory flow rate 25-75% (FEF 25-75%) and maximum voluntary ventilation (MVV) values compared with the BRT and control groups, although there were no significant differences between the BRT and control groups (P<0.01). Peak expiratory flow rate (PEF) value was increased significantly in the BTR group compared with the IMT and control groups. The IMT group also had significantly higher peak oxygen consumption (Vo(2peak)) than the BRT and control groups, although there were no significant differences between the BRT and control groups (P<0.001). There was a statistically significant increase in maximum inspiratory pressure (PI(max)) and maximum inspiratory and expiratory pressure (PE(max)) in the BRT group and, PI(max) in the IMT group compared with baseline and the control group. In the IMT group, this was associated with improvements in exercise capacity, sensation of dyspnoea and quality of life.
CONCLUSIONS: Significant short-term effects of the respiratory muscle training programme on respiratory muscle function, exercise capacity and quality of life were recorded in this study.

Eur J Heart Fail. 1999 Aug;1(3):297-300.
Effects of resistive breathing on exercise capacity and diaphragm function in patients with ischaemic heart disease.
Darnley GM, Gray AC, McClure SJ, Neary P, Petrie M, McMurray JJ, MacFarlane NG.
Institute of Biomedical and Life Sciences, Glasgow University, Scotland, UK.
BACKGROUND: Muscle weakness has been suggested to result from the deconditioning that accompanies decreased activity levels in chronic cardiopulmonary diseases. The benefits of standard exercise programmes on exercise capacity and muscular strength in disease and health are well documented and exercise capacity is a significant predictor of survival in patients with chronic heart failure (CHF). Selective respiratory muscle training has been shown to improve exercise tolerance in CHF and such observations have been cited to support the suggestion that respiratory muscle weakness contributes to a reduced exercise capacity (despite biopsies showing the metabolic profile of a well trained muscle).
AIMS: This study aimed to determine the effects of selective inspiratory muscle training on patients with chronic coronary artery disease to establish if an improved exercise capacity can be obtained in patients that are not limited in their daily activities.
METHODS: Nine male patients performed three exercise tests (with respiratory and diaphragm function assessed before the third test) then undertook a 4-week programme of inspiratory muscle training. Exercise tolerance, respiratory and diaphragmatic function were re-assessed after training.
RESULTS: Exercise capacity improved from 812+/-42 to 864+/-49 s, P<0.05, and velocity of diaphragm shortening increased (during quiet breathing from 12.8+/-1.6 to 19.4+/-1.1 mm s(-1), P<0.005, and sniffing from 71.9+/-9.4 to 110.0+/-12.3 mm s(-1), P<0.005). In addition, five from nine patients were stopped by breathlessness before training; whereas only one patient was stopped by breathlessness after training.
CONCLUSION: The major findings in this study were that a non-intensive 4-week training programme of resistive breathing in patients with chronic coronary artery disease led to an increase in exercise capacity and a decrease in dyspnoea when assessed by symptom limited exercise testing. These changes were associated with significant increases in the velocity of diaphragmatic excursions during quiet breathing and sniffing. Patients that exhibited small diaphragmatic excursions during quiet breathing were most likely to improve their exercise capacity after the training programme. However, the inspiratory muscle-training programme was not associated with any significant changes in respiratory mechanics when peak flow rate, forced expiratory volume and forced vital capacity were measured. The resistive breathing programme used here resulted in a significant increase in the velocity of diaphragm movement during quiet breathing and sniffing. In other skeletal muscles, speed of contraction can be determined by the relative proportion of fibre types and muscle length (Jones, Round, Skeletal Muscle in Health and Disease. Manchester: University Press, 1990). The intensity of the training programme used here, however, is unlikely to significantly alter muscle morphology or biochemistry. Short-term training studies have shown that there can be increases in strength and velocity of shortening that do not relate to changes in muscle biochemistry or morphology. These changes are attributed to the neural adaptations that occur early in training (Northridge et al., Br. Heart J. 1990; 64: 313-316). Independent of the mechanisms involved, this small, uncontrolled study suggests that inspiratory muscle training may improve exercise capacity, diaphragm function and symptoms of breathlessness in patients with chronic coronary artery disease even in the absence of heart failure.

J Am Coll Cardiol. 2006 Feb 21;47(4):757-63. Epub 2006 Jan 26.
Inspiratory muscle training in patients with heart failure and inspiratory muscle weakness: a randomized trial.
Dall'Ago P, Chiappa GR, Guths H, Stein R, Ribeiro JP.
Department of Physiological Sciences, Fundaooo Faculdade Federal de Cioncias Modicas de Porto Alegre, Porto Alegre, Brazil.
OBJECTIVES: This study sought to evaluate the effects of inspiratory muscle training in inspiratory muscle strength, as well as in functional capacity, ventilatory responses to exercise, recovery oxygen uptake kinetics, and quality of life in patients with chronic heart failure (CHF) and inspiratory muscle weakness.
BACKGROUND: Patients with CHF may have reduced strength and endurance in inspiratory muscles, which may contribute to exercise intolerance and is associated with a poor prognosis.
METHODS: Thirty-two patients with CHF and weakness of inspiratory muscles (maximal inspiratory pressure [Pi(max)] <70% of predicted) were randomly assigned to a 12-week program of inspiratory muscle training (IMT, 16 patients) or to a placebo-inspiratory muscle training (P-IMT, 16 patients). The following measures were obtained before and after the program: Pi(max) at rest and 10 min after maximal exercise; peak oxygen uptake, circulatory power, ventilatory oscillations, and oxygen kinetics during early recovery (VO2/t-slope); 6-min walk test; and quality of life scores.
RESULTS: The IMT resulted in a 115% increment Pi(max), 17% increase in peak oxygen uptake, and 19% increase in the 6-min walk distance. Likewise, circulatory power increased and ventilatory oscillations were reduced. The VO2/t-slope was improved during the recovery period, and quality of life scores improved.
CONCLUSIONS: In patients with CHF and inspiratory muscle weakness, IMT results in marked improvement in inspiratory muscle strength, as well as improvement in functional capacity, ventilatory response to exercise, recovery oxygen uptake kinetics, and quality of life.

Am Heart J. 2009 Nov;158(5):768.e1-7. Epub 2009 Oct 2.
Addition of inspiratory muscle training to aerobic training improves cardiorespiratory responses to exercise in patients with heart failure and inspiratory muscle weakness.
Winkelmann ER, Chiappa GR, Lima CO, Viecili PR, Stein R, Ribeiro JP.
Hospital de Clinicas de Porto Alegre, RS, Brazil.
BACKGROUND: This small clinical trial tested the hypothesis that the addition of inspiratory muscle training (IMT) to aerobic exercise training (AE) results in further improvement in cardiorespiratory responses to exercise than those obtained with AE in patients with chronic heart failure (CHF) and inspiratory muscle weakness (IMW).
METHODS: Twenty-four patients with CHF and IMW (maximal inspiratory pressure <70% of predicted) were randomly assigned to a 12-week program of AE plus IMT (AE + IMT, n = 12) or to AE alone (AE, n = 12). Before and after intervention, the following measures were obtained: maximal inspiratory muscle pressure (PI(max)), peak oxygen uptake (Vo(2)peak), peak circulatory power, oxygen uptake efficiency slope, ventilatory efficiency, ventilatory oscillation, oxygen uptake kinetics during recovery (T(1/2)Vo(2)), 6-minute walk test distance, and quality of life scores.
RESULTS: Compared to AE, AE + IMT resulted in additional significant improvement in PI(max) (110% vs 72%), Vo(2)peak (40% vs 21%), circulatory power, oxygen uptake efficiency slope, ventilatory efficiency, ventilatory oscillation, and T(1/2)Vo(2). Six-minute walk distance and quality of life scores improved similarly in the 2 groups.
CONCLUSION: This randomized trial demonstrates that the addition of IMT to AE results in improvement in cardiorespiratory responses to exercise in selected patients with CHF and IMW. The clinical significance of these findings should be addressed by larger randomized trials.

Circulation. 1995 Jan 15;91(2):320-9.
Benefit of selective respiratory muscle training on exercise capacity in patients with chronic congestive heart failure.
Mancini DM, Henson D, La Manca J, Donchez L, Levine S.
Cardiovascular and Pulmonary Sections, Philadelphia Veterans Administration Medical Center, Pa.
Abstract
BACKGROUND: Diminished respiratory muscle strength and endurance have been demonstrated in patients with heart failure. This may contribute to exertional dyspnea and reduced exercise capacity in these patients. The purpose of this study was to investigate whether selective respiratory muscle training could alleviate dyspnea and improve exercise performance in patients with chronic congestive heart failure.
METHODS AND RESULTS: Fourteen patients with chronic heart failure (left ventricular ejection fraction, 22 +/- 9%) were enrolled in a supervised respiratory muscle training program. This consisted of three weekly sessions of isocapnic hyperpnea at maximal sustainable ventilatory capacity, resistive breathing, and strength training. Maximum sustainable ventilatory capacity, maximum voluntary ventilation, maximal inspiratory and expiratory pressures, peak VO2, and the 6-minute walk test were measured before (pre) and after (post) 3 months of training. Eight patients completed the training program. Respiratory muscle endurance was improved with training, as evidenced by increases in maximal sustainable ventilatory capacity (pre, 48.6 +/- 10.7 versus post, 76.9 +/- 14.5 L/min; P < .05) and in maximal voluntary ventilation (pre, 100 +/- 36 versus post, 115 +/- 39 L/min; P < .05). Respiratory muscle strength was also increased with training as maximal inspiratory (pre, 64 +/- 31 versus post, 78 +/- 33 cm, H2O; P < .01) and expiratory (pre, 94 +/- 30 versus post, 133 +/- 53 cm H2O; P < .001) pressures rose. Submaximal and maximal exercise capacity were significantly improved with selective respiratory muscle training as the 6-minute walk (pre, 1101 +/- 351 versus post, 1421 +/- 328 ft; P < .001) and peak exercise VO2 (pre, 11.4 +/- 3.3 versus post, 13.3 +/- 2.7 mL.kg-1.min-1; P < .05) both significantly increased. Dyspnea during activities of daily living was subjectively improved in the majority of trained patients. Dyspnea quantified by the Borg scale was significantly reduced during progressive isocapnic hypernea but not during bicycle exercise. No statistically significant improvement in maximal sustainable ventilatory capacity, maximum voluntary ventilation, maximal inspiratory or expiratory mouth pressures, 6-minute walk, or peak VO2 was observed in the 6 patients who did not complete the training program.
CONCLUSIONS: Selective respiratory muscle training improves respiratory muscle endurance and strength, with an enhancement of submaximal and maximal exercise capacity in patients with heart failure. Dyspnea during activities of daily living was subjectively improved in the majority of trained patients.

Cystic Fibrosis
Respir Med. 2001 Jan;95(1):31-6.
Inspiratory muscle training in patients with cystic fibrosis.
de Jong W, van Aalderen WM, Kraan J, Kooter GH, van der Schans CP.
Department of Rehabilitation, University Hospital Groningen, The Netherlands. w.de.jong@rev.azg.nl
Little information is available about the effects of inspiratory muscle training in patients with cystic fibrosis (CF). In this study the effects of inspiratory-threshold loading in patients with CF on strength and endurance of the inspiratory muscles, pulmonary function, exercise capacity, dyspnoea and fatigue were evaluated. Sixteen patients were assigned to one of two groups using the minimization method: eight patients in the training group and eight patients in the control group. The training was performed using an inspiratory-threshold loading device. Patients were instructed to use the threshold trainer 20 min a day, 5 days a week for 6 weeks. Patients in the training group trained at inspiratory threshold loads up to 40% of maximal static inspiratory pressure (Pimax) and patients in the control group got 'sham' training at a load of 10% of Pimax. No significant differences were found among the two groups in gender, age, weight, height, pulmonary function, exercise capacity, inspiratory-muscle strength and inspiratory-muscle endurance before starting the training programme. Mean (SD) age in the control group was 19 (5.5) years, mean (SD) age in the training group was 17 (5.2) years. Mean FEV1 in both groups was 70% predicted, mean inspiratory-muscle strength in both groups was above 100% predicted. All patients except one, assigned to the training group, completed the programme. After 6 weeks of training, mean inspiratory-muscle endurance (% Pimax) in the control group increased from 50% to 54% (P = 0.197); in the training group mean inspiratory muscle endurance (% Pimax) increased from 49% to 66% (P = 0.003). Statistical analysis showed that the change in inspiratory-muscle endurance (% Pimax) in the training group was significantly higher than in the control group (P = 0.012). After training, in the training group there was a tendency of improvement in Pimax with an increase from 105 to 123% predicted, which just fell short of statistical significance (P = 0.064). After training no significant differences were found in changes from baseline in pulmonary function, exercise capacity, dyspnoea and fatigue. It is concluded that low-intensity inspiratory-threshold loading at 40% of Pimax was sufficient to elicit an increased inspiratory-muscle endurance in patients with CF.

Clin Rehabil. 2008 Oct-Nov;22(10-11):1003-13.
Effects of inspiratory muscle training in cystic fibrosis: a systematic review.
Reid WD, Geddes EL, O'Brien K, Brooks D, Crowe J.
Department of Physical Therapy, University of British Columbia, Muscle Biophysics Laboratory, Vancouver, BC, Canada. darlene.reid@ubc.ca
OBJECTIVE: We performed a systematic review to determine the effect of inspiratory muscle training (IMT) on inspiratory muscle strength and endurance, exercise capacity, dyspnoea and quality of life for adolescents and adults living with cystic fibrosis.
DATA SOURCES: MEDLINE, EMBASE and CINAHL electronic databases were searched up to January 2008.
REVIEW METHODS: We performed a systematic review using the methodology outlined in the Cochrane Collaboration protocol. Articles were included if: (1) participants were adolescents or adults with cystic fibrosis (> 13 years of age); (2) an IMT group was compared to a sham IMT, no intervention or other intervention group; (3) the study used a randomized controlled trial or cross-over design; and (4) it was published in English. Data were abstracted and methodological quality was assessed independently by two reviewers.
RESULTS: The search strategy yielded 36 articles, of which two met the inclusion criteria. Both studies used a targeted or threshold device for IMT. Meta-analyses were limited to forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC), which showed no difference in effect between the IMT group and the sham and/or control group. Individual study results were inconclusive for improvement in inspiratory muscle strength. One study demonstrated improvement in inspiratory muscle endurance.
CONCLUSION: The benefit of IMT in adolescents and adults with cystic fibrosis for outcomes of inspiratory muscle function is supported by weak evidence. Its impact on exercise capacity, dyspnoea and quality of life is not clear. Future research should investigate the characteristics of the subgroup of people with cystic fibrosis that might benefit most from IMT.

Chest. 2004 Aug;126(2):405-11.
Inspiratory muscle training improves lung function and exercise capacity in adults with cystic fibrosis.
Enright S, Chatham K, Ionescu AA, Unnithan VB, Shale DJ.
School of Health Care Professions, University of Salford, Manchester, UK. s.enright@salford.ac.uk
STUDY OBJECTIVES: To investigate the effects of high-intensity inspiratory muscle training (IMT) on inspiratory muscle function (IMF), diaphragm thickness, lung function, physical work capacity (PWC), and psychosocial status in patients with cystic fibrosis (CF).
DESIGN: Twenty-nine adult patients with CF were randomly assigned to three groups. Two groups were required to complete an 8-week program of IMT in which the training intensity was set at either 80% of maximal effort (group 1; 9 patients) or 20% of maximal effort (group 2; 10 patients). A third group of patients did not participate in any form of training and acted as a control group (group 3; 10 patients).
INTERVENTIONS: In all patients, baseline and postintervention measures of IMF were determined by maximal inspiratory pressure (Pimax), and sustained Pimax (SPimax); pulmonary function, body composition, and physical activity status were also determined. In addition, diaphragm thickness was measured at functional residual capacity (FRC) and total lung capacity (TLC) [TDIcont], and the diaphragm thickening ratio (TR) was calculated (TR = thickness during Pimax at FRC/mean thickness at FRC). Subjects also completed an incremental cycle ergometer test to exhaustion and two symptom-related questionnaires, prior to and following training.
RESULTS: Following training, significant increases in Pimax and SPimax (p < 0.05), TDIcont (p < 0.05), TR (p < 0.05), vital capacity (p < 0.05), TLC (p < 0.05), and PWC (p < 0.05) were identified, and decreases in anxiety scores (p < 0.05) and depression scores (p < 0.01) were noted in group 1 patients compared to group 3 patients. Group 2 patients significantly improved Pimax and SPimax (both p < 0.05) only with respect to group 3 patients. No significant differences were observed in group 3 patients.
CONCLUSION: An 8-week program of high-intensity IMT resulted in significant benefits for CF patients, which included increased IMF and thickness of the diaphragm (during contraction), improved lung volumes, increased PWC, and improved psychosocial status.

Diabetes
Med Sci Sports Exerc. 2010 Dec 21. [Epub ahead of print]
Inspiratory muscle training in type 2 diabetes with inspiratory muscle weakness.
Corroa AP, Ribeiro JP, Balzan FM, Mundstock L, Ferlin EL, Moraes RS.
Exercise Pathophysiology Research Laboratory and Cardiovascular Division, Hospital de Clonicas de Porto Alegre. Rua Ramiro Barcelos 2350, 90035-007, Porto Alegre, RS, Brazil 2Department of Medicine, Faculty of Medicine, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
PURPOSE: Patients with type 2 diabetes mellitus may present weakness of the inspiratory muscles. We tested the hypothesis that inspiratory muscle training (IMT) could improve inspiratory muscle strength, pulmonary function, functional capacity, and autonomic modulation in patients with type 2 diabetes and weakness of the inspiratory muscles.
METHODS: Maximal inspiratory muscle pressure (PImax) was evaluated in a sample of 148 patients with type 2 diabetes. Of these, 25 patients with PImax < 70% of predicted were randomized to an 8 week program of IMT (n=12) or placebo-IMT (n=13). PImax, inspiratory muscle endurance time, pulmonary function, peak oxygen uptake, and heart rate variability were evaluated before and after intervention.
RESULTS: The prevalence of inspiratory muscle weakness was 29 %. IMT significantly increased the PImox (118 %) and the inspiratory muscle endurance time (495 %), with no changes in pulmonary function, functional capacity, or autonomic modulation. There were no significant changes with placebo-IMT.
CONCLUSIONS: Patients with type 2 diabetes may frequently present inspiratory muscle weakness. In these patients, IMT improves inspiratory muscle function with no consequences in functional capacity or autonomic modulation.

Asthma and COPD
Prim Care Respir J. 2005 Aug;14(4):186-94. Epub 2005 Jun 27.
The role of inspiratory muscle function and training in the genesis of dyspnoea in asthma and COPD.
McConnell AK.
Sport Sciences Department, Brunel University, Uxbridge, Middlesex UB8 3PH, UK.
The cardinal symptom of both asthma and COPD is dyspnoea, and from a patient perspective, the most troublesome. There are a multitude of inputs to the sensation of dyspnoea, few of which are readily modifiable. The level of inspiratory muscle work contributes to the sense of respiratory muscle effort and thence dyspnoea. Inspiratory muscle work is elevated in patients with COPD and asthma due to hyperinflation and an increased ventilatory requirement for exercise. Treatment tends to concentrate on reducing the load upon the inspiratory muscles induced by hyperinflation. Bronchodilators are the mainstay of treatment for COPD and asthma; they reduce hyperinflation, inspiratory muscle loading and dyspnoea. In addition, programmes of pulmonary rehabilitation have an excellent evidence base for improving dyspnoea, exercise tolerance and quality of life. However, provision within the NHS is limited and not all patients are suitable. One component of pulmonary rehabilitation that can be implemented safely in a home-based setting is specific inspiratory muscle training (IMT). There is a strong theoretical rationale for IMT in patients with airway obstruction, which is also supported by empirical evidence. IMT offers a relatively accessible non-pharmacological treatment for dyspnoea that also improves exercise tolerance and quality of life.

Minerva Anestesiol. 2001 Sep;67(9):653-8.
Respiratory muscles in chronic obstructive pulmonary disease and asthma.
Barbarito N, Ceriana P, Nava S.
Divisione di Pneumologia Riabilitativa, IRCCS Fondazione S. Maugeri, Centro Medico di Pavia, Pavia, Italy.
Chronic obstructive pulmonary disease (COPD) and asthma are characterized by airflow obstruction and significant increase of respiratory muscle workload, with concrete risk of ventilatory pump failure. Respiratory muscles, the main component of this pump, undergo structural and functional changes during the course of these diseases. Aim of the present paper is to analyze modifications of respiratory muscles in COPD and asthma. An analysis of the most important controlled clinical studies released during the past years was carried out. The patients suffered from chronic obstructive pulmonary disease and asthma. In COPD, respiratory muscles have to cope with an increased load, an intrinsic weakness and a mechanical disadvantage, especially in the diaphragmatic length-force relationship; in patients with acute asthma, the main features are a massive hyperinflation and a persistent inspiratory muscle activity during expiration. Modifications of respiratory muscles deserve great consideration not only for the complete comprehension of the underlying physiopathologic aspects of these diseases, but also for the optimal clinical management: a reduced pulmonary hyperinflation in COPD place the respiratory muscles in a better position of the force-length curve while great care must be payed to the metabolic and nutritional aspects. During asthmatic crisis respiratory muscles are subjected to a sort of intense training but anyway persistence of bronchospasm in most severe attacks can lead to exhaustion of the ventilatory pump and need of mechanical ventilatory support.

Asthma
Cochrane Database Syst Rev. 2003;(4):CD003792.
Inspiratory muscle training for asthma.
Ram FS, Wellington SR, Barnes NC.
National Collaborating Centre for Women's and Children's Health, Royal College of Obstetricians and Gynaecologists, 27, Sussex Place, Regent's Park, London, UK, NW1 4RG.
BACKGROUND: In moderate to severe chronic obstructive pulmonary disease there is good evidence of a generalised loss of muscle bulk (including the respiratory muscles). It is possible that similar loss of respiratory muscle strength occur particularly in more severe asthma related in part to the effects of steroid therapy. Thus the respiratory muscle function may well be of relevance in asthma and if dysfunctional, may be a suitable target for training.
OBJECTIVES: To evaluate the efficacy of inspiratory muscle training with an external resistive device in patients with asthma.
SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 1, 2002), MEDLINE (January 1966 to March 2002), EMBASE (January 1985 to March 2002), CINAHL (to March 2002) and the UK National Research Register of trials (January 1982 to March 2002) and reference lists of articles. We also searched on line respiratory journals and contacted manufacturers of training devices to obtain trials.
SELECTION CRITERIA: All randomised-controlled trials that involved the use of an external inspiratory muscle training device versus a control (sham or no inspiratory training device) were considered for inclusion.
DATA COLLECTION AND ANALYSIS: Two reviewers independently selected articles for inclusion, evaluated methodological quality of the studies and abstracted data.
MAIN RESULTS: Five studies were included in the review with four of the studies being produced by the same group. PI(max) (maximum inspiratory pressure) reported in three studies with 76 patients showed significant improvement with inspiratory muscle training when compared to the control group (WMD 23.07 cmH(2)O, 95%CI 15.65 to 30.50). Unfortunately, due to the paucity of included studies and data no other outcome was reported by more than one study. Therefore it is not possible to confirm whether this increase seen with PI(max) translates into any measurable clinical benefit.
REVIEWER'S CONCLUSIONS: Currently there is insufficient evidence to suggest that inspiratory muscle training provides any clinical benefit to patients with asthma. Due to the limited availability of studies in this area there is a need for further trials evaluating the efficacy of inspiratory muscle training devices in patients with asthma. These studies should investigate asthmatics with a range of severity. They should investigate clinically relevant outcomes such as lung function, symptoms, exacerbation rate and concomitant medications.

Chest. 2002 Jul;122(1):197-201.
Influence of gender and inspiratory muscle training on the perception of dyspnea in patients with asthma.
Weiner P, Magadle R, Massarwa F, Beckerman M, Berar-Yanay N.
Department of Medicine A, Hillel Yaffe, Medical Center, Hadera, Israel. weiner@hillel-yaffe.health.gov.il
BACKGROUND: Men and women respond differently to asthma.
PATIENTS AND METHODS: Maximal inspiratory mouth pressure (P(Imax)), beta(2)-agonist consumption, and perception of dyspnea (POD) were measured in 22 women and 22 men with mild persistent-to-moderate asthma. Next, the women were randomized into two groups: those who received inspiratory muscle training and those who received sham training. The training ended when the P(Imax) of the training group was equal to that of the male subjects. POD was then measured once again.
RESULTS: Baseline P(Imax) was significantly lower (p < 0.01) while POD and mean daily beta(2)-agonist consumption were significantly higher in the female subjects. P(Imax) reached the level of the male subjects at the end of the 20th week of training. The increase in the P(Imax) was associated with a statistically significant decrease in mean daily beta(2)-agonist use and in POD to a similar level as in male subjects.
CONCLUSIONS: POD and mean daily beta(2)-agonist consumption in asthmatic women are significantly higher, and the P(Imax) significantly lower, than that of their male counterparts. When the P(Imax) of female subjects following training is equal to that in male subjects, the differences in POD and mean daily beta(2)-agonist consumption disappear.

Chest. 2000 Mar;117(3):722-7.
Specific inspiratory muscle training in patients with mild asthma with high consumption of inhaled beta(2)-agonists.
Weiner P, Berar-Yanay N, Davidovich A, Magadle R, Weiner M.
Department of Medicine A, Hillel-Yaffe Medical Center, Hadera, Israel.
BACKGROUND: It has been known for many years that there are variations between asthmatic patients in terms of their perception of breathlessness during airway obstruction.
STUDY OBJECTIVE: To investigate the relationship between beta(2)-agonist consumption and the score of perception of dyspnea, in mild asthmatics, and the relationship between the effect of specific inspiratory muscle training (SIMT) on the score of perception of dyspnea and beta(2)-agonist consumption in "high perceivers."
METHODS: Daily beta(2)-agonist consumption was assessed during a 4-week run-in period in 82 patients with mild asthma. Patients with a mean beta(2)-agonist consumption of > 1 puff/d ("high consumers") then were randomized into two groups: one group of patients received SIMT for 3 months; the other group of patients was assigned as a control group and received sham training. Inspiratory muscle strength and perception of dyspnea were assessed before patients entered the study, following the 4-week run-in period, and after completing the training period.
RESULTS: Following the 4-week run-in period, 23 high-consumer patients (mean [+/- SEM] beta(2)-agonist consumption, 2.7 +/- 0.4 puffs/d) were detected. The mean Borg score during breathing against resistance was significantly higher (p < 0.05) in the patients with high beta(2)-agonist consumption than in the subjects with low mean beta(2)-agonist consumption. Following SIMT, the mean maximal inspiratory pressure increased significantly from 94.1 +/- 5.1 to 109.7 +/- 5.2 cm H(2)O (p < 0.005) in the training group. The increase in inspiratory muscle strength was associated with a statistically significant decrease in the mean Borg score during breathing against resistance (p < 0.05) as well as in the mean daily beta(2)-agonist consumption.
CONCLUSIONS: We have shown that patients with mild asthma, who have a high beta(2)-agonist consumption, have a higher perception of dyspnea than those with normal consumption. In addition, SIMT was associated with a decrease in perception of dyspnea and a decrease in beta(2)-agonist consumption.

Chest. 1992 Nov;102(5):1357-61.
Inspiratory muscle training in patients with bronchial asthma.
Weiner P, Azgad Y, Ganam R, Weiner M.
Department of Medicine A, Hillel-Yaffe Medical Center, Hadera, Israel.
In patients with asthma, the respiratory muscles have to overcome the increased resistance while they become progressively disadvantaged by hyperinflation. We hypothesized that increasing respiratory muscle strength and endurance with specific inspiratory muscle training (SIMT) would result in improvement in asthma symptoms in patients with asthma. Thirty patients with moderate to severe asthma were recruited into 2 groups; 15 patients received SIMT (group A) and 15 patients were assigned to the control group (group B) and got sham training in a double-blind group-comparative trial. The training was performed using a threshold inspiratory muscle trainer. Subjects of both groups trained five times a week, each session consisted of 1/2-h training, for six months. Inspiratory muscle strength, as expressed by the PImax at RV, increased significantly, from 84.0 +/- 4.3 to 107.0 +/- 4.8 cm H2O (p < 0.0001) and the respiratory muscle endurance, as expressed by the relationship between Pmpeak and PImax from 67.5 +/- 3.1 percent to 93.1 +/- 1.2 percent (p < 0.0001), in patients of group A, but not in patients of group B. This improvement was associated with significant improvements compared with baseline for asthma symptoms (nighttime asthma, p < 0.05; morning tightness, p < 0.05; daytime asthma, p < 0.01; cough, p < 0.005), inhaled B2 usage (p < 0.05), and the number of hospital (p < 0.05) and sick-leave (p < 0.05) days due to asthma. Five patients were able to stop taking oral/IM corticosteroids while on training and one in the placebo group. We conclude that SIMT, for six months, improves the inspiratory muscle strength and endurance, and results in improvement in asthma symptoms, hospitalizations for asthma, emergency department contact, absence from school or work, and medication consumption in patients with asthma.

Harefuah. 1992 Feb 2;122(3):155-9.
[Inspiratory muscle training for bronchial asthma].
[Article in Hebrew]
Weiner P, Azgad Y, Ganam R.
Dept. of Medicine A, Hillel Yaffe Medical Center, Hadera.
In patients with asthma the respiratory muscles have to overcome increased resistance while they become progressively disadvantaged by hyperinflation. We hypothesized that increasing respiratory muscle strength and endurance with specific inspiratory muscle training would improve asthmatic symptoms. Of 8 women and 12 men, aged 17-55, with moderate to severe asthma, 10 received such training (group A) and 10 were controls who were given sham training (group B) in a double-blind, group comparative trial. Both groups trained 3 times a week in 1-hour sessions for 6 months. Inspiratory muscle strength, as expressed by the PImax at RV, increased from 72.6 +/- 3.9 to 97.0 +/- 4.6 cm H2O (p less than 0.001) and respiratory muscle endurance, as expressed by the relationship between PmPeak and PImax, increased from 70.6 +/- 3.8 to 94.6 +/- 4.6% (p less than 0.001), in group A patients, but not those of group B. This improvement was associated with significant improvement in asthmatic symptoms: night-time asthma (p less than 0.05), morning tightness (p less than 0.05), daytime asthma (p less than 0.01), cough (p less than 0.005), use of inhaled B2 (p +/- 0.05), and hospital days (p less than 0.05) and days of sick-leave due to asthma. 5 patients were able to stop oral or IM corticosteroids during training, but only 1 in the sham training group. We conclude that 6-months of specific inspiratory muscle training in asthmatic patients improves inspiratory muscle strength and endurance and results in improvement in asthmatic symptoms, hospitalizations for asthma, emergency room contacts, absence from school or work, and use of medication.

Asthma in Children
J Bras Pneumol. 2008 Aug;34(8):552-8.
Inspiratory muscle training and respiratory exercises in children with asthma.
[Article in English, Portuguese]
Lima EV, Lima WL, Nobre A, dos Santos AM, Brito LM, Costa Mdo R.
Faculdade Santa Terezinha - CEST, Santa Terezinha College - Soo Luos, Brazil. elicrispim@oi.com.br
OBJECTIVE: The aim of the present study was to evaluate the effects that inspiratory muscle training (IMT) and respiratory exercises have on muscle strength, peak expiratory flow (PEF) and severity variables in children with asthma.
METHODS: This was a randomized analytical study involving 50 children with asthma allocated to one of two groups: an IMT group, comprising 25 children submitted to IMT via an asthma education and treatment program; and a control group, comprising 25 children who were submitted only to monthly medical visits and education on asthma. The IMT was performed using a pressure threshold load of 40% of maximal inspiratory pressure (MIP). The results were evaluated using analysis of variance, the chi-square test and Fisher's exact test, values of p > 0.05 being considered significant.
RESULTS: In the comparative analysis, pre- and post-intervention values of MIP, maximal expiratory pressure (MEP) and PEF increased significantly in the IMT group: MIP from -;48.32 +/- 5.706 to -;109.92 +/- 18.041 (p < 0.0001); MEP from 50.64 +/- 6.55 to 82.04 +/- 17.006 (p < 0.0001); and PEF from 173.6 +/- 50.817 to 312 +/- 54.848 (p < 0.0001). In the control group, however, there were no significant differences between the two time points in terms of MIP or MEP, although PEF increased from 188 +/- 43.97 to 208.80 +/- 44.283 (p < 0.0001). There was a significant improvement in the severity variables in the IMT group (p < 0.0001).
CONCLUSIONS: Programs involving IMT and respiratory exercises can increase mechanical efficiency of the respiratory muscles, as well as improving PEF and severity variables.

Others than COPD
Res Theory Nurs Pract. 2007;21(2):98-118.
Inspiratory muscle training: integrative review of use in conditions other than COPD.
Padula CA, Yeaw E.
University of Rhode Island, College of Nursing, Kingston 02881, USA. cpadula@cox.net
Inspiratory muscle training (IM training) is a technique that is designed to improve the performance of the respiratory muscles (RMs) that may be impaired in a variety of conditions. Interest in IM training has expanded over the past two decades, and IM training has been used in an increasingly wide range of clinical conditions. However, the benefits of IM training continue to be debated, primarily because of methodological limitations of studies conducted to date. The focus of this article is to provide a critical review of IM training research in conditions other than chronic obstructive pulmonary disease for which it has been used, including asthma, bronchiectasis, cystic fibrosis, pre- and postsurgery, ventilator weaning, neuromuscular diseases, and chronic heart failure. Emphasis is placed on what has been learned, remaining questions, future applications, and significance to practice.

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