Sham Inspiratory Muscle Training Research Articles

Does multifactorial inspiratory muscle training improve postural stability and quality of life of patients with diabetes in Pakistan? A randomised controlled trial

ObjectiveTo determine the effects of multifactorial inspiratory muscle training (IMT) combined with Otago Exercise Programme (OEP) on balance and quality of life (QoL) in patients with diabetes.MethodsPretest–post-test randomised controlled trial.SettingRehabilitation...

Inspiratory Muscle Training in Nemaline Myopathy.

Respiratory muscle weakness is a common feature in nemaline myopathy. Inspiratory muscle training (IMT) is an intervention that aims to improve inspiratory muscle strength. The aim of this controlled before-and-after pilot study was to investigate if IMT improves respiratory muscle strength in patients with nemaline myopathy. Nine patients (7 females; 2 males, age 36.6±20.5 years) with respiratory muscle weakness and different clinical phenotypes and genotypes were included. Patients performed eight weeks of sham IMT followed by eight weeks of active threshold IMT. The patients trained twice a day five days a week for 15 minutes at home. The intensity was constant during the training after a gradual increase to 30% of maximal inspiratory pressure (MIP). Active IMT significantly improved MIP from 43±15.9 to 47±16.6 cmH2O (p = 0.019). The effect size was 1.22. There was no significant effect of sham IMT. Sniff nasal inspiratory pressure, maximal expiratory pressure, spirometry, and diaphragm thickness and thickening showed no significant improvements. This pilot study shows that threshold IMT is feasible in patients with nemaline myopathy and improves inspiratory muscle strength. Our findings provide valuable preliminary data for the design of a larger, more comprehensive trial.

Effectiveness of Respiratory Muscle Training in Adults With Pulmonary Hypertension. A Systematic Review and Meta-Analysis.

Patients with pulmonary hypertension (PH) may have impaired exercise capacity and quality of life; this may possibly be due to the early onset of dyspnoea associated with respiratory muscle weakness. Respiratory muscle training could improve the condition of these patients, so this study aimed to determine, through a systematic review and meta-analysis, the effectiveness of respiratory muscle training in adult patients with PH. Medline, Embase, CENTRAL, clinical trial registries databases, and grey literature and reference lists of reviews related to the objective were searched up to March 2022. Controlled clinical trials comparing the effectiveness of respiratory muscle training with sham or no intervention in adults with PH were included. Records were independently screened by two authors. The primary outcomes were maximal and functional exercise capacity, quality of life, and dyspnoea. The secondary outcomes were respiratory muscle strength, physical activity, lung function, and adverse events. Two authors independently extracted data and the study quality was assessed using the Cochrane risk-of-bias tool 2 (RoB 2). The certainty of the evidence was assessed according to the GRADE approach. A total of 5,524 records were screened, and seven randomised clinical trials (RCTs) (257 participants) were included. It was uncertain whether inspiratory muscle training (IMT), compared with sham IMT or no intervention, increased the distance walked in the 6-minute walk test (6MWT) (MD, 39 m; 95% CI, 20.72-57.39; I2=27%; four RCTs; very low certainty of evidence) and slightly decreased the perceived sensation of dyspnoea (MD, 0.5 points on the mMRC scale; 95% CI, -0.87 to -0.13; I2=0%; two RCTs; very low certainty of evidence). In addition, it was uncertain whether IMT had no effect on the emotional (SMD,-0.34; 95% CI, -1.06 to 0.38; I2=64%; three RCTs; very low certainty of evidence) and physical (SMD,0.06; 95% CI, -0.41 to 0.52; I2=16%; three RCTs; very low certainty of evidence) component of quality of life. It is uncertain whether IMT increases functional exercise capacity and slightly decreases the sensation of dyspnoea. In addition, it is uncertain whether IMT does not affect the quality of life. More RCTs and with a better methodological design are needed to increase the certainty of the evidence and determine the real effect of this intervention.

The Effects of Inspiratory Muscle Training (IMT) on Patients Undergoing Coronary Artery Bypass Graft (CABG) Surgery: A Systematic Review and Meta-Analysis.

To determine the effects of inspiratory muscle training (IMT) alone on inspiratory muscle strength and endurance, pulmonary function, pulmonary complications, and length of hospital stay in patients undergoing coronary artery bypass graft surgery (CABG). We conducted a literature search across databases (Ovid MEDLINE(R) and Epub Ahead of Print, In-Process & Other Non-Indexed Citations and Daily; Ovid Embase; Ovid Cochrane Central Register of Controlled Trials; Ovid Cochrane Database of Systematic Reviews; and Scopus) from inception to December 2021. The eligibility criteria were randomized controlled trials that investigated the effects of IMT versus usual care or sham IMT in patients undergoing CABG. A total of 12 randomized clinical trials with 918 patients were included in the meta-analysis. Postoperative IMT was associated with improved maximal inspiratory pressure (MIP), maximum inspiratory pressure (PImax), and six-minute walking test (6MWT) and with a decrease in length of hospital stay (LOS). For preoperative IMT, there was statistical significance between intervention and MIP, PImax, forced expiratory volume in one second (FEV1), forced vital capacity (FVC), postoperative pulmonary complications (PPCs), and LOS. Pre- and postoperative IMT resulted in improvements in MIP. Isolated IMT in patients who underwent CABG improved their inspiratory muscle strength and endurance, pulmonary function, and 6MWT and helped decrease postoperative pulmonary complications and the length of hospital stay.

The Benefits of Inspiratory Muscle Training in Heart Failure Patients – A Systematic Review

Background: Patients with heart failure (HF) have impaired function of respiratory system and frequently experience dyspnea. Inspiratory muscle training (IMT) offers an alternative way of exercise with a lot of benefits for HF patients. Aim: The aim of this review was to summarize and to reveal the effects of IMT in HF patients. Methods: Electronic searches were performed using Pubmed Database, Physiotherapy Evidence Database (PEDro) and Cochrane Library. Inclusion criteria were: RCTs, patients with HF, full text articles after 2010 and at least one intervention group with IMT. Methodological quality was assessed using the PEDro (Physiotherapy Evidence Database) scale. Results: Nineteen articles met the inclusion criteria and were included in this review. In most studies training protocols involved 3 to 7 sessions per week with intensity ≤30-60% of maximal inspiratory pressure (MIP), for a total duration of 4-12 weeks. Respiratory muscle strength improved in 11/12 studies, peripheral muscle strength in 4/5 studies, exercise capacity (peak VO2, VE/VCO2 slope) in 4/10, pulmonary function (FEV1, FEV1/FVC, FVC) in 0/5, functional capacity (6MWT) in 6/8, echocardiography parameters in 1/6, quality of life and dyspnea in 9/16. Control groups followed sham IMT, usual care, no intervention, intervention without exercise, or aerobic training, which could explain in some cases the conflicting results. Conclusions: IMT is beneficial for HF patients and should be included as a complementary method in cardiac rehabilitation programs. The optimal characteristics of ΙΜΤ as well as the benefits when combined with common forms of exercise need further research.

Training the equine respiratory muscles: Inspiratory muscle strength.

Little is known about the response of the equine respiratory muscles to training. To measure an index of inspiratory muscle strength (IMSi) before and after a period of conventional exercise training (phase 1) and inspiratory muscle training (IMT), comparing high-load (treatment) and low-load (control) groups (phase 2). Prospective randomised controlled trial. Phase 1: Twenty National Hunt Thoroughbred racehorses performed an inspiratory muscle strength test (IMST) twice on two occasions; when unfit at timepoint A (July), and when race fit at timepoint B (October). Phase 2: Thirty-five Thoroughbred racehorses at race fitness were randomly assigned into a high-load (treatment, n=20) or low-load (control, n=15) IMT group. The high-load group followed an IMT protocol that gradually increased the inspiratory pressure applied every 4 days. The low-load group underwent sham IMT with a low training load. The IMT was performed 5 days/week for 10 weeks. The IMST was performed twice on two occasions, timepoint B (October) and timepoint C (January). Conventional exercise training and racing continued during the study period. The peak IMSi values obtained from the different groups at timepoints A, B and C were compared using a Wilcoxon Signed Rank Test. Phase 1: There was a significant increase in IMSi from timepoint A: 22.5 cmH2 O (21-25) to timepoint B: 26 cmH2 O (24-30) (p =0.015). Phase 2: From timepoint B to C there was a significant increase in IMSi for the high-load group 34 cmH2 O (28-36) (p =0.001) but not the low-load group 26 cmH2 O (24-30) (p =0.929). The peak IMSi at timepoint C was significantly higher for the high-load than low-load group (p =0.019). Single centre study with only National Hunt horses undergoing race-training included. In horses undergoing race training there is a significant increase in IMSi in response to conventional exercise training and high-load IMT.

Effects of inspiratory muscle training on walking capacity of individuals after stroke: A double-blind randomized trial

Objectives: Identify the effects of inspiratory muscle training (IMT) on walking capacity, strength and inspiratory muscle endurance, activities of daily living, and quality of life poststroke. Design: Double-blind randomized trial. Setting: The Sarah Network of Rehabilitation Hospitals. Subjects: Adult poststroke inpatients with inspiratory muscle weakness. Interventions: The Experimental Group (EG) (n = 23) underwent IMT for 30 minutes/day, five times/week over six weeks. The Control Group (CG) (n = 27) performed sham IMT. Both groups underwent standard rehabilitation. Main measures: Primary outcome was post-intervention six-minute walking test (6MWT) distance. We also measured maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), inspiratory muscle endurance, activities of daily living (functional independence measure – FIM), and quality of life at baseline and post-intervention. Three months after intervention, we measured MIP, walking capacity and quality of life. Results: Baseline characteristics were similar, with mean age 53 ± 11 years and FIM 74 ± 10p. Both groups similarly increased the walking capacity at six weeks (63 vs 67 m, P = 0.803). Compared to the CG, the EG increased the inspiratory endurance (22 vs 7 cmH2O, P = 0.034) but there was no variation in MEP (14 vs 5 cmH2O, P = 0.102), MIP (27 vs 19 cmH2O, P = 0.164), FIM (6 vs 6, P = 0.966) or quality of life (0 vs 0.19, P = 0.493). Gains in both groups were sustained at three months. Conclusion: Adding IMT to a rehabilitation program improves inspiratory muscle endurance, but does not further improve MIP, 6-MWT distance, activities of daily living or quality of life of individuals after stroke beyond rehabilitation alone. Registered in Clinical Trials, NCT03171272.

A Transfer Entropy Approach for the Assessment of the Impact of Inspiratory Muscle Training on the Cardiorespiratory Coupling of Amateur Cyclists.

The strength of cardiorespiratory interactions diminishes with age. Physical exercise can reduce the rate of this trend. Inspiratory muscle training (IMT) is a technique capable of improving cardiorespiratory interactions. This study evaluates the effect of IMT on cardiorespiratory coupling in amateur cyclists. Thirty male young healthy cyclists underwent a sham IMT of very low intensity (SHAM, n = 9), an IMT of moderate intensity at 60% of the maximal inspiratory pressure (MIP60, n = 10) and an IMT of high intensity at the critical inspiratory pressure (CIP, n = 11). Electrocardiogram, non-invasive arterial pressure, and thoracic respiratory movement (RM) were recorded before (PRE) and after (POST) training at rest in supine position (REST) and during active standing (STAND). The beat-to-beat series of heart period (HP) and systolic arterial pressure (SAP) were analyzed with the RM signal via a traditional non-causal approach, such as squared coherence function, and via a causal model-based transfer entropy (TE) approach. Cardiorespiratory coupling was quantified via the HP-RM squared coherence at the respiratory rate (K2HP–RM), the unconditioned TE from RM to HP (TERM→HP) and the TE from RM to HP conditioned on SAP (TERM→HP| SAP). In PRE condition we found that STAND led to a decrease of TERM→HP| SAP. After SHAM and CIP training this tendency was confirmed, while MIP60 inverted it by empowering cardiorespiratory coupling. This behavior was observed in presence of unvaried SAP mean and with usual responses of the baroreflex control and HP mean to STAND. TERM→HP and K2HP–RM were not able to detect the post-training increase of cardiorespiratory coupling strength during STAND, thus suggesting that conditioning out SAP is important for the assessment of cardiorespiratory interactions. Since the usual response of HP mean, SAP mean and baroreflex sensitivity to postural stressor were observed after MIP60 training, we conclude that the post-training increase of cardiorespiratory coupling during STAND in MIP60 group might be the genuine effect of some rearrangements at the level of central respiratory network and its interactions with sympathetic drive and vagal activity.

Respiratory muscle training in children and adults with neuromuscular disease

Respiratory muscle training in children and adults with neuromuscular disease

The effect of inspiratory muscle training on fatigue and dyspnea in patients with heart failure: A randomized, controlled trial.

Fatigue and dyspnea are debilitating symptoms in patients with heart failure (HF). The purpose of this study was to evaluate the effects of inspiratory muscle training (IMT) on dyspnea, fatigue and the New York Heart Association (NYHA) functional classification in patients with HF. In this prospective, randomized, controlled trial, 84 patients with HF (NYHA classes II-III/IV) with a mean age of 56.62 ± 9.56 years were randomly assigned to a 6-week IMT (n = 42) or a sham IMT (n = 42) program. The IMT was performed at 40% of the maximal inspiratory pressure (MIP) in the IMT group and at 10% in the sham group. The main outcomes were assessed at baseline and after the intervention and included dyspnea severity scale (Modified Medical Research Council [MMRC], Fatigue Severity Scale [FSS] and the NYHA functional classification (based on the presenting symptoms). The between-group analysis showed significant improvements in dyspnea, fatigue and the NYHA functional classification in the IMT group compared to the sham group (P < .05). The within-group analysis showed significant improvements in dyspnea (from 2.63 ± 0.79 to 1.38 ± 0.66, P < .001), fatigue (from 43.36 ± 8.5 to 28.95 ± 9.11, P < .001) and the NYHA functional classification (from 2.73 ± 0.5 to 2.1 ± 0.6, P = .001) in the IMT group, while fatigue and dyspnea increased significantly in the sham group. The 6-week home-based IMT was found to be an effective and safe tool for reducing dyspnea and fatigue and improving the NYHA functional classification.

Inspiratory muscle training does not improve clinical outcomes in 3-week COPD rehabilitation: results from a randomised controlled trial.

The value of inspiratory muscle training (IMT) in pulmonary rehabilitation in chronic obstructive pulmonary disease (COPD) is unclear. The RIMTCORE (Routine Inspiratory Muscle Training within COPD Rehabilitation) randomised controlled trial examined the effectiveness of IMT added to pulmonary rehabilitation.In total, 611 COPD patients (Global Initiative for Chronic Obstructive Lung Disease stage II-IV) received a 3-week inpatient pulmonary rehabilitation, of which 602 patients were included in the intention-to-treat analyses. The intervention group (n=300) received highly intensive IMT and the control group (n=302) received sham IMT. The primary outcome was maximal inspiratory pressure (PImax). The secondary outcomes were 6-min walk distance, dyspnoea, quality of life and lung function. Outcomes were assessed pre- and post-pulmonary rehabilitation. ANCOVA was used.The intervention group showed higher effects in PImax (p<0.001) and forced inspiratory volume in 1 s (p=0.013). All other outcomes in both study groups improved significantly, but without further between-group differences. Sex and pulmonary rehabilitation admission shortly after hospitalisation modified quality of life effects.IMT as an add-on to a 3-week pulmonary rehabilitation improves inspiratory muscle strength, but does not provide additional benefits in terms of exercise capacity, quality of life or dyspnoea. A general recommendation for COPD patients to add IMT to a 3-week pulmonary rehabilitation cannot be made.

Safety and efficacy of inspiratory muscle training for preventing adverse outcomes in patients at risk of prolonged hospitalisation

BackgroundThe early institution of inspiratory muscle training on hospitalised patients with no established respiratory deficits could prevent in-hospital adverse outcomes that are directly or indirectly associated to the loss of respiratory muscle mass inherent to a prolonged hospital stay. The objective of the clinical trial is to assess the impact of inspiratory muscle training on hospital inpatient complications.MethodsThis is a double-blind randomised controlled trial. Subjects in the intervention group underwent an inspiratory muscle training loaded with 50% maximum inspiratory pressure twice daily for 4 weeks from study enrolment. Patients were randomly assigned to an inspiratory muscle training group or a sham inspiratory muscle training group. All patients received conventional physiotherapy interventions. Baseline and post-intervention respiratory and peripheral muscle strength, functionality (performance of activities of daily living), length of hospital stay, and death were evaluated. Clinical outcomes were assessed until hospital discharge. This study was approved by the Institutional Hospital Ethics Committee (03/2014).ResultsThirty-one patients assigned to the inspiratory muscle training group and 34 to the sham inspiratory muscle training group were analysed. Patients in the inspiratory muscle training group had a shorter mean length of hospital stay (35.3 ± 2.7 vs. 41.8 ± 3.5 days, p < 0.01) and a lower risk of endotracheal intubation (relative risk (RR) = 0.36; 95% confidence interval (CI) 0.27–0.97; p = 0.03) as well as muscle weakness (RR = 0.36; 95% CI 0.19–0.98; p = 0.02) and mortality (RR = 0.23; 95% CI 0.2–0.94; p = 0.04). The risk of adverse events did not differ significantly between groups.ConclusionInspiratory muscle training was a protective factor against endotracheal intubation, muscle weakness, and mortality.Trial registrationClinicalTrials.gov, ID: NCT02459444. Registered on 19 May 2015.

Inspiratory Muscle Training Effects on Cycling During Acute Hypoxic Exposure.

Hypoxic environments increase the physiological demands of exercise. Inspiratory muscle training can reduce the demands of exhaustive exercise in this environment. This study examined the impact of inspiratory muscle training on moderate intensity hypoxic cycling exercise. There were 17 healthy adult men who undertook 4 wk of inspiratory muscle training (N = 8) or 4 wk of sham inspiratory muscle training (N = 9). Subjects completed four fixed intensity (100 W) and duration (10 min) cycle ergometry tests. Two were undertaken breathing normoxic ambient air and two breathing a hypoxic gas mixture (14.6% oxygen, balance nitrogen). One normoxic and hypoxic test occurred before, and one after, inspiratory muscle training. Inspiratory muscle training increased maximal inspiratory mouth pressure by 21 ± 16 cmH2O. Arterial oxygen saturation and its ratio to minute ventilation also increased after inspiratory muscle training during hypoxic exercise from 83 ± 4% to 86 ± 3% (approximately 3%) and 2.95 ± 0.48 to 3.52 ± 0.54% · L · min-1(approximately 21%), respectively. In addition, minute ventilation and carbon dioxide output fell by 12-13% after inspiratory muscle training during hypoxic exercise. Inspiratory muscle training reduced the physiological demand of moderate intensity exercise during acute hypoxic, but not normoxic, exercise. It may therefore be of benefit in adults exercising in a hypoxic environment.Lomax M, Massey HC, House JR. Inspiratory muscle training effects on cycling during acute hypoxic exposure. Aerosp Med Hum Perform. 2017; 88(6):544-549.

Respiratory muscle training in children and adults with neuromuscular disease

Respiratory muscle training in children and adults with neuromuscular disease

Inspiratory muscle training in pulmonary arterial hypertension.

The purpose of this study was to investigate the effects of inspiratory muscle training (IMT) on functional capacity, respiratory muscle strength, pulmonary function, quality of life, and fatigue and dyspnea perception in patients with pulmonary arterial hypertension (PAH). Twenty-nine clinically stable PAH patients were included in this study. These patients were randomly assigned to a 6-week IMT program (14 patients) or to a sham IMT protocol (15 patients). Before and after the treatment, pulmonary function, respiratory muscle strength, functional capacity, dyspnea and fatigue perception, and quality of life were evaluated. There were significant increases in maximal inspiratory and expiratory pressure, forced expiratory volume in 1 second (% predicted) and 6-minute walk distance in the IMT group compared with the control group (P < .05). There were significant decreases in the Fatigue Severity Scale score, Modified Medical Research Council dyspnea scores, and Nottingham Health Profile emotional reactions subscale in the IMT group compared with the control group (P < .05). Inspiratory muscle training promotes significant improvements in respiratory muscle strength and functional capacity, thus resulting in a reduction of dyspnea during activities of daily living and less fatigue in PAH patients. Inspiratory muscle training is a clinically practical treatment for PAH without any complications.

High‐intensity vs. sham inspiratory muscle training in patients with chronic heart failure: a prospective randomized trial

The purpose of this study was to evaluate the effectiveness, feasibility, and safety of a 4-week high-intensity inspiratory muscle training (hi-IMT) in patients with chronic heart failure (CHF). A double-blind randomized clinical trial was carried out in 22 patients with CHF. Participants were assigned to the hi-IMT or sham-IMT group. The trainer device was a prototype of the Orygen-Dual Valve. The training workloads were adjusted weekly at the inspiratory pressure which allowed the performance of 10 consecutive maximal repetitions (10RM). Main outcomes were strength and endurance of the respiratory muscles assessed by maximal respiratory pressures (PImax and PEmax) and a 10RM manoeuvre, respectively. Twenty-one patients presented impairment in respiratory muscle strength and endurance. Patients in the hi-IMT group showed a significant improvement in both strength and endurance: inspiratory muscle strength in the intervention group increased 57.2% compared with 25.9% in the control group (P = 0.001). The percentage change in endurance was 72.7% for the hi-IMT group compared with 18.2% in the sham-IMT group (P < 0.001). No adverse effects occurred during the intervention. A 4-week hi-IMT with the use of the Orygen-Dual Valve is shown to be an effective, feasible, and safe tool to improve weakness and fatigue of the inspiratory muscles. The key point of this study is to discuss immediate practical implications in terms of respiratory muscle dysfunction postulated as a potential prognostic factor and as an additional therapeutic target. NCT01606553.

Inspiratory muscle training for the recovery of function after stroke

Inspiratory muscle weakness has been observed in patients with stroke. Inspiratory muscle training is an intervention that has shown possible effects for functional recovery of patients with stroke. To investigate the effect and safety of inspiratory muscle training for improving activities of daily living, respiratory muscle function, quality of life and cardiorespiratory fitness after stroke. We searched the Cochrane Stroke Group's Trials Register (August 2011), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, October Issue 4), MEDLINE (1948 to October 2011), EMBASE (1974 to October 2011), CINAHL (1982 to October 2011), AMED (1985 to October 2011), PEDro (October 2011) and four Chinese databases. In an effort to identify further published, unpublished and ongoing trials, we searched ongoing trials registers and conference proceedings, checked reference lists, and contacted authors of relevant studies and training devices manufactures. There were no language restrictions. Randomised controlled trials (RCTs) comparing inspiratory muscle training with no intervention, sham inspiratory muscle training or other cardiorespiratory training for patients with stroke were eligible. Two review authors independently assessed trial quality and extracted data. The primary outcomes were activities of daily living and respiratory muscle strength; the secondary outcomes were quality of life, cardiorespiratory fitness and adverse effects. We included two trials involving a total of 66 patients in this review.Pooling analyses of data was not possible due to considerable heterogeneity between the trials and a lack of data in both trials. One study found a significant increase in respiratory muscle strength favouring inspiratory muscle training over sham inspiratory muscle training, but there was no significant difference between groups on quality of life. The other study showed that patients receiving inspiratory muscle training were more likely to improve their activities of daily living, quality of life and cardiorespiratory fitness than those patients who received no intervention. However, the main results were not compared directly with breathing retraining. Furthermore, neither of the trials assessed the safety and tolerance of inspiratory muscle training. There is insufficient evidence to support inspiratory muscle training as an effective treatment to improve function after stroke, and no evidence relating to the safety of inspiratory muscle training. Further well-designed RCTs are required.

Inspiratory muscle training improves 100 and 200 m swimming performance

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.

Systematic Review: Inspiratory Muscle Training in Patients with Chronic Obstructive Pulmonary Disease: The State of the Evidence

Purpose: The purpose of the present review was to assess the quality of evidence in the literature regarding the specific benefits of inspiratory muscle training (IMT) with an emphasis on training intensity and the relationships between changes in inspiratory muscle function and other clinical outcome measures. Methods: Articles were found by searching CINAHL, PubMed, Medline via First Search, and ProQuest databases. Articles used in the review were randomized trials of IMT vs. sham IMT or no intervention, published in English in a peer-reviewed journal, included patients with chronic obstructive pulmonary disease (COPD), and specified the intensity of training. The quality of the studies was evaluated by 2 independent reviewers using the methodological rigor scale described by Medlicott and Harris as well as Sackett's levels of evidence. Fifteen articles met the inclusion criteria and were used in this review. Results: Consistent improvements in maximal inspiratory pressures (ranging from -11 to -30 cm H2O) and inspiratory muscle endurance were found. Improvements in dyspnea and health-related quality of life were also observed. Inspiratory muscle training may result in improved exercise tolerance as measured using walking tests. High-intensity IMT resulted in improved training efficiency with respect to inspiratory muscle strength, but evidence of the effect of high-intensity IMT on other clinical outcomes is lacking. Conclusion: Despite research spanning decades, there are numerous limitations in the literature regarding IMT. IMT appears to improve dyspnea, waking test distance, and health-related quality of life in individuals with COPD, but it is not clear whether this improvement is mediated through improved inspiratory muscle strength and endurance. This review discussed several considerations critical to the design of future trials.

Inspiratory muscle training in adults with chronic obstructive pulmonary disease: An update of a systematic review

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.