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Search Results (221)

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Keywords = inspiratory muscles

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16 pages, 1132 KB  
Entry
Inspiratory Muscle Training in Heart Failure as a Promising Tool in the Heart Failure Toolkit: From Physiology to Practice
by Maria Isakoglou and Eleni A. Kortianou
Encyclopedia 2026, 6(5), 111; https://doi.org/10.3390/encyclopedia6050111 - 18 May 2026
Viewed by 307
Definition
Heart failure (HF) is a heterogeneous clinical syndrome with increasing prevalence among adults worldwide. It is characterized by complex central and peripheral alterations that contribute to exercise intolerance, fatigue, dyspnea, and reduced quality of life. Inspiratory muscle weakness (IMW) plays a key role [...] Read more.
Heart failure (HF) is a heterogeneous clinical syndrome with increasing prevalence among adults worldwide. It is characterized by complex central and peripheral alterations that contribute to exercise intolerance, fatigue, dyspnea, and reduced quality of life. Inspiratory muscle weakness (IMW) plays a key role in this vicious cycle by exacerbating symptoms and further limiting functional capacity. Inspiratory muscle training (IMT) has emerged as a potential adjuvant in comprehensive HF management and is a physiologically grounded and promising tool in the contemporary HF therapeutic toolkit. Its integration into multimodal rehabilitation programs may mitigate the cycle of dyspnea and deconditioning in patients with HF. On this basis, we provide an overview of the pathophysiological mechanisms underlying IMW and present the practical characteristics of IMT programs, synthesizing current evidence regarding its clinical efficacy and implementation challenges. Full article
(This article belongs to the Section Medicine & Pharmacology)
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29 pages, 643 KB  
Review
Prehabilitation Before Cardiac Surgery and Structural Heart Interventions: An Umbrella Review of Pooled Evidence
by Elen H. Hughes, Robyn Lotto, Ellen A. Dawson, Mohamed Saber, Ethan Richards, Adrian Morris, David Mayhew, Fahmi Faraz, Reza Ashrafi and Julia D. Jones
J. Clin. Med. 2026, 15(10), 3821; https://doi.org/10.3390/jcm15103821 - 15 May 2026
Viewed by 99
Abstract
Background: Prehabilitation aims to optimise patients before cardiac procedures through interventions including exercise training, respiratory conditioning, nutritional support, psychological preparation and multimodal lifestyle programmes. Evidence from systematic reviews and meta-analyses is increasing but remains heterogeneous due to variation in intervention design, patient [...] Read more.
Background: Prehabilitation aims to optimise patients before cardiac procedures through interventions including exercise training, respiratory conditioning, nutritional support, psychological preparation and multimodal lifestyle programmes. Evidence from systematic reviews and meta-analyses is increasing but remains heterogeneous due to variation in intervention design, patient populations and overlap of primary studies. Methods: We conducted an umbrella review of 17 systematic reviews and meta-analyses evaluating prehabilitation prior to cardiac surgery and structural heart interventions in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Methodological quality of included reviews was assessed using A Measurement Tool to Assess Systematic Reviews 2 (AMSTAR 2). Outcomes of interest were postoperative pneumonia, hospital length of stay (LOS), and mortality. Results: Across pooled analyses, the most consistent finding was a reduction in postoperative pneumonia, particularly in studies incorporating inspiratory muscle training (IMT), with relative risk reductions of approximately 55–62%, corresponding to a modest absolute risk reduction. Reductions in hospital LOS were also reported, although effect sizes were smaller and more variable. In contrast, no consistent reduction in short-term mortality was demonstrated, likely reflecting low event rates. The evidence base was limited by substantial overlap between reviews and predominantly low or critically low methodological quality. Conclusions: Prehabilitation, particularly when incorporating IMT, is consistently associated with a reduction in postoperative pneumonia and may contribute to modest reductions in hospital LOS. However, the evidence base is constrained by heterogeneity, study overlap and low methodological quality. Further high-quality, adequately powered randomised trials are required to define the role of prehabilitation in contemporary cardiac surgical and structural intervention practice. Full article
(This article belongs to the Special Issue Clinical Insights and Advances in Structural Heart Disease)
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17 pages, 701 KB  
Article
Heart Rate Recovery After Six-Minute Walk Test, Pulmonary Function, Dyspnea, and Functional Status After COVID-19
by Adriano Luis Fonseca, Miriã Cândida Oliveira, Daniela Rosana Pedro Fonseca, João Pedro R. Afonso, Heren Nepomuceno Costa Paixão, Jairo Belém Soares Ribeiro Júnior, Larissa Rodrigues Alves, Tiago Vieira Fernandes, Daniel Grossi Marconi, Rodrigo A. C. Andraus, Carlos Hassel Mendes Silva, Iransé Oliveira-Silva, Orlando Aguirre Guedes, Claudia S. Oliveira, Natasha Yumi Matsunaga Spicacci, Maria Clara Real Pedro Fonseca, Wilson Rodrigues Freitas Júnior, Paolo Capodaglio and Luis Vicente F. Oliveira
COVID 2026, 6(5), 82; https://doi.org/10.3390/covid6050082 (registering DOI) - 14 May 2026
Viewed by 98
Abstract
Introduction: Coronavirus disease 2019 (COVID-19) can cause persistent cardiovascular alterations, including autonomic dysfunction. Heart rate (HR) recovery (HRR) after exercise is a simple marker of autonomic modulation associated with functional capacity and clinical prognosis. Evaluating HRR during the six-minute walk test (6MWT) may [...] Read more.
Introduction: Coronavirus disease 2019 (COVID-19) can cause persistent cardiovascular alterations, including autonomic dysfunction. Heart rate (HR) recovery (HRR) after exercise is a simple marker of autonomic modulation associated with functional capacity and clinical prognosis. Evaluating HRR during the six-minute walk test (6MWT) may help identify residual functional limitations in diverse patients. Objective: To compare pulmonary function, maximal inspiratory pressure (MIP), functional capacity, dyspnea, fatigue, and functional status in post-COVID-19 patients. Methods: This cross-sectional study included 75 adults (mean age: 47.6 ± 13.1 years; 54.7% male) who recovered from COVID-19 divided into 2 groups based on HRR 1 min after the 6MWT: delayed (≤12 beats/min); and non-delayed (>12 beats/min). Pulmonary function, MIP, exercise capacity (via 6MWT), dyspnea, muscle fatigue, and functional status were assessed. Results: Based on HRR 1 min after 6MWT, 27 (36%) participants were classified with abnormal HRR and 48 (64%) with normal HRR. There were statistical differences between the groups regarding demographic or clinical characteristics, pulmonary function, MIP, muscle fatigue, or functional status (p > 0.05). The delayed HRR group exhibited a smaller reduction in HR in first minute of recovery (ΔHR = 6 vs. 23 beats/min), higher baseline HR (p = 0.010), and greater dyspnea (p = 0.020). Furthermore, this group exhibited worse functional performance in the 6MWT, with shorter distance walked (437.33 vs. 494.27 m; p = 0.019) and a lower percentage of predicted distance (74.66 ± 12.98% vs. 82.94 ± 15.71%; p = 0.023) compared with the non-delayed HRR group. Conclusion: Delayed HRR post-COVID-19 was associated with poorer functional performance and greater dyspnea, regardless of pulmonary function. The blunted reduction in HRR after exertion suggests impaired cardiovascular autonomic modulation, possibly related to attenuated vagal reactivation, which may contribute to exercise intolerance observed in this population. Full article
(This article belongs to the Special Issue Post-COVID-19 Muscle Health and Exercise Rehabilitation)
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14 pages, 636 KB  
Article
Effects of Resistance Respiratory Training on Respiratory Muscle Strength in Healthy Active Individuals
by Antonela Karmen Ivišić, Dario Vrdoljak, Nikola Foretić, Vladimir Pavlinović and Ivan Drviš
Muscles 2026, 5(2), 34; https://doi.org/10.3390/muscles5020034 - 8 May 2026
Viewed by 200
Abstract
Background: Respiratory muscle strength (RMS) is a critical factor influencing athletic performance, particularly in high-intensity or prolonged activities. RMS encompasses inspiratory (IMs) and expiratory muscles (EMs), which differ in anatomical structure, fiber composition, and responsiveness to training. Methods: This pilot interventional within-subject study [...] Read more.
Background: Respiratory muscle strength (RMS) is a critical factor influencing athletic performance, particularly in high-intensity or prolonged activities. RMS encompasses inspiratory (IMs) and expiratory muscles (EMs), which differ in anatomical structure, fiber composition, and responsiveness to training. Methods: This pilot interventional within-subject study investigated the effects of two resistive respiratory muscle training (RMT) protocols on RMS and small airway function in eight physically active adults (two females, six males). Maximal inspiratory (MIP) and expiratory pressures (MEP), along with pulmonary function tests (PFTs), were measured using the Airofit PRO™ device and spirometry before and after two consecutive 7-day training protocols, with a 2-day break between interventions. The workload was progressively increased by lengthening the duration of forced inhalation and exhalation, while keeping the air resistance constant. Results: Results demonstrated significant improvements in MEP across both protocols and after a 10-day washout period (p < 0.001–0.03), whereas MIP showed no significant changes (p = 0.19–0.66). Moderate transient improvements were observed in small airway flow (MEF25%) following the first protocol (ES = 0.62), which regressed after the second. Conclusions: These outcomes suggest differential responsiveness of respiratory muscles to RMT; EMs, characterized by a higher proportion of fast-twitch type II fibers and a predominantly passive role in normal breathing, respond rapidly to short-duration, high-intensity forced expiration training through neuromuscular adaptations. Conversely, IMs, dominated by slow-twitch type I fibers, require longer-duration, higher-load training to elicit meaningful adaptations, explaining the limited changes in MIP. Small airway function appeared minimally trainable due to structural and physiological constraints, with short-term improvements likely reflecting effort-dependent factors rather than lasting adaptations. Finally, RMT can selectively enhance EM performance through appropriately designed short-duration, high-intensity interventions, while IMs may necessitate prolonged or higher-load stimuli. The findings highlight the importance of targeted training strategies, individualized to muscle fiber composition and functional demands, to optimize respiratory performance. Future research should investigate longer interventions, larger diverse cohorts, and precise measurement methods to further elucidate RMT’s effects on both respiratory muscles and small airway function. Full article
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22 pages, 628 KB  
Article
Exercise-Based Rehabilitation in Severe COVID-19 Survivors with Long COVID: A Randomized Controlled Pilot Study
by Edson Fonseca Pinto, Nailton José Brandão Albuquerque Filho, Jéssica Costa Leite, Tatianne Moura Estrela Gusmão, Larissa Nayara de Souza, Roque Ribeiro da Silva Júnior, Maria Irany Knackfuss and Grasiela Piuvezam
Med. Sci. 2026, 14(2), 222; https://doi.org/10.3390/medsci14020222 - 29 Apr 2026
Viewed by 448
Abstract
Introduction: Post-hospital rehabilitation is essential for survivors of severe COVID-19, as prolonged immobility and clinical severity often lead to muscle weakness, reduced cardiovascular capacity, and impaired respiratory function. Physical exercise during and after hospitalization may mitigate these effects and support functional recovery. This [...] Read more.
Introduction: Post-hospital rehabilitation is essential for survivors of severe COVID-19, as prolonged immobility and clinical severity often lead to muscle weakness, reduced cardiovascular capacity, and impaired respiratory function. Physical exercise during and after hospitalization may mitigate these effects and support functional recovery. This study aimed to evaluate the effectiveness of a physical exercise-based rehabilitation program in survivors of severe COVID-19. Methodology: A randomized clinical trial was conducted with 30 survivors allocated to two groups: multicomponent exercise (GEm) and multicomponent exercise combined with inspiratory muscle training (GEmTMI). The interventions were performed three times per week for 40–60 min. Quality of life, physical activity level, functional status, and physical capacity were assessed before and after six weeks. Results: Comparisons between GEm and GEmTMI showed significant differences in the 6 min walk test (6MWT) at baseline (p = 0.043) and in the Physical Activity Index (IPAQ) after the intervention (p = 0.002). When the total sample was analyzed, significant improvements were observed across all outcomes after rehabilitation, including quality of life (SF-36), functional capacity (PCFS), physical activity level (IPAQ), respiratory muscle strength, and additional functional tests. Notable improvements included SF-36 Physical Functioning (p = 0.006) and Social Functioning (p = 0.009), PCFS (p = 0.011), IPAQ (p = 0.012), and performance in the 6MWT, STS, STS-1min, TUG, handgrip strength, PEmax, and PImax (all p < 0.001). Discussion: Multicomponent physical rehabilitation, with or without inspiratory muscle training, produced significant gains in physical activity level, functional capacity, dynamic balance, neuromuscular fitness, respiratory muscle strength, and quality of life. These findings underscore the importance of structured post-ICU rehabilitation to support comprehensive physical and psychosocial recovery in survivors of severe COVID-19. Full article
(This article belongs to the Section Pneumology and Respiratory Diseases)
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13 pages, 2003 KB  
Article
Respiratory Cycle Influence on Lumbosacral Muscle Function: A Tensiomyographic Analysis
by Anthony B. Trombetta, William J. Hanney, Abigail W. Anderson and Morey J. Kolber
Muscles 2026, 5(2), 30; https://doi.org/10.3390/muscles5020030 - 28 Apr 2026
Viewed by 215
Abstract
Background: Tensiomyography (TMG) offers a noninvasive means of evaluating skeletal muscle contractile properties, including muscle displacement (Dm), delay time (Td), contraction time (Tc), half-relaxation time (Tr), and sustain time (Ts). When applied to lumbosacral musculature, interpretation may be influenced by changes in muscle [...] Read more.
Background: Tensiomyography (TMG) offers a noninvasive means of evaluating skeletal muscle contractile properties, including muscle displacement (Dm), delay time (Td), contraction time (Tc), half-relaxation time (Tr), and sustain time (Ts). When applied to lumbosacral musculature, interpretation may be influenced by changes in muscle stiffness that occur across the respiratory cycle. Understanding these fluctuations is essential for improving measurement consistency and data interpretation. Methods: Thirty healthy young adults (mean ± SD age = 21.07 ± 1.55 years) underwent TMG assessment of the erector spinae (ES) and latissimus dorsi (LD) at four distinct lung volumes: end-tidal inspiratory volume (ETIV), end-tidal expiratory volume (ETEV), total lung capacity (TLC), and residual volume (RV). Visual cues were used to guide participants’ respiratory phases. Paired-samples t-tests compared TMG parameters across respiratory conditions. Results: For the ES, significant differences were observed in Dm, Tr, and Ts between ETIV and ETEV (p ≤ 0.05), ETIV and TLC (p ≤ 0.05), and ETEV and RV (p ≤ 0.05). No statistically significant differences were identified for the LD (p ≥ 0.12). Conclusions: Some erector spinae contractile properties vary across the respiratory cycle, which may affect TMG outcomes. The findings of this research lend belief to the idea that a standardized respiratory phase during data collection may improve the reliability and comparability of TMG measurements involving trunk musculature. Future research could address the negative findings for latissimus dorsi and further determine which muscles require respiratory standardization. Full article
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27 pages, 3221 KB  
Systematic Review
Prehabilitation in Patients Undergoing Cardiac Surgery: An Umbrella Review of Systematic Reviews and Meta-Analysis
by Abubakar I. Sidik, Maxim L. Khavandeev, Malik K. Al-Ariki, Vladislav V. Dontsov, Ivan G. Karpenko, Anvar K. Djumanov, Alina V. Ogurchikova, Sergey A. Kurnosov and Dadaev Shirin
Surgeries 2026, 7(2), 49; https://doi.org/10.3390/surgeries7020049 - 23 Apr 2026
Viewed by 474
Abstract
Background/Objective: Prehabilitation aims to improve physiological reserve before surgery to enhance postoperative outcomes. Multiple systematic reviews have evaluated preoperative interventions in adult cardiac surgery; however, variability in scope, methodological quality, and overlap of primary trials complicates interpretation. The aim of this study [...] Read more.
Background/Objective: Prehabilitation aims to improve physiological reserve before surgery to enhance postoperative outcomes. Multiple systematic reviews have evaluated preoperative interventions in adult cardiac surgery; however, variability in scope, methodological quality, and overlap of primary trials complicates interpretation. The aim of this study is to synthesise and critically appraise evidence from systematic reviews and meta-analyses evaluating prehabilitation interventions in adults undergoing cardiac surgery. No funding was received for this study. Methods: We conducted an umbrella systematic review following a prospectively registered protocol (PROSPERO: CRD420261292354) and PRISMA 2020 guidance. PubMed, Web of Science, and Scopus were searched from inception to 31 December 2025. Eligible reviews included adults (≥18 years) undergoing cardiac surgery, evaluated and compared preoperative inspiratory muscle training (IMT), respiratory muscle training, and exercise-based, educational, or multimodal prehabilitation with usual care or sham intervention. Reviews focused solely on postoperative interventions or non-cardiac surgery were excluded. Methodological quality was assessed using AMSTAR-2. Certainty of evidence was evaluated using GRADE. Overlap of primary studies was quantified using the Corrected Covered Area (CCA). A structured narrative synthesis with a direction-of-effect framework was applied. Results: Eighteen systematic reviews (published 2012–2025) were included, comprising 46 unique primary studies and more than 6674 participants (exact totals unavailable due to incomplete reporting in at least one review). Overall overlap was high (CCA 12.5%). Respiratory-focused prehabilitation, particularly IMT, demonstrated consistent reductions in postoperative pulmonary complications (PPCs) (risk ratios approximately 0.42–0.53), pneumonia (RR ~0.44–0.45), and atelectasis (RR ~0.49–0.59), favouring prehabilitation over usual care. Hospital length of stay was reduced by approximately 1.5–3 days across multiple reviews. Inspiratory muscle strength improved consistently (mean difference ~+12 to +17 cmH2O). Effects on ICU length of stay and mechanical ventilation duration were inconsistent or non-significant. Exercise-based programmes improved functional capacity (6 min walk distance increase ~50–75 m) and showed modest reductions in hospital stay, but heterogeneity was substantial. No intervention demonstrated a consistent reduction in postoperative mortality. Evidence was limited by clinical heterogeneity, performance bias in primary trials, inconsistent outcome definitions, and high overlap of key IMT trials across reviews. Mortality outcomes were underpowered. Conclusions: Preoperative IMT provides evidence for reducing pulmonary complications and shortening hospital stays in adult cardiac surgery. Exercise-based prehabilitation improves functional capacity but requires further high-quality, standardised trials. Integration of respiratory prehabilitation into cardiac surgical pathways appears supported by the current evidence. Full article
(This article belongs to the Section Cardiothoracic and Vascular Surgery)
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14 pages, 879 KB  
Systematic Review
Physical Exercise in Myasthenia Gravis: A Systematic Review
by Claudia Vinciguerra, Ignazio Leale, Nicasio Rini, Fabio Tiziano Orlando, Liliana Bevilacqua, Paolo Barone, Filippo Brighina, Vincenzo Di Stefano and Giuseppe Battaglia
Healthcare 2026, 14(8), 1100; https://doi.org/10.3390/healthcare14081100 - 20 Apr 2026
Viewed by 695
Abstract
Background: Myasthenia gravis (MG) is a chronic autoimmune disorder characterized by fluctuating skeletal muscle weakness and fatigue, leading to reduced functional independence and impaired quality of life (QoL). Although exercise has historically been discouraged due to concerns about symptom exacerbation, emerging evidence suggest [...] Read more.
Background: Myasthenia gravis (MG) is a chronic autoimmune disorder characterized by fluctuating skeletal muscle weakness and fatigue, leading to reduced functional independence and impaired quality of life (QoL). Although exercise has historically been discouraged due to concerns about symptom exacerbation, emerging evidence suggest that structured exercise programs may be safe and beneficial in clinically stable patients. This systematic review critically evaluates current evidence on exercise and physical activity interventions in MG, focusing on effectiveness, safety, and impact on functional outcomes, fatigue, and QoL. Materials and Methods: A systematic review was conducted following PRISMA guidelines. Searches were performed in PubMed, Web of Science, Google Scholar, Scopus and ScienceDirect for studies published between 2015 and 2025. Keywords included MG, physical activity, aerobic training, resistance training, and respiratory muscle training. Methodological quality was assessed using the Downs and Black checklist. Results: Eight controlled studies met the inclusion criteria, encompassing aerobic, resistance, combined, and respiratory muscle training interventions. Sample sizes ranged from small pilot studies to moderate-size randomized controlled trials. Overall, exercise interventions were well tolerated, with no evidence of sustained symptoms exacerbation. Aerobic and combined programs consistently improved functional capacity, muscle strength, and activities of daily living. Respiratory muscle training demonstrated improvements in pulmonary function and inspiratory muscle strength, although findings were more heterogeneous. Study quality ranged from poor to excellent, with common limitations including small sample size, short follow-up duration, and heterogeneity in exercise programs. Conclusions: Current evidence supports the safety and potential efficacy of individualized, symptom-guided exercise interventions in clinically stable MG. Regular physical activity exercise may reduce secondary deconditioning, improve functional outcomes, and enhance QoL. However, larger, high-quality randomized controlled trials with standardized programs and longer follow-up periods are required to strengthen clinical recommendations and clarify long-term effects. Full article
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15 pages, 513 KB  
Article
Comparisons of Respiratory Function and Cardiorespiratory Responses Induced by the Modified Shuttle Walk Test in Children Finswimmers and Age-Matched Sedentary Non-Athletes
by Theano Michailidou, Aspasia Mavronasou and Eleni A. Kortianou
J. Clin. Med. 2026, 15(7), 2806; https://doi.org/10.3390/jcm15072806 - 7 Apr 2026
Viewed by 401
Abstract
Background: Regular aerobic exercise during childhood promotes critical physiological adaptations in the cardiovascular and respiratory system. Finswimming, a unique aquatic sport, requires high-intensity demands and specific breathing patterns. The present study aimed to compare respiratory function and cardiorespiratory responses between young male [...] Read more.
Background: Regular aerobic exercise during childhood promotes critical physiological adaptations in the cardiovascular and respiratory system. Finswimming, a unique aquatic sport, requires high-intensity demands and specific breathing patterns. The present study aimed to compare respiratory function and cardiorespiratory responses between young male finswimmers and sedentary age-matched non-athletes. Methods: Thirty-two boys aged 8 to 12 years old were stratified into the finswimmers group (FSG, n = 16) and the non-athletes group (NAG, n = 16). Assessments included pulmonary function (spirometry) and respiratory muscle strength (Maximum Inspiratory Pressure, MIP/Maximum Expiratory Pressure, MEP). Exercise capacity was evaluated using the modified shuttle walk test (MSWT). Results: The FSG exhibited significantly higher pulmonary function (Forced Vital Capacity, Forced Expiratory Volume in 1 s, Maximum Voluntary Ventilation; p < 0.05) and superior MIP compared to the NAG (105.3 ± 24.8 versus 87.3 ± 24.7 cmH2O; p = 0.022). During the MSWT, FSG covered substantially greater distances (746.6 ± 97.2 versus 591.1 ± 86.4 m; p < 0.001) with lower levels of leg fatigue (Borg 0–10) (0.53 ± 0.39 versus 2.13 ± 1.93; p = 0.004) and demonstrated lower heart rate recovery time (4.47 ± 0.68 versus 5.75 ± 0.68 min; p < 0.001) compared to NAG. At the iso-level (8th level of MSWT), FSG scored lower levels of leg fatigue (0.13 ± 0.12 versus 2.02 ± 2.0; p = 0.001) compared to NAG, indicating better peripheral oxygen % saturation (100 ± 0.0 versus 98.14 ± 1.16; p < 0.001). Conclusions: Systematic exercise training enhances profound cardiorespiratory and peripheral muscle adaptations in children. Enhanced cardiorespiratory function allows young athletes to achieve higher workloads and recover faster than sedentary peers, highlighting the sport’s role in establishing a robust cardiorespiratory fitness. Full article
(This article belongs to the Special Issue Insights and Innovations in Sports Cardiology)
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17 pages, 736 KB  
Article
The Mediating Role of Adiposity in the Association Between Respiratory Muscle Strength and Exercise Energy Expenditure in Adult Women: A Cross-Sectional Study
by Monira I. Aldhahi, Daad Alhumaid, Dalia Binshaye, Fatimah Almohsen, Rand Alotaibi and Leen Bahathiq
J. Clin. Med. 2026, 15(7), 2629; https://doi.org/10.3390/jcm15072629 - 30 Mar 2026
Viewed by 601
Abstract
Background and Objectives: Obesity affects over 1.9 billion adults globally, with a disproportionately higher prevalence in Saudi Arabia among women. While excessive adiposity is known to impair respiratory mechanics and lung function, its relationship with respiratory muscle strength and exercise energy expenditure remains [...] Read more.
Background and Objectives: Obesity affects over 1.9 billion adults globally, with a disproportionately higher prevalence in Saudi Arabia among women. While excessive adiposity is known to impair respiratory mechanics and lung function, its relationship with respiratory muscle strength and exercise energy expenditure remains inadequately elucidated. This study examined differences in respiratory muscle strength, metabolic equivalents (METs) of physical activity, and energy expenditure during exercise between adults with normal and high body fat percentage (BF%) and explored the statistical role of body fat as a potential mediator in the cross-sectional association between respiratory muscle strength and energy expenditure. Methods: In this cross-sectional study, 126 Saudi women aged 18–45 years (mean age: 21.7 ± 4.2 years) were stratified into normal (n = 63) and high (n = 63) BF% groups. Body composition was assessed via bioelectrical impedance analysis, and respiratory muscle strength (MIP and MEP) was measured using a MicroRPM device. Peak oxygen consumption (VO2peak) and energy expenditure were obtained through the Bruce Submaximal Treadmill Protocol, and physical activity was self-reported via the IPAQ. Hierarchical regression and structural equation modeling were used to examine variable associations and explore statistical mediation patterns. Results: Participants with high body fat demonstrated significantly low MIP (−26%) and MEP (−31%), low VO2peak (−13%), and approximately 26% high energy expenditure during exercise compared to the normal-BF group (all p < 0.001), despite comparable self-reported physical activity levels. Body fat percentage was the most strongly associated with energy expenditure (β = 0.078, R2 = 0.329), with maximal inspiratory pressure contributing an additional 7.3% of explained variance in hierarchical regression (total R2 = 0.414). Mediation analyses revealed that body fat percentage was statistically consistent with a partial mediation model in the relationship between MIP and energy expenditure (indirect association = −0.016, p = 0.033), accounting for 27% of the total association, and between MEP and energy expenditure (indirect association = −0.013, p = 0.035), accounting for 38% of the total association. Conclusions: High BF% is independently associated with low respiratory muscle strength and high exercise metabolic cost. Body fat is statistically associated with (and consistent with a mediating role in) an inverse relationship between respiratory muscle strength and energy expenditure. Alternative directional relationships and shared underlying factors may explain these observations. Full article
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18 pages, 2214 KB  
Systematic Review
The Impact of Inspiratory Muscle Training on Diaphragm Thickness in Healthy Adults: A Systematic Review and Meta-Regression
by Cemre Didem Eyipınar, Tolga Altuğ, Mesut Süleymanoğulları, Aslıhan Tekin, Nicola Luigi Bragazzi, Valentina Stefanica and Halil İbrahim Ceylan
Medicina 2026, 62(3), 609; https://doi.org/10.3390/medicina62030609 - 23 Mar 2026
Viewed by 806
Abstract
Background and Objectives: The hypertrophic adaptation of the diaphragm to inspiratory muscle training (IMT) remains insufficiently characterized, particularly in healthy and athletic populations. To address this gap, we conducted a meta-analysis and meta-regression to evaluate the effects of IMT on diaphragm thickness [...] Read more.
Background and Objectives: The hypertrophic adaptation of the diaphragm to inspiratory muscle training (IMT) remains insufficiently characterized, particularly in healthy and athletic populations. To address this gap, we conducted a meta-analysis and meta-regression to evaluate the effects of IMT on diaphragm thickness and identify potential moderating factors. Materials and Methods: A systematic search was conducted across PubMed, MEDLINE, Embase, CINAHL, and SPORTDiscus as well as Google Scholar (gray literature) through November 2025. Eight studies involving 203 healthy participants met the inclusion criteria. A random-effects model was used to calculate pooled effect sizes and meta-regression estimates. Results: IMT produced a statistically significant moderate increase in diaphragm muscle thickness, with a standardized mean difference (SMD) of Hedges’ g = 0.52 (95% CI: 0.19 to 0.85; p < 0.05). Subgroup analyses indicated that IMT with 50% maximal inspiratory pressure (MIP) produces a statistically significant effect (p = 0.0069), whereas fitness status and age did not significantly influence outcomes (p = 0.589 and p = 0.126, respectively). Meta-regression analyses revealed that only baseline MIP value (β = 0.030; 95% CI: 0.009 to 0.050; p = 0.004) was associated with diaphragm hypertrophy. Conclusions: IMT with 50% of MIP elicits meaningful diaphragmatic hypertrophy in healthy individuals. This response appears independent of fitness status or age, but is significantly influenced by baseline inspiratory muscle strength (MIP). These findings support the utility of IMT in enhancing respiratory muscle morphology in health and performance contexts. Full article
(This article belongs to the Section Sports Medicine and Sports Traumatology)
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12 pages, 596 KB  
Article
Effects of Trunk Extension-Based Inspiratory Muscle Strengthening on Respiratory Function, Balance, and Gait in Patients with Stroke: A Randomized Controlled Trial
by Kwang-Bin An, Hye-Joo Jeon, Yu-Sik Choi, Soo-Yong Lee and Woo-Nam Chang
J. Clin. Med. 2026, 15(5), 2017; https://doi.org/10.3390/jcm15052017 - 6 Mar 2026
Viewed by 556
Abstract
Objectives: This study investigated the effects of trunk extension-based inspiratory muscle strengthening on respiratory function, balance, and gait in patients with stroke. Methods: Thirty stroke patients were randomly assigned to the study group (n = 15) or control group (n = [...] Read more.
Objectives: This study investigated the effects of trunk extension-based inspiratory muscle strengthening on respiratory function, balance, and gait in patients with stroke. Methods: Thirty stroke patients were randomly assigned to the study group (n = 15) or control group (n = 15). The study group performed inspiratory muscle strengthening exercises in a trunk extension posture, while the control group received conventional inspiratory muscle training. Both groups trained five times per week for six weeks. Outcome measures included maximal inspiratory pressure (MIP), maximal inspiratory flow rate (MIFR), maximal inspiratory volume (MIV), peak expiratory flow (PEF), forced expiratory volume in 1 s (FEV1), Berg Balance Scale (BBS), weight distribution ratio (WDR), limits of stability (LOSs), Timed Up and Go (TUG), gait velocity, cadence, and stride length. Results: The study group showed significantly greater improvements in respiratory parameters (MIP, MIFR, MIV, PEF, FEV1) and functional outcomes (WDR, LOS, BBS, TUG, gait velocity, cadence, stride length) compared to the control group. Conclusions: Trunk extension-based inspiratory muscle strengthening effectively improves respiratory function, balance, and gait in stroke patients, and may serve as a valuable addition to stroke rehabilitation programs. Full article
(This article belongs to the Section Clinical Rehabilitation)
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13 pages, 423 KB  
Systematic Review
The Effect of Home-Based Inspiratory Muscle Training in Post-COVID Population—Systematic Review
by Stiliani Andreadou, Georgia Tziouvara, Georgios Mitsiou, Aphrodite Evangelodimou, Stavros Dimopoulos and Irini Patsaki
J. Respir. 2026, 6(1), 5; https://doi.org/10.3390/jor6010005 - 5 Mar 2026
Viewed by 905
Abstract
Background/Objective: Post-COVID survivors present significant respiratory deficiency that has been associated with ongoing shortness of breath and impaired lung function. Inspiratory muscle training (IMT) is increasingly used in survivors of COVID-19 rehabilitational programs as a means to facilitate recovery of the respiratory system. [...] Read more.
Background/Objective: Post-COVID survivors present significant respiratory deficiency that has been associated with ongoing shortness of breath and impaired lung function. Inspiratory muscle training (IMT) is increasingly used in survivors of COVID-19 rehabilitational programs as a means to facilitate recovery of the respiratory system. Yet, its home-based effectiveness across clinically relevant outcomes remains unclear. This systematic review aimed to present current evidence on home- or tele-delivered IMT in the post-COVID-19 population. Methods: PubMed, Scopus, Cochrane library and Science Direct were systematically searched for studies evaluating home-based (or telerehabilitation) IMT, alone or as part of a respiratory muscle training program, in adults with post-COVID-19 symptoms. The primary outcome was inspiratory muscle strength. Secondary outcomes included dyspnea, pulmonary function, exercise capacity and health-related quality of life. The methodological quality of the included studies was assessed via the PEDro scale. Owing to clinical and methodological heterogeneity, we performed only a qualitative synthesis. Results: Eight studies met the inclusion criteria. Two included both inspiratory and expiratory muscles training and three included physical training as well. The methodological quality was found to be good. IMT consistently increased inspiratory muscle strength across trials. Respiratory muscle training (RMT) programs that combined inspiratory and expiratory training also improved maximal expiratory pressure. IMT reduced dyspnea versus control/sham or baseline and several studies reported improvements in exercise capacity and physical function. Spirometry/DLCO changes were small or null in most cohorts. HRQoL gains were domain-specific in anxiety and depression. Adherence was generally good. No serious adverse events attributable to IMT were reported. Conclusions: Home-based IMT for adults with post-COVID-19 conditions is safe and seems to improve inspiratory muscle strength and dyspnea, with signs of benefit for exercise capacity, physical function, and selected HRQoL domains. Effects on ventilatory efficiency and conventional lung function appear limited. Future multicenter, sham-controlled RCTs should further explore the characteristics of IMT, employ core outcome sets, include longer follow-up, and predefine phenotype-based subgroups. Full article
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12 pages, 255 KB  
Article
Ultrasonographic Assessment of the Diaphragm and the Effects of Smoking on Respiratory Function in Individuals Attending a Smoking Cessation Center
by Ahmet Utus, Semiramis Ozyilmaz, Turgay Karatas, Nurullah Dag, Gurkan Ural, Ipek Balikci Cicek and Murat Kılıc
J. Clin. Med. 2026, 15(5), 1950; https://doi.org/10.3390/jcm15051950 - 4 Mar 2026
Viewed by 462
Abstract
Background: Smoking adversely affects pulmonary function and systemic health; however, its impact on diaphragm muscle morphology and its relationship with functional capacity and psychosocial outcomes in individuals without clinically diagnosed respiratory disease remain unclear. This study aimed to evaluate diaphragm muscle thickness [...] Read more.
Background: Smoking adversely affects pulmonary function and systemic health; however, its impact on diaphragm muscle morphology and its relationship with functional capacity and psychosocial outcomes in individuals without clinically diagnosed respiratory disease remain unclear. This study aimed to evaluate diaphragm muscle thickness in smokers and to investigate its associations with pulmonary function, functional capacity, sleep quality, and depression. Methods: This cross-sectional observational study included 20 smokers and 20 age-matched never-smokers. Pulmonary function was assessed using spirometry. Functional capacity was evaluated with the 6-Minute Walk Test (6 MWT) and the 30 s sit-to-stand test (30 s STST). Sleep quality and depression were assessed using the Pittsburgh Sleep Quality Index (PSQI) and the Beck Depression Inventory (BDI). Inspiratory and expiratory diaphragm muscle thicknesses were measured by ultrasonography. Between-group comparisons and correlation analyses were performed. Results: Smokers exhibited significant impairments in all assessed parameters except expiratory diaphragm thickness compared with controls (p < 0.05). Large to very large effect sizes were observed for FEV1, FEF25–75%, functional capacity, and inspiratory diaphragm thickness. Inspiratory diaphragm thickness showed moderate to strong positive correlations with pulmonary function parameters and a very strong positive correlation with functional capacity, while strong negative correlations were observed with sleep quality and depression (p < 0.05). Smoking duration was strongly associated with poorer functional and psychosocial outcomes. Conclusions: Smoking is associated with early and multidimensional impairments in diaphragm muscle morphology, pulmonary function, functional capacity, and psychosocial status, even in individuals without overt respiratory disease. Reduced inspiratory diaphragm thickness may represent an early and clinically meaningful marker of smoking-related respiratory muscle dysfunction. Full article
(This article belongs to the Special Issue Aiming for Early Detection and Prevention of Pulmonary Diseases)
11 pages, 330 KB  
Study Protocol
Impact of Inspiratory Muscle Training in Individuals with Gastroesophageal Reflux Disease: A Randomized Controlled Trial Protocol
by Stylianos Syropoulos, Maria Moutzouri, Eirini Grammatopoulou and Irini Patsaki
Methods Protoc. 2026, 9(2), 32; https://doi.org/10.3390/mps9020032 - 27 Feb 2026
Viewed by 889
Abstract
Gastroesophageal reflux disease (GERD) is a common chronic condition mainly caused by the dysfunction of the antireflux mechanism at the gastroesophageal junction. This is composed of the lower esophageal sphincter and the crural diaphragm. Increasing evidence suggests that diaphragmatic dysfunction and reduced inspiratory [...] Read more.
Gastroesophageal reflux disease (GERD) is a common chronic condition mainly caused by the dysfunction of the antireflux mechanism at the gastroesophageal junction. This is composed of the lower esophageal sphincter and the crural diaphragm. Increasing evidence suggests that diaphragmatic dysfunction and reduced inspiratory muscle strength may contribute to the persistence of GERD symptoms. Although respiratory physiotherapy has shown beneficial effects, the role of a structured inspiratory muscle training (IMT) program has not been sufficiently examined. This study aims to investigate the effects of an inspiratory muscle training program on inspiratory muscle strength and secondary clinical outcomes in individuals with GERD. A total of thirty adults with a confirmed GERD diagnosis will be enrolled in a two-arm randomized controlled trial. These volunteers will be randomly assigned either to the experimental group, which will undergo a 3-month inspiratory muscle training (IMT) using tapered flow resistive loading at 40% of maximal inspiratory pressure (MIP), or to the control group, which will receive sham IMT with a consistent low resistance. Primary outcomes will include maximal inspiratory pressure (MIP) and maximal dynamic inspiratory pressure (S-index). Secondary outcomes will assess GERD symptoms, disease-related quality of life, and pulmonary function. Measurements will be performed at baseline, at three months of intervention, and at six months from recruitment (follow-up). IMT is expected to lead to significant improvements in inspiratory muscle strength, symptom burden, and quality of life compared with sham training. This trial will provide novel evidence regarding the role of inspiratory muscle training as a non-pharmacological intervention in the management of GERD. Trial registration: ClinicalTrials.gov Identifier: NCT07131397. Full article
(This article belongs to the Section Public Health Research)
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