Effect of Respiratory Muscle Training on Exercise Performance in Healthy Individuals

The Impact of an Orofacial Muscle Strengthening Program on Temporomandibular Muscles and on the Performance of Wind Instrumentalists

INTRODUCTION

Playing a wind instrument is one of the most complex tasks for the musculoskeletal system.

OBJECTIVE

Verify the effectiveness of a strengthening exercise programme on musical performance and the strength of the temporomandibular muscles.

METHODS

The sample was 60 participants (36 men; 24 women), with a mean age of 24.67 ± 13.06 years, divided into experimental group (EG) (16 brass; 15 woodwind) and control group (CG) (15 brass; 14 woodwind). The initial assessment (T0) consisted of a sociodemographic questionnaire, the EQ-5D-5L, an assessment of maximum bite force and endurance time and sound recording, before (T0) and after a musical practice of 8.5 min (T1). The EG, during 5 weeks, underwent 10 sessions of a temporomandibular muscle strengthening program, consisting of a series of 25 repetitions of isometric bite contraction, followed by a reassessment (T2) and sound recording (T2 and T3).

RESULTS

Statistically significant differences were found between groups in maximum bite force between T0 and T2, explained by the improvement in the EG (p = 0.014, bilaterally). We found no differences in endurance. In musical performance, statistically significant differences were found in the mean intensity values. There was an improvement in performance in the brass EG, with statistically significant differences in the high-piano note (p = 0.025) and in the woodwind EG all the notes were played at a significantly lower intensity (p ≤ 0.05), compared to the CG, where all the notes increased in intensity.

CONCLUSION

The isometric exercise improves the maximum bite force, accompanied by an improvement in the high note's performance in brass and greater sound stability in woodwinds.

Self-reported dyspnea and interest in a respiratory muscle training program among callers to the New York State Quitline

INTRODUCTION

Cigarette smoking is an important risk factor in the development of dyspnea. Programs designed to strengthen the respiratory muscles can improve dyspnea in people with or without lung disease. As a first step in understanding the feasibility of offering a respiratory muscle training (RMT) program to people who are seeking help to try to quit smoking, we asked callers who contacted the New York State Quitline about their dyspnea and potential interest in a home-based RMT program.

METHODS

Consecutive callers who contacted the New York State Quitline (n=1019) between 19 May and 9 June 2023 completed the Modified Medical Research Council (mMRC) dyspnea scale and reported their level of interest in RMT. Participants were categorized as: high breathlessness (HB: 0-1), or low breathlessness (LB: 2-4). We examined characteristic differences between participants who reported HB versus LB and examined differences in level of interest in home-based RMT.

RESULTS

Those with HB were older [mean (SD): 61.3 (12.5) vs 53.6 (15.0) years, p<0.001], had more cumulative years of smoking [38.8 (15.1) vs 28.8 (15.4) years, p<0.001], smoked more cigarettes per day [19.3 (10.5) vs 17.3 (8.8), p<0.01], reported more disability (p<0.001) and chronic health conditions (78.5% vs 53.9%, p<0.001). Those with HB also expressed greater interest in RMT [7.8 (3.3) vs 6.2 (4.1), p<0.001].

CONCLUSIONS

These preliminary findings suggest that about 20% of quitline callers report clinically significant levels of breathlessness and most respondents, regardless of their level of breathlessness, report interest in a home-based RMT program, underscoring a potential opportunity to offer this program along with cessation support.

Expiratory muscle strength training reduces oxidative stress and systemic inflammation in men with obstructive sleep apnea syndrome: a double-blinded, randomized parallel trial

STUDY OBJECTIVES

This study aimed to evaluate and compare the effects of high and low-intensity expiratory muscle strength training (EMST) on disease severity, systemic inflammation, oxidative stress, respiratory muscle strength, exercise capacity, symptoms, daytime sleepiness, fatigue severity, and sleep quality in male patients with obstructive sleep apnea syndrome (OSAS).

METHODS

Thirty-one male patients diagnosed with moderate OSAS were included in this double-blind, randomized, parallel study. Patients were randomized into two groups: High-EMST and Low-EMST groups. EMST was used at home 7 days/week, once a day, for 25 breaths, 12 weeks. Respiratory muscle strength was measured using a mouth pressure device. Disease severity (Apnea-Hypopnea Index [AHI]) and, respiratory sleep events by polysomnography, total oxidant level(TOS), total antioxidant level(TAS), oxidative stress index (OSI), C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin-10 (IL-10) levels by blood serum were evaluated.

RESULTS

The percentage of AHI change in the high-EMST group(50.8%) was significantly higher than in the low-EMST group(6.3%; p = .002, d = 1.31). In general, as MEP increased by one unit, AHI decreased by 0.149 points (b = -0.149; CR = -3.065; p = .002), and as AHI increased by one unit, ODI increased by 0.746 points (b = 0.746; CR = 10.604; p < .001). TOS, OSI, TNF-α and IL-6 levels decreased at similar rates in both groups.

CONCLUSIONS

EMST significantly reduces systemic inflammation and oxidative stress while improving expiratory muscle strength in male patients with moderate OSAS. High-EMST is more effective in enhancing the severity of disease than low-EMST. EMST is a practical, effective, and promising treatment for pulmonary rehabilitation in patients with moderate OSAS.

CLINICAL TRIALS

Effect of EMST systemic inflammation and oxidative stress in patients with moderate OSAS, https://clinicaltrials.gov/study/NCT05242406, with the number NCT05242406.

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.

Updates in inspiratory muscle training for older adults: A systematic review

Systematic reviews support the benefits of inspiratory muscle training (IMT) for exercise performance. Recently, many health benefits from IMT have been reported in older adults. Therefore, this work reviewed the literature focusing on IMT effects beyond physical performance in older adults, such as cardiorespiratory, metabolic, and postural balance outcomes. Searches were conducted with the following terms: ("respiratory muscle training" OR "inspiratory muscle training") OR ("inspiratory muscle strength training") AND ("elderly" OR "older" OR "aging" OR "aging"), and using the databases: MEDLINE (PubMed), SCOPUS and EUROPE PMC. Of the 356 articles found, 13 matched the inclusion criteria after screening. Based on reviewed studies, four to eight weeks of IMT (Mostly from 50 % up to 75 % of MIP, 7 days/week) improve cardiac autonomic control at rest and post-exercise, cerebrovascular response to orthostatic stress, static and dynamic balance, blood pressure control, endothelial function, and oxidative stress in older adults. The benefits of IMT in cardiac autonomic and vascular functions are reversed after training cessation. It thus appears that IMT promotes broad physiological gains for the older population. It is necessary to carry out more randomized clinical trials on the subject to confirm the findings of this research.

The misuse of respiratory resistive loading during aerobic exercises: revisiting mechanisms of "standalone" inspiratory muscle training

Systematic reviews and meta-analyses support the benefits of inspiratory muscle training (IMT) for sports and clinical populations. A typical application of "standalone" IMT intervention consists of breathing against an inspiratory load (IRL), twice daily, for 5-7 days/wk, for 4-12 wk. However, the application of IRL during aerobic exercise is often seen in a training routine of sports and rehabilitation centers with no evidence-based guide. In this Perspective, we will revisit putative mechanisms underlying the established benefits of "standalone" IMT to support our contention that IMT need not and should not be used during aerobic exercise.

Lung function parameters are associated with acute mountain sickness and are improved at high and extreme altitude

At altitude, factors such as decreased barometric pressure, low temperatures, and acclimatization might affect lung function. The effects of exposure and acclimatization to high-altitude on lung function were assessed in 39 subjects by repetitive spirometry up to 6022 m during a high-altitude expedition. Subjects were classified depending on the occurrence of acute mountain sickness (AMS) and summit success to evaluate whether lung function relates to successful climb and risk of developing AMS. Peak expiratory flow (PEF), forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1) increased with progressive altitude (max. +20.2 %pred, +9.3 %pred, and +6.7 %pred, all p<0.05). Only PEF improved with acclimatization (BC1 vs. BC2, +7.2 %pred, p=0.044). At altitude FEV1 (p=0.008) and PEF (p<0.001) were lower in the AMS group. The risk of developing AMS was associated with lower baseline PEF (p<0.001) and longitudinal changes in PEF (p=0.008) and FEV1 (p<0.001). Lung function was not related to summit success (7126 m). Improvement in PEF after acclimatization might indicate respiratory muscle adaptation.

Diaphragmatic Ultrasonography in Sports Performance: A Systematic Review

This paper aims to investigate and analyze the correlation between diaphragmatic parameters through ultrasonography and sports performance in various sports disciplines. This systematic review followed the PRISMA methodology. The search strategy was applied in the Medline database through Ovid, EMBASE, LILACS, the Cochrane Central Register of Controlled Trials, and Open Gray. Clinical trials, cohort, case-control, and cross-sectional studies were included, and animal experiments were excluded. A total of 388 studies were identified. After removing duplicates and screening titles and abstracts, sixteen studies were selected for full review, and six were included in the qualitative analysis. The results demonstrated a positive correlation between diaphragm excursion and thickness during inspiration with the anaerobic power, highlighting their importance in high-intensity performance. Additionally, one study reported a positive correlation between diaphragm thickness and aerobic power, suggesting the need for further research. The impact of inspiratory muscle training in Paralympic athletes was also evaluated, providing valuable insights into diaphragmatic adaptation in disabled populations. Ultrasonography is a feasible tool for evaluating the structure and function of the diaphragm, the main element of the respiratory process during sports practice. Its use could contribute to the evaluation and planning of sports training and be a possible indicator of performance improvement.

A Randomized Trial of Inspiratory Training in Children and Adolescents With Obesity

Introduction: Children with obesity suffer excess dyspnea that contributes to sedentariness. Developing innovative strategies to increase exercise tolerance and participation in children with obesity is a high priority. Because inspiratory training (IT) has reduced dyspnea, we sought to assess IT in children with obesity. Methods: We conducted a 6-week randomized IT trial involving 8- to 17-year-olds with obesity. Participants were randomized 1:1 to either high [75% of maximal inspiratory pressure (MIP)] or low resistance control (15% of MIP) three times weekly. Assessments included adherence, patient satisfaction, and changes in inspiratory strength and endurance, dyspnea scores and total activity level. Results: Among 27 randomized, 24 (89%) completed the intervention. Total session adherence was 72% which did not differ between treatment groups. IT was safe, and more than 90% felt IT benefitted breathing and general health. IT led to a mean improvement (95% CI) in inspiratory strength measured by MIP of 10.0 cm H2O (-3.5, 23.6; paired t-test, p = 0.139) and inspiratory endurance of 8.9 (1.0, 16.8; paired t-test, p = 0.028); however, there was no significant difference between high- and low-treatment groups. IT led to significant reductions in dyspnea with daily activity (p < 0.001) and in prospectively reported dyspnea during exercise (p = 0.024). Among the high- versus low-treatment group, we noted a trend for reduced dyspnea with daily activity (p = 0.071) and increased daily steps (865 vs. -51, p = 0.079). Discussion: IT is safe and feasible for children with obesity and holds promise for reducing dyspnea and improving healthy activity in children with obesity. Breathe-Fit trial NCT05412134.

The acute effect of respiratory muscle training on cortisol, testosterone, and testosterone-to-cortisol ratio in well-trained triathletes - exploratory study

The study investigated acute changes in cortisol (C) and testosterone (T) associated with a popular RMT method, voluntary isocapnic hyperpnoea (VIH), in well-trained triathletes. 19 athletes (7 females, 12 males) performed a VIH training session with pre- and post- serum C and T measurements. Repeated measures ANOVA was employed to analyze hormone changes during VIH, with additional time-sex interaction. Pearson correlation coefficient has been computed to identify the relationship between hormonal changes and age, anthropometric indices, respiratory muscle strength, and training experience. There was a statistically significant effect for C changes (F = 13.101, p = 0.002, ηp2 = 0.421, ω2 = 0.08). The C concentration was significantly lower after VIH (Mean Difference = -32.49 ± 39.13 nmol*L-1). No significant effects for T, T/C ratio, and time-sex interactions were observed (p > 0.05). Amongst many, significant correlations between the percentage of body fat and changes in C (r=-0.464, p=0.045), body mass and changes in T (r=0.516, p=0.024), height and changes in T (r=0.509, p=0.026) were found. VIH significantly lowered C concentration. No significant effects for T, T/C ratio, and no between-sex differences were observed. Noteworthy individual variability was observed in all the monitored indices. Significant correlations were found between acute hormone changes associated with VIH and selected anthropometric indices. The study provides initial insight into VIH's role in athletes' hormonal balance to possibly guide exercise prescription, autoregulation, arousal state management, and recovery practices in athletes.

Comparative Study of Different Respiratory Muscle Training Methods: Effects on Cardiopulmonary Indices and Athletic Performance in Elite Short-Track Speedskaters

Respiratory muscle training (RMT) improves endurance performance, balance, and ability to repeat high-intensity exercise bouts, providing a rationale to be applied in short-track speedskating. To establish a preferable RMT method for short-track speedskating, the influence of inspiratory pressure threshold loading (IPTL) and voluntary isocapnic hyperpnoea (VIH) on cardiopulmonary indices and athletic performance was investigated. Sixteen elite short-track speedskaters completed 6 weeks of RMT based on IPTL or VIH. Wingate Anaerobic Tests (WAnTs), cardiopulmonary exercise tests (CPETs), spirometry assessments, and on-ice time trials were performed before and after RMT intervention. Repeated measures ANOVA was used to assess the differences between each method's influence. No statistically significant (p > 0.05) differences between RMT methods were found in performance during the WAnT, CPET, or specific on-ice time trials. Spirometry measures were similar between both methods. Significant effects were found for the interaction between maximum breathing frequency during CPET (BFmax) and method (p = 0.009), as well as for the interaction between BFMax, method, and sex (p = 0.040). BFmax decreased for IPTL and increased for VIH. The interaction between method and sex revealed that BFmax increased only in males performing VIH. Our findings suggest that IPTL and VIH lead to analogous effects in the study participants, highlighting a negligible practical disparity in the impact of different RMT methods in elite short-track speedskaters.

The Effectiveness and Validity of Inspiratory Muscle Training in the Training Process of Disabled Swimmers

Objectives: The aim of this study was to evaluate the effect of medium-intensity inspiratory muscle training added to standard swimming training on inspiratory muscle strength and aerobic endurance levels and training status in disabled swimming athletes. Methods: This study involved 16 disabled athletes: group I-athletes performing swimming training with 8 weeks inspiratory muscle training-IMT (50% of the maximum inspiratory pressure); group II-athletes performing standard swimming training with 8 weeks inspiratory muscle training (15% MIP). The following tests were performed three times: MIP, MEP, Borg RPE scale and swimming test: T-30 test; 8 × 100 progressive test. Results: There was a significant increase in the MIP and MEP in group I after IMT. There was a significant increase in the distance swam during the T-30 only in group I after IMT. Significant differences were found between the first and third measurements in group I, and the effect was maintained at follow-up. There was also a significant reduction in La concentration in group I after IMT. There was a significant reduction in heart rate at 88% and 93% of the maximum speed in group I after the applied training. Conclusion: Inspiratory muscle training with 50% of the maximum inspiratory pressure load significantly increased the respiratory muscle strength of disabled swimmers. The application of higher-intensity IMT effectively improved the training level and physiological parameters of the swimmers' effort, indicating the need to include this type of training in the standard preparation of disabled swimmers.

Inspiratory muscle training impact on respiratory muscle strength, pulmonary function, and quality of life in children with chest burn: A randomized controlled trial

PURPOSE

Respiratory muscle function is compromised in children recovering from chest wall burns, which potentially leads to more impact on exercise capacity and quality of life. This study investigates the effects of an inspiratory muscle training intervention accompanied with a pulmonary rehabilitation program on respiratory muscle strength, lung function, functional capacity, and quality of life in chest burned children.

METHODS

Forty children with burns, aged from 10 to 18 years old and total body surface area of 30% to 50%, were randomly allocated to the inspiratory muscle training group (IMT- G: n = 20) or control group (CG: n = 20). They received IMT plus pulmonary rehabilitation or pulmonary rehabilitation with sham IMT, respectively for eight weeks. The outcomes were the respiratory muscle strength measured by maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP); lung functions (FEV1, FVC and FEV1/FVC ratio); functional capacity as well as Pediatric Quality of Life to measure physical and psychosocial functioning. outcome measures were assessed at before and after intervention (after eight weeks).

RESULTS

Based on the pre-intervention assessments, we found no significant difference between both groups (p > 0.05). Significant post-intervention differences were reported between both groups in MIP (P = .003), MEP (P = .017), FVC (P = .001), FEV1 (P = .007), FEV1/FVC ratio (P = .028), functional capacity (P = .003), physical domain of QoL (P = .006) and psychological domain of QoL (P = .002) in favor of the IMT group.

CONCLUSIONS

Eight weeks of inspiratory muscle training combined with pulmonary rehabilitation program improved children with chest burns' respiratory muscles strength, lung functions, functional capacity, and quality of life. Inspiratory muscle training may be employed in burn rehabilitation programs. It is a safe and effective therapy in chest burned children.

Effects of trunk muscle strength training on lung function in healthy runners

BACKGROUND

Abdominal pressure is important for athlete performance and conditioning, and lung function is implicated in running performance and economy. We aimed to determine the synergistic effects of trunk muscle strength training on abdominal pressure and lung function in university student runners.

METHODS

A total of 18 healthy male runners participated in the study. Abdominal pressure was measured against air pressure applied by a cuff belt wrapped around the trunk. Forced expiratory volume in 1 second (FEV1) and FEV in 6 seconds (FEV6) were measured. Trunk muscle strength training was performed for 8 weeks, and abdominal pressure and lung function were compared preintervention as well as at 8 weeks and 6 months postintervention. Correlations between the preintervention abdominal pressure and FEV1 and FEV6, as well as the rate of change (Δ) of each item at each time point, were examined.

RESULTS

Preintervention correlations between abdominal pressure and lung function were significant for abdominal pressure and FEV1 (r=0.475, P=0.047) and abdominal pressure and FEV6 (r=0.473, P=0.047). Significant correlations were found between Δabdominal pressure and ΔFEV1 (r=0.489, P=0.040) and Δabdominal pressure and ΔFEV6 (r=0.478, P=0.045) between preintervention and 8 weeks postintervention. Significant correlations were found between Δabdominal pressure and ΔFEV6 (r=0.557, P=0.016) between 8 weeks and 6 months postintervention.

CONCLUSIONS

The trunk muscle strength training intervention improved abdominal pressure and lung function, and the rate of change was also positively correlated, suggesting a synergistic effect between the two.

Effects of respiratory muscular training in post-covid-19 patients: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Post-Covid-19 syndrome is defined as non-self-sustaining signs and/or symptoms lasting more than 12 weeks, occurring during or after a Covid-19 infection. The primary outcome was the analysis of the respiratory muscle training (RMT) result in respiratory muscle strength, (maximum inspiratory pressure (MIP) e maximum expiratory pressure (MEP)); and the secondary results were the analysis of lung function, dyspnea, quality of life (QoL), fatigue and functional performance.

METHODS

The PICO description for this research was: P: patients diagnosed with post-Covid-19; I: RMT; C: Sham or simulated inspiratory or expiratory muscle training and usual care; O: MIP, MEP, Lung Function, level of dyspnea, QoL and functional performance. On January 15, 2024, the following databases were consulted: PubMed, Lilacs, Cochrane Library, PEDro and EMBASE. Randomized clinical trials were included without restrictions on year of publication or language. The data selection and extraction steps were carried out by two independent reviewers.

RESULTS

The search in the databases resulted in a total of 14,216 studies, and after the eligibility process, 7 studies were included with a sample of 527 patients. The MIP results suffered a statistically significant increase, that is, the RMT was favorable to improve the MIP (MD = 29.55cmH2O IC 95%: 7.56cmH2O to 51.54cmH2O, p = 0,00001). For the MEP outcome, the results were statistically significant in favor of RMT (MD = 10.93cmH2O CI 95%: 3.65cmH2O to 18.21cmH2O, p = 0.00001). We also noticed a significant improvement for the group that received the RMT in the distance covered in the 6-Minute Walk Test (6MWT) MD = 40.70 m CI 95%: 18.23 m to 65.17 m%, p = 0.01).

CONCLUSION

We noticed that RMT is being used in patients with respiratory diseases, including post-Covid-19. Our systematic review observed that this training provides an increase in inspiratory and expiratory muscle strength, a reduction in dyspnea levels, and an increase in the distance covered in the 6MWT and improved QoL in post-covid patients after intervention.

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.

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.

Influence of voluntary isocapnic hyperpnoea on recovery after high-intensity exercise in elite short-track speedskaters - randomized controlled trial

Respiratory muscle training plays a significant role in reducing blood lactate concentration (bLa) and attenuating negative physiological stress reactions. Therefore, we investigated if voluntary isocapnic hyperpnoea (VIH) performed after a maximum anaerobic effort influences bLa and perceived fatigue level in well-trained speedskaters. 39 elite short-track speedskaters participated in a trial with two parallel groups: experimental and control. All the participants performed the Wingate Anaerobic Test (WAnT). The experimental group performed a VIH-based recovery protocol 20 min after exercise, the control group used passive recovery only. Blood samples were taken 3 and 30 min after the WAnT to measure bLa. Fatigue was self-appraised on a 0-10 perceived rating-of-fatigue (ROF) scale 3 and 30 min after the WAnT. Noteworthy, but not statistically significant changes between the experimental and control groups were observed for changes in bLa (p = 0.101). However, statistically significant changes between the groups were found for ROF (p = 0.003, ηp2 = 0.211, ω2 = 0.106). Moreover, statistically significant interactions between post-exercise bLa clearance and VO2max (p = 0.028) and inspiratory muscle strength (p = 0.040) were observed. Our findings provided preliminary insight that VIH may be an efficient recovery protocol after anaerobic exercise performed by elite athletes. The association between VO2max and post-exercise bLa clearance indicates the vital role of aerobic fitness in repeated-efforts ability in short-track speedskaters. The study was registered at ClinicalTrials.gov as NCT05994092 on 15th August 2023.

Potential Therapeutic Role of Respiratory Muscle Training in Dyspnea Management of Cancer Survivors: A Narrative Review

Dyspnea is a disabling symptom presented in approximately half of all cancer survivors. From a clinical perspective, despite the availability of pharmacotherapies, evidence-based effective treatments are limited for relieving dyspnea in cancer survivors. Preliminary evidence supports the potential of respiratory muscle training to reduce dyspnea in cancer survivors, although large randomized controlled studies are warranted. The aims of this article were to review the relevant scientific literature on the potential therapeutic role of respiratory muscle training in dyspnea management of cancer survivor, and to identify possible mechanisms, strengths and limitations of the evidence as well as important gaps for future research directions.

Incremental Load Respiratory Muscle Training Improves Respiratory Muscle Strength and Pulmonary Function in Children with Bronchiectasis

Methods

Participants underwent respiratory muscle training for 24 weeks. The main results were changes in respiratory muscle strength and pulmonary function indices (forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), FEV1/FVC, peak expiratory flow rate (PEF), forced expiratory flow 25-75% (FEF25-75%), and maximal midexpiratory flow 75/25 (MMEF75/25)) before, 12 weeks after, and 24 weeks after the intervention. The secondary outcomes were changes in the exercise load and work rate, exercise work, Leicester Cough Questionnaire (LCQ) scale, and Fatigue Severity Scale (FSS).

Results

Compared with before the intervention, after 24 weeks of respiratory muscle training, the maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) were significantly enhanced (P < 0.05), while FVC, FEV1, and PEF were significantly increased (P < 0.01). FEF25-75 and MMEF75/25 values showed significant improvement compared to those before training (P < 0.05). The exercise loading, work, and exercise work rate of expiratory muscle training were significantly improved compared to those before intervention (P < 0.05). The LCQ score increased significantly (P <  0.001), and the FSS score decreased significantly (P <  0.001).

Conclusion

Incremental load respiratory muscle training effectively improved children's lung function over the long term, improved the strength of their inspiratory and expiratory muscles, and improved their quality of life.

Inspiratory Training for Improving Respiratory Strength, Pulmonary Function, and Walking in Cerebral Palsy: A Meta-Analysis

PURPOSE

To investigate the effects of inspiratory strength training on respiratory muscle strength, pulmonary function, and walking capacity in children with cerebral palsy, with Gross Motor Function Classification System I to III.

METHODS

Searches were conducted in CINAHL, LILACS, MEDLINE, and Physiotherapy Evidence Database (PEDro) databases. The outcomes of interest were respiratory muscle strength, pulmonary function, and walking capacity. The quality was assessed by PEDro Scale. The Grading of Recommendations Assessment, Development, and Evaluation system was used to summarize the quality of evidence.

RESULTS

Inspiratory strength training increased the strength of inspiratory muscles and may increase the strength of the expiratory muscles. No changes were observed in pulmonary function or walking capacity.

CONCLUSIONS

This systematic review provides moderate-quality evidence that inspiratory strength training is effective for increasing inspiratory muscle strength in children with cerebral palsy. Benefits may be carried over to improving expiratory muscle strength but were not observed on pulmonary function or walking capacity.

Respiratory training effects in Long COVID-19 patients: a systematic review and meta-analysis

INTRODUCTION

To date, it is unknown whether respiratory training interventions can benefit Long COVID-19 patients. The main objective was to analyze the effects of respiratory training on patients with Long COVID-19, concretely on respiratory muscle strength, lung function, dyspnea, and functional capacity.

METHODS

We performed a systematic review following PRISMA statement using PubMed, Scopus, and PEDro (last search November 2023). The risk of bias was assessed using the Cochrane tool. We included randomized controlled trials testing the effect of respiratory training interventions in Long COVID-19 patients versus no intervention, control, or placebo intervention. The data was pooled, and a meta-analysis was complete.

RESULTS

We selected 7 studies, which included 572 patients. Meta-analysis results show significant differences in favor of respiratory training in respiratory muscle strength (MD = 13.71; 95% CI = 5.41; 22; p = 0.001), dyspnea (SDM = 1.39; 95% CI = 0.33; 2.46; p = 0.01) and functional capacity (SDM = 0.90; 95% CI = 0.37; 1.43; p = 0.0009), but not in lung function (MD = 0.28; 95%CI = -0.27; 0.83; p = 0.32).

CONCLUSION

The results of this systematic review with meta-analysis suggest that respiratory training improves respiratory muscle strength and functional capacity in Long COVID-19 patients, as well as dyspnea if combined with therapeutic exercise. However, respiratory training does not improve lung function in these patients.

REVIEW REGISTRATION PROSPERO IDENTIFIER

CRD42022371820.

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.

The effects of respiratory muscle training on respiratory function and functional capacity in patients with early stroke: a meta-analysis

BACKGROUND

Respiratory muscle training is a continuous and standardized training of respiratory muscles, but the evidence of the effects on early stroke patients is not clear. This meta-analysis aimed to investigate the effects of respiratory muscle training on respiratory function and functional capacity in patients with early stroke.

METHODS

PubMed, Embase, PEDro, ScienceDirect, AMED, CINAHL, and China National Knowledge Infrastructure databases were searched from inception to December 8, 2023 for articles about studies that 1) stroke patients with age ≥ 18 years old. Early stroke < 3 months at the time of diagnosis, 2) respiratory muscle training, including inspiratory and expiratory muscle training, 3) the following measurements are the outcomes: respiratory muscle strength, respiratory muscle endurance, pulmonary function testing, dyspnea fatigue score, and functional capacity, 4) randomized controlled trials. Studies that met the inclusion criteria were extracted data and appraised the methodological quality and risk of bias using the Physiotherapy Evidence Database scale and the Cochrane Risk of Bias tool by two independent reviewers. RevMan 5.4 with a random effect model was used for data synthesis and analysis. Mean differences (MD) or standard mean differences (SMD), and 95% confidence interval were calculated (95%CI).

RESULTS

Nine studies met inclusion criteria, recruiting 526 participants (mean age 61.6 years). Respiratory muscle training produced a statistically significant effect on improving maximal inspiratory pressure (MD = 10.93, 95%CI: 8.51-13.36), maximal expiratory pressure (MD = 9.01, 95%CI: 5.34-12.69), forced vital capacity (MD = 0.82, 95%CI: 0.54-1.10), peak expiratory flow (MD = 1.28, 95%CI: 0.94-1.63), forced expiratory volume in 1 s (MD = 1.36, 95%CI: 1.13-1.59), functional capacity (SMD = 0.51, 95%CI: 0.05-0.98) in patients with early stroke. Subgroup analysis showed that inspiratory muscle training combined with expiratory muscle training was beneficial to the recovery of maximal inspiratory pressure (MD = 9.78, 95%CI: 5.96-13.60), maximal expiratory pressure (MD = 11.62, 95%CI: 3.80-19.43), forced vital capacity (MD = 0.87, 95%CI: 0.47-1.27), peak expiratory flow (MD = 1.51, 95%CI: 1.22-1.80), forced expiratory volume in 1 s (MD = 0.76, 95%CI: 0.41-1.11), functional capacity (SMD = 0.61, 95%CI: 0.08-1.13), while inspiratory muscle training could improve maximal inspiratory pressure (MD = 11.60, 95%CI: 8.15-15.05), maximal expiratory pressure (MD = 7.06, 95%CI: 3.50-10.62), forced vital capacity (MD = 0.71, 95%CI: 0.21-1.21), peak expiratory flow (MD = 0.84, 95%CI: 0.37-1.31), forced expiratory volume in 1 s (MD = 0.40, 95%CI: 0.08-0.72).

CONCLUSIONS

This study provides good-quality evidence that respiratory muscle training is effective in improving respiratory muscle strength, pulmonary function, and functional capacity for patients with early stroke. Inspiratory muscle training combined with expiratory muscle training seems to promote functional recovery in patients with early stroke more than inspiratory muscle training alone.

TRIAL REGISTRATION

Prospero registration number: CRD42021291918.

Breathing Pattern Response after 6 Weeks of Inspiratory Muscle Training during Exercise

(1) Background: The breathing pattern is defined as the relationship between the tidal volume (VT) and breathing frequency (BF) for a given VE. The aim of this study was to evaluate whether inspiratory muscle training influenced the response of the breathing pattern during an incremental effort in amateur cyclists. (2) Methods: Eighteen amateur cyclists completed an incremental test to exhaustion, and a gas analysis on a cycle ergometer and spirometry were conducted. Cyclists were randomly assigned to two groups (IMTG = 9; CON = 9). The IMTG completed 6 weeks of inspiratory muscle training (IMT) using a PowerBreathe K3® device at 50% of the maximum inspiratory pressure (Pimax). The workload was adjusted weekly. The CON did not carry out any inspiratory training during the experimental period. After the 6-week intervention, the cyclists repeated the incremental exercise test, and the gas analysis and spirometry were conducted. The response of the breathing pattern was evaluated during the incremental exercise test. (3) Results: The Pimax increased in the IMTG (p < 0.05; d = 3.1; +19.62%). Variables related to the breathing pattern response showed no differences between groups after the intervention (EXPvsCON; p > 0.05). Likewise, no differences in breathing pattern were found in the IMTG after training (PREvsPOST; p > 0.05). (4) Conclusions: IMT improved the strength of inspiratory muscles and sport performance in amateur cyclists. These changes were not attributed to alterations in the response of the breathing pattern.

Impact of high-intensity interval hyperpnea on aerobic energy release and inspiratory muscle fatigue

Respiratory muscle endurance training reportedly has beneficial effects on whole-body endurance performance. We produced a novel high-intensity interval (HII) protocol and characterized the associated physiological responses and respiratory muscle fatigue. Peak oxygen uptake of respiratory muscle (V̇O2peakRM) was estimated during the respiratory incremental test. The HII session consisted of five 3-minute hyperpnea periods at 100%V̇O2peakRM interspersed with 2-minute periods at 40%V̇O2peakRM (25 min total). The high-intensity continuous (HIC) session involved a single time-to-end bout of hyperpnea at 100%V̇O2peakRM. The moderate-intensity continuous (MIC) session involved 25 min of hyperpnea at 60% of maximal voluntary ventilation. V̇O2RM was recorded continuously, and maximal inspiratory pressure (PImax) was assessed before and after the sessions. HII session: V̇O2RM gradually increased as the sets proceeded, whereas PImax decreased significantly. HIC session: V̇O2RM increased progressively, and the time to end was 6.5 ± 0.5 min. PImax decreased significantly. MIC session: V̇O2RM did not change for 25 min, and PImax remained unchanged. The duration of V̇O2RM at near- and supra-maximal levels in the HII session (10 ± 1 min) was longer than that in the HIC session (4 ± 1 min). The decrease in PImax was larger in the HII session (-12 ± 3 %) than MIC session (-4 ± 3 %). The HII protocol is characterized by a longer time to maximally stimulate the aerobic energy system of respiratory muscle than the HIC protocol and greater inspiratory muscle fatigue than the traditional MIC protocol. These results suggest that the HII protocol could enhance the efficacy of respiratory muscle training programs.

Respiratory Muscle Strength Training in Patients Post-COVID-19: A Systematic Review

Estimates of 10-49% of patients may experience ongoing symptoms after COVID-19, including dyspnea. Respiratory muscle strength training has been used to reduce dyspnea in other respiratory diseases, thus, it may be a viable option for individuals with post-COVID-19 symptoms. The objective of this review was to evaluate the evidence for the effectiveness of respiratory muscle strength training for individuals with post-COVID-19 dyspnea. A systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. CINAHL, Web of Science, PubMed, EMBASE, Google Scholar, and Scopus databases were searched from 2020-2023. Eleven articles met the inclusion criteria. Pulmonary measures were improved in all but one study, and dyspnea, physical capacity and quality of life measures achieved statistical significance. Outcomes improved following respiratory muscle strength training as a standalone intervention, or with aerobic and peripheral muscle strength training.

A Comparison of Two Methods of Pre-operative Inspiratory Muscle Training on Post-operative Outcome Following Esophagectomy

Esophageal carcinoma is a multifaceted and complex disease of rapidly rising incidence that exerts an increasing social and financial burden on global healthcare systems. Esophagectomy is associated with high rates of peri- and post-operative morbidity and mortality because of complex anatomy, frail health of patients, and late diagnosis of the disease. The most common complication seen is post-operative pulmonary complication (PPC). This study was planned to compare and analyze the outcome of two different protocols of preoperative IMT program on the rate of PPCs in patients undergoing esophagectomy. Twenty patients who underwent esophagectomy for carcinoma esophagus were included in the study and were randomly divided into 2 groups of 10 each. Group A received IMT-HI training for 4 weeks, whereas the group B received IMT-E training for 4 weeks pre-operatively. All the patients included in the study underwent a baseline pulmonary assessment which included pulmonary function test (FVC, FEV1, and FEV1/FVC), maximum inspiratory pressure (MIP), and maximum expiratory pressure (MEP). Four-week preoperative IMT-HI lead to better outcome following esophagectomy as compared to IMT-E. Relative risk of PPC was 4:1 (IMT-E:IMT-HI). However, there was no statistically significant improvement in PFTs, MEP, and MIP from baseline or between two groups. The difference in PPC in two groups did not reach statistical significance despite the fact that relative risk of PPC was 4:1 (IMT-E:IMT-HI).

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.

Basis of preventive and non-pharmacological interventions in asthma

Asthma is one of the most common atopic disorders in all stages of life. Its etiology is likely due to a complex interaction between genetic, environmental, and lifestyle factors. Due to this, different non-pharmacological interventions can be implemented to reduce or alleviate the symptoms caused by this disease. Thus, the present narrative review aimed to analyze the preventive and non-pharmacological interventions such as physical exercise, physiotherapy, nutritional, ergonutritional, and psychological strategies in asthma treatment. To reach these aims, an extensive narrative review was conducted. The databases used were MedLine (PubMed), Cochrane (Wiley), Embase, PsychINFO, and CinAhl. Asthma is an immune-mediated inflammatory condition characterized by increased responsiveness to bronchoconstrictor stimuli. Different factors have been shown to play an important role in the pathogenesis of asthma, however, the treatments used to reduce its incidence are more controversial. Physical activity is focused on the benefits that aerobic training can provide, while physiotherapy interventions recommend breathing exercises to improve the quality of life of patients. Nutritional interventions are targeted on implement diets that prioritize the consumption of fruits and vegetables and supplementation with antioxidants. Psychological interventions have been proposed as an essential non-pharmacological tool to reduce the emotional problems associated with asthma.

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.

Similar effects on exercise performance following different respiratory muscle training programs in healthy young men

Both respiratory muscle endurance training (RMET) and inspiratory resistive training (IMT) seem to increase whole-body exercise performance, but direct comparisons between the two are scarce. We hypothesized that the similarity of RMET to exercise-induced ventilation would induce larger improvements compared to IMT. Twenty-six moderately-trained men performed either 4 weeks of RMET, IMT or SHAM training. Before and after the interventions, respiratory muscle endurance, 3-km running time-trial performance and leg muscle fatigue after intense constant-load cycling (assessed with femoral nerve magnetic stimulation) were measured. Both RMET (+ 59%) and IMT (+ 38%) increased respiratory muscle endurance (both p < 0.01 vs. SHAM) but only IMT increased inspiratory strength (+ 32%, p < 0.001 vs. SHAM). 3-km time improved showing a main effect of training (p = 0.026), however with no differences between groups. Leg fatigue after cycling was not attenuated with training (p = 0.088 for group-training interaction). All groups showed a significant (~ 0.3 l) increase in average tidal volume during cycling exercise combined with a concomitant reduction in respiratory exertion. While RMET and IMT improved specific aspects of respiratory muscles performance, no benefits beyond SHAM were seen during whole-body exercise. Changes in respiratory sensations might be a result of altered breathing pattern.

Effects of high-intensity respiratory muscle training on respiratory muscle strength in individuals with Parkinson's disease: Protocol of a randomized clinical trial

OBJECTIVE

To investigate the efficacy of high-intensity respiratory muscle training (combined inspiratory and expiratory muscle training) in improving inspiratory and expiratory muscle strength, inspiratory muscle endurance, peak cough flow, dyspnea, fatigue, exercise capacity, and quality of life in this population.

METHODS

A randomized controlled trial, concealed allocation, blinded assessments, and intention-to-treat analysis will be carried out. Altogether, 34 individuals with PD (age ≥ 50 years old, with maximum inspiratory pressure (MIP) <80cmH2O or maximum expiratory pressure (MEP) <90cmH2O) will be recruited. Patients will be randomly assigned to either (1) high-intensity respiratory muscle training (experimental group, 60% of MIP and MEP) or (2) sham training (control group, 0cmH2O). Individuals will perform a home-based intervention, with indirect home supervision, consisting of two daily 20-min sessions (morning and afternoon), seven times a week, during eight weeks. Primary outcomes are MIP and MEP. Secondary outcomes are inspiratory muscle endurance, peak cough flow, dyspnea, fatigue, exercise capacity, and quality of life. The effects of the training will be analyzed from the collected data using intention-to-treat. Between-group differences will be measured using a two-way ANOVA with repeated measures (2*3), considering baseline, post-intervention, and 12-week follow-up.

IMPACT

The results of this trial will provide valuable new information on the efficacy of high-intensity respiratory muscle training in improving muscle strength, functional outcomes, and quality of life in individuals with PD. Performing combined inspiratory and expiratory muscle training using a single equipment is cheaper and feasible, takes less time and is easy to use. In addition, this intervention will be carried out in the home environment that increases accessibility, reduces time, and costs of transport, which increases the feasibility to reproduce their findings in clinical practice.

TRIAL REGISTRATION

NCT05608941. Registered on November 8, 2022.

Monitoring and Management of Respiratory Function in Pompe Disease: Current Perspectives

Pompe disease (PD) is a neuromuscular disorder caused by a deficiency of acid alpha-glucosidase (GAA) - a lysosomal enzyme responsible for hydrolyzing glycogen. GAA deficiency leads to accumulation of glycogen in lysosomes, causing cellular disruption. The severity of PD is directly related to the extent of GAA deficiency - if no or minimal GAA is produced, symptoms are severe and manifest in infancy, known as infantile onset PD (IOPD). If left untreated, infants with IOPD experience muscle hypotonia and cardio-respiratory failure leading to significant morbidity and mortality in the first year of life. In contrast, late-onset PD (LOPD) patients have more GAA activity and present later in life, but also have significant respiratory function decline. Despite FDA-approved enzyme replacement therapy, respiratory insufficiency remains a major cause of morbidity and mortality, emphasizing the importance of early detection and management of respiratory complications. These complications include impaired cough and airway clearance, respiratory muscle weakness, sleep-related breathing issues, and pulmonary infections. This review aims to provide an overview of the respiratory pathology, monitoring, and management of PD patients. In addition, we discuss the impact of novel approaches and therapies on respiratory function in PD.

Effects of Sprint Interval and Endurance Respiratory Muscle Training on Postcycling Inspiratory and Quadriceps Fatigue

PURPOSE

We investigated whether a 4-wk period of respiratory muscle endurance training (RMET) or respiratory muscle sprint interval training (RMSIT) would lead to an attenuation of inspiratory muscle and quadriceps fatigue after a bout of high-intensity cycling compared with a placebo intervention (PLAT), as predicted by the respiratory metaboreflex model.

METHODS

Thirty-three active, young healthy adults performed RMET, RMSIT, or PLAT. Changes in inspiratory muscle and quadriceps twitches in response to a cycling test at 90% of peak work capacity were assessed before and after training. EMG activity and deoxyhemoglobin (HHb, via near-infrared spectroscopy) of the quadriceps and inspiratory muscles were also monitored during the cycling test, along with cardiorespiratory and perceptual variables.

RESULTS

At pretraining, cycling reduced the twitch force of the inspiratory muscles (86% ± 11% baseline) and quadriceps (66% ± 16% baseline). Training did not attenuate the drop in twitch force of the inspiratory muscles (PLAT, -3.5 ± 4.9 percent-points [p.p.]; RMET, 2.7 ± 11.3 p.p.; RMSIT, 4.1 ± 8.5 p.p.; group-training interaction, P = 0.394) or quadriceps (PLAT, 3.8 ± 18.6 p.p.; RMET, -2.6 ± 14.0 p.p.; RMSIT, 5.2 ± 9.8 p.p.; group-training interaction P = 0.432). EMG activity and HHb levels during cycling did not change after training for either group. Only RMSIT showed a within-group decrease in the perception of respiratory exertion with training.

CONCLUSIONS

Four weeks of RMET or RMSIT did not attenuate the development of exercise-induced inspiratory or quadriceps fatigue. The ergogenic effects of respiratory muscle training during whole-body exercise might be related to an attenuation of perceptual responses.

Distinguishing science from pseudoscience in commercial respiratory interventions: an evidence-based guide for health and exercise professionals

Respiratory function has become a global health priority. Not only is chronic respiratory disease a leading cause of worldwide morbidity and mortality, but the COVID-19 pandemic has heightened attention on respiratory health and the means of enhancing it. Subsequently, and inevitably, the respiratory system has become a target of the multi-trillion-dollar health and wellness industry. Numerous commercial, respiratory-related interventions are now coupled to therapeutic and/or ergogenic claims that vary in their plausibility: from the reasonable to the absurd. Moreover, legitimate and illegitimate claims are often conflated in a wellness space that lacks regulation. The abundance of interventions, the range of potential therapeutic targets in the respiratory system, and the wealth of research that varies in quality, all confound the ability for health and exercise professionals to make informed risk-to-benefit assessments with their patients and clients. This review focuses on numerous commercial interventions that purport to improve respiratory health, including nasal dilators, nasal breathing, and systematized breathing interventions (such as pursed-lips breathing), respiratory muscle training, canned oxygen, nutritional supplements, and inhaled L-menthol. For each intervention we describe the premise, examine the plausibility, and systematically contrast commercial claims against the published literature. The overarching aim is to assist health and exercise professionals to distinguish science from pseudoscience and make pragmatic and safe risk-to-benefit decisions.

Respiratory issues in patients with multiple sclerosis as a risk factor during SARS-CoV-2 infection: a potential role for exercise

Coronavirus disease-2019 (COVID-19) is associated with cytokine storm and is characterized by acute respiratory distress syndrome (ARDS) and pneumonia problems. The respiratory system is a place of inappropriate activation of the immune system in people with multiple sclerosis (MS), and this may cause damage to the lung and worsen both MS and infections.The concerns for patients with multiple sclerosis are because of an enhance risk of infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The MS patients pose challenges in this pandemic situation, because of the regulatory defect of autoreactivity of the immune system and neurological and respiratory tract symptoms. In this review, we first indicate respiratory issues associated with both diseases. Then, the main mechanisms inducing lung damages and also impairing the respiratory muscles in individuals with both diseases is discussed. At the end, the leading role of physical exercise on mitigating respiratory issues inducing mechanisms is meticulously evaluated.

Managing respiratory muscle weakness during weaning from invasive ventilation

Weaning is a critical stage of an intensive care unit (ICU) stay, in which the respiratory muscles play a major role. Weakness of the respiratory muscles, which is associated with significant morbidity in the ICU, is not limited to atrophy and subsequent dysfunction of the diaphragm; the extradiaphragmatic inspiratory and expiratory muscles also play important parts. In addition to the well-established deleterious effect of mechanical ventilation on the respiratory muscles, other risk factors such as sepsis may be involved. Weakness of the respiratory muscles can be suspected visually in a patient with paradoxical movement of the abdominal compartment. Measurement of maximal inspiratory pressure is the simplest way to assess respiratory muscle function, but it does not specifically take the diaphragm into account. A cut-off value of -30 cmH2O could identify patients at risk for prolonged ventilatory weaning; however, ultrasound may be better for assessing respiratory muscle function in the ICU. Although diaphragm dysfunction has been associated with weaning failure, this diagnosis should not discourage clinicians from performing spontaneous breathing trials and considering extubation. Recent therapeutic developments aimed at preserving or restoring respiratory muscle function are promising.

VO2max (VO2peak) in elite athletes under high-intensity interval training: A meta-analysis

Consensus is lacking regarding whether high-intensity interval training (HIIT) effectively improves VO₂max (VO₂peak) in elite athletes (Athlete must be involved in regular competition at the national level). This meta-analysis compared the effects of HIIT and conventional training methods (continuous training, repeated-sprint training, high volume low-intensity training, high-intensity continuous running, sprint-interval training, moderate-intensity continuous training)on VO₂max in elite athletes. Nine studies were included, comprising 176 elite athletes (80 female). Compared to that with conventional training, VO₂max was significantly increased after HIIT (overall: 0.58 [0.30, 0.87], I² = 0.49, P = 0.03; males: 0.41 [0.06, 0.76], I² = 0%, P = 0.89). VO₂max had positive training effects when the HIIT recovery period had an interval time ≥2 min (0.44 [0.03, 0.84], I² = 0%, P = 0.99) and recovery phase intensity ≤40% (0.38 [0.05, 0.71], I² = 0%, P = 0.96). Thus, HIIT shows superiority over conventional training methods in improving VO₂max, promoting aerobic capacity, in elite athletes.

Respiratory muscle training: a bibliometric analysis of 60 years' multidisciplinary journey

BACKGROUND

Over the decades, many publications have established respiratory muscle training (RMT) as an effective way in improving respiratory dysfunction in multiple populations. The aim of the paper is to determine the trend of research and multidisciplinary collaboration in publications related to RMT over the last 6 decades. The authors also sought to chart the advancement of RMT among people with spinal cord injury (SCI) over the last 60 years.

METHODS

Bibliometric analysis was made, including the publications' profiles, citation analysis and research trends of the relevant literature over the last 60 years. Publications from all time frames were retrieved from Scopus database. A subgroup analysis of publications pertinent to people with SCI was also made.

RESULTS

Research on RMT has been steadily increasing over the last 6 decades and across geographical locations. While medicine continues to dominate the research on RMT, this topic also continues to attract researchers and publications from other areas such as engineering, computer science and social science over the last 10 years. Research collaboration between authors in different backgrounds was observed since 2006. Source titles from non-medical backgrounds have also published articles pertinent to RMT. Among people with SCI, researchers utilised a wide range of technology from simple spirometers to electromyography in both intervention and outcome measures. With various types of interventions implemented, RMT generally improves pulmonary function and respiratory muscle strength among people with SCI.

CONCLUSIONS

While research on RMT has been steadily increasing over the last 6 decades, more collaborations are encouraged in the future to produce more impactful and beneficial research on people who suffer from respiratory disorders.

Role of breathing training programs on quality of life in chronic kidney disease patients

Background

Due to its chronic and progressive nature, chronic kidney disease (CKD) affects patients in many spheres including their perception of quality of life (QOL). Breathing training techniques have shown positive effects on health and QOL for different conditions.

Objective

The aim of this study was to perform a scoping review to examine the characteristics related to the application of breathing training on patients with CKD, and to identify the relevant outcomes and target group for the application of breathing training.

Methods

This scoping review was performed in accordance with PRISMA-SRc guidelines. We systematically searched three electronic databases for articles published before March 2022. The studies included patients with chronic kidney disease that received breathing training programs. The breathing training programs were compared to usual care or no treatment.

Results

A total of four studies were included in this scoping review. The four studies had heterogeneous disease stages and breathing training programs. All the studies included reported positive effects of breathing training programs on QOL of CKD patients.

Conclusion

The breathing training programs were able to improve the quality of life of patients with CKD undergoing hemodialysis treatment.

Sports Performance and Breathing Rate: What Is the Connection? A Narrative Review on Breathing Strategies

Breathing is a natural and necessary process for humans. At the same time, the respiratory pace and frequency can vary so much, depending on the status of the subject. Specifically, in sports, breathing can have the effect of limiting performance from a physiological point of view, or, on the other hand, breathing can regulate the psychological status of the athletes. Therefore, the aim of this narrative review is to focus on the literature about the physiological and psychological aspects of breathing pace in sports performance, merging these two aspects because they are usually considered split, in order to create a new integrated vision of breathing and sports performance. Voluntary breathing can be divided into a slow or fast pace (VSB and VFB, respectively), and their effects on both the physiological and psychological parameters are very different. VSB can benefit athletes in a variety of ways, not just physically but mentally as well. It can help improve cardiovascular fitness, reduce stress and anxiety, and improve overall health and well-being, allowing athletes to maintain focus and concentration during training and competition. VFB is normal during physical training and competition, but away from training, if it is not voluntary, it can cause feelings of anxiety, panic, dizziness, and lightheadedness and trigger a stress response in the body, affecting the athlete's quality of life. In summary, the role of breathing in the performance of athletes should be considered, although no definitive data are available. The connection between breathing and sports performance is still unclear, but athletes can obtain benefits in focus and concentration using slow breathing strategies.

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.

Effect of breathing exercises on oxidative stress biomarkers in humans: A systematic review and meta-analysis

Background

Breathing exercises improve oxidative stress in healthy young adults and patients with diabetes, hypertension, and chronic obstructive pulmonary disease. Furthermore, the mechanism of respiratory intervention is controversial. Therefore, in this meta-analysis, we aimed to systematically evaluate the effects of breathing exercises on oxidative stress biomarkers in humans and provide evidence for the clinical application of breathing exercises.

Methods

The Embase, PubMed, Cochrane Library, Web of Science, CNKI, and WANFANG databases were searched for studies about the effects of breathing exercises on human oxidative stress levels, with no restraints regarding time, race, or language. The experimental group included various breathing exercises, and the outcome index included malondialdehyde, superoxide dismutase, and glutathione, nitric oxide, vitamin C, or total antioxidant capacity levels from a randomized controlled trial. Data were extracted by more than two authors and reviewed by one author.

Results

Ten studies were included from five countries. Data from patients with no disease, chronic obstructive pulmonary disease, hypertension, or diabetes were included. Participants who performed breathing exercises had greater changes in the included biomarkers than those who did not, suggesting that these biomarkers can be used to evaluate oxidative stress after respiratory interventions.

Conclusion

Breathing exercises increased SOD and GSH activities and decreased MDA content.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022337119, identifier CRD42022337119.

Training the equine respiratory muscles: Ultrasonographic measurement of muscle size

BACKGROUND

Limited information exists regarding changes in the size of respiratory and locomotor muscles in response to exercise training in the Thoroughbred racehorse.

OBJECTIVES

To describe and compare the responses of the respiratory and locomotor muscles to conventional exercise training and inspiratory muscle training (IMT).

STUDY DESIGN

Prospective randomised controlled trial.

METHODS

Thoroughbred racehorses, in training for competition in National Hunt races, were recruited from two training establishments. Ultrasonographic images were obtained for selected muscles of the upper airway, diaphragm, accessory respiratory, and locomotor systems and their sizes measured. Examinations were performed at three timepoints: (A) when unfit, (B) following 12 weeks of conventional exercise training and (C) following 10-12 weeks continued training at race fitness. In addition, horses at yard 1 performed IMT, between timepoint B and C, and were randomly assigned into high-load (treatment) or low-load (control) group. Repeated measures models were constructed to compare the change in muscle measurements over time, and to investigate the effects of yard, previous airway surgery and IMT on the change in ultrasonographic size measurements obtained.

RESULTS

Upper airway muscle size increased in response to conventional race training between timepoints A-C, and B-C. Diaphragm size increased in response to conventional exercise training between timepoints A and B. The diaphragm size of horses that undertook high-load IMT was either maintained or increased, whereas diaphragm size decreased in horses that undertook low-load IMT or no IMT between timepoints B and C. A significant interaction between gluteal muscle size and airway surgery status was observed, with greater gluteal muscle thicknesses measured in horses that had not previously undergone airway surgery (left gluteal 3.9%, p < 0.001; right 4.5%, p = 0.04).

MAIN LIMITATIONS

Low number of horses underwent IMT.

CONCLUSIONS

Respiratory and locomotor muscles increase in size in response to conventional exercise training, with a further change in diaphragm size in response to inspiratory muscle training.

Training the equine respiratory muscles: Inspiratory muscle strength

BACKGROUND

Little is known about the response of the equine respiratory muscles to training.

OBJECTIVES

To measure an index of inspiratory muscle strength (IMSi) before and after a period of conventional exercise training (phase 1) and inspiratory muscle training (IMT), comparing high-load (treatment) and low-load (control) groups (phase 2).

STUDY DESIGN

Prospective randomised controlled trial.

METHODS

Phase 1: Twenty National Hunt Thoroughbred racehorses performed an inspiratory muscle strength test (IMST) twice on two occasions; when unfit at timepoint A (July), and when race fit at timepoint B (October). Phase 2: Thirty-five Thoroughbred racehorses at race fitness were randomly assigned into a high-load (treatment, n = 20) or low-load (control, n = 15) IMT group. The high-load group followed an IMT protocol that gradually increased the inspiratory pressure applied every 4 days. The low-load group underwent sham IMT with a low training load. The IMT was performed 5 days/week for 10 weeks. The IMST was performed twice on two occasions, timepoint B (October) and timepoint C (January). Conventional exercise training and racing continued during the study period. The peak IMSi values obtained from the different groups at timepoints A, B and C were compared using a Wilcoxon Signed Rank Test.

RESULTS

Phase 1: There was a significant increase in IMSi from timepoint A: 22.5 cmH₂ O (21-25) to timepoint B: 26 cmH₂ O (24-30) (p = 0.015). Phase 2: From timepoint B to C there was a significant increase in IMSi for the high-load group 34 cmH₂ O (28-36) (p = 0.001) but not the low-load group 26 cmH₂ O (24-30) (p = 0.929). The peak IMSi at timepoint C was significantly higher for the high-load than low-load group (p = 0.019).

MAIN LIMITATIONS

Single centre study with only National Hunt horses undergoing race-training included.

CONCLUSIONS

In horses undergoing race training there is a significant increase in IMSi in response to conventional exercise training and high-load IMT.

Effects of an incentive spirometer versus a threshold inspiratory muscle trainer on lung functions in Parkinson's disease patients: a randomized trial

Upper airway obstruction, reduced maximal expiratory and inspiratory flows, reduced lung volumes, abnormal ventilatory control, and diaphragmatic dyskinesias are reported in patients with Parkinson's disease (PD). Inspiratory muscle training (IMT) has been reported to be effective in improving respiratory functions; however, no studies have compared the effects of the incentive spirometer (IS) with the threshold inspiratory muscle trainer (TIMT) in patients with PD. The study aimed to compare the effects of IS and TIMT on maximum inspiratory pressure (MIP), 6-min walk distance (6-MWD), forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), and peak expiratory flow rate (PEFR) in patients with stage 1-3 according to the Hoehn and Yahr scale. 18 patients were randomly assigned to two groups, i.e., incentive spirometer (IS) and threshold inspiratory muscle trainer (TIMT) group. The IS group received IMT with volume-based IS, and the TIMT group received IMT with TIMT. MIP, 6-MWD, FVC, FEV1, and PEFR were measured before and after six weeks of training. In IS group: A significant increase (p < 0.05) was observed in MIP and 6-MWD by 18.13 and 5%, respectively. In the TIMT group: A significant increase (p < 0.05) was observed in MIP and 6-MWD by 30.15 and 8.94%, respectively. Both groups observed no significant difference (p > 0.05) in FVC, FEV1, and PEFR. When the two groups were compared, a greater increase (p < 0.05) was observed in the MIP and 6-MWD in the TIMT group compared to IS group. IMT with IS or TIMT for six weeks effectively increased MIP and 6-MWD in patients with stage 1-3 (Hoehn and Yahr scale) of PD. No improvement was observed in FVC, FEV1, or PEFR with any of the techniques. TIMT is more effective than IS in improving MIP and 6-MWD.

The effect of exercise hyperpnea on gross efficiency and anaerobic capacity estimates during a 3-min cycle time trial

This study aimed to analyze the effect of exercise-induced hyperpnea on gross efficiency (GE) and anaerobic capacity estimates during a self-paced 3-min supramaximal cycle time trial (TT). Fourteen highly trained male cyclists performed 7 × 4-min submaximal stages, a 6-min passive rest, a 3-min TT, a 5-min passive rest, and a 6-min submaximal stage. Three models were based on the 7 × 4-min linear regression extrapolation method, using 1) the conventional model (7-Y_LIN); 2) the same 7-Y_LIN model but correcting for the additional ventilatory cost (i.e., hyperpnea) (7-Y_LIN-V-cor); and 3) accounting for linearly declining GE during the TT (7-Y_LIN-D). The other three models were based on GE from the last submaximal stage, using the conventional model (GE_LAST) and the same modifications as described for 7+Y_LIN, i.e., 1) GE_LAST, 2) GE_LAST-V-cor, and 3) GE_LAST-D. The GE_LAST model generated 18% higher values of anaerobic capacity than the 7-Y_LIN model (P < 0.05). During the TT, the hyperpnea-corrected model (i.e., 7-Y_LIN-V-cor or GE_LAST-V-cor) generated, compared with the respective conventional model (i.e., 7-Y_LIN or GE_LAST), ∼0.7 percentage points lower GE and ∼11% higher anaerobic capacity (all, P < 0.05). The post-TT GE was 1.9 percentage points lower (P < 0.001) and the 7-Y_LIN-D or GE_LAST-D model generated, compared with the respective conventional model, a lower GE (∼1.0 percentage points) and ∼17% higher anaerobic capacity during the TT (all, P < 0.05). In conclusion, the correction for a declining GE due to hyperpnea during a supramaximal TT resulted in an increased required total metabolic rate and anaerobic energy expenditure compared with the conventional models.NEW & NOTEWORTHY This study demonstrates that GE declines during a 3-min supramaximal cycle TT, which is possibly related to the hyperpneic response during supramaximal exercise. The finding from this study also provides novel insight into how the increased ventilatory energy cost from exercise-induced hyperpnea contributes to decreased GE, increased required total metabolic rate, and increased anaerobic energy expenditure during supramaximal exercise. Therefore, conventional linear models for estimating anaerobic capacity are likely to generate underestimated values.

Functional assessment of respiratory muscles and lung capacity of CrossFit athletes

CrossFit is a high-intensity training related to physical fitness and respiratory capacity that can promote changes in lung function. This cross-sectional study was aimed at evaluating respiratory muscle strength, electromyographic (EMG) activity, and lung capacity in CrossFit athletes. Thirty subjects aged between 25 and 35 years were divided into groups: CrossFit athletes (n=15) and sedentary individuals without comorbidities (n=15). Respiratory muscle strength was evaluated using maximal inspiratory and expiratory pressures, lung capacity, and EMG of the sternocleidomastoid, serratus anterior, external intercostal, and diaphragm muscles at respiratory rest, maximal inspiration and expiration, and respiratory cycle. Data were tabulated and subjected to statistical analyses (t-test and Spearman test, P<0.05). Respiratory muscle strength on EMG of the sternocleidomastoid, serratus, external intercostal, and diaphragm muscles at the respiratory cycle and maximal forced inspiration and expiration were higher in the CrossFit athletes group than in the sedentary group without comorbidities. CrossFit athlete group showed significantly strong positive correlation between maximal inspiratory and expiratory muscle strengths (Spearman rho= 0.903, P=0.000), with increasing muscle strength during inspiration favoring an increase in strength during expiration. The forced vital capacity (FVC) and forced expiratory volume in 1 sec (FEV₁) also showed a significantly high positive correlation (Spearman rho=0.912, P=0.000) in the CrossFit athletes group, showing that higher FVC favors higher FEV₁. The results of this study suggest that improved fitness is based on increased respiratory muscle strength on EMG in CrossFit athletes.