Effect of Passive Stretching of Respiratory Muscles on Chest Expansion and 6-Minute Walk Distance in COPD Patients

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality worldwide. Hyperinflation of the lungs leads to a remodeling of the inspiratory muscles that causes postural deformities and more labored breathing. Postural changes include elevated, protracted, or abducted scapulae with medially rotated humerus, and kyphosis that leads to further tightening of respiratory muscles. As the severity of the disease progresses, use of the upper limbs for functional tasks becomes difficult due to muscle stiffness. There are various studies that suggest different rehabilitation programs for COPD patients; however, to the best of our knowledge none recommends passive stretching techniques. The aim of this study was to assess the effect of respiratory muscle passive stretching on chest expansion and 6-min walk distance (6MWD) in patients with moderate to severe COPD.

METHODS

Thirty patients were divided into two groups, experimental (n = 15) and control (n = 15). The experimental group received a hot pack followed by stretching of the respiratory muscles and relaxed passive movements of the shoulder joints. The control group received a hot pack followed by relaxed passive movements of the shoulder joints.

RESULTS

In the control group, there was no difference in chest expansion at the levels of both the axilla and the xiphisternum or in 6MWD between baseline and post treatment (p > 0.05). In the experimental group, chest expansion at the level of the axilla (p < 0.05) and 6MWD (p < 0.001) were significantly higher post treatment, while there was no difference in chest expansion at the level of the xiphisternum (p > 0.05). A comparison between control and experimental groups showed that chest expansion at the level of the axilla (p < 0.05) and 6MWD (p < 0.01) were significantly higher in the experimental group, while there was no difference in chest expansion at the level of the xiphisternum (p > 0.05).

CONCLUSIONS

Although COPD is an irreversible disease, results of this study indicate that passive stretching of respiratory muscles can clinically improve the condition of such patients, especially in terms of chest expansion and 6MWD. Given the good effects of muscle stretching and the fact that such an exercise is harmless, clinicians and physiotherapists should consider including passive stretching of respiratory muscles in the rehabilitation plan of COPD patients.

Long-Term Combined Training in Idiopathic Pulmonary Fibrosis: A Case Study

A supervised combined training program was applied to a sedentary 56-year-old man with idiopathic pulmonary fibrosis (IPF) along three years, until lung transplantation. It included: (a) aerobic continuous (CT) and interval training (IT), (b) high load resistance training (RT) and (c) inspiratory muscle training (IMT). IT and IMT were applied for two years, while CT and RT could be maintained until transplantation using supplemental oxygen. Maximal inspiratory pressure (MIP) kept above 180 cm H₂O and forced vital capacity (FVC) remained stable until lung transplantation. Peak oxygen uptake VO₂ increased during 1.5 years before its decline, staying above the poor prognosis level two years. Finally, the patient maintained his walking capacity and independence for 2 years, before the decline due to the disease. After receiving a two-lung transplant, the patient remained intubated for 12 h, left the intensive care unit after 3.5 days and was discharged after 18 days (average values: 48 h, 7–10 days and 25–35 days, respectively). These results show that systematic and supervised combined training can be safety applied in an IPF patient to maintain functionality and quality of life. In addition, we show that RT can be maintained for as long as necessary without complications.

Cardiopulmonary Rehabilitation Improves Respiratory Muscle Function and Functional Capacity in Children with Congenital Heart Disease. A Prospective Cohort Study

Critical surgical and medical advances have shifted the focus of congenital heart disease (CHD) patients from survival to achievement of a greater health-related quality of life (HRQoL). HRQoL is influenced, amongst other factors, by aerobic capacity and respiratory muscle strength, both of which are reduced in CHD patients. This study evaluates the influence of a cardiopulmonary rehabilitation program (CPRP) on respiratory muscle strength and functional capacity. Fifteen CHD patients, ages 12 to 16, with reduced aerobic capacity in cardiopulmonary exercise testing (CPET) were enrolled in a CPRP involving strength and aerobic training for three months. Measurements for comparison were obtained at the start, end, and six months after the CPRP. A significant improvement of inspiratory muscle strength was evidenced (maximum inspiratory pressure 21 cm H₂O, 23%, p < 0.01). The six-minute walking test showed a statistically and clinically significant rise in walked distance (48 m, p < 0.01) and a reduction in muscle fatigue (1.7 out of 10 points, p = 0.017). These results suggest CPRP could potentially improve respiratory muscle function and functional capacity, with lasting results, in children with congenital heart disease, but additional clinical trials must be conducted to confirm this finding.

Effectiveness of inspiratory muscle training associated with a cardiac rehabilitation program on sympathetic activity and functional capacity in patients with heart failure: a study protocol for a randomized controlled trial

BACKGROUND

Individuals affected by heart failure (HF) may present fatigue, dyspnea, respiratory muscle weakness, and sympathetic activity hyperstimulation of the myocardium, among other symptoms. Conducting cardiac rehabilitation (CR) programs can be associated with inspiratory muscle training. The aim of this study was to evaluate the efficacy of inspiratory muscular training (IMT) associated with a CR program on modulating myocardial sympathetic activity and maximal functional capacity, submaximal functional capacity, thickness, and mobility of the diaphragm muscle in patients with HF.

METHODS

We will conduct a clinical, controlled, randomized, double-blind trial that will include sedentary men and women who are 21-60 years old and who have diagnosed systolic HF and a left ventricular ejection fraction of less than 45%. Participants will be randomly assigned to one of two groups: experimental and control. The control group will follow the conventional CR protocol, and the experimental group will follow the conventional CR protocol associated with IMT 7 days a week. The two proposed exercise protocols will have a frequency of three times a week for a period of 12 weeks. The sympathetic innervation of the cardiac muscle, the maximum and submaximal functional capacity, diaphragm mobility and thickness, and the quality of life of the participants will be evaluated before and after the intervention protocol.

DISCUSSION

This clinical trial will be the first study to investigate the additional effects of IMT on CR in sympathetic hyperstimulation in the myocardium. The results of this study will contribute to developing therapeutic strategies collaborating to elucidate whether the association of IMT with CR can induce clinical benefits for patients with HF.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02600000. Registered November 9, 2015. Retrospectively registered.

Pulmonary and Respiratory Muscle Function in Response to Marathon and Ultra-Marathon Running: A Review

The physiological demands of marathon and ultra-marathon running are substantial, affecting multiple body systems. There have been several reviews on the physiological contraindications of participation; nevertheless, the respiratory implications have received relatively little attention. This paper provides an up-to-date review of the literature pertaining to acute pulmonary and respiratory muscle responses to marathon and ultra-marathon running. Pulmonary function was most commonly assessed using spirometry, with infrequent use of techniques including single-breath rebreathe and whole-body plethysmography. All studies observed statistically significant post-race reductions in one-or-more metrics of pulmonary function, with or without evidence of airway obstruction. Nevertheless, an independent analysis revealed that post-race values rarely fell below the lower-limit of normal and are unlikely, therefore, to be clinically significant. This highlights the virtue of healthy baseline parameters prior to competition and, although speculative, there may be more potent clinical manifestations in individuals with below-average baseline function, or those with pre-existing respiratory disorders (e.g., asthma). Respiratory muscle fatigue was most commonly assessed indirectly using maximal static mouth-pressure manoeuvres, and respiratory muscle endurance via maximum voluntary ventilation (MVV₁₂). Objective nerve-stimulation data from one study, and others documenting the time-course of recovery, implicate peripheral neuromuscular factors as the mechanism underpinning such fatigue. Evidence of respiratory muscle fatigue was more prevalent following marathon compared to ultra-marathon, and might be a factor of work rate, and thus exercise ventilation, which is tempered during longer races. Potential implications of respiratory muscle fatigue on health and marathon/ultra-marathon performance have been discussed, and include a diminished postural stability that may increase the risk of injury when running on challenging terrain, and possible respiratory muscle fatigue-induced effects on locomotor limb blood flow. This review provides novel insights that might influence marathon/ultra-marathon preparation strategies, as well as inform medical best-practice of personnel supporting such events.

Inspiratory muscle training in young, race-fit Thoroughbred racehorses during a period of detraining

Although inspiratory muscle training (IMT) is reported to improve inspiratory muscle strength in humans little has been reported for horses. We tested the hypothesis that IMT would maintain and/or improve inspiratory muscle strength variables measured in Thoroughbreds during detraining. Thoroughbreds from one training yard were placed into a control (Con, n = 3 males n = 7 females; median age 2.2±0.4 years) or treatment group (Tr, n = 5 males, n = 5 females; median age 2.1±0.3 years) as they entered a detraining period at the end of the racing/training season. The Tr group underwent eight weeks of IMT twice a day, five days per week using custom-made training masks with resistance valves and an incremental threshold of breath-loading protocol. An inspiratory muscle strength test to fatigue using an incremental threshold of breath-loading was performed in duplicate before (T₀) and after four (T₁) and eight weeks (T₂) of IMT/no IMT using a custom-made testing mask and a commercial testing device. Inspiratory measurements included the total number of breaths achieved during the test, average load, peak power, peak volume, peak flow, energy and the mean peak inspiratory muscle strength index (IMSi). Data were analysed using a linear mixed effects model, P≤0.05 significant. There were no differences for inspiratory measurements between groups at T₀. Compared to T₀, the total number of breaths achieved (P = 0.02), load (P = 0.003) and IMSi (P = 0.01) at T₂ had decreased for the Con group while the total number of breaths achieved (P<0.001), load (P = 0.03), volume (P = 0.004), flow (P = 0.006), energy (P = 0.01) and IMSi (P = 0.002) had increased for the Tr group. At T₂ the total number of breaths achieved (P<0.0001), load (P<0.0001), volume (P = 0.02), energy (P = 0.03) and IMSi (P<0.0001) were greater for the Tr than Con group. In conclusion, our results support that IMT can maintain and/or increase aspects of inspiratory muscle strength for horses in a detraining programme.

Acute inspiratory muscle exercise effect on glucose levels, glucose variability and autonomic control in patients with type 2 diabetes: A crossover randomized trial

Inspiratory muscle exercise (IME) can be an alternative to conventional exercise. We aimed to evaluate the effect of IME on glucose, glucose variability, and autonomic cardiovascular control in type 2 diabetes. Fourteen diabetic subjects were randomly assigned to IME with 2% maximal inspiratory pressure (PImax) or 60% PImax wearing a continuous glucose monitoring system for three days. Glucose variability [glucose variance (VAR), glucose coefficient of variation (CV%), glucose standard deviation (SD), and mean amplitude of glycemic excursions (MAGE)] were evaluated. Glucose reduction was observed in 5 min (60% of PImax 33.2% and 2% of PImax 32.0%), 60 min (60% of PImax 29.6% and 2% of PImax 31.4%) and 120 min (60% of PImax 21.4% and 2% of PImax 24.0%) after IME (vs.1 h before the exercise), with no difference between loads. This reduction in glucose levels was observed in all moments of the IME protocol. Glucose variability was reduced after 12 h and 18 h of the IME (ΔCV: P < 0.001, ΔSD: P < 0.001 and ΔVAR: P < 0.001) for both loads. No difference was found in MAGE (P = 0.594) after IME. Mean arterial pressure and heart rate rose during the exercise session with 60% of PImax. Although sufficiently strong to induce cardiovascular changes, an inspiratory muscle exercise session with 60% of PImax in subjects with type 2 diabetes has failed to induce any significant improvement in glucose, glucose variability and autonomic control, compared to the 2% Plmax exercise session.

Comparison of balance changes after inspiratory muscle or Otago exercise training

The inspiratory muscles contribute to balance via diaphragmatic contraction and by increasing intra-abdominal pressure. We have shown inspiratory muscle training (IMT) improves dynamic balance significantly with healthy community-dwellers. However, it is not known how the magnitude of balance improvements following IMT compares to that of an established balance program. This study compared the effects of 8-week of IMT for community-dwellers, to 8-week of the Otago exercise program (OEP) for care-residents, on balance and physical performance outcomes. Nineteen healthy community-dwellers (74 ± 4 years) were assigned to self-administered IMT. Eighteen, healthy care-residents (82 ± 4 years) were assigned to instructor-led OEP. The IMT involved 30 breaths twice-daily at ~50% of maximal inspiratory pressure (MIP). The OEP group undertook resistance and mobility exercises for ~60 minutes, twice-weekly. Balance and physical performance were assessed using the mini Balance Evaluation System Test (mini-BEST) and time up and go (TUG). After 8-week, both groups improved balance ability significantly (mini-BEST: IMT by 24 ± 34%; OEP by 34 ± 28%), with no between-group difference. Dynamic balance sub-tasks improved significantly more for the IMT group (P < 0.01), than the OEP group and vice versa for static balance sub-tasks (P = 0.01). The IMT group also improved MIP (by 66 ± 97%), peak inspiratory power (by 31 ± 12%) and TUG (by -11 ± 27%); whereas the OEP did not. IMT and OEP improved balance ability similarly, with IMT eliciting greater improvement in dynamic balance, whilst OEP improved static balance more than IMT. Unlike IMT, the OEP did not provide additional benefits in inspiratory muscle function and TUG performance. Our findings suggest that IMT offers a novel method of improving dynamic balance in older adults, which may be more relevant to function than static balance and potentially a useful adjunct to the OEP in frailty prevention.

Blood pressure and limb blood flow responses during hyperpnoea are not affected by menstrual cycle phase in young women

The purpose of this study was to clarify whether the menstrual cycle affects the cardiovascular and limb blood flow responses during hyperpnoea. Fifteen young female subjects participated. An incremental respiratory endurance test was performed at the early follicular (EF) and midluteal (ML) phases. Target minute ventilation was initially set at 30 % of maximal voluntary ventilation (MVV12) and was increased by 10 %MVV12 every 3 min. The test was terminated when the subjects no longer maintained the target ventilation. Mean arterial blood pressure (MBP) and mean blood flow in the brachial artery were continuously measured. There were no significant differences in the increase in MBP (EF: +13.0 ± 7.9 mmHg vs. ML: + 15.4 ± 12.9 mmHg during the test, F = 0.70, P = 0.59) and the decrease in brachial blood flow between the phases. These results suggest that menstrual cycle does not affect respiratory muscle-induced metaboreflex in young women.

Chest Movement and Respiratory Volume both Contribute to Thoracic Bioimpedance during Loaded Breathing

Bioimpedance has been widely studied as alternative to respiratory monitoring methods because of its linear relationship with respiratory volume during normal breathing. However, other body tissues and fluids contribute to the bioimpedance measurement. The objective of this study is to investigate the relevance of chest movement in thoracic bioimpedance contributions to evaluate the applicability of bioimpedance for respiratory monitoring. We measured airflow, bioimpedance at four electrode configurations and thoracic accelerometer data in 10 healthy subjects during inspiratory loading. This protocol permitted us to study the contributions during different levels of inspiratory muscle activity. We used chest movement and volume signals to characterize the bioimpedance signal using linear mixed-effect models and neural networks for each subject and level of muscle activity. The performance was evaluated using the Mean Average Percentage Errors for each respiratory cycle. The lowest errors corresponded to the combination of chest movement and volume for both linear models and neural networks. Particularly, neural networks presented lower errors (median below 4.29%). At high levels of muscle activity, the differences in model performance indicated an increased contribution of chest movement to the bioimpedance signal. Accordingly, chest movement contributed substantially to bioimpedance measurement and more notably at high muscle activity levels.

Beneficial Effects of Inspiratory Muscle Training Combined With Multicomponent Training in Elderly Active Women

Purpose: This study aims to analyze changes in Maximum Inspiratory Pressure (MIP), lung function, cardiorespiratory fitness, and blood pressure, in 10 healthy active elderly women, following 7 weeks of inspiratory muscle training (IMT) combined with a multicomponent training program (MCTP). The association among these health parameters, their changes after training (deltas), and the influence of MIP at baseline (MIP_pre) are also considered. Methods: IMT involved 30 inspirations at 50% of the MIP, twice daily, 7 days a week, while MCTP was 1 hr, twice a week. MIP, lung function (FVC, FEV₁, FEV₁/FVC, FEF_25-75%, PEF), 6MWT, and blood pressure (SBP, DBP), jointly with body composition, were assessed before and after the intervention. Results: Seven weeks were enough to improved MIP (p = .019; d = 1.397), 6MWT (p = .012; d = .832), SBP (p = .003; d = 1.035) and DBP (p = .024; d = .848). Despite the high physical fitness (VO₂ peak: M = 23.38, SD = 3.39 ml·min·Kg^-1), MIP_pre was low (M = 39.00, SD = 7.63 cmH₂O) and displayed a significant negative correlation with ΔMIP_pre-post (r = -.821; p < .004), showing that women who started the intervention with lower MIP achieved higher improvements in inspiratory muscle strength after training. Conclusions: No significant changes in spirometric parameters may signal that lung function is independent of early improvements in inspiratory muscles and cardiorespiratory fitness. Absence of correlation between physical fitness and respiratory outcomes suggests that being fit does not ensure cardiorespiratory health in active elderly women, so IMT might be beneficial and should supplement the MCTP in this population.

Functional training of the inspiratory muscles improves load carriage performance

Inspiratory Muscle Training (IMT) whilst adopting body positions that mimic exercise (functional IMT; IMT_F) improves running performance above traditional IMT methods in unloaded exercise. We investigated the effect of IMT_F during load carriage tasks. Seventeen males completed 60 min walking at 6.5 km·h^-1 followed by a 2.4 km load carriage time-trial (LC_TT) whilst wearing a 25 kg backpack. Trials were completed at baseline; post 4 weeks IMT (consisting of 30 breaths twice daily at 50% of maximum inspiratory pressure) and again following either 4 weeks IMT_F (comprising four inspiratory loaded core exercises) or maintenance IMT (IMT_CON). Baseline LC_TT was 15.93 ± 2.30 min and was reduced to 14.73 ± 2.40 min (mean reduction 1.19 ± 0.83 min, p < 0.01) after IMT. Following phase two, LC_TT increased in IMT_F only (13.59 ± 2.33 min, p < 0.05) and was unchanged in post-IMT_CON. Performance was increased following IMT_F, providing an additional ergogenic effect beyond IMT alone. Practitioner Summary: We confirmed the ergogenic benefit of Inspiratory Muscle Training (IMT) upon load carriage performance. Furthermore, we demonstrate that functional IMT methods provide a greater performance benefit during exercise with thoracic loads. Abbreviations: [Lac^-]_B: blood lactate; FEV₁: forced expiratory volume in one second; FEV₁/FVC: forced expiratory volume in one second/forced vital capacity ratio; FVC: forced vital capacity; HR: heart rate; IMT: inspiratory muscle training; IMT_CON: inspiratory muscle training maintenance; IMT_F: functional inspiratory muscle training; LC: load carriage; LC_TT: load carriage time trial; P_di: transdiaphragmatic pressure; PEF: peak expiratory flow; P_Emax: maximum expiratory mouth pressure; P_Imax: maximum inspiratory mouth pressure; RPE: rating of perceived exertion; RPE_breating: rating of perceived exertion for the breathing; RPE_leg: rating of perceived exertion for the legs; SEPT: sport-specific endurance plank test; V̇ O₂: oxygen consumption; V̇ O_2peak: peak oxygen consumption.

Respiratory muscle activation and action during voluntary cough in healthy humans

Cough is a defensive airway reflex consisting of a modified respiratory act which involves the sequential activation of several laryngeal and respiratory muscles. The contraction of the latter results in thoraco-abdominal volume variations in order to provide enough amount of air available, the operating volume (OV), to be expelled. Because both posture and OV could influence muscular activation and thoraco-abdominal displacements during voluntary cough, we aimed to verify if and how they play a role during inspiratory (ICP) and expiratory (ECP) cough phases, in terms of flow, volumes and surface electromyography activity (sEMG). In 10 healthy subjects, we measured sEMG of 7 muscles (scalene, sternocleidomastoid, parasternal, intercostal, diaphragm (assessed at the 8^th intercostal space), external abdominal oblique and rectus abdominis) in supine and seated position during cough maneuvers performed at 4 different OV measured by opto-electronic plethismography: total lung capacity (TLC), functional residual capacity and two intermediate volumes. The amplitude of sEMG signals tended to be maximal at TLC (p < 0.005) during ICP in the neck and parasternal muscles and during ECP in abdominal muscles. Postures slightly affected only sEMG of the thoracic muscles. sEMG data were similar (p > 0.05) in the other OV, but cough peak flow increased with OV. Thoraco-abdominal volume variations during cough were unaffected by posture and OV as well, being predominantly thoracic (supine: 60 and 64%; seated: 68 and 69%, respectively during ICP and ECP). Our results suggest that voluntary cough OV or posture do not have an important effect on voluntary cough that seems more likely to be resulting from a motor mechanism that activates a synergetic antagonistic contraction of inspiratory and expiratory muscles leading to a specific thoraco-abdominal pattern, in which the rib cage is the predominant.

Effects of Specific Core Re-Warm-Ups on Core Function, Leg Perfusion and Second-Half Team Sport-Specific Sprint Performance: A Randomized Crossover Study

This study examined the effects of a specific core exercise program, as a re-warm-up regime during the half-time period, on inspiratory (IM) and core (CM) muscle functions, leg perfusion and the team sport-specific sprint performance in the initial stage of the second half of a simulated exercise task. Nine team-sports players performed a simulated team-sport intermittent exercise protocol (IEP) in two phases, on a non-motorized treadmill, interspersed by a 15-min half-time break. During the half-time period subsequent to the 25-min Phase-1 IEP, the players either rested passively or performed 4-min CM exercise concomitant with inspiratory loaded breathing following 11-min passive recovery. The changes in IM and CM functions, leg perfusion and repeated-sprint ability mediated by the two recovery modes were compared. Following Phase-1 IEP, there was a significant decline in IM and CM functions respectively, revealed by the decreases in maximal inspiratory pressure (PImax: -8.1%) and performance of a sport-specific endurance plank test (SEPT: -29.7%, p < 0.05). With the 15-min passive recovery, the decline in IM and CM functions from pre-exercise levels were not restored satisfactorily (PImax: -6.4%, SEPT: -19.0%, p < 0.05). Moreover, repeated-sprint ability during the Phase-2 IEP tended to decrease (peak velocity: -2.3%, mean velocity: -2.1%) from the levels recorded in Phase-1. In contrast, following the re-warm-up exercises during half-time, the restoration of IM and CM function was accelerated (PImax: -0.9%, SEPT: -3.3%, p <0 .05). This was associated with enhanced repeated-sprint ability (peak velocity: +3.0%, mean velocity: +2.0%, p < 0.05) in Phase-2 IEP. Nevertheless, the changes in the anterior thigh muscle perfusion assessed by near-infrared spectroscopy following the re-warm-up exercises was not different from that of passive recovery (p > 0.05). The findings suggest that a brief inspiratory-loaded CM exercise regime appears to be an effective re-warm-up strategy that optimizes second-half repeated-sprint performance and core function of players in team sports.

Effectiveness of the muscle energy technique on respiratory muscle strength and endurance in patients with fibromyalgia

BACKGROUND

Fibromyalgia is characterized by a chronic and common musculoskeletal system pain that affects cervical mobility and inspiration. This may cause changes in thoracic mechanics.

OBJECTIVE

To investigate the effectiveness of the muscle energy technique applied to cervical accessory respiratory muscles on respiratory muscle strength and endurance in patients with fibromyalgia.

METHODS

The participants were 37 women diagnosed with fibromyalgia. They were assessed for their respiratory muscle strength, respiratory muscle endurance, pain and fatigue severity, flexibility and disability. The muscle energy technique was applied to the scalene, upper trapezius, and sternocleidomastoid muscles after a superficial heat application. The treatment was continued for 3 weeks with 3 sessions per week.

RESULTS

After the treatment, expiratory muscle strength and respiratory muscle endurance increased significantly. Severity of pain and fatigue and disability were reduced, cervical flexibility increased significantly (p< 0.05). The effect size was r⩾ 0.4 for all the variables.

CONCLUSION

The muscle energy technique applied to cervical accessory respiratory muscles in patients with fibromyalgia who had complaints in the neck and back region positively increased respiratory muscle strength and endurance, cervical flexibility, and decrease pain intensity, fatigue and disability. It is recommended that subsequent randomized studies are carried out with a placebo control group.

[Not Available]

INTRODUCTION:

Morbidity and mortality in adults with late-onset Pompe disease (LOPD) results primarily from persistent progressive respiratory muscle weakness despite treatment with enzyme replacement therapy (ERT). To address this need, we have developed a 12-week respiratory muscle training (RMT) program that provides calibrated, individualized, and progressive pressure-threshold resistance against inspiration and expiration. Our previous results suggest that our RMT regimen is safe, well-tolerated, and results in large increases in respiratory muscle strength. We now conduct an exploratory double-blind, randomized control trial (RCT) to determine: 1) utility and feasibility of sham-RMT as a control condition, 2) the clinically meaningful outcome measures for inclusion in a future efficacy trial. This manuscript provides comprehensive information regarding the design and methods used in our trial and will aid in the reporting and interpretation of our future findings.

METHODS:

Twenty-eight adults with LOPD will be randomized (1:1) in blocks of 4 to RMT (treatment) or sham-RMT (control). Assessments will be conducted at pretest, posttest, 3-months detraining, and 6-months detraining. The primary outcome is maximum inspiratory pressure (MIP). Secondary outcomes include maximum expiratory pressure (MEP), 6-minute walk test (6MWT), Gait, Stairs, Gowers, and Chair test (GSGC), peak cough flow (PCF), and patient-reported life activity/social participation (Rasch-built Pompe-specific Activity scale [R-Pact]). Exploratory outcomes include quantitative measures from polysomnography; patient reported measures of fatigue, daytime sleepiness, and sleep quality; and ultrasound measures of diaphragm thickness. This research will use a novel tool to provide automated data collection and user feedback, and improve control over dose.

ETHICS AND DISSEMINATION:

The results of this clinical trial will be promptly analyzed and submitted for publication. Results will also be made available on clinicaltrials.gov.

CLINICALTRIALS.GOV:

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The effects of 8 weeks of inspiratory muscle training on the balance of healthy older adults: a randomized, double-blind, placebo-controlled study

To examine the effects of 8-week unsupervised, home-based inspiratory muscle training (IMT) on the balance and physical performance of healthy older adults. Fifty-nine participants (74 ± 6 years) were assigned randomly in a double-blinded fashion to either IMT or sham-IMT, using a pressure threshold loading device. The IMT group performed 30-breath twice daily at ~50% of maximal inspiratory pressure (MIP). The sham-IMT group performed 60-breaths once daily at ~15% MIP; training was home-based and unsupervised, with adherence self-reported through training diaries. Respiratory outcomes were assessed pre- and postintervention, including forced vital capacity, forced expiratory volume, peak inspiratory flow rate (PIFR), MIP, and inspiratory peak power. Balance and physical performance outcomes were measured using the shortened version of the Balance Evaluation System test (mini-BEST), Biodex® postural stability test, timed up and go, five sit-to-stand, isometric "sit-up" and Biering-Sørensen tests. Between-group effects were examined using two-way repeated measures ANOVA, with Bonferroni correction. After 8-week, the IMT group demonstrated greater improvements (P ≤ 0.05) in: PIFR (IMT = 0.9 ± 0.3 L sec-1 ; sham-IMT = 0.3 L sec-1 ); mini-BEST (IMT = 3.7 ± 1.3; sham-IMT = 0.5 ± 0.9) and Biering-Sørensen (IMT = 62.9 ± 6.4 sec; sham-IMT = 24.3 ± 1.4 sec) tests. The authors concluded that twice daily unsupervised, home-based IMT is feasible and enhances inspiratory muscle function and balance for community-dwelling older adults.

Inspiratory muscle training improves pulmonary functions and respiratory muscle strength in healthy male smokers

The aim of the present study is to investigate the effects of inspiratory muscle training (IMT) on pulmonary function and respiratory muscle strength of both healthy smokers and nonsmokers. Forty-two healthy males (16 in the IMT smokers group [IMT_S], 16 in the IMT nonsmokers group [IMT_N], and 10 in the placebo group) participated in the present study. Using a randomized, double-blind, placebo-controlled design, IMT_S and IMT_N underwent 4 weeks of 30 breaths twice daily at 50% (+5% increase each week) of maximum inspiratory pressure (MIP), while the placebo group maintained 30 breaths twice daily at 15% MIP using an IMT device. The data were analyzed with repeated measures for one-way analysis of variance, 3 × 2 mixed factor analysis of variance, and least significant difference tests. Respiratory muscle strength (MIP and maximal expiratory pressure [MEP]) and pulmonary functions significantly improved after a 4-week period (between the pre and posttests) in the IMT_N and IMT_S groups (p < 0.05). The mean difference and percentage differences showed significant alterations in the respiratory muscle strength, forced and slow pulmonary capacities, and pulmonary volume between the IMT_N and IMT_S groups (p < 0.05). There were significant changes in the expiratory muscle strength (MEP), slow vital capacity (SVC), and forced pulmonary measurements (forced expiratory volume after 1 s and maximal voluntary ventilation) between IMT_N and IMT_S groups in favor of smokers (p < 0.05). These results show that greater improvements occurred in smokers after IMT. Increased respiratory muscle strength may be the underlying mechanism responsible for this improvement. Additionally, the benefits of IMT were greater in smokers than nonsmokers. This difference between smokers and nonsmokers may potentially be explained by higher influence of exercise on smokers' lung microbiome, resulting in greater reversal of negative effects.

Assessment of respiratory muscle strength and airflow before and after microimplant-assisted rapid palatal expansion

OBJECTIVES

To assess alterations in respiratory muscle strength and inspiratory and expiratory peak flow, as well as skeletal and dental changes in patients diagnosed with transverse maxillary deficiency before and after microimplant-assisted rapid maxillary expansion (MARPE).

MATERIALS AND METHODS

Twenty patients (13 female and 7 male) were assessed by respiratory tests in three different periods: T0 initial, T1 immediately after expansion, and T2 after 5 months. Tests included: maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP), oral expiratory peak flow, and inspiratory nasal flow. Cone-beam computed tomography measurements were performed in the maxillary arch, nasal cavity, and airway before and immediately after expansion.

RESULTS

There was a significant increase in MIP between T0 and T2 and MEP between T0 and T1 (P<.05). Oral and nasal peak flow increased immediately after and 5 months later, especially in patients with initial signs of airway obstruction (P<.05). In addition, after expansion there was a significant enlargement of the nasal cavity, alveolar bone, and interdental widths at the premolar and molar region. Molars tipped buccally (P<.05) but no difference was found in premolar inclination. MARPE increased airway volume significantly.

CONCLUSIONS

Skeletal changes promoted by MARPE directly affected airway volume, resulting in a significant improvement in muscle strength and nasal and oral peak flow.

Acute effects of three pulmonary reexpansion modalities on thoracoabdominal motion of healthy subjects: Randomized crossover study

BACKGROUND

Chest physiotherapy can be an alternative to increase lung volumes through pulmonary expansion therapies, but there is still inconsistency in the literature in order to determine which device can promote a greater volume increase at the expense of a better ventilatory pattern. Therefore, the aim of this study was to evaluate and compare the chest wall kinematics of healthy subjects submitted to the use of three different devices for pulmonary reexpansion.

METHODS

Chest wall compartmental and operational volumes, breathing pattern and thoracoabdominal asynchrony were evaluated in 12 healthy individuals through optoelectronic plethysmography during quiet breathing, pulmonary reexpansion and recovery. Three different devices (volume-oriented incentive spirometer-IS-v; positive expiratory pressure-PEP; and incentive spirometer volume and pressure oriented-IS-vp) were administered in a random order with at least 48h between the devices.

RESULTS

A greater volume variation in the chest wall and its compartments was observed when the IS-vp was used in comparison with the other devices (p<0.05). Furthermore, the IS-vp mobilizes a greater amount of volume accompanied by greater synchronism between the compartments when compared to IS-v (p <0.05).

CONCLUSION

The IS-vp may be able to increase total and compartmental chest wall volumes, as well as improve synchrony among compartments when compared to IS-v and PEP devices, thus constituting an important tool for treating patients with restrictive ventilatory pattern.

Respiratory motoneuron properties during the transition from gill to lung breathing in the American bullfrog

Amphibian respiratory development involves a dramatic metamorphic transition from gill to lung breathing and coordination of distinct motor outputs. To determine whether the emergence of adult respiratory motor patterns was associated with similarly dramatic changes in motoneuron (MN) properties, we characterized the intrinsic electrical properties of American bullfrog trigeminal MNs innervating respiratory muscles comprising the buccal pump. In premetamorphic tadpoles (TK stages IX-XVIII) and adult frogs, morphometric analyses and whole cell recordings were performed in trigeminal MNs identified by fluorescent retrograde labeling. Based on the amplitude of the depolarizing sag induced by hyperpolarizing voltage steps, two MN subtypes (I and II) were identified in tadpoles and adults. Compared with type II MNs, type I MNs had larger sag amplitudes (suggesting a larger hyperpolarization-activated inward current), greater input resistance, lower rheobase, hyperpolarized action potential threshold, steeper frequency-current relationships, and fast firing rates and received fewer excitatory postsynaptic currents. Postmetamorphosis, type I MNs exhibited similar sag, enhanced postinhibitory rebound, and increased action potential amplitude with a smaller-magnitude fast afterhyperpolarization. Compared with tadpoles, type II MNs from frogs received higher-frequency, larger-amplitude excitatory postsynaptic currents. Input resistance decreased and rheobase increased postmetamorphosis in all MNs, concurrent with increased soma area and hyperpolarized action potential threshold. We suggest that type I MNs are likely recruited in response to smaller, buccal-related synaptic inputs as well as larger lung-related inputs, whereas type II MNs are likely recruited in response to stronger synaptic inputs associated with larger buccal breaths, lung breaths, or nonrespiratory behaviors involving powerful muscle contractions.

Inhibitory Thoracic Interneurons are not Essential to Generate the Rostro-caudal Gradient of the Thoracic Inspiratory Motor Activity in Neonatal Rat

The inspiratory motor activities are greater in the intercostal muscles positioned at more rostral thoracic segments. This rostro-caudal gradient of the thoracic inspiratory motor activity is thought to be generated by the spinal interneurons. To clarify the involvement of the inhibitory thoracic interneurons in this rostro-caudal gradient, we examined the effects of 10 μM strychnine, an antagonist of glycine and GABA_A receptors, applied to the neonatal rat thoracic spinal cord. The respiratory-related interneuron activities were optically recorded from thoracic segments in the isolated neonatal rat brainstem-spinal cord preparations stained with voltage-sensitive dye, and the electrical inspiratory motor activities were obtained from the third and eleventh thoracic ventral roots (T3VR, T11VR). Although strychnine caused seizure-like activities in all of the ventral roots recorded, the inspiratory motor activities continued. The inspiratory optical signals in the rostral thoracic segments (T2-T5) were significantly larger than those in the caudal thoracic segments (T9-T11) regardless of the existence of strychnine. Similarly, the percent ratio of the amplitude of the inspiratory electrical activity in the T3VR under control and strychnine was significantly larger than that in the T11VR regardless of the existence of strychnine. Strychnine significantly increased the inspiratory activity in both the T3VR and T11VR. These results suggest that the glycinergic and GABAergic inhibitory interneurons are not essential to generate the rostro-caudal gradient in the neonatal rat thoracic inspiratory motor outputs, but these interneurons are likely to play a role in the inhibitory control of inspiratory motor output.

Surface electromyography in inspiratory muscles in adults and elderly individuals: A systematic review

INTRODUCTION

Electromyography (EMG) helps to evaluate disorders and pulmonary behavior, as impairments in respiratory muscle function are associated with the development of diseases. There is a wide range of methods and protocols used to record and analyze EMG obtained from respiratory muscles, demonstrating a lack of standardization.

OBJECTIVE

To identify the most common procedures used to record surface EMG (sEMG) of inspiratory muscles in adults and elderly individuals through a systematic review (primary), and to evaluate the quality of the report presented by the studies (secondary).

METHOD

Studies published from January 1995 until June 2018 were searched for in the Web of Science, PubMed, LILACS, EBSCO and Embase databases. Only studies evaluating sEMG of inspiratory muscles were included.

RESULTS

The electronic search retrieved a total of 6697 titles and 92 of them were included. A great variability on the methods applied to both recording and processing/analyzing data was found. Therefore, the synthesis of practical/clinical evidence to support immediate recommendations was impaired. In general, the descriptions presented by the studies are poor.

CONCLUSION

The most common procedures used for sEMG were identified. Methodological studies with objective comparisons were fundamental for improving standardization, given the impossibility of recommendations from this review.

Relationship between maximal respiratory pressures and multiple childbearing in Brazilian middle-aged and older women: A cross-sectional community-based study

Objective

Previous studies show that multiparity and a number of chronic conditions are correlated among women. Also, low respiratory muscle strength has been associated to adverse health outcomes such as chronic lung disease and early mortality. This study aimed to investigate associations between the number of lifetime pregnancies and maximal inspiratory/expiratory pressures.

Methods

In a cross-sectional study, 204 women ages 41–80 years-old, from the rural community of Santa Cruz, Brazil, provided data regarding demographics, socioeconomic characteristics, health behaviors, and number of lifetime pregnancies (≤3, 4–6 or ≥7). Maximal respiratory pressures were measured with a digital manometer. Multiple linear regression analysis was used to examine the association of multiple childbearing on maximal respiratory pressures.

Results

Of the participants, 44.1% had ≤3 pregnancies, 30.4% had 4–6 pregnancies and 25.5% had >7 pregnancies. In the unadjusted analyses, maximal inspiratory and expiratory pressures varied significantly according to multiple childbearing categories. After adjustment, the values remained statistically significant only for maximal expiratory pressure. Compared to women with ≤3 lifetime pregnancies, those who had ≥7 pregnancies had significantly lower maximal expiratory pressure values (β = -18.07, p = 0.01)

Conclusion

Multiple childbearing appears to be negatively associated with maximal respiratory pressures; women with a higher number of lifetime pregnancies had lower values of maximal respiratory pressures when compared to those with fewer pregnancies. This association may be due to biomechanical changes in the respiratory muscles promoted by multiple lifetime pregnancies. This finding indicates a need to motivate women, from the prenatal to postpartum period, to safely exercise their respiratory muscles, including abdominal muscle exercises as well as respiratory muscle training.

Surface mechanomyography and electromyography provide non-invasive indices of inspiratory muscle force and activation in healthy subjects

The current gold standard assessment of human inspiratory muscle function involves using invasive measures of transdiaphragmatic pressure (Pdi) or crural diaphragm electromyography (oesEMGdi). Mechanomyography is a non-invasive measure of muscle vibration associated with muscle contraction. Surface electromyogram and mechanomyogram, recorded transcutaneously using sensors placed over the lower intercostal spaces (sEMGlic and sMMGlic respectively), have been proposed to provide non-invasive indices of inspiratory muscle activation, but have not been directly compared to gold standard Pdi and oesEMGdi measures during voluntary respiratory manoeuvres. To validate the non-invasive techniques, the relationships between Pdi and sMMGlic, and between oesEMGdi and sEMGlic were measured simultaneously in 12 healthy subjects during an incremental inspiratory threshold loading protocol. Myographic signals were analysed using fixed sample entropy (fSampEn), which is less influenced by cardiac artefacts than conventional root mean square. Strong correlations were observed between: mean Pdi and mean fSampEn |sMMGlic| (left, 0.76; right, 0.81), the time-integrals of the Pdi and fSampEn |sMMGlic| (left, 0.78; right, 0.83), and mean fSampEn oesEMGdi and mean fSampEn sEMGlic (left, 0.84; right, 0.83). These findings suggest that sMMGlic and sEMGlic could provide useful non-invasive alternatives to Pdi and oesEMGdi for the assessment of inspiratory muscle function in health and disease.