Specific Inspiratory Muscle Training Research Articles

Resistance Training of Inspiratory Muscles After Coronary Artery Disease May Improve Obstructive Sleep Apnea in Outpatient Cardiac Rehabilitation: RICAOS Study

BackgroundObstructive sleep apnea (OSA) affects 5% of the adult population and its prevalence is up to 13 times higher in coronary artery disease (CAD) patients. However, OSA in this population is less symptomatic, leading to lower adherence to positive airway pressure (CPAP). While oropharyngeal exercise showed a significant decrease in apnea-hypopnea index (AHI) in patients with moderate OSA, there have been no studies testing the impact of specific inspiratory muscle training (IMT) for these patients. The aim of our study was to assess the effectiveness of IMT on AHI reduction in CAD patients with moderate OSA.MethodsWe included patients with CAD involved in a cardiac rehabilitation program and presenting an AHI between 15 and 30. Patients were randomized in a 1:1 allocation to a control group (CTL – classic training) or an IMT group (classic training + IMT). IMT consisted in 60 deep inspirations a day, 6 days a week, into a resistive load device set at 70% of the maximum inspiratory pressure (MIP). After 6 weeks, we compared AHI, neck circumference, Epworth Sleepiness Scale, Pittsburgh Sleep Quality index, and quality of life with the 12-item Short Form Survey before and after rehabilitation.ResultsWe studied 45 patient (60 ± 9 y, BMI = 27 ± 6 kg.m−2). The IMT group (n = 22) significantly improved MIP ( p < 0.05) and had a significant decrease in AHI by 25% (−6.5 ± 9.5, p = 0.02). In the CTL group (n = 23), AHI decreased only by 3.5% (−0.7 ± 13.1; p = 0.29). Between groups, we found a significant improvement in MIP ( p = 0.003) and neck circumference ( p = 0.01) in favor of the IMT group. However, we did not find any significant improvement of AHI in the IMT group compared to CTL ( p = 0.09).ConclusionA specific IMT during cardiac rehabilitation contributes to reduce significantly AHI in CAD patients with moderate OSA. Magnitude of the decrease in OSA severity could be enhanced according to implementation of specific IMT in this population.

Time to Move Beyond a "One-Size Fits All" Approach to Inspiratory Muscle Training.

Inspiratory muscle training (IMT) has been studied as a rehabilitation tool and ergogenic aid in clinical, athletic, and healthy populations. This technique aims to improve respiratory muscle strength and endurance, which has been seen to enhance respiratory pressure generation, respiratory muscle weakness, exercise capacity, and quality of life. However, the effects of IMT have been discrepant between populations, with some studies showing improvements with IMT and others not. This may be due to the use of standardized IMT protocols which are uniformly applied to all study participants without considering individual characteristics and training needs. As such, we suggest that research on IMT veer away from a standardized, one-size-fits-all intervention, and instead utilize specific IMT training protocols. In particular, a more personalized approach to an individual’s training prescription based upon goals, needs, and desired outcomes of the patient or athlete. In order for the coach or practitioner to adjust and personalize a given IMT prescription for an individual, factors, such as frequency, duration, and modality will be influenced, thus inevitably affecting overall training load and adaptations for a projected outcome. Therefore, by integrating specific methods based on optimization, periodization, and personalization, further studies may overcome previous discrepancies within IMT research.

Effects of specific inspiratory muscle training combined with whole-body endurance training program on balance in COPD patients: Randomized controlled trial.

PurposeThis study aims to assess the effect of inspiratory muscle training (IMT) combined with endurance training (ET) on balance in patients with chronic obstructive pulmonary disease (COPD).MethodsWe studied 32 male patients (62 ± 6 years) with moderate to very severe COPD. They were randomly assigned to an experimental group (IMT+ET) n = 16 or a control group (ET) n = 16 with similar characteristics. The evaluations were carried out at inclusion and after eight weeks of the training period. Functional balance was assessed by the Berg Balance Scale (BBS), the Timed-up and Go (TUG), the Single Leg Stance test (SLS), and the Activities-specific Balance Confidence (ABC) scale. The strength of the inspiratory muscles (PImax) was assessed by maximal inspiratory mouth pressure. Functional exercise performance was assessed by the 6 minutes walking test (6MWT). IMT program consists in performing two daily sets of 30 inspirations with 50% of PImax increased by 10% every two weeks. ET program consists in performing 30 min treadmill exercise at 60% to 80% of the average speed achieved during the 6MWT three days per week.ResultsAfter the training period, the experimental group demonstrated greater improvements in BBS (IMT+ET vs. ET; p = 0.019), and in ABC (IMT+ET vs. ET; p = 0.014). However, no significant differences between groups were observed for TUG, SLS, and 6MWT. There was a significant difference between groups in PImax (IMT+ET vs. ET; p = 0.030). Significant moderate correlations were obtained between ΔPImax and ΔBBS for both groups (IMT+ET: r = 0.624, p = 0.010; ET r = 0.550, p = 0.027) as well as for ΔABC but only in the experimental group (IMT+ET: r = 0.550, p = 0.027).ConclusionCompared to ET alone, the results suggest that IMT combined with ET enhances inspiratory muscle function and functional balance according to BBS and ABC in patients with COPD. We suggest that inspiratory muscle training might be introduced as additional training to pulmonary rehabilitation programs aimed at improving balance in COPD patients.Trial registrationThe trial registry name: Clinical Trials; Registration number: NCT04084405; URL: https://clinicaltrials.gov/ct2/show/NCT04084405.

Inspiratory muscle strength and walking capacity in patients with COPD

ABSTRACT Purpose: It has been suggested that patients with inspiratory muscle weakness could benefit from specific inspiratory muscle training (IMT). We aimed to examine the frequency of patients with inspiratory muscle weakness in a Danish hospital-based outpatient pulmonary rehabilitation program, and to evaluate the association between inspiratory muscle strength and peripheral muscle strength and walking capacity. Methods: Maximal Inspiratory Pressure (MIP) was assessed in 97 patients with COPD (39 men, 58 women, mean age years 70 ± 9, forced expiratory volume in 1 s ((FEV1) = 35 ± 10% pred.). The impact of MIP on knee-extension strength, walking distance, and symptom burden was evaluated using multiple linear regression analyses. Results: The MIP of the patients with COPD was 63 (95% CI 59; 67) cmH2O and it was significantly reduced compared to gender and age-matched reference values 76 (95% CI 73; 79) cmH2O (p < 0.001). Seven patients (7.2%) were under the lower limit of normal. MIP was negatively correlated with increasing age, female gender, decreasing knee-extension strength and lower FEV1% pred. Walking distance was associated with knee-extension strength and it was not associated with MIP. Conclusion: Maximal inspiratory pressure was reduced in patients with COPD but only a few patients had a weak MIP. Whilst MIP was associated with leg muscle strength, it was not associated with walking distance or symptoms.

Impact of inspiratory muscle training on obstructive sleep apnea in coronary patients. The Ricaos Study: Preliminary results

Obstructive sleep apnea (OSA) syndrome affects 5% of the adult population and its prevalence is 13 times higher in coronary patients. However, OSA in coronary patients is less suggestive, leading to under diagnosis and lower adherence to continuous positive airway pressure (CPAP) treatment. While oropharyngeal exercises showed significant decrease in Apnea-Hypopnea Index (AHI) in patients with moderate OSA, there were no studies on specific inspiratory muscle training (IMT). The aim of our study was to assess the effectiveness of IMT on AHI reduction in coronary patients with moderate OSA and already engaged in a cardiac rehabilitation program post-infarction. We included coronary patients involving in a cardiac rehabilitation program after infarction, presenting an AHI between 15 and 30, and without clinical symptoms requiring CPAP. Patients were randomized in a 1:1 allocation in a control group (CTL - classic training) or in an IMT group (classic training + IMT). IMT consisted in a prolonged inspiration into a device allowing the air to pass during the inspiration only according to the force developed. The resistance applied was 70% of the maximum inspiratory pressure (Pi max ). Patients in the IMT group perform 2 sets of 30 breaths per day, 6 days a week for 2 months. We included 19 patients (59 ± 10 years; BMI = 27 ± 3 kg/m 2 ). All the patients showed a significant decrease in AHI after rehabilitation (21.5 ± 5.1 to 16.3 ± 7.8, P < 0.009). The IMT group ( n = 10) significantly improved Pi max ( P < 0.05) and had a significant decrease of AHI by 25% (−8.7, P = 0.02). In the CTL group ( n = 9), the AHI decreased by 23% (−5.2; P = 0.1). No significant differences were observed in anthropometric data. A specific IMT during a cardiac rehabilitation contributes to reduce significantly AHI in coronary patients with moderate OSA. Further research is needed to determine which patients benefit more of this alternative therapy.

Benefits of skeletal-muscle exercise training in pulmonary arterial hypertension: The WHOLEi + 12 trial

BackgroundPulmonary arterial hypertension is often associated with skeletal-muscle weakness. The purpose of this randomized controlled trial was to determine the effects of an 8-week intervention combining muscle resistance, aerobic and inspiratory pressure-load exercises on upper/lower-body muscle power and other functional variables in patients with this disease. MethodsParticipants were allocated to a control (standard care) or intervention (exercise) group (n=20 each, 45±12 and 46±11years, 60% women and 10% patients with chronic thromboembolic pulmonary hypertension per group). The intervention included five, three and six supervised (inhospital) sessions/week of aerobic, resistance and inspiratory muscle training, respectively. The primary endpoint was peak muscle power during bench/leg press; secondary outcomes included N-terminal pro-brain natriuretic peptide levels, 6-min walking distance, five-repetition sit-to-stand test, maximal inspiratory pressure, cardiopulmonary exercise testing variables (e.g., peak oxygen uptake), health-related quality of life, physical activity levels, and safety. ResultsAdherence to training sessions averaged 94±0.5% (aerobic), 98±0.3% (resistance) and 91±1% (inspiratory training). Analysis of variance showed a significant interaction (group×time) effect for leg/bench press (P<0.001/P=0.002), with both tests showing an improvement in the exercise group (P<0.001) but not in controls (P>0.1). We found a significant interaction effect (P<0.001) for five-repetition sit-to-stand test, maximal inspiratory pressure and peak oxygen uptake (P<0.001), indicating a training-induced improvement. No major adverse event was noted due to exercise. ConclusionsAn 8-week exercise intervention including aerobic, resistance and specific inspiratory muscle training is safe for patients with pulmonary arterial hypertension and yields significant improvements in muscle power and other functional variables.

Effects Of Inspiratory Muscle Training On Inspiratory And Locomotor Muscle Hemodynamics During Exercise In Men

High levels of respiratory muscle work may elicit a redistribution of blood flow from the locomotor to the respiratory muscles during exercise. It is unknown if specific inspiratory muscle training (IMT) can attenuate this response during high-intensity, whole-body exercise. PURPOSE: To examine the hemodynamic responses of multiple inspiratory muscles and the vastus lateralis (VL) during incremental cycling before and after 5 weeks of IMT. METHODS: After a comprehensive familiarization visit, 25 recreationally active healthy men (mean±SD; age=24±4; maximal aerobic power (V[Combining Dot Above]O2max)=52±10 ml·kg-1·min-1) completed two maximal incremental cycle exercise tests (25W/2min steps) separated by 5 weeks of pressure threshold IMT or sham-control training (SC). The IMT group (n=12) performed 30 inspiratory efforts twice daily against a minimum resistance of 50% of maximum inspiratory pressure (MIP), adjusted weekly. The SC (n=13) group performed a daily bout of 60 inspiratory efforts against 10% MIP using the same device with no weekly adjustments. During the incremental cycle tests, participants were instrumented with NIRS optodes on the sternocleidomastoid (SCM), parasternal intercostals (PIC), 7th intercostal space (7IC), and VL to measure changes in oxygenated, deoxygenated, and total hemoglobin (tHb) concentrations. RESULTS: The IMT and SC groups were well matched for age, height, mass, and V[Combining Dot Above]O2max. There was a significant increase in MIP in the IMT group (mean±SD, 135±44 vs. 159±35 cmH2O, p<0.05) but not in the SC group (134±39 vs. 134±44 cmH2O, p>0.05). No differences were detected when comparing pre vs. post-IMT for any NIRS derived variables at relative percentages of maximal work rate (20, 40, 60, 80,100%) for any muscle in both the IMT and SC groups. The tHb (muscle blood volume) at the highest equivalent absolute work rate achieved by an individual on each test in the IMT group (pre vs. post-IMT) was 3±15 vs. 1±25, 1±9 vs. 2±11, -6±12 vs. -6±12, and 12±10 vs. 11±9[INCREMENT]μM whereas the SC group was 2±11 vs. 3±6, 1±9 vs. 4±8, -6±6 vs. -6±8, and 12±8 vs. 9±10[INCREMENT]μM in the SCM, PIC, 7IC, and VL, respectively (all p>0.05). CONCLUSION: Five weeks of pressure-threshold IMT had no effect on respiratory or locomotor muscle hemodynamics during incremental cycle exercise in healthy recreationally active men. Supported NSERC

Effects of inspiratory muscle training on exercise responses in Paralympic athletes with cervical spinal cord injury

We asked whether specific inspiratory muscle training (IMT) improves respiratory structure and function and peak exercise responses in highly trained athletes with cervical spinal cord injury (SCI). Ten Paralympic wheelchair rugby players with motor-complete SCI (C5-C7) were paired by functional classification then randomly assigned to an IMT or placebo group. Diaphragm thickness (B-mode ultrasonography), respiratory function [spirometry and maximum static inspiratory (PI ,max ) and expiratory (PE ,max ) pressures], chronic activity-related dyspnea (Baseline and Transition Dyspnea Indices), and physiological responses to incremental arm-crank exercise were assessed before and after 6 weeks of pressure threshold IMT or sham bronchodilator treatment. Compared to placebo, the IMT group showed significant increases in diaphragm thickness (P = 0.001) and PI ,max (P = 0.016). There was a significant increase in tidal volume at peak exercise in IMT vs placebo (P = 0.048) and a strong trend toward an increase in peak work rate (P = 0.081, partial eta-squared = 0.33) and peak oxygen uptake (P = 0.077, partial eta-squared = 0.34). No other indices changed post-intervention. In conclusion, IMT resulted in significant diaphragmatic hypertrophy and increased inspiratory muscle strength in highly trained athletes with cervical SCI. The strong trend, with large observed effect, toward an increase in peak aerobic performance suggests IMT may provide a useful adjunct to training in this population.

Specific inspiratory muscle training is safe in selected patients who are ventilator-dependent: A case series

Mechanical ventilation of intensive care patients results in inspiratory muscle weakness. Inspiratory muscle training may be useful, but no studies have specifically described the physiological response to training. Is inspiratory muscle training with a threshold device safe in selected ventilator-dependent patients? Does inspiratory muscle strength increase with high-intensity inspiratory muscle training in ventilator-dependent patients? Prospective cohort study of 10 medically stable ventilator-dependent adult patients. Tertiary adult intensive care unit. Inspiratory muscle training 5-6 days per week with a threshold device attached to the tracheostomy without supplemental oxygen. Physiological response to training (heart rate, mean arterial pressure, oxygen saturation and respiratory rate), adverse events, training pressures. No adverse events were recorded in 195 sessions studied. For each patient's second training session, no significant changes in heart rate (Mean Difference 1.3 bpm, 95% CI -2.7 to 5.3), mean arterial pressure (Mean Difference -0.9 mmHg, 95% CI -6.4 to 4.6), respiratory rate (Mean Difference 1.2 bpm, 95% CI -1.1 to 3.5 bpm) or oxygen saturation (Mean Difference 1.2%, 95% CI -0.6 to 3.0) were detected Training pressures increased significantly (Mean Difference 18.6 cmH(2)O, 95% CI 11.8-25.3). Threshold-based inspiratory muscle training can be delivered safely in selected ventilator-dependent patients without supplemental oxygen. Inspiratory muscle training is associated with increased muscle strength, which may assist ventilatory weaning.

Respiratory exercise in amyotrophic lateral sclerosis

We have evaluated the potential role of respiratory exercise by implementing specific inspiratory muscle training in a selected population of early-affected amyotrophic lateral sclerosis (ALS) patients. We studied 26 patients with ALS with normal respiratory function using two groups of patients in a parallel, control-group, randomized, delayed-start design. Patients in the first group (G1) started the active inspiratory exercise programme at entry and were followed for eight months, while the second group (G2) of patients followed a placebo exercise programme for the first four months and then active exercise for the second four-month period. The primary outcome measure was the ALSFRS. Respiratory tests, neurophysiological measurements, fatigue and quality of life scales were secondary outcomes. Analysis of covariance was used to compare changes between and within groups. Results showed that there was no significant difference between the two patient groups. Within-group analysis suggested that inspiratory exercise promotes a transient improvement in the respiratory subscore and in the maximal voluntary ventilation, peak expiratory flow, and sniff inspiratory pressure. In conclusion, there was no clear positive or negative outcome of the respiratory exercise protocol we have proposed, but we cannot rule out a minor positive effect. Exercise regimes merit more detailed clinical evaluation in ALS.

Pre-operative inspiratory muscle training preserves postoperative inspiratory muscle strength following major abdominal surgery – a randomised pilot study

The aim of this pilot study was to assess the effect of pre-operative inspiratory muscle training (IMT) on respiratory variables in patients undergoing major abdominal surgery. Respiratory muscle strength (maximum inspiratory [MIP] and expiratory [MEP] mouth pressure) and pulmonary functions were measured at least 2 weeks before surgery in 80 patients awaiting major abdominal surgery. Patients were then allocated randomly to one of four groups (Group A, control; Group B, deep breathing exercises; Group C, incentive spirometry; Group D, specific IMT). Patients in groups B, C and D were asked to train twice daily, each session lasting 15 min, for at least 2 weeks up to the day before surgery. Outcome measurements were made immediately pre-operatively and postoperatively. In groups A, B and C, MIP did not increase from baseline to pre-operative assessments. In group D, MIP increased from 51.5 cmH(2)O (median) pre-training to 68.5 cmH(2)O (median) post-training pre-operatively (P < 0.01). Postoperatively, groups A, B and C showed a fall in MIP from baseline (P < 0.01, P < 0.01) and P = 0.06, respectively). No such significant reduction in postoperative MIP was seen in group D (P = 0.36). Pre-operative specific IMT improves MIP pre-operatively and preserves it postoperatively. Further studies are required to establish if this is associated with reduced pulmonary complications.

Inspiratory Muscle Training, Altitude, and Arterial Oxygen Desaturation: A Preliminary Investigation

Specific inspiratory muscle training (IMT) has been shown to significantly attenuate the fall in arterial oxygen saturation (SpO2) during exhaustive exercise while breathing a hypoxic gas mixture of 14% oxygen. The aim of the current study was to assess the impact of IMT on resting SpO2 over a range of altitudes in healthy individuals. Resting SpO2 and the Borg Score were examined at altitudes of 0 or 400 m (0-400 m; 0-1312.3 ft), 1400 m, 4880 m, and 5550 m (4593 ft, 16,011 ft, and 18,209 ft) in 14 military personnel who were part of a climbing expedition to the Nepali Himalaya. Volunteer participants were randomly assigned to either a control (N = 7) or IMT (N = 7) group: IMT consisted of 1 set of 30 breaths twice daily at 50% maximal inspiratory mouth pressure (MIP) for 4 wk prior to departure. MIP was similar between groups pre-IMT but increased significantly by 15% post-IMT. Baseline maximal expiratory mouth pressure was not different between groups. The Borg Score increased significantly from 1400 m, but was not different between groups at any altitude. Resting SpO2 declined significantly at ascending altitudes in both groups and was similar between groups at altitudes of 0-400 m and 1400 m. However, at altitudes of 4880 m and 5550 m, SpO2 was significantly higher (6%) in the IMT group. IMT can attenuate the fall in resting SpO2, but only at altitudes of 4880 m and above. Conversely, IMT had no effect on resting levels of dyspnea as measured by the Borg Score.

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.

Respiratory muscle function and exercise intolerance in heart failure

Inspiratory muscle weakness (IMW) is prevalent in patients with chronic heart failure (CHF) caused by left ventricular systolic dysfunction, which contributes to reduced exercise capacity and the presence of dyspnea during daily activities. Inspiratory muscle strength (estimated by maximal inspiratory pressure) has independent prognostic value in CHF. Overall, the results of trials with inspiratory muscle training (IMT) indicate that this intervention improves exercise capacity and quality of life, particularly in patients with CHF and IMW. Some benefit from IMT may be accounted for by the attenuation of the inspiratory muscle metaboreflex. Moreover, IMT results in improved cardiovascular responses to exercise and to those obtained with standard aerobic training. These findings suggest that routine screening for IMW is advisable in patients with CHF, and specific IMT and/or aerobic training are of practical value in the management of these patients.

Inspiratory muscle training in COPD patients

AimThe aim of this study was to evaluate the impact a specific inspiratory muscle training (IMT) protocol had on dyspnoea, lung function, respiratory muscle pressure, tolerance to exercise and quality of life in a group of patients with ch ronic obstructive pulmonary disease (COPD). PopulationWe studied 13 patients with moderate to very severe COPD divided into a control group (n=5) with an average FEV1 43.9±10.1% of predicted value and an IMT group (n=8) with FEV1 57.8±12.1% of predicted value. While this study group underwent IMT for five consecutive weeks, the control group did not undergo any kind of training. ResultsUsing a specific IMT protocol significantly improved maximal inspiratory pressure (MIP) in the study group (initial MIP – 83.3±21.4 versus final MIP- 98.4±17.8 cmH2O; p<0.01). The same result was seen with the St. George Respiratory Question-naire (SGRQ) score in the study group (initial score 58±2.2 versus final score 50±2.1; p<0.05). No changes were recorded in the variables studied in the control group. ConclusionsThe use of IMT in patients with moderate to very severe COPD induced an improvement in inspiratory muscle force with a consequent improvement in the quality of life in relation to symptoms.

Treino de músculos inspiratórios em doentes com DPOC

Aim: The aim of this study was to evaluate the impact a specific inspiratory muscle training (IMT) protocol had on dyspnoea, lung function, respiratory muscle pressure, tolerance to exercise and quality of life in a group of patients with ch ronic obstructive pulmonary disease (COPD)Population: We studied 13 patients with moderate to very severe COPD divided into a control group (n=5) with an average FEV1 43.9±10.1% of predicted value and an IMT group (n=8) with FEV1 57.8±12.1 % of predicted value. While this study group underwent IMT for five consecutive weeks, the control group did not undergo any kind of training.Results: Using a specific IMT protocol significantly improved maximal inspiratory pressure (MIP) in the study group (initial MIP – 83.3±21.4 versus final MIP- 98.4±17.8 cmH2O; p<0.01). The same result was seen with the St. George Respiratory Questionnaire (SGRQ) score in the study group (initial score 58±2.2 versus final score 50±2.1; p<0.05). No changes were recorded in the variables studied in the control group.Conclusions: The use of IMT in patients with moderate to very severe COPD induced an improvement in inspiratory muscle force with a consequent improvement in the quality of life in relation to symptoms.Rev Port Pneumol 2007; XIV (2): 177-194

Inspiratory Muscle Training to Enhance Weaning from Mechanical Ventilation

This report describes the use of specific inspiratory muscle training to enhance weaning from mechanical ventilation in a patient who had failed conventional weaning strategies. A 79-year-old man remained ventilator-dependent 17 days following laparotomy. A program of daily inspiratory muscle training was initiated. The mean training threshold increased progressively during the program and simultaneously the periods of unassisted breathing achieved gradually increased. By day 27, mechanical ventilation was no longer required. Inspiratory muscle training can be implemented effectively in the difficult to wean patient and should be considered for patients who have failed conventional weaning strategies.

The influence of inspiratory muscle work history and specific inspiratory muscle training upon human limb muscle fatigue

The purpose of this study was to assess the influence of the work history of the inspiratory muscles upon the fatigue characteristics of the plantar flexors (PF). We hypothesized that under conditions where the inspiratory muscle metaboreflex has been elicited, PF fatigue would be hastened due to peripheral vasoconstriction. Eight volunteers undertook seven test conditions, two of which followed 4 week of inspiratory muscle training (IMT). The inspiratory metaboreflex was induced by inspiring against a calibrated flow resistor. We measured torque and EMG during isometric PF exercise at 85% of maximal voluntary contraction (MVC) torque. Supramaximal twitches were superimposed upon MVC efforts at 1 min intervals (MVC(TI)); twitch interpolation assessed the level of central activation. PF was terminated (T(lim)) when MVC(TI) was <50% of baseline MVC. PF T(lim) was significantly shorter than control (9.93 +/- 1.95 min) in the presence of a leg cuff inflated to 140 mmHg (4.89 +/- 1.78 min; P = 0.006), as well as when PF was preceded immediately by fatiguing inspiratory muscle work (6.28 +/- 2.24 min; P = 0.009). Resting the inspiratory muscles for 30 min restored the PF T(lim) to control. After 4 weeks, IMT, inspiratory muscle work at the same absolute intensity did not influence PF T(lim), but T(lim) was significantly shorter at the same relative intensity. The data are the first to provide evidence that the inspiratory muscle metaboreflex accelerates the rate of calf fatigue during PF, and that IMT attenuates this effect.

Inspiratory Muscle Training May Increase Peak Inspiratory Flow in Chronic Obstructive Pulmonary Disease

Background: When choosing a specific inhalation device for a chronic obstructive pulmonary disease (COPD) patient, the internal airflow resistance and the ability of the patient to overcome it and to create an optimal inspiratory flow are essential. Objectives: The purpose of the present study was to investigate: (1) the peak inspiratory flow (PIF) that a patient with COPD can generate while breathing through two dry powder inhalers and (2) whether in patients with low PIF specific inspiratory muscle training (SIMT) will increase the PIF and exceed the minimal PIF that is considered necessary to guarantee optimal lung deposition of the drug. Methods: Inspiratory muscle strength and PIFs were measured in 60 patients with COPD. Then 28 patients with severe COPD and low PIF were randomized to receive SIMT or to a control group. Results: With the Turbuhaler, 12 patients (20%) could not generate the optimal flow of 60 l/min. PIF correlated very well with maximal inspiratory mouth pressure (PI_max) for the Diskus and the Turbuhaler, as well as for both males and females (p < 0.001). Following the training period, there was a statistically significant increase in the PI_max in the training group. This increase was associated with a significant increase in the PIF. All patients overcame the minimal threshold PIF following the training. Conclusions: Some patients with severe COPD are not able to generate adequate flow to secure optimal lung deposition of the inhalation with the Turbuhaler. SIMT improves inspiratory muscle strength as well as PIF. Following 8 weeks of training, the optimal PIF enabling adequate lung deposition of the drug was attained in all the trained patients.

The effects of 1 year of specific inspiratory muscle training in patients with COPD: Chest 2005;128:3177–82

Aim We assessed the long-term benefits of inspiratory muscle training (IMT) on inspiratory muscle strength, exercise capacity, the perception of dyspnea, quality of life, primary care use, and hospitalizations in patients with significant COPD. Patients Forty-two consecutive COPD patients with FEV1 Results There was a statistically significant increase in inspiratory muscle strength (at the end of the third month of training) as assessed by maximal inspiratory pressure (from 71±4.9 to 90±5.1 cm H(2)O [± sem ], P 0.005 ) and 6-min walk distance (at the end of the third month of training; from 256±41 to 312±54 m; P 0.005 ), a decrease in the mean Borg score during breathing against resistance (at the end of the ninth month of training), improvement in the health-related quality-of-life scores (at the end of the sixth month of training) in the training group but not in the control group. At the end of the training year, these changes were maintained; in addition, a decrease in primary health-care use and hospitalization days was observed. Conclusions Our study shows that during IMT in patients with significant COPD, there is an increase in exercise capacity, improvement in quality of life, and decrease in dyspnea. Our study also provides evidence that long-term IMT can decrease the use of health services and hospitalization days.