Recent Advancements in Our Understanding of the Ergogenic Effect of Respiratory Muscle Training in Healthy Humans: A Systematic Review

Effect of respiratory rehabilitation on quality of life in individuals with post-COVID-19 symptoms: A randomised controlled trial

BACKGROUND

Inspiratory and expiratory muscle training (RMT) has been shown to have beneficial effects in individuals with long-term post-COVID-19 symptoms.

OBJECTIVE

To assess the effects of adding RMT to an aerobic exercise (AE) training program for health-related quality of life (HRQoL) and exercise tolerance in individuals with long-term post-COVID-19 symptoms, and to evaluate the effects on physical and lung function, and psychological status.

METHODS

64 individuals with long-term post-COVID-19 symptoms of fatigue and dyspnoea were randomly assigned to AE+RMT or AE+RMTsham groups for an 8-wk intervention (AE: 50min/day, 2 times/wk; RMT: 40min/day, 3 times/wk). Primary outcomes were HRQoL (EuroQol-5D questionnaire) and exercise tolerance (cardiopulmonary exercise test). Secondary outcomes were physical function: respiratory muscle function (inspiratory/expiratory muscle strength and inspiratory muscle endurance), lower and upper limb strength (1-min Sit-to-Stand and handgrip force); lung function: spirometry testing and lung diffusing capacity; and psychological status (anxiety/depressive levels).

RESULTS

Postintervention, there were no statistically significant improvements in HRQoL or exercise tolerance in the AE+RMT compared with the AE+RMTsham group. In the AE+RMT group, large improvements in respiratory muscle function (d = 0.7 to 1.3) and low-moderate improvements in peak expiratory flow (d = 0.4) occurred compared with the AE+RMTsham group. Lung function outcomes, lower and upper limb strength and psychological status did not increase more in the AE+RMT group than in the AE+RMTsham group.

CONCLUSION

For individuals with long-term post-COVID-19 symptoms, combining RMT with an AE training program resulted in improvements in respiratory muscle strength, inspiratory muscle endurance and peak expiratory flow; however, the differences between groups were not statistically significant for HRQoL, exercise tolerance, psychological distress, and lung diffusing capacity.

DATABASE REGISTRATION

United States Clinical Trials Registry (NCT05597774).

Effects of 5-Wk Repeated Sprint Training in Hypoxia on Global Inspiratory and Core Muscle Functions

Repeated-sprint training in hypoxia (RSH) has been shown to boost team-sport players' repeated-sprint ability (RSA). Whether players' global inspiratory muscle (IM) and core muscle (CM) functions would be altered concomitantly with RSH was not reported. This study was designed to compare the concomitant alternations in players' RSA and their IM and CM functions during a team-sport-specific intermittent exercise protocol (IEP) before and after the intervention. Twenty players were assigned into either RSH or control (CON) groups (n = 10 for each). RSH players participated in 5-wk RSH (15 sessions, 3 sets 5x5-s all-out treadmill sprints interspersed with 25-s passive recovery under the hypoxia of 13.5%) while CON players had no corresponding training. The changes in RSA between pre- and post-intervention, and the alterations in IM and CM functions that were revealed by maximum inspiratory mouth pressure (PImax) and sport-specific endurance plank test (SEPT) performance, respectively, between pre- and post-IEP and across pre- and post-intervention in the RSH group were compared with that of CON. Following the 5-wk RSH, players' RSA improved significantly (>6%, p < 0.05) while PImax and SEPT performance did not alter (P > 0.05). Nevertheless, PImax which declined markedly in pre-intervention IEP (pre-IEP 155.4 ± 22.7 vs post-IEP 140.6 ± 22.8 cmH2O, p < 0.05) was alleviated significantly in post-intervention IEP (152.2 ± 27.4 vs 152.6 ± 31.8, p > 0.05), while the concomitant declined SEPT performance in the pre-intervention IEP (155 ± 24.6 vs 98.1 ± 21.7 s, p < 0.05) was retained post intervention (170.7 ± 38.1 vs 100.5 ± 33.4, p < 0.05). For the CON, all variables were unchanged (p > 0.05). Such findings suggest that 5-wk RSH could enhance players' RSA but not global IM and CM functions. Nonetheless, the decline in PImax in pre-intervention IEP alleviated significantly post intervention led to a postulation that players' IM endurance, rather than strength, might improve with the 5-wk RSH regimen, while the possible improved IM endurance did not advance the fatigue resistance of CM.

The Effect of Inspiratory Muscle Training on Health-Related Fitness in College Students

In an era characterized by rapid economic growth and evolving lifestyles, college students encounter numerous challenges, encompassing academic pressures and professional competition. The respiratory muscle endurance capability is important for college students during prolonged aerobic exercise. Therefore, it is of great significance to explore an effective intervention to enhance the endurance level of college students. This study explores the transformative potential of inspiratory muscle training (IMT) to improve the physical functions of college students. This research comprised a group of 20 participants who underwent IMT integrated into their daily physical education classes or regular training sessions over an 8-week period, with 18 participants forming the control group. The IMT group adhered to the manufacturer's instructions for utilizing the PowerBreathe device. The findings indicated a significant positive effect on inspiratory muscle strength (p < 0.001), showing improvements in pulmonary function, exercise tolerance, cardiac function, and overall athletic performance. These results revealed the substantial benefits of IMT in enhancing physical fitness and promoting health maintenance among college students.

Combined effects of a Mediterranean diet and respiratory muscle training on higher education woodwind musicians: A randomized controlled trial

A two-factor within subjects and randomized controlled was conducted with three groups (two experimental and one control) to explore the effects of the Mediterranean diet and respiratory muscle training on ventilatory fatigue, stress, and emotional performance of woodwind musicians. 70 students from the Valencia Conservatory of Music were recruited and randomized into three groups: respiratory training group + nutrition program (RTG; n = 17), control group (CG; n = 35) and nutrition program group (NPG; n = 18). The nutritional program was based on Mediterranean a diet. Body composition, emotional intelligence, physiological stress and ventilatory response were assessed for all groups before and after intervention. Mixed ANOVA showed main effects of diet and training interventions on emotional attention (F = 8.042; p = 0.006), clarity (F = 9.306; p = 0.003), repair (F = 5.527; p = 0.022), Forced-Expiratory-Volume (F = 30.196; p < 0.000) and Forced-Vital-Capacity (F = 21.052; p < 0.000), with both interventions improving emotional intelligence and ventilatory variables. Bonferroni post-hoc analysis revealed significant differences of RTG and CG for emotional attention (MD = 4.60; p = 0.023), comprehension (MD = 5.734; p = 0.005), repair (MD = 8.576; p < 0.000), FEV1 (MD = 0.862; p = 0.005), and FCV (MD = 1.608; p < 0.001); with similar results when comparing NTG and CG: emotional attention (MD = 4.156; p = 0.041), comprehension (MD = 4.473; p = 0.033), repair (MD = 6.511; p = 0.001), Forced-Expiratory-Volume (MD = 1.608; p < 0.001), and Forced-Vital-Capacity (MD = 1.183; p < 0.001). No significant effects of experimental groups were observed for physiological stress variables (p > 0.05). This results suggests that respiratory training enhances emotional intelligence and lessens respiratory fatigue in musicians, and a combination of a Mediterranean diet and respiratory muscle training further boosts emotional intelligence, albeit with limited impact on physiological stress. This study represents a novel investigation into the approach by dietary interventions and respiratory muscle training in wind musicians since there are no studies that analyze it.

Cumulative Effects of Concurrent Inspiratory Muscle Training and Postural Correction Bands on Older Individuals Community Dwellers: A Randomized Study

PURPOSE

Posture correction bands (PCBs) have been proposed as aids to help chest expansion and to enhance respiratory function. However, the impact of PCBs on community-based older individuals engaged in inspiratory muscle training (IMT) at home remains unclear.

MATERIALS AND METHODS

Community-based individuals aged 65 years and older were divided into the PCB group, wearing PCBs, and the NPCB group, not wearing PCBs. The IMT regimen lasted 8 weeks, with sessions 5 times a week, including 4 sets per day and 15 repetitions per set. Training intensity was set at 50% of the maximum inspiratory pressure of each subject. To assess the effects of IMT, respiratory function, 6-minute walk test, and grip strength were measured before, during, and after the training period. Data were analyzed using repeated-measures analysis of variance, with post-hoc evaluation employing Bonferroni correction.

RESULTS

A total of 40 subjects were evenly divided into the PCB group and the NPCB group, with 20 subjects in each group. No significant difference was observed in respiratory muscle strength based on PCB use. However, during the initial 4 weeks, the PCB group exhibited a trend towards an increase in respiratory muscle strength compared to the NPCB group; this trend, however, did not prove to be statistically significant by the end of the 8-week period. Performance on the 6-minute walk test significantly improved in both groups.

CONCLUSION

The PCB group exhibited a tendency for increase in respiratory muscle strength in the first 4 weeks; however, ultimately there was no significant difference compared to the NPCB group.

CLINICAL TRIAL REGISTRATION

This study was registered with the Clinical Research Information Service, part of the World Health Organization's International Clinical Trials Registry Platform (Clinical Research Information Service No. KCT0008075).

Respiratory Muscle Training in Para-Athletes: A Systematic Review on the Training Protocols and Effects on Reported Outcomes

CONTEXT AND OBJECTIVES

Respiratory muscle training (RMT) is considered an effective tool to improve cardiorespiratory limitations in athletes. The goals of this systematic review were to explore the role of RMT and its implementation within sport rehabilitation programs in para-athletes.

EVIDENCE ACQUISITION

Several databases were searched until January 2024. Eligible studies were independently reviewed by 2 reviewers. Quality assessment was made using the PEDro scale and version 2 of the Cochrane Risk-of-Bias Tool for Randomized Trials. Eight studies (a total of 108 participants) were selected for the analysis.

EVIDENCE SYNTHESIS

Five studies preferred using resistive loading, while 2 studies used normocapnic hyperpnea, and 1 study used threshold inspiratory muscle training. Respiratory functions (respiratory muscle strength and endurance, spirometry measures) and exercise performance were assessed as the main outcomes. Significant increases in respiratory muscle strength were reported in 5 studies. Two studies observed improvement in respiratory muscle endurance and 3 studies reported increased exercise capacity.

CONCLUSIONS

This review suggests that although RMT can enhance respiratory muscle strength and endurance, it should not be considered the primary method for boosting the exercise performance of para-athletes. Additional research is necessary to explore the impact of various RMT techniques on different outcomes from the perspective of sport rehabilitation in para-athletes.

The influence of low resistance respiratory muscle training on pulmonary function and high intensity exercise performance

Background/objectives

Respiratory muscle training (RMT) was recognized as an effective means to improve respiratory muscle (RM) strength and enhance exercise performance. The purpose of this study was to examine the effect of low-intensity RMT on RM strength, pulmonary function, and performance.

Methods

Fourteen healthy active adults were assigned randomly to either a training or placebo group. The training group completed six weeks of RMT, which consisted of a first week, 1 set of 15 min/d, 5 d/wk at 10-25% of maximal inspiratory pressure (PImax), and the remaining 5 weeks, 2 sets of 15 min/d, 5 d/wk, at 30% PImax. The placebo group followed the same protocol but with almost no additional ventilatory resistance. Measurement of RM strength and endurance, spirometry, and endurance exercise performance were obtained before and after the RMT program.

Results

In the training group, PImax (+14%) and maximal expiratory pressure (PEmax, +27%), forced vital capacity (FVC, +3.6%), maximal oxygen uptake (VO2max, +11%), and time to exhaustion (Tlim90%, +25%) increased significantly from baseline values (P < 0.05). No significant changes were observed in the placebo group. Also, no significant interaction in maximum voluntary ventilation (MVV12), minute ventilation (VE), and respiratory rate (RR) were detected.

Conclusions

These data suggest that low-intensity RMT is an effective tool to improve RM strength, pulmonary elastic properties and endurance exercise performance.

Multi-Modal Prehabilitation in Thoracic Surgery: From Basic Concepts to Practical Modalities

Over the last two decades, the invasiveness of thoracic surgery has decreased along with technological advances and better diagnostic tools, whereas the patient's comorbidities and frailty patterns have increased, as well as the number of early cancer stages that could benefit from curative resection. Poor aerobic fitness, nutritional defects, sarcopenia and "toxic" behaviors such as sedentary behavior, smoking and alcohol consumption are modifiable risk factors for major postoperative complications. The process of enhancing patients' physiological reserve in anticipation for surgery is referred to as prehabilitation. Components of prehabilitation programs include optimization of medical treatment, prescription of structured exercise program, correction of nutritional deficits and patient's education to adopt healthier behaviors. All patients may benefit from prehabilitation, which is part of the enhanced recovery after surgery (ERAS) programs. Faster functional recovery is expected in low-risk patients, whereas better clinical outcome and shorter hospital stay have been demonstrated in higher risk and physically unfit patients.

Effects of High-Intensity Inspiratory Muscle Warm-Up on High-Intensity Exercise Performance and Muscle Oxygenation

PURPOSE

An inspiratory muscle warm-up (IMW) improves inspiratory muscle function, but the effects of high-intensity exercise are inconsistent. We aimed to determine the effects of high-intensity IMW on high-intensity exercise performance and muscle oxygenation.

METHODS

Ten healthy men (maximal oxygen uptake [V˙O2max] 52.2 [5.0] mL·kg-1·min-1) performed constant-load exercise to exhaustion on a cycle ergometer at V˙O2max under 2 IMW conditions: a placebo condition (PLA) and a high-intensity IMW condition (HIGH). The inspiratory loads were set at 15% and 80% of maximal inspiratory pressure, respectively. Maximal inspiratory pressure was measured before and after IMW. Oxyhemoglobin was measured in the vastus lateralis by near-infrared spectroscopy during exercise. Rating of perceived exertion (RPE) for a leg was measured after 1 and 2 minutes of exercise.

RESULTS

Exercise tolerance was significantly higher under HIGH than PLA (228 [49] s vs 218 [49] s, P = .003). Maximal inspiratory pressure was significantly increased by IMW under HIGH (from 125 [20] to 136 [25] cm H2O, P = .031). Oxyhemoglobin was significantly higher under HIGH than PLA at 80% of the total duration of exercise (P = .048). RPE for the leg was significantly lower under HIGH than PLA after 2 minutes of exercise (P = .019).

CONCLUSIONS

Given that oxyhemoglobin is an index of local oxygen supply, the results of this study suggest that high-intensity IMW increases the oxygen supply to active limbs. It may also reflect a reduction in RPE in the leg. In addition, high-intensity IMW may improve exercise performance.

A preliminary exploration of the regression equation for performance in amateur half-marathon runners: a perspective based on respiratory muscle function

This document presents a study on the relationship between physical characteristics, respiratory muscle capacity, and performance in amateur half-marathon runners. The aim of this study was to establish a preliminary predictive model to provide insights into training and health management for runners. Participants were recruited from the 2023 Beijing Olympic Forest Park Half-Marathon, comprising 233 individuals. Personal information including age, gender, height, weight, and other relevant factors were collected, and standardized testing methods were used to measure various parameters. Correlation analysis revealed significant associations between gender, height, weight, maximum expiratory pressure, maximal inspiratory pressure, and half-marathon performance. Several regression equations were developed to estimate the performance of amateur marathon runners, with a focus on gender, weight, maximum expiratory pressure, and height as predictive factors. The study found that respiratory muscle training can delay muscle fatigue and improve athletic performance. Evaluating the level of respiratory muscle capacity in marathon athletes is crucial for defining the potential speed limitations and achieving optimal performance. The information from this study can assist amateur runners in optimizing their training methods and maintaining their physical wellbeing.

Effects of Respiratory Muscle Training on Exercise Capacity, Quality of Life, and Respiratory and Pulmonary Function in People With Ischemic Heart Disease: Systematic Review and Meta-Analysis

OBJECTIVE

This systematic review and meta-analysis aimed to evaluate the effects of respiratory muscle training (RMT) on functional exercise capacity, health-related quality of life (HRQoL), respiratory muscle function, and pulmonary function in individuals with ischemic heart disease (IHD).

METHODS

The MEDLINE, Web of Science, Scopus, PEDro, CINAHL, Science Direct, and CENTRAL electronic databases were searched in January 2023. Randomized controlled trials published in English, Spanish, or Portuguese that were conducted to determine the effect of RMT versus passive control and/or sham RMT on the target variables in individuals with IHD, irrespective of age or sex were included. Two reviewers performed the searches and extraction of the most relevant data. The quality and risk of bias for each included study were examined with the PEDro scale and Cochrane risk-of-bias tool.

RESULTS

Thirteen studies (849 participants) were included. The meta-analysis showed a significant increase in peak oxygen consumption (mean difference [MD] = 2.18 mL·kg-1·min-1 [95% CI = 0.54 to 3.83]), inspiratory muscle strength (MD = 16.62 cm H2O [95% CI = 12.48 to 20.77]), inspiratory muscle endurance (standardized mean difference = 0.39 [95% CI = 0.19 to 0.60]), and expiratory muscle strength (MD = 14.52 cm H2O [95% CI = 5.51 to 23.53]). There were no benefits in 6-minute walking distance (MD = 37.57 m [95% CI = -36.34 to 111.48]), HRQoL (standardized mean difference = 0.22 [95% CI = -0.16 to 0.60]), pulmonary function (forced vital capacity; MD = 2.07% of predicted value [95% CI = -0.90 to 5.03], or forced expiratory volume at the first second (MD = -0.75% of predicted value [95% CI = -5.45 to 3.95]).

CONCLUSION

This meta-analysis provided high- and moderate-quality evidence that inspiratory muscle training (IMT) improves inspiratory muscle strength and endurance, respectively; and very low-quality evidence for effects on peak oxygen consumption and expiratory muscle strength in individuals with IHD. No superior effects were found in the 6-minute walking test, HRQoL, or pulmonary function compared with the control group.

IMPACT

The results shown in this systematic review with meta-analysis will provide clinicians a better understanding of the effects of IMT in people with IHD. IMT could be integrated into the cardiac rehabilitation management, although more research is needed.

Effects of low workload respiratory training with steam inhalation on lung function in stable asthma: A controlled clinical study

To investigate effects of low workload respiratory muscle training (RMT) on respiratory muscle power and lung function in asthmatics, we recruited asthmatic persons who performed a 4-week training programme. The training included 20 daily ex- and inhalations with counter pressure 30% from the individual maximal expiratory pressure (MEP). Lung function was measured before and after the training programme and a follow-up period. The study also included several subjective endpoints for respiratory symptoms. A significant increase in a training group (n = 27) compared with a control group (n = 20) was seen in MEP (+12.4%, vs. +3.5%, p = 0.086), maximal inspiratory pressure (MIP) (+21.1% vs. +0.82%, p = 0.023), slow vital capacity (VC) (+3.7% vs. +1.5%, p = 0.023) and in forced expiratory time (FET, +15.5%, vs. -5.0%, p = 0.022). After being a control for group A, also group B performed similar RMT as group A. In the combined group (A and B, n = 47) MEP (11.3%, p = 0.003), MIP (19.73%, p < 0.001), VC (4.1%, p < 0.001) and FET (14.7%, p < 0.001) increased significantly from the baseline. Changes in other lung function variables were not indicative. On a scale of 1-5, the subjects perceived improvement in reduction of mucus secretion in the airways (median 3, p < 0.001), alleviation of coughing (median 3, p < 0.001) and reduction in dyspnoea (median 3, p < 0.001). As a conclusion, low workload respiratory training of 4 weeks improved respiratory muscle power and increased VC in patients with stable asthma.

Insights into the Serum Metabolic Adaptations in Response to Inspiratory Muscle Training: A Metabolomic Approach Based on 1H NMR and UHPLC-HRMS/MS

Inspiratory muscle training (IMT) is known to promote physiological benefits and improve physical performance in endurance sports activities. However, the metabolic adaptations promoted by different IMT prescribing strategies remain unclear. In this work, a longitudinal, randomized, double-blind, sham-controlled, parallel trial was performed to investigate the effects of 11 weeks (3 days·week-1) of IMT at different exercise intensities on the serum metabolomics profile and its main regulated metabolic pathways. Twenty-eight healthy male recreational cyclists (30.4 ± 6.5 years) were randomized into three groups: sham (6 cm·H2O of inspiratory pressure, n = 7), moderate-intensity (MI group, 60% maximal inspiratory pressure (MIP), n = 11) and high-intensity (HI group, 85-90% MIP, n = 10). Blood serum samples were collected before and after 11 weeks of IMT and analyzed by 1H NMR and UHPLC-HRMS/MS. Data were analyzed using linear mixed models and metabolite set enrichment analysis. The 1H NMR and UHPLC-HRMS/MS techniques resulted in 46 and 200 compounds, respectively. These results showed that ketone body metabolism, fatty acid biosynthesis, and aminoacyl-tRNA biosynthesis were upregulated after IMT, while alpha linolenic acid and linoleic acid metabolism as well as biosynthesis of unsaturated fatty acids were downregulated. The MI group presented higher MIP, Tryptophan, and Valine levels but decreased 2-Hydroxybutyrate levels when compared to the other two studied groups. These results suggest an increase in the oxidative metabolic processes after IMT at different intensities with additional evidence for the upregulation of essential amino acid metabolism in the MI group accompanied by greater improvement in respiratory muscle strength.

The therapeutic role of inspiratory muscle training in the management of asthma: a narrative review

Asthma is a disorder of the airways characterized by chronic airway inflammation, hyperresponsiveness, and variable recurring airway obstruction. Treatment options for asthma include pharmacological strategies, whereas nonpharmacological strategies are limited. Established pharmacological approaches to treating asthma may cause unwanted side effects and do not always afford adequate protection against asthma, possibly because of an individual's variable response to medications. A potential nonpharmacological intervention that is most available and cost effective is inspiratory muscle training (IMT), which is a technique targeted at increasing the strength and endurance of the diaphragm and accessory muscles of inspiration. Studies examining the impact of IMT on asthma have reported increases in inspiratory muscle strength and a reduction in the perception of dyspnea and medication use. However, because of the limited number of studies and discordant methods between studies more evidence is required to elucidate in individuals with asthma the efficacy of IMT on inspiratory muscle endurance, exercise capacity, asthma control, symptoms, and quality of life as well as in adolescents with differing severities of asthma. Large randomized controlled trials would be a significant step forward in clarifying the effectiveness of IMT in individuals with asthma. Although IMT may have favorable effects on inspiratory muscle strength, dyspnea, and medication use, the current evidence that IMT is an effective treatment for asthma is inconclusive.

Respiratory muscle training induces additional stress and training load in well-trained triathletes-randomized controlled trial

Background: Respiratory muscle training (RMT) has been investigated in the context of improved athletic performance and pulmonary function. However, psychophysiological costs of RMT remain understudied. Voluntary isocapnic hyperpnoea (VIH) and inspiratory pressure threshold loading (IPTL) are widely applied RMT methods. The main purposes of this study were to assess whether RMT induces additional load on well-trained triathletes and determine differences in RMT-induced load between sexes and applied methods. Materials and Methods: 16 well-trained triathletes (n = 16, 56% males) underwent 6 weeks of VIH or IPTL program with progressive overload. Blood markers, subjective measures, cardiac indices, near-infrared spectroscopy indices, inspiratory muscle fatigue, and RMT-induced training load were monitored pre-, in and post-sessions. We used multiple ANOVA to investigate effects of sex, training method, and time on measured parameters. Results: There were significant interactions for acid-base balance (p = 0.04 for sex, p < 0.001 for method), partial carbon dioxide pressure (p = 0.03 for sex, p < 0.001 for method), bicarbonate (p = 0.01 for method), lactate (p < 0.001 for method), RMT-induced training load (p = 0.001 for method for single session, p = 0.03 for method per week), average heart rate (p = 0.03 for sex), maximum heart rate (p = 0.02 for sex), intercostales muscle oxygenation (p = 0.007 for testing week), and intercostales muscle oxygenation recovery (p = 0.003 for testing week and p = 0.007 for method). Conclusion: We found that RMT induced additional load in well-trained triathletes. Elicited changes in monitored variables depend on sex and training method. VIH significantly increased subjective training load measures. IPTL was associated with disbalance in blood gasometry, increase in lactate, and reports of headaches and dizziness. Both methods should be applied with consideration in high-performance settings.

Effects of high-intensity inspiratory muscle warm-up on inspiratory muscle strength and accessory inspiratory muscle activity

This study aimed to determine the effects of work-matched moderate-intensity and high-intensity inspiratory muscle warm-up (IMW) on inspiratory muscle strength and accessory inspiratory muscle activity. Eleven healthy men performed three IMWs at different intensities, namely, placebo, moderate-intensity, and high-intensity, set, respectively, at 15%, 40%, and 80% of maximal inspiratory mouth pressure (MIP). MIP was measured before and after IMW. Electromyography (EMG) was recorded for the sternocleidomastoid muscle (SCM) and intercostal muscles (IC) during IMW. MIP increased significantly in the moderate-intensity condition (104.2 ± 5.1%, p<0.05) and high-intensity condition (106.5 ± 6.2%, p<0.01) after IMW. The EMG amplitudes of the SCM and IC during IMW were significantly higher in the order of high-intensity, moderate-intensity, and placebo conditions. There was a significant correlation between changes in MIP and EMG amplitude of the SCM (r=0.60, p<0.01) and IC (r=0.47, p<0.01) during IMW. These findings suggest that high-intensity IMW increases neuromuscular activity in the accessory inspiratory muscles, which may improve inspiratory muscle strength.

Evaluation and Management of Dyspnea in Hypermobile Ehlers-Danlos Syndrome and Generalized Hypermobility Spectrum Disorder: Protocol for a Pilot and Feasibility Randomized Controlled Trial

BACKGROUND

Dyspnea is a prevalent symptom in individuals with hypermobile Ehlers-Danlos Syndrome (hEDS) and generalized hypermobility spectrum disorder (G-HSD), yet its contributors have not been identified. One known contributor to dyspnea is respiratory muscle weakness. The feasibility and effectiveness of inspiratory muscle training (IMT) in combination with standard-of-care rehabilitation (aerobic, resistance, neuromuscular stabilization, and balance and proprioception exercises) in improving respiratory muscle strength and patient-reported outcomes in patients with hEDS or G-HSD have not been evaluated.

OBJECTIVE

This study aims to evaluate dyspnea, respiratory muscle strength, and patient-reported outcome measures (PROMs) in hEDS or G-HSD compared with healthy controls and to assess the feasibility of a randomized controlled trial of IMT and standard-of-care rehabilitation for improving respiratory muscle strength, exercise capacity, and PROMs compared with standard-of-care rehabilitation in hEDS and G-HSD.

METHODS

The study will include 34 participants with hEDS or G-HSD and 17 healthy, age- and sex-matched controls to compare respiratory muscle structure and function and PROMs. After baseline assessments, participants with hEDS or G-HSD will be randomized into the intervention group and provided IMT combined with Ehlers-Danlos Syndrome standard-of-care rehabilitation or into the usual care group, and provided only standard-of-care rehabilitation for 8 weeks. The intervention group will be prescribed IMT in their home environment using the POWERbreathe K5 IMT device (POWERbreathe International Ltd). IMT will comprise 2 daily sessions of 30 breaths for 5 days per week, with IMT progressing from 20% to 60% of the baseline maximal inspiratory pressure (MIP) over an 8-week period. Feasibility will be assessed through rates of recruitment, attrition, adherence, adverse events, and participant satisfaction. The primary pilot outcome is MIP change over an 8-week period in hEDS or G-HSD. Secondary outcomes will include the evaluation of dyspnea using Medical Research Council Scale and 18-point qualitative dyspnea descriptors; diaphragmatic thickening fraction using ultrasound; respiratory muscle endurance; pulmonary function; prefrontal cortical activity using functional near-infrared spectroscopy; aerobic capacity during cardiopulmonary exercise testing; quality of life using Short Form-36; and scores from the Depression, Anxiety, and Stress scale-21. These measures will also be performed once in healthy controls to compare normative values. Multivariable regression will be used to assess the contributors to dyspnea. Paired 2-tailed t tests will be used to assess the changes in MIP and secondary measures after 8 weeks of IMT.

RESULTS

Study recruitment began in August 2021 and, with several disruptions owing to COVID-19, is expected to be completed by December 2023.

CONCLUSIONS

This study will provide a better understanding of the factors associated with dyspnea and the feasibility and effectiveness of IMT combined with standard-of-care rehabilitation. IMT may be a novel therapeutic strategy for improving respiratory muscle function and patient-reported outcomes in individuals with hEDS or G-HSD.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04972565; https://clinicaltrials.gov/ct2/show/NCT04972565.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/44832.

The Effects of Respiratory Muscle Training on Resting-State Brain Activity and Thoracic Mobility in Healthy Subjects: A Randomized Controlled Trial

BACKGROUND

Although inspiratory muscle training (IMT) is an effective intervention for improving breath perception, brain mechanisms have not been studied yet.

PURPOSE

To examine the effects of IMT on insula and default mode network (DMN) using resting-state functional MRI (RS-fMRI).

STUDY TYPE

Prospective.

POPULATION

A total of 26 healthy participants were randomly assigned to two groups as IMT group (n = 14) and sham IMT groups (n = 12).

FIELD STRENGTH/SEQUENCE

A 3-T, three-dimensional T2* gradient-echo echo planar imaging sequence for RS-fMRI was obtained.

ASSESSMENT

The intervention group received IMT at 60% and sham group received at 15% of maximal inspiratory pressure (MIP) for 8 weeks. Pulmonary and respiratory muscle function, and breathing patterns were measured. Groups underwent RS-fMRI before and after the treatment.

STATISTICAL TESTS

Statistical tests were two-tailed P < 0.05 was considered statistically significant. Student's t test was used to compare the groups. One-sample t-test for each group was used to reveal pattern of functional connectivity. A statistical threshold of P < 0.001 uncorrected value was set at voxel level. We used False discovery rate (FDR)-corrected P < 0.05 cluster level.

RESULTS

The IMT group showed more prominent alterations in insula and DMN connectivity than sham group. The MIP was significantly different after IMT. Respiratory rate (P = 0.344), inspiratory time (P = 0.222), expiratory time (P = 1.000), and inspiratory time/total breath time (P = 0.572) of respiratory patterns showed no significant change after IMT. All DMN components showed decreased, while insula showed increased activation significantly.

DATA CONCLUSION

Differences in brain activity and connectivity may reflect improved ventilatory perception with IMT with a possible role in regulating breathing pattern by processing interoceptive signals.

EVIDENCE LEVEL

2 TECHNICAL EFFICACY: Stage 4.

Home-based respiratory muscle training on quality of life and exercise tolerance in long-term post-COVID-19: Randomized controlled trial

OBJECTIVE

To evaluate the effects of a home-based respiratory muscle training programme (inspiratory [IMT] or inspiratory/expiratory muscles [RMT]) supervised by telerehabilitation on quality of life and exercise tolerance in individuals with long-term post-COVID-19 symptoms. The secondary objective was to evaluate the effects of these programmes on respiratory muscle function, physical and lung function, and psychological state.

METHODS

88 individuals with long-term symptoms of fatigue and dyspnoea after COVID-19 diagnosis were randomly (1:1 ratio) assigned to IMT, IMT_sham, RMT or RMT_sham groups for an 8-week intervention (40min/day, 6 times/week). Primary outcomes were quality of life (EuroQol-5D questionnaire) and exercise tolerance (Ruffier test). Secondary outcomes were respiratory muscle function (inspiratory/expiratory muscle strength; inspiratory muscle endurance), physical function (lower and upper limb strength [1-min Sit-to-Stand and handgrip force]), lung function (forced spirometry), and psychological status (anxiety/depression levels and post-traumatic stress disorder). All outcomes were measured pre-, intermediate- (4^th week), and post-intervention.

RESULTS

At post-intervention, there was a statistically significant and large (d>0.90) improvement in quality of life, but not in exercise tolerance, in the RMT group compared with the RMT_sham group. Both of the real training groups produced a statistically significant and large increase in inspiratory muscle strength and endurance (d≥0.80) and in lower limb muscle strength (d≥0.77) compared with the 2 sham groups. Expiratory muscle strength and peak expiratory flow showed a statistically significant and large (d≥0.87) increase in the RMT group compared with the other 3 groups.

CONCLUSION

Only an 8-week supervised home-based RMT programme was effective in improving quality of life, but not exercise tolerance, in individuals with long-term post-COVID-19 symptoms. In addition, IMT and RMT programmes were effective in improving respiratory muscle function and lower limb muscle strength, but had no impact on lung function and psychological status.

Effects of Inspiratory Muscle Training on Muscle Oxygenation during Vascular Occlusion Testing in Trained Healthy Adult Males

Inspiratory muscle training (IMT) may have an additional effect on cardiovascular autonomic modulation, which could improve the metabolism and vascular function of the muscles.

AIM

To determine the effects of IMT on vascular and metabolic muscle changes and their relationship to changes in physical performance.

METHODS

Physically active men were randomly placed into an experimental (IMTG; n = 8) or IMT placebo group (IMTPG; n = 6). For IMT, resistance load was set at 50% and 15% of the maximum dynamic inspiratory strength (S-Index), respectively. Only the IMTG's weekly load was increased by 5%. In addition, both groups carried out the same concurrent training. Besides the S-Index, a 1.5-mile running test, spirometry, and deoxyhemoglobin (HHb_AUC during occlusion) and reperfusion tissue saturation index (TSI_MB and TSI_MP: time from minimum to baseline and to peak, respectively) in a vascular occlusion test were measured before and after the 4-week training program. In addition, resting heart rate and blood pressure were registered.

RESULTS

IMTG improved compared to IMTPG in the S-Index (Δ = 28.23 ± 26.6 cmH₂O), maximal inspiratory flow (MIF: Δ = 0.91 ± 0.6 L/s), maximum oxygen uptake (Δ = 4.48 ± 1.1 mL/kg/min), 1.5-mile run time (Δ = -0.81 ± 0.2 s), TSI_MB (Δ = -3.38 ± 3.1 s) and TSI_MP (Δ = -5.88 ± 3.7 s) with p < 0.05. ΔVO_2max correlated with S-Index (r = 0.619) and MIF (r = 0.583) with p < 0.05. Both ΔTSI_MB and TSI_MP correlated with ΔHHb_AUC (r = 0.516 and 0.596, respectively) and with Δ1.5-mile run time (r = 0.669 and 0.686, respectively) with p < 0.05.

CONCLUSION

IMT improves vascular function, which is related to additional improvements in physical performance.

Physiological impact of load carriage exercise: Current understanding and future research directions

Load carriage (LC) refers to the use of personal protective equipment (PPE) and/or load-bearing apparatus that is mostly worn over the thoracic cavity. A commonplace task across various physically demanding occupational groups, the mass being carried during LC duties can approach the wearer's body mass. When compared to unloaded exercise, LC imposes additional physiological stress that negatively impacts the respiratory system by restricting chest wall movement and altering ventilatory mechanics as well as circulatory responses. Consequently, LC activities accelerate the development of fatigue in the respiratory muscles and reduce exercise performance in occupational tasks. Therefore, understanding the implications of LC and the effects specific factors have on physiological capacities during LC activity are important to the implementation of effective mitigation strategies to ameliorate the detrimental effects of thoracic LC. Accordingly, this review highlights the current physiological understanding of LC activities and outlines the knowledge and efficacy of current interventions and research that have attempted to improve LC performance, whilst also highlighting pertinent knowledge gaps that must be explored via future research activities.

Acute psychophysiological responses during exercise while using resistive respiratory devices: A systematic review

Different studies have observed that respiratory muscle training (RMT) improve the endurance and strength of the respiratory muscles, having a positive impact on performance of endurance sports. Nevertheless, it remains to be clarified how to improve the efficiency of such training. The objective of this systematic review was to evaluate the acute physiological responses produced by training the respiratory muscles during exercise with flow resistive devices because such information may support us improve the efficiency of this type of training. A search in the Medline, Science Direct, Web of Science and Scopus databases was conducted, following the PRISMA guidelines. The methodological quality of the articles was assessed using the PEDro scale. Nineteen studies met the inclusion criteria and a total of 212 subjects were included in the studies. The RMT method used in all studies was flow resistive loading, whereas the constant load exercise was the most common type of exercise among the studies. The results obtained seem to indicate that the use of this type of training during exercise reduces the performance, the lactate (La^-) values and the ventilation, whereas the end - tidal partial pressure of carbon dioxide (P_CO2) is increased.

Breath Tools: A Synthesis of Evidence-Based Breathing Strategies to Enhance Human Running

Running is among the most popular sporting hobbies and often chosen specifically for intrinsic psychological benefits. However, up to 40% of runners may experience exercise-induced dyspnoea as a result of cascading physiological phenomena, possibly causing negative psychological states or barriers to participation. Breathing techniques such as slow, deep breathing have proven benefits at rest, but it is unclear if they can be used during exercise to address respiratory limitations or improve performance. While direct experimental evidence is limited, diverse findings from exercise physiology and sports science combined with anecdotal knowledge from Yoga, meditation, and breathwork suggest that many aspects of breathing could be improved via purposeful strategies. Hence, we sought to synthesize these disparate sources to create a new theoretical framework called “Breath Tools” proposing breathing strategies for use during running to improve tolerance, performance, and lower barriers to long-term enjoyment.

Effect of Two Different Rehabilitation Approaches on Pulmonary Functional Tests, Neuromuscular Functions and Quality of Life in Juvenile Myasthenia Gravis: A Randomized Controlled Trial Study

Background and Objectives: Children with juvenile myasthenia gravis have a variety of symptoms, ranging from isolated intermittent ocular complaints to overall muscle weakness with or without respiratory insufficiency. This study aimed to investigate the efficacy of a specialized physical therapy with or without partial body weight supported treadmill training on pulmonary functional tests, neuromuscular functions, and quality of life. Materials and Methods: Thirty children, ranging in age from 13 to 16 years, were distributed randomly into two study groups (A or B). Both groups underwent a designed physical therapy program. In addition, group A underwent the partial body weight supported treadmill training. The treatment was conducted three times a week for 12 weeks successively. Pulmonary functional tests (FVC, FEV1, PEFR, and MVV), neuromuscular function tests (compound motor action potential, isometric muscle force of biceps brachii and rectus femoris, balance, walking endurance, and fatigue), and quality of life were measured before and after 12 successive weeks. Results: A significant improvement in all investigated variables were recorded in both groups in favor of group A. Conclusions: Both a specialized physical therapy and partial body weight supported treadmill training are effective in terms of enhancing pulmonary functional tests, neuromuscular functions, and quality of life. Partial body weight supported treadmill training is an excellent adjunctive to the physical therapy program.

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.

Respiratory muscle training improves exercise tolerance and respiratory muscle function/structure post-stroke at short term: A systematic review and meta-analysis

BACKGROUND

Previous reviews relating to the effects of respiratory muscle training (RMT) after stroke tend to focus on only one type of training (inspiratory or expiratory muscles) and most based the results on poor-quality studies (PEDro score ≤4).

OBJECTIVES

With this systematic review and meta-analysis, we aimed to determine the effects of RMT (inspiratory or expiratory muscle training, or mixed) on exercise tolerance, respiratory muscle function and pulmonary function and also the effects depending on the type of training performed at short- and medium-term in post-stroke.

METHODS

Databases searched were MEDLINE, PEDro, CINAHL, EMBASE and Web of Science up to the end of April 2020. The quality and risk of bias for each included study was examined by the PEDro scale (including only high-quality studies) and Cochrane Risk of Bias tool.

RESULTS

Nine studies (463 patients) were included. The meta-analysis showed a significant increase in exercise tolerance [4 studies; n = 111; standardized mean difference [SMD] = 0.65 (95% confidence interval 0.27-1.04)]; inspiratory muscle strength [9 studies; n = 344; SMD = 0.65 (0.17-1.13)]; inspiratory muscle endurance [3 studies; n = 81; SMD = 1.19 (0.71-1.66)]; diaphragm thickness [3 studies; n = 79; SMD = 0.9 (0.43-1.37)]; and peak expiratory flow [3 studies; n = 84; SMD = 0.55 (0.03-1.08)] in the short-term. There were no benefits on expiratory muscle strength and pulmonary function variables (forced expiratory volume in 1 s) in the short-term.

CONCLUSIONS

The meta-analysis provided moderate-quality evidence that RMT improves exercise tolerance, diaphragm thickness and pulmonary function (i.e., peak expiratory flow) and low-quality evidence for the effects on inspiratory muscle strength and endurance in stroke survivors in the short-term. None of these effects are retained in the medium-term. Combined inspiratory and expiratory muscle training seems to promote greater respiratory changes than inspiratory muscle training alone.

Sex-Specific Effects of Respiratory Muscle Endurance Training on Cycling Time Trial Performance in Normoxia and Hypoxia

Objectives: We tested the hypotheses that respiratory muscle endurance training (RMET) improves endurance cycling performance differently in women and men and more so in hypoxia than in normoxia. Design: A prospective pre-post cross-over study with two testing conditions. Methods: Healthy and active women (seven, 24 ± 4 years, mean ± standard deviation [SD]) and men (seven, 27 ± 5 years) performed incremental cycling to determine maximum oxygen consumption (VO_2peak) and power output (W_peak) and on different days two 10-km cycling time trials (TTs) in normoxia and normobaric hypoxia (FiO₂, 0.135, ~3,500 m equivalent), in a balanced randomized order. Next they performed supervised RMET in normoxia (4 weeks, 5 days/week, 30 min/day eucapnic hyperpnea at ~60% predicted maximum voluntary ventilation) followed by identical post-tests. During TTs, heart rate, ear oximetry reading, and W_peak were recorded. Results: The VO_2peak and W_peak values were unchanged after RMET. The TT was improved by 7 ± 6% (p < 0.001) in normoxia and 16 ± 6% (p < 0.001) in hypoxia. The difference between normoxic and hypoxic TT was smaller after RMET as compared with that before RMET (14% vs. 21%, respectively, p < 0.001). All effects were greater in women (p < 0.001). The RMET did not change the heart rate or ear oximetry reading during TTs. Conclusion: We found a greater effect of RMET on cycling TT performance in women than in men, an effect more pronounced in hypoxia. These findings are congruent with the contention of a more pronounced performance-limiting role of the respiratory system during endurance exercise in hypoxia compared with normoxia and more so in women whose respiratory system is undersized compared with that of men.

Inspiratory Muscle Training Program Using the PowerBreath®: Does It Have Ergogenic Potential for Respiratory and/or Athletic Performance? A Systematic Review with Meta-Analysis

This systematic review and meta-analysis aim to provide scientific evidence regarding the effects of training on respiratory muscle training’s impact with the PowerBreath^®. A systematic analysis based on the PRISMA guides and a conducted research structured around the bases of Web of Science, Scopus, Medline/PubMed, SciELO y Cochrane Library Plus. Six articles published before January 2021 were included. The documentation and quantification of heterogeneity in every meta-analysis were directed through Cochran’s Q test and the statistic I²; additionally, a biased publication analysis was made using funnel plots, whose asymmetry was quantified Egger’s regression. The methodological quality was assessed through McMaster’s. PowerBreath^® administering a ≥ 15% resistive load of the maximum inspiratory pressure (PIM) achieves significant improvements (54%) in said pressure within 4 weeks of commencing the inspiratory muscle training. The maximal volume of oxygen (VO₂max) considerable enhancements was achieved from the 6 weeks associated with the maximum inspiratory pressure ≥ 21.5% post inspiratory muscle training onwards. Conversely, a significant blood lactate concentration decrement occurred from the 4th week of inspiratory muscle training, after a maximum inspiratory pressure ≥ 6.8% increment. PowerBreath^® is a useful device to stimulate sport performance and increase pulmonary function.

Impact of two different pulmonary rehabilitation methods in children with down syndrome

PURPOSE

To investigate and compare the effect of proprioceptive neuromuscular facilitation of respiratory muscles with that of inspiratory muscle training as a preventive measure on respiratory muscle strength, chest expansion, spirometry, and functional capacity in children with Down syndrome.

METHODS

Forty-five Down syndrome participants with an age ranged from 10 to 13 years were enrolled. There were distributed into three groups. The study group A (n = 15) underwent proprioceptive neuromuscular facilitation of respiratory muscles while study group B (n = 15) underwent inspiratory muscle training. Third group C (n = 15) was a control group. The three groups received aerobic exercises using the bicycle ergometer for 20 min, 5 times/week for 12 successive weeks. The treatment program for both study groups was conducted for 20-30 min, 5 times/week for 12 successive weeks. Measurements of respiratory muscle strength (MIP, MEP), chest expansion, spirometry test (VC, FEV1, PEFR, MVV) and 6 min walk test were measured pre and post treatment.

RESULTS

The post treatment mean values of all investigated variables were significantly increased in both study groups with higher effect to group underwent proprioceptive neuromuscular facilitation of respiratory muscles.

CONCLUSION

Both proprioceptive neuromuscular facilitation of respiratory muscles and inspiratory muscle training are effective in children with Down syndrome on improving respiratory muscle strength, chest expansion, spirometry and functional capacity with superior effect of proprioceptive neuromuscular facilitation.

Effects of a Rehabilitation Programme Using a Nasal Inspiratory Restriction Device in COPD

Chronic obstructive pulmonary disease (COPD) patients are characterised for presenting dyspnea, which reduces their physical capacity and tolerance to physical exercise. The aim of this study was to analyse the effects of adding a Feel-Breathe (FB) device for inspiratory muscle training (IMT) to an 8-week pulmonary rehabilitation programme. Twenty patients were randomised into three groups: breathing with FB (FBG), oronasal breathing without FB (ONBG) and control group (CG). FBG and ONBG carried out the same training programme with resistance, strength and respiratory exercises for 8 weeks. CG did not perform any pulmonary rehabilitation programme. Regarding intra group differences in the value obtained in the post-training test at the time when the maximum value in the pre-training test was obtained (Post_PRE), FBG obtained lower values in oxygen consumption (VO₂, mean = -435.6 mL/min, Bayes Factor (BF₁₀) > 100), minute ventilation (VE, -8.5 L/min, BF₁₀ = 25), respiratory rate (RR, -3.3 breaths/min, BF₁₀ = 2), heart rate (HR, -13.7 beats/min, BF₁₀ > 100) and carbon dioxide production (VCO₂, -183.0 L/min, BF₁₀ = 50), and a greater value in expiratory time (Tex, 0.22 s, BF₁₀ = 12.5). At the maximum value recorded in the post-training test (Post_FINAL), FBG showed higher values in the total time of the test (T_t, 4.3 min, BF₁₀ = 50) and respiratory exchange rate (RER, 0.05, BF₁₀ = 1.3). Regarding inter group differences at Pre_POST, FBG obtained a greater negative increment than ONBG in the ventilatory equivalent of CO₂ (EqCO₂, -3.8 L/min, BF₁₀ = 1.1) and compared to CG in VE (-8.3 L/min, BF₁₀ = 3.6), VCO₂ (-215.9 L/min, BF₁₀ = 3.0), EqCO2 (-3.7 L/min, BF₁₀ = 1.1) and HR (-12.9 beats/min, BF₁₀ = 3.4). FBG also showed a greater Pre_POST positive increment in Tex (0.21 s, BF₁₀ = 1.4) with respect to CG. At Pre_FINAL, FBG presented a greater positive increment compared to CG in T_t (4.4 min, BF₁₀ = 3.2) and negative in VE/VCO₂ intercept (-4.7, BF₁₀ = 1.1). The use of FB added to a pulmonary rehabilitation programme in COPD patients could improve tolerance in the incremental exercise test and energy efficiency. However, there is only a statically significant difference between FBG and ONBG in EqCO₂. Therefore, more studies are necessary to reach a definitive conclusion about including FB in a pulmonary rehabilitation programme.

Acute impairment in respiratory muscle strength following a high-volume versus low-volume resistance exercise session

BACKGROUND

Diminished respiratory muscle has been shown following a strenuous bout of sit-ups however there is a paucity of evidence for this effect following a strenuous upper and lower body resistance training session. This study investigated the acute effect of a highvolume compared to a low-volume resistance exercise session on respiratory muscle strength.

METHODS

Twenty resistance-trained males (age 25.1 ± 7.4 y) participated in this randomised and cross-over design study. Participants completed two resistance training protocols (highand low-volume) and a control session (no exercise). Sessions involved 5 sets (high-volume) and 2 sets (low-volume) of 10 repetitions at 65% one-repetition maximum for each exercise (bench press, squat, seated shoulder press, and deadlift) with 90 s recovery between sets. Maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) was assessed pre-and post-session and respiratory gases were measured during the recovery between sets.

RESULTS

Following the high-volume session MIP and MEP decreased by a median of 10.0% (interquartile range, IQR = -15.2 to -2.6%) and 12.1% (IQR = -22.2 to -3.9%), respectively, which was significant compared to the low-volume (p<0.001) and control sessions (p≤ 0.001). At 20-min post high-volume session MEP returned to baseline whereas MIP returned to baseline values at 40-min. Greater metabolic stress was associated with the higher-volume session as demonstrated by a lower recovery end-tidal CO2 partial pressure across the majority of exercises (p≤0.008).

CONCLUSIONS

Findings suggest that respiratory muscle strength is impaired following a highvolume session resistance exercise session, however it appears to be restored within an hour post-exercise.

Five-year outcome of respiratory muscle weakness at intensive care unit discharge: secondary analysis of a prospective cohort study

PURPOSE

To assess the association between respiratory muscle weakness (RMW) at intensive care unit (ICU) discharge and 5-year mortality and morbidity, independent from confounders including peripheral muscle strength.

METHODS

Secondary analysis of the prospective 5-year follow-up of the EPaNIC cohort (ClinicalTrials.gov: NCT00512122), limited to 366 patients screened for respiratory and peripheral muscle strength in the ICU with maximal inspiratory pressure (MIP) after removal of the artificial airway, and the Medical Research Council sum score. RMW was defined as an absolute value of MIP <30 cmH₂O. Associations between RMW at (or closest to) ICU discharge and all-cause 5-year mortality, and key measures of 5-year physical function, comprising respiratory muscle strength (MIP), hand-grip strength (HGF), 6 min walk distance (6MWD) and physical function of the SF-36 quality-of-life questionnaire (PF-SF-36), were assessed with Cox proportional hazards and linear regression models, adjusted for confounders including peripheral muscle strength.

RESULTS

RMW was present in 136/366 (37.2%) patients at ICU discharge. RMW was not independently associated with 5-year mortality (HR with 95% CI 1.273 (0.751 to 1.943), p=0.352). Among 156five-year survivors, those with, as compared with those without RMW demonstrated worse physical function (MIP (absolute value, cmH₂O): 62(42-77) vs 94(78-109), p<0.001; HGF (%pred): 67(44-87) vs 96(68-110), p<0.001; 6MWD (%pred): 87(74-102) vs 99 (80-111), p=0.009; PF-SF-36 (score): 55 (30-80) vs 80 (55-95), p<0.001). Associations between RMW and morbidity endpoints remained significant after adjustment for confounders (effect size with 95% CI: MIP: -23.858 (-32.097 to -15.027), p=0.001; HGF: -18.591 (-30.941 to -5.744), p=0.001; 6MWD (transformed): -1587.007 (-3073.763 to -179.253), p=0.034; PF-SF-36 (transformed): 1.176 (0.144-2.270), p=0.036).

CONCLUSIONS

RMW at ICU discharge is independently associated with 5-year morbidity but not 5-year mortality.

Chronic Effects of a Training Program Using a Nasal Inspiratory Restriction Device on Elite Cyclists

This study compared the response of a 9-week cycling training on ventilatory efficiency under two conditions: (i) Combined with respiratory muscle training (RMT) using a new nasal restriction device (FeelBreathe) (FB group) and (ii) without RMT (Control group). Eighteen healthy elite cyclists were randomly separated into the FB group (n = 10) or Control group (n = 8). Gas exchange was measured breath by breath to measure ventilatory efficiency during an incremental test on a cycloergometer before (Pre) and after (Post) the nine weeks of training. The FB group showed higher peak power (Δ (95%HDI) (0.82 W/kg (0.49, 1.17)), VO₂max (5.27 mL/kg/min (0.69, 10.83)) and VT₁ (29.3 W (1.8, 56.7)) compared to Control at Post_FINAL. The FB group showed lower values from Pre to Post_PRE in minute ventilation (VE) (−21.0 L/min (−29.7, −11.5)), Breathing frequency (BF) (−5.1 breaths/min (−9.4, −0.9)), carbon dioxide output (VCO₂) (−0.5 L/min (−0.7, −0.2)), respiratory equivalents for oxygen (EqO₂) (−0.8 L/min (−2.4, 0.8)), heart rate (HR) (−5.9 beats/min (−9.2, −2.5)), respiratory exchange ratio (RER) (−0.1 (−0.1, −0.0) and a higher value in inspiratory time (Tin) (0.05 s (0.00, 0.10)), expiratory time (Tex) (0.11 s (0.05, 0.17)) and end-tidal partial pressure of CO₂ (PETCO₂) (0.3 mmHg (0.1, 0.6)). In conclusion, RMT using FB seems to be a new and easy alternative ergogenic tool which can be used at the same time as day-to-day training for performance enhancement.

Respiratory muscle training for cystic fibrosis

BACKGROUND

Cystic fibrosis is the most common autosomal recessive disease in white populations, and causes respiratory dysfunction in the majority of individuals. Numerous types of respiratory muscle training to improve respiratory function and health-related quality of life in people with cystic fibrosis have been reported in the literature. Hence a systematic review of the literature is needed to establish the effectiveness of respiratory muscle training (either inspiratory or expiratory muscle training) on clinical outcomes in cystic fibrosis. This is an update of a previously published review.

OBJECTIVES

To determine the effectiveness of respiratory muscle training on clinical outcomes in people with cystic fibrosis.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials register comprising of references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. Date of most recent search: 11 June 2020. A hand search of the Journal of Cystic Fibrosis and Pediatric Pulmonology was performed, along with an electronic search of online trial databases. Date of most recent search: 05 October 2020.

SELECTION CRITERIA

Randomised controlled studies comparing respiratory muscle training with a control group in people with cystic fibrosis.

DATA COLLECTION AND ANALYSIS

Review authors independently selected articles for inclusion, evaluated the methodological quality of the studies, and extracted data. Additional information was sought from trial authors where necessary. The quality of the evidence was assessed using the GRADE system.

MAIN RESULTS

Authors identified 20 studies, of which 10 studies with 238 participants met the review's inclusion criteria. There was wide variation in the methodological and written quality of the included studies. Four of the 10 included studies were published as abstracts only and lacked concise details, thus limiting the information available. Eight studies were parallel studies and two of a cross-over design. Respiratory muscle training interventions varied dramatically, with frequency, intensity and duration ranging from thrice weekly to twice daily, 20% to 80% of maximal effort, and 10 to 30 minutes, respectively. Participant numbers ranged from 11 to 39 participants in the included studies; five studies were in adults only, one in children only and four in a combination of children and adults. No differences between treatment and control were reported in the primary outcome of pulmonary function (forced expiratory volume in one second and forced vital capacity) or postural stability (very low-quality evidence). Although no change was reported in exercise capacity as assessed by the maximum rate of oxygen use and distance completed in a six minute walk test, a 10% improvement in exercise duration was found when working at 60% of maximal effort in one study (n = 20) (very low-quality evidence). In a further study (n = 18), when working at 80% of maximal effort, health-related quality of life improved in the mastery and emotion domains (very low-quality evidence). With regards to the review's secondary outcomes, one study (n = 11) found a change in intramural pressure, functional residual capacity and maximal inspiratory pressure following training (very low-quality evidence). Another study (n=36) reported improvements in maximal inspiratory pressure following training (P < 0.001) (very low-quality evidence). A further study (n = 22) reported that respiratory muscle endurance was longer in the training group (P < 0.01). No studies reported significant differences on any other secondary outcomes. Meta-analyses could not be performed due to a lack of consistency and insufficient detail in reported outcome measures.

AUTHORS' CONCLUSIONS

There is insufficient evidence to suggest whether this intervention is beneficial or not. Healthcare practitioners should consider the use of respiratory muscle training on a case-by-case basis. Further research of reputable methodological quality is needed to determine the effectiveness of respiratory muscle training in people with cystic fibrosis. Researchers should consider the following clinical outcomes in future studies; respiratory muscle function, pulmonary function, exercise capacity, hospital admissions, and health-related quality of life. Sensory-perceptual changes, such as respiratory effort sensation (e.g. rating of perceived breathlessness) and peripheral effort sensation (e.g. rating of perceived exertion) may also help to elucidate mechanisms underpinning the effectiveness of respiratory muscle training.

Physical activity interventions for people with congenital heart disease

BACKGROUND

Congenital heart disease (ConHD) affects approximately 1% of all live births. People with ConHD are living longer due to improved medical intervention and are at risk of developing non-communicable diseases. Cardiorespiratory fitness (CRF) is reduced in people with ConHD, who deteriorate faster compared to healthy people. CRF is known to be prognostic of future mortality and morbidity: it is therefore important to assess the evidence base on physical activity interventions in this population to inform decision making.

OBJECTIVES

To assess the effectiveness and safety of all types of physical activity interventions versus standard care in individuals with congenital heart disease.

SEARCH METHODS

We undertook a systematic search on 23 September 2019 of the following databases: CENTRAL, MEDLINE, Embase, CINAHL, AMED, BIOSIS Citation Index, Web of Science Core Collection, LILACS and DARE. We also searched ClinicalTrials.gov and we reviewed the reference lists of relevant systematic reviews.

SELECTION CRITERIA

We included randomised controlled trials (RCT) that compared any type of physical activity intervention against a 'no physical activity' (usual care) control. We included all individuals with a diagnosis of congenital heart disease, regardless of age or previous medical interventions.  DATA COLLECTION AND ANALYSIS: Two review authors (CAW and CW) independently screened all the identified references for inclusion. We retrieved and read all full papers; and we contacted study authors if we needed any further information. The same two independent reviewers who extracted the data then processed the included papers, assessed their risk of bias using RoB 2 and assessed the certainty of the evidence using the GRADE approach. The primary outcomes were: maximal cardiorespiratory fitness (CRF) assessed by peak oxygen consumption; health-related quality of life (HRQoL) determined by a validated questionnaire; and device-worn 'objective' measures of physical activity.

MAIN RESULTS

We included 15 RCTs with 924 participants in the review. The median intervention length/follow-up length was 12 weeks (12 to 26 interquartile range (IQR)). There were five RCTs of children and adolescents (n = 500) and 10 adult RCTs (n = 424). We identified three types of intervention: physical activity promotion; exercise training; and inspiratory muscle training. We assessed the risk of bias of results for CRF as either being of some concern (n = 12) or at a high risk of bias (n = 2), due to a failure to blind intervention staff. One study did not report this outcome. Using the GRADE method, we assessed the certainty of evidence as moderate to very low across measured outcomes. When we pooled all types of interventions (physical activity promotion, exercise training and inspiratory muscle training), compared to a 'no exercise' control CRF may slightly increase, with a mean difference (MD) of 1.89 mL/kg^-1/min^-1 (95% CI -0.22 to 3.99; n = 732; moderate-certainty evidence). The evidence is very uncertain about the effect of physical activity and exercise interventions on HRQoL. There was a standardised mean difference (SMD) of 0.76 (95% CI -0.13 to 1.65; n = 163; very low certainty evidence) in HRQoL. However, we could pool only three studies in a meta-analysis, due to different ways of reporting. Only one study out of eight showed a positive effect on HRQoL. There may be a small improvement in mean daily physical activity (PA) (SMD 0.38, 95% CI -0.15 to 0.92; n = 328; low-certainty evidence), which equates to approximately an additional 10 minutes of physical activity daily (95% CI -2.50 to 22.20). Physical activity and exercise interventions likely result in an increase in submaximal cardiorespiratory fitness (MD 2.05, 95% CI 0.05 to 4.05; n = 179; moderate-certainty evidence). Physical activity and exercise interventions likely increase muscular strength (MD 17.13, 95% CI 3.45 to 30.81; n = 18; moderate-certainty evidence). Eleven studies (n = 501) reported on the outcome of adverse events (73% of total studies). Of the 11 studies, six studies reported zero adverse events. Five studies reported a total of 11 adverse events; 36% of adverse events were cardiac related (n = 4); there were, however, no serious adverse events related to the interventions or reported fatalities (moderate-certainty evidence). No studies reported hospital admissions.

AUTHORS' CONCLUSIONS

This review summarises the latest evidence on CRF, HRQoL and PA. Although there were only small improvements in CRF and PA, and small to no improvements in HRQoL, there were no reported serious adverse events related to the interventions. Although these data are promising, there is currently insufficient evidence to definitively determine the impact of physical activity interventions in ConHD. Further high-quality randomised controlled trials are therefore needed, utilising a longer duration of follow-up.

[Improving parasympathetic functioning to contain the inflammatory response of COVID-19 infection]

COVID-19 infection results in an unrestrained inflammatory reaction in serious cases. The autonomic nervous system (ANS), in particular the parasympathetic branch, helps to regulate the inflammatory response. A dysfunction of this branch, frequent in people at risk of developing COVID-19, favours a pro-inflammatory effect. Reinforcing and stimulating the parasympathetic ANS is possible and accessible to paramedical and medical professionals.

The effect of inspiratory muscle training on swimming performance, inspiratory muscle strength, lung function, and perceived breathlessness in elite swimmers: a randomized controlled trial

Background:

According to studies performed on terrestrial sports athletes, inspiratory muscle training (IMT) may improve athletes’ performance. However, evidence of its effects in elite swimmers is lacking. Therefore, we aimed to assess the effect of 12-week IMT on swimming performance, inspiratory muscle strength, lung function, and perceived breathlessness in elite swimmers.

Methods:

Elite swimmers from the main FC Porto swimming team (in competitive training for a minimum period of 3 years) were invited to participate and were randomly allocated into intervention or control groups. The intervention group performed 30 inspiratory efforts, twice a day, 5 times a week, against a pressure threshold load equivalent to 50% of maximal inspiratory pressure, whereas the control group performed inspiratory efforts at the same frequency but against a 15% load. Swimming performance was assessed through time trials, converted into points according to International Swimming Federation Points Table. Outcomes were evaluated before and following the 12-week study period.

Results:

A total of 32 participants (22 girls) were included. The median age was 15 and 14 years old for the intervention (n = 17) and control (n = 12) groups, respectively. No differences were found in swimming performance (P = .271), inspiratory muscle strength (P = .914), forced vital capacity (P = .262), forced expiratory volume in 1st second (P = .265), peak expiratory flow (P = .270), and perceived breathlessness (P = .568) between groups after 12 weeks of intervention.

Conclusion:

Twelve weeks of IMT had no effect on swimming performance, lung function, and perceived breathlessness in elite swimmers. These results may be related to swimming-specific factors and/or an applied load insufficient to achieve training overload that could induce further improvements.

Inspiration for the Future: The Role of Inspiratory Muscle Training in Cystic Fibrosis

Cystic fibrosis (CF) is an inherited, multi-system, life-limiting disease characterized by a progressive decline in lung function, which accounts for the majority of CF-related morbidity and mortality. Inspiratory muscle training (IMT) has been proposed as a rehabilitative strategy to treat respiratory impairments associated with CF. However, despite evidence of therapeutic benefits in healthy and other clinical populations, the routine application of IMT in CF can neither be supported nor refuted due to the paucity of methodologically rigorous research. Specifically, the interpretation of available studies regarding the efficacy of IMT in CF is hampered by methodological threats to internal and external validity. As such, it is important to highlight the inherent risk of bias that differences in patient characteristics, IMT protocols, and outcome measurements present when synthesizing this literature prior to making final clinical judgments. Future studies are required to identify the characteristics of individuals who may respond to IMT and determine whether the controlled application of IMT can elicit meaningful improvements in physiological and patient-centered clinical outcomes. Given the equivocal evidence regarding its efficacy, IMT should be utilized on a case-by-case basis with sound clinical reasoning, rather than simply dismissed, until a rigorous evidence-based consensus has been reached.

Eight Weeks of Inspiratory Muscle Training Improves Pulmonary Function in Disabled Swimmers-A Randomized Trial

BACKGROUND

According to the literature, inspiratory muscle fatigue may increase after swimming training (ST). This study aimed to examine the efficacy of 8-week inspiratory muscular training (IMT) in disabled swimmers, combined with standard sports training, on selected parameters of lung ventilation and the function of respiratory muscles.

METHODS

A total of 16 disabled swimming division athletes from Wroclaw's 'Start' Regional Sports Association qualified for the study. The subjects were randomly divided into two groups (ST and IMT). Both groups participated in swimming training for 8 weeks (8 times a week). The IMT group additionally participated in inspiratory muscle training (8 weeks). In all respondents, a functional lung test and the respiratory muscle strength was measured.

RESULTS

After 8 weeks of training, a significant increase in ventilation parameters and respiratory muscle strength was observed only in the IMT group. In ST group 1, a 20% improvement in the strength of inspiratory muscles was achieved.

CONCLUSIONS

The inclusion of IMT is an important element that complements swimming training, allowing for greater increases in lung ventilation parameters and the strength of respiratory muscles in disabled swimmers.