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Transversus abdominis muscle function in humans
Abstract
We used a high-resolution ultrasound to make electrical recordings from the transversus abdominis muscle in humans. The behavior of this muscle was then compared with that of the external oblique and rectus abdominis in six normal subjects in the seated posture. During voluntary efforts such as expiration from functional residual capacity, speaking, expulsive maneuvers, and isovolume "belly-in" maneuvers, the transversus in general contracted together with the external oblique and the rectus abdominis. In contrast, during hyperoxic hypercapnia, all subjects had phasic expiratory activity in the transversus at ventilations between 10 and 18 l/min, well before activity could be recorded from either the external oblique or the rectus abdominis. Similarly, inspiratory elastic loading evoked transversus expiratory activity in all subjects but external oblique activity in only one subject and rectus abdominis activity in only two subjects. We thus conclude that in humans 1) the transversus abdominis is recruited preferentially to the superficial muscle layer of the abdominal wall during breathing and 2) the threshold for abdominal muscle recruitment during expiration is substantially lower than conventionally thought.
... Furthermore, the abdominal muscles have three important anatomical features that contribute to the effective volume change in the abdominal cavity. First, they compactly cover the abdominal cavity and compress it radially inward [22], [23]. Second, the muscles, especially the external oblique muscle, lead the wall movement upward and project more pressure to the diaphragm [24]. ...
... Regarding the transient response, k D must be selected as a large value to achieve overdamped response, which ensures safe user-system interaction by preventing the chattering associated with P exo . If k P and k D are selected so that k D k P k, (22) approximates to a fast first-order dynamics: ...
... Recently, reported robotic-assistive technologies hint toward the design of a system that can enable everyday assistance by capitalizing on the recent advances in bioinspiration, soft materials, and intelligent assistance strategies. We designed a physiological and safe actuation mechanism with reference to human abdominal muscles, which natively engages in the control of the volumetric states in the lungs [22], [29]. In addition, we developed a customized sensor combination that can be used in conjunction with our actuation mechanism to realize a resilient context-aware control policy capable of all-day assistance, inspired by the control schemes of human-assistive robots [30], [31]. ...
Existing technologies for patients with respiratory insufficiency have focused on providing reliable assistance in their breathing. However, the need for assistance in other everyday respiratory functions, such as coughing and speaking, has remained unmet in these patients. Here, we propose Exo-Abs, a wearable robotic system that can universally assist wide-ranging respiratory functions by applying compensatory force to a user's abdomen in synchronization with their air usage. Inspired by how human abdominal muscles transmit pressure to the lungs via abdominal cavity compression, a biomechanically interactive platform was developed to optimally utilize the abdominal compression while aligning the assistance with a user's spontaneous respiratory effort. In addition to the compact form factor, thorough analytic procedures are described as initial steps toward taking the human respiratory system into the scope of robotics technology. We demonstrate the validity of the overall human–system interaction with the assistance performance under three essential respiratory functions: breathing, coughing, and speaking. Our results show that the system can significantly improve the performance of all these functions by granting on-demand and self-reliant assistance to its users.
... The transverse abdominal muscle contributes to respiratory function in humans and is preferentially recruited to the superficial muscle layer of the abdominal wall during breathing [10]. Although this muscle is relatively thin compared to the other two lateral abdominal wall muscles, it is known to play an integral role in truncal stability [7]. ...
... As these complications are largely missing from the literature to date, it may be possible that patients with lateral abdominal wall hernias are more likely to develop pulmonary difficulties following chemical CST. As the transversus abdominis muscle has a relatively large contribution to the respiratory function [10], patients with large lateral hernias may have an a priori compromised respiratory function compared to the more common patient with a large midline incisional hernia. To date, this statement is solely based on theoretical grounds. ...
... Conversely, IAP decreases during tidal expiration. However, in situations requiring higher respiratory demands, IAP may increase during expiration due to abdominal muscle activity assisting in the respiratory pump [6,7]. ...
... First, the examination procedures were explained, and written informed consent was signed by each subject. The exclusion criteria were: (1) low back pain, (2) previous abdominal or spine surgery, (3) respiratory or musculoskeletal disorder, (4) any symptoms of any kind of disease, (5) medical/ surgical procedure or trauma within four weeks before initiation of the study, (6) pregnancy, (7) and waist to height ratio (WHtR) greater than 0.59. The study was conducted in accordance with the Declaration of Helsinki, approved by the Ethics Committee of the University Hospital Motol in Prague, Czech Republic (Approval ID: EK-237/21), and was prospectively registered at clinicaltrials.gov ...
Objectives
The diaphragm changes position and respiratory excursions during postural loading. However, it is unclear how it reacts to lifting a load while breath-holding or breathing with simultaneous voluntary contraction of the abdominal muscles (VCAM). This study analyzed diaphragm motion in healthy individuals during various postural-respiratory situations.
Methods
31 healthy participants underwent examination of the diaphragm using M-mode ultrasonography, spirometry, and abdominal wall tension (AWT) measurements. All recordings were performed simultaneously during three consecutive scenarios, i.e., 1. Lifting a load without breathing; 2. Lifting a load and breathing naturally; 3. Lifting a load and breathing with simultaneous VCAM.
Results
Using paired-samples t-tests, lifting a load without breathing displaced the diaphragm’s expiratory position more caudally (P < .001), with no change noted in the inspiratory position (P = .373). During lifting a load breathing naturally, caudal displacement of the diaphragm’s inspiratory position was presented (P < .001), with no change noted in the expiratory position (P = 0.20) compared to tidal breathing. Total diaphragm excursion was greater when loaded (P = .002). Lifting a load and breathing with VCAM demonstrated no significant changes in diaphragm position for inspiration, expiration, or total excursion compared to natural loaded breathing. For all scenarios, AWT measures were greater when lifting a load (P < .001).
Conclusion
In healthy individuals, caudal displacement and greater excursions of the diaphragm occurred when lifting a load. The postural function of the diaphragm is independent of its respiratory activity and is not reduced by the increase in AWT.
... Measurements of sMMG lic have also been used, in combination with measurements of mouth pressure (P mo ), to calculate the mechanical efficiency (MEff) of lower chest wall inspiratory muscles, that is the transformation of muscle mechanical activation into pressure generation, in healthy subjects and patients with chronic obstructive pulmonary disease (COPD) [20]. Lower chest wall recordings are, however, less easily accessible and more contaminated by non-respiratory chest wall and abdominal muscle activation than parasternal intercostal recordings [21,22]. Nevertheless, the use of parasternal intercostal muscle sMMG (sMMG para ) as a noninvasive measure of inspiratory muscle mechanical output has not previously been investigated. ...
... Parasternal intercostal recordings have the advantage, over lower chest wall inspiratory muscle recordings, of being less affected by the limitations generally associated with surface recordings, such as the difficulty in finding the optimal sensor position or the strong influence of chest wall thickness and subcutaneous fat [44,45]. Moreover, parasternal intercostal recordings are less susceptible to crosstalk from postural chest wall and abdominal muscle activity [21,22]. The noninvasive indices of NMC MMG-EMGpara , NMC Pmo-EMGpara , and MEff Pmo-MMGpara proposed in this study would therefore make the evaluation of respiratory muscle function easier and faster to perform, and thus more acceptable in patients with altered respiratory mechanics, such as in obstructive lung disease and neuromuscular disease. ...
This study aims to investigate noninvasive indices of neuromechanical coupling (NMC) and mechanical efficiency (MEff) of parasternal intercostal muscles. Gold standard assessment of diaphragm NMC requires using invasive techniques, limiting the utility of this procedure. Noninvasive NMC indices of parasternal intercostal muscles can be calculated using surface mechanomyography (sMMGpara) and electromyography (sEMGpara). However, the use of sMMGpara as an inspiratory muscle mechanical output measure, and the relationships between sMMGpara, sEMGpara, and simultaneous invasive and noninvasive pressure measurements have not previously been evaluated. sEMGpara, sMMGpara, and both invasive and noninvasive measurements of pressures were recorded in twelve healthy subjects during an inspiratory loading protocol. The ratios of sMMGpara to sEMGpara, which provided muscle-specific noninvasive NMC indices of parasternal intercostal muscles, showed nonsignificant changes with increasing load, since the relationships between sMMGpara and sEMGpara were linear (R2 = 0.85 (0.75–0.9)). The ratios of mouth pressure (Pmo) to sEMGpara and sMMGpara were also proposed as noninvasive indices of parasternal intercostal muscle NMC and MEff, respectively. These indices, similar to the analogous indices calculated using invasive transdiaphragmatic and esophageal pressures, showed nonsignificant changes during threshold loading, since the relationships between Pmo and both sEMGpara (R2 = 0.84 (0.77–0.93)) and sMMGpara (R2 = 0.89 (0.85–0.91)) were linear. The proposed noninvasive NMC and MEff indices of parasternal intercostal muscles may be of potential clinical value, particularly for the regular assessment of patients with disordered respiratory mechanics using noninvasive wearable and wireless devices.
... The expiratory muscles include those of the abdominal wall (transversus abdominis muscle, internal oblique muscle, external oblique muscle, and rectus abdominis muscle) and some of the rib cage ones (e.g., the internal intercostal muscles and the triangularis sterni muscle) [1, 12-16] (Fig. 1). During tidal breathing, the expiratory muscles are largely inactive, although the transversus abdominis muscle may occasionally show some activity during quiet breathing [16]. Also, in the upright position, the abdominal wall muscles exhibit tonic activity to counteract the gravitational forces acting on the abdominal contents and thus to maintain the diaphragm at optimal length for pressure generation [17][18][19]. ...
... Low inspiratory muscle capacity (high relative load on inspiratory muscles) is common in ICU patients due to ICU-acquired respiratory muscle weakness [20]. In the presence of an imbalance between inspiratory muscle load and capacity, the abdominal wall muscles are recruited during expiration in a fixed hierarchy [21][22][23][24]: initially the transversus abdominis muscle, followed by the internal oblique muscle and the external oblique muscle, and finally the rectus abdominis muscle [16,17,25]. Activation of the abdominal wall muscles increases abdominal pressure in the expiratory phase. ...
Introduction
This narrative review summarizes current knowledge on the physiology and pathophysiology of expiratory muscle function in ICU patients, as shared by academic professionals from multidisciplinary, multinational backgrounds, who include clinicians, clinical physiologists and basic physiologists.
Results
The expiratory muscles, which include the abdominal wall muscles and some of the rib cage muscles, are an important component of the respiratory muscle pump and are recruited in the presence of high respiratory load or low inspiratory muscle capacity. Recruitment of the expiratory muscles may have beneficial effects, including reduction in end-expiratory lung volume, reduction in transpulmonary pressure and increased inspiratory muscle capacity. However, severe weakness of the expiratory muscles may develop in ICU patients and is associated with worse outcomes, including difficult ventilator weaning and impaired airway clearance. Several techniques are available to assess expiratory muscle function in the critically ill patient, including gastric pressure and ultrasound.
Conclusion
The expiratory muscles are the "neglected component" of the respiratory muscle pump. Expiratory muscles are frequently recruited in critically ill ventilated patients, but a fundamental understanding of expiratory muscle function is still lacking in these patients.
... The rectus abdominis, transverses abdominis, internal oblique, and external oblique muscles are the most powerful muscles involved in expiration [31]. Although the transverse abdominis has the lowest threshold for the respiratory activity of the ATMS [32], it is thought to be important for the control of the intersegmental stiffness of the spine via the increased IAP or the tension in the thoracolumbar fascia [33]. Therefore, the abdominal trunk muscles activated by the device play an important role in both respiratory function and trunk stability. ...
Objectives: Respiration plays an important function in sustaining life. The diaphragm is the primary muscle involved in respiration, and plays an important role in trunk stabilization. Although it has been reported that respiratory function is important for trunk muscle stability, the correlation between respiratory function and abdominal trunk muscle strength remains undetermined. This study aimed to clarify this correlation among middle-aged and older patients. Methods: This observational study included 398 patients scheduled for surgery for degenerative conditions of the lower extremities. Respiratory function was evaluated using forced vital capacity and forced expiratory volume in 1 s measured using spirometry. Each patient underwent a physical function test before surgery, which included the assessment of the abdominal trunk muscle strength, grip power, knee extensor strength, one-leg standing time, and gait speed. Correlations between abdominal trunk muscle strength, respiratory function, and physical function were evaluated. Results: Abdominal trunk muscle strength was significantly correlated with forced vital capacity, forced expiratory volume in 1 s, grip power, knee extensor strength, one-leg standing time, and gait speed. Multiple linear regression analyses revealed that sex, forced vital capacity, forced expiratory volume in 1 s, and knee extensor strength were significant factors associated with abdominal trunk muscle strength. Conclusions: In middle-aged and older patients, abdominal trunk muscle strength including that of the diaphragm, is associated with forced vital capacity and forced expiratory volume in 1 s.
... exercise, impaired respiratory system mechanics, increased PaCO2, etc.) and their capacity to respond to this load (e.g. respiratory muscle weakness) [8][9][10] . High respiratory load and impaired contracting ability of inspiratory muscles are commonly observed in critically ill patients. ...
Background
Patient-ventilator dyssynchrony is frequently observed during assisted mechanical ventilation (MV). However, the effects of expiratory muscle contraction on patient-ventilator interaction are underexplored. We hypothesized that active expiration would affect patient-ventilator interaction and we tested our hypothesis in a mixed cohort of invasively ventilated patients with spontaneous breathing activity.
Methods
This is a retrospective observational study involving patients on assisted MV who had their esophageal (Pes) and gastric (Pgas) pressures monitored for clinical purposes. Active expiration was defined as Pgas rise (ΔPgas) ≥1.0 cmH2O during expiratory flow without a corresponding change in diaphragmatic pressure (Pdi). Waveforms of Pes, Pgas, Pdi, flow, and airway pressure (Paw) were analyzed to identify and characterize abnormal patient-ventilator interaction.
Results
We identified 76 patients with Pes and Pgas recordings, of whom 58 demonstrated active expiration with a median ΔPgas of 3.4 cmH2O (IQR=2.4-5.3) observed in this subgroup. Among these 58 patients, 23 presented the following events associated with expiratory muscle activity: (1) distortions in Paw and flow that resembled ineffective efforts, (2) distortions similar to autotriggering, (3) multiple triggering, (4) prolonged ventilatory cycles with biphasic inspiratory flow, with a median % (IQR) increase in mechanical inflation time and tidal volume of 54% (44-70%) and 25% (8-35%), respectively and (5) breathing exclusively by expiratory muscle relaxation. Gastric pressure monitoring was required to identify the association of active expiration with these events. Respiratory drive, assessed by the rate of inspiratory Pes decrease, was significantly higher in patients with active expiration (median [IQR] dPes/dt: 12.7 [9.0-18.5] vs 9.2 [6.8-14.2] cmH2O/sec; p<0.05).
Conclusions
Active expiration can impair patient-ventilator interaction in critically ill patients. Without documenting Pgas, abnormal patient-ventilator interaction associated with expiratory muscle contraction may be mistakenly attributed to a mismatch between the patient´s inspiratory effort and mechanical inflation. This misinterpretation could potentially influence decisions regarding clinical management.
... From a functional perspective, this latter observation is relevant to the existence of bi-functional muscles, as is the case for the abdominal muscles, which participate in both respiration and locomotion (Saunders et al., 2004;Iizuka et al., 2022). Indeed, axial musculature, which is involved in expiration in mammals (Koterba et al., 1988;De Troyer et al., 1990;Deban and Carrier, 2002), is also engaged in locomotion (Grillner et al., 1978;Puckree et al., 1998;Deban and Carrier, 2002;Reilly et al., 2009). It has been proposed that this influence of the lumbar locomotor generator on expiratory neurons that control trunk movements could induce bending of the spine, thereby generating a forward displacement of the pelvis, which is known to facilitate exhalation. ...
Central motor rhythm-generating networks controlling different functions are generally considered to operate mostly independently from one another, each controlling the specific behavioral task to which it is assigned. However, under certain physiological circumstances, central pattern generators (CPGs) can exhibit strong uni- or bidirectional interactions that render them closely inter-dependent. One of the best illustrations of such an inter-CPG interaction is the functional relationship that may occur between rhythmic locomotor and respiratory functions. It is well known that in vertebrates, lung ventilatory rates accelerate at the onset of physical exercise in order to satisfy the accompanying rapid increase in metabolism. Part of this acceleration is sustained by a coupling between locomotion and ventilation, which most often results in a periodic drive of the respiratory cycle by the locomotor rhythm. In terrestrial vertebrates, the likely physiological significance of this coordination is that it serves to reduce the mechanical interference between the two motor systems, thereby producing an energetic benefit and ultimately, enabling sustained aerobic activity. Several decades of studies have shown that locomotor-respiratory coupling is present in most species, independent of the mode of locomotion employed. The present article aims to review and discuss mechanisms engaged in shaping locomotor-respiratory coupling (LRC), with an emphasis on the role of sensory feedback inputs, the direct influences between CPG networks themselves, and finally on spinal cellular candidates that are potentially involved in the coupling of these two vital motor functions.
... Identification of the costal diaphragm in the lower 7 th /8 th intercostal spaces is challenging and recording high quality sEMG lic and sMMG lic signals requires significant skill. However, the second intercostal space is more easily accessible, and sEMG para and sMMG para recordings, in comparison with sEMG lic and sMMG lic , are less influenced by chest wall thickness and subcutaneous fat [32], [33], and by crosstalk from postural chest wall and abdominal muscles [34], [35]. Therefore, it is relatively easier to acquire high quality sEMG and sMMG signals over the second intercostal space. ...
This study explored the use of parasternal second intercostal space and lower intercostal space surface electromyogram (sEMG) and surface mechanomyogram (sMMG) recordings (sEMG
para
and sMMG
para
, and sEMG
lic
and sMMG
lic
, respectively) to assess neural respiratory drive (NRD), neuromechanical (NMC) and neuroventilatory (NVC) coupling, and mechanical efficiency (MEff) noninvasively in healthy subjects and chronic obstructive pulmonary disease (COPD) patients. sEMG
para
, sMMG
para
, sEMG
lic
, sMMG
lic
, mouth pressure (P
mo
), and volume (V
i
) were measured at rest, and during an inspiratory loading protocol, in 16 COPD patients (8 moderate and 8 severe) and 9 healthy subjects. Myographic signals were analyzed using fixed sample entropy and normalized to their largest values (fSEsEMG
para%max
, fSEsMMG
para%max
, fSEsEMG
lic%max
, and fSEsMMG
lic%max
). fSEsMMG
para%max
, fSEsEMG
para%max
, and fSEsEMG
lic%max
were significantly higher in COPD than in healthy participants at rest. Parasternal intercostal muscle NMC was significantly higher in healthy than in COPD participants at rest, but not during threshold loading. P
mo
-derived NMC and MEff ratios were lower in severe patients than in mild patients or healthy subjects during threshold loading, but differences were not consistently significant. During resting breathing and threshold loading, V
i
-derived NVC and MEff ratios were significantly lower in severe patients than in mild patients or healthy subjects. sMMG is a potential noninvasive alternative to sEMG for assessing NRD in COPD. The ratios of P
mo
and V
i
to sMMG and sEMG measurements provide wholly noninvasive NMC, NVC, and MEff indices that are sensitive to impaired respiratory mechanics in COPD and are therefore of potential value to assess disease severity in clinical practice.
... Improvements in inspiratory muscle function seem to depend on the magnitude of the inspiratory load, with more substantial gains achieved in individuals training at higher loads (%80% of baseline MIP) [56,66−68]. Moreover, the improvements with IMT +EMT could relate to the fact that the inspiratory act occurs most effectively when the diaphragm obtains support from the abdominal muscles in movement (placing it in a mechanical advantage position by optimizing its length−tension relationship) [69]; thus higher values for MIP would be obtained if the abdominal muscle strength is increased. However, a possible explanation for improved endurance performance after RMT is reduced perception of respiratory exertion and/or breathlessness. ...
Background:
Previous reviews relating to the effects of respiratory muscle training (RMT) after stroke tend to focus on only one type of training (inspiratory or expiratory muscles) and most based the results on poor-quality studies (PEDro score ≤4).
Objectives:
With this systematic review and meta-analysis, we aimed to determine the effects of RMT (inspiratory or expiratory muscle training, or mixed) on exercise tolerance, respiratory muscle function and pulmonary function and also the effects depending on the type of training performed at short- and medium-term in post-stroke.
Methods:
Databases searched were MEDLINE, PEDro, CINAHL, EMBASE and Web of Science up to the end of April 2020. The quality and risk of bias for each included study was examined by the PEDro scale (including only high-quality studies) and Cochrane Risk of Bias tool.
Results:
Nine studies (463 patients) were included. The meta-analysis showed a significant increase in exercise tolerance [4 studies; n = 111; standardized mean difference [SMD] = 0.65 (95% confidence interval 0.27-1.04)]; inspiratory muscle strength [9 studies; n = 344; SMD = 0.65 (0.17-1.13)]; inspiratory muscle endurance [3 studies; n = 81; SMD = 1.19 (0.71-1.66)]; diaphragm thickness [3 studies; n = 79; SMD = 0.9 (0.43-1.37)]; and peak expiratory flow [3 studies; n = 84; SMD = 0.55 (0.03-1.08)] in the short-term. There were no benefits on expiratory muscle strength and pulmonary function variables (forced expiratory volume in 1 sec) in the short-term.
Conclusions:
The meta-analysis provided moderate-quality evidence that RMT improves exercise tolerance, diaphragm thickness and pulmonary function (i.e., peak expiratory flow) and low-quality evidence for the effects on inspiratory muscle strength and endurance in stroke survivors in the short-term. None of these effects are retained in the medium-term. Combined inspiratory and expiratory muscle training seems to promote greater respiratory changes than inspiratory muscle training alone.
... The respiratory muscle pump consists of several muscle groups: the diaphragm, which is the main muscle for inspiration; the accessory inspiratory muscles, including the parasternal, external intercostal, scalene, and sternocleidomastoid muscles; and the expiratory muscles, including the lateral abdominal wall muscles, the internal intercostal muscles, and transverse thoracic muscle. [1][2][3][4][5][6] With impending respiratory failure, mechanical ventilation is a life-saving intervention to support the respiratory pump. However, it is now recognized that mechanical ventilation may have adverse effects on the respiratory muscles. ...
Background
The lateral abdominal wall muscles are recruited with active expiration, as may occur with high breathing effort, inspiratory muscle weakness, or pulmonary hyperinflation. The effects of critical illness and mechanical ventilation on these muscles are unknown. This study aimed to assess the reproducibility of expiratory muscle (i.e., lateral abdominal wall muscles and rectus abdominis muscle) ultrasound and the impact of tidal volume on expiratory muscle thickness, to evaluate changes in expiratory muscle thickness during mechanical ventilation, and to compare this to changes in diaphragm thickness.
Methods
Two raters assessed the interrater and intrarater reproducibility of expiratory muscle ultrasound (n = 30) and the effect of delivered tidal volume on expiratory muscle thickness (n = 10). Changes in the thickness of the expiratory muscles and the diaphragm were assessed in 77 patients with at least two serial ultrasound measurements in the first week of mechanical ventilation.
Results
The reproducibility of the measurements was excellent (interrater intraclass correlation coefficient: 0.994 [95% CI, 0.987 to 0.997]; intrarater intraclass correlation coefficient: 0.992 [95% CI, 0.957 to 0.998]). Expiratory muscle thickness decreased by 3.0 ± 1.7% (mean ± SD) with tidal volumes of 481 ± 64 ml (P < 0.001). The thickness of the expiratory muscles remained stable in 51 of 77 (66%), decreased in 17 of 77 (22%), and increased in 9 of 77 (12%) patients. Reduced thickness resulted from loss of muscular tissue, whereas increased thickness mainly resulted from increased interparietal fasciae thickness. Changes in thickness of the expiratory muscles were not associated with changes in the thickness of the diaphragm (R2 = 0.013; P = 0.332).
Conclusions
Thickness measurement of the expiratory muscles by ultrasound has excellent reproducibility. Changes in the thickness of the expiratory muscles occurred in 34% of patients and were unrelated to changes in diaphragm thickness. Increased expiratory muscle thickness resulted from increased thickness of the fasciae.
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... At least from a theoretical perspective, MACM appears to be inappropriate for retraining abdominal muscles in patients with lower back pain (LBP), because abdominal muscles must contract in sequence with appropriate timing and tension to achieve optimal core stability [7]. Recent reports suggest individual abdominal muscles differently contribute to respiration [29,30], which suggests MACM may not be ideal for achieving contraction of specific abdominal muscles during the early phase of motor rehabilitation. However, forceful contraction of abdominal muscles is necessary to generate intra-abdominal pressure, which is known to reduce spine compression force [26,31]. ...
Background and objectives: The maximal abdominal contraction maneuver (MACM) was designed as an effective and efficient breathing exercise to increase the stability of the spinal joint. However, it has not been determined whether MACM is more effective and efficient than the maximal expiration method. Thus, the present study was undertaken to investigate whole abdominal muscle thickness changes after MACM. Materials and Methods: Thirty healthy subjects (17 males and 13 females) participated in this study. An experimental comparison between MACM and the maximal expiration task was conducted by measuring the change of abdominal muscle thickness such as the transverse abdominis (TrA), internal oblique (IO), external oblique (EO) and rectus abdominis (RA) using ultrasound images. Results: The results indicated that MACM resulted in significantly greater muscle thickness increases of the TrA and RA than the maximal expiration exercise (p < 0.05). Conclusion: MACM provided better exercise than the maximal expiration exercise in terms of increasing spine stability, at least from a co-contraction perspective.
... In contrast, the local muscles involve the lumbar multifidus (LM), internal oblique (IO), and transversusabdominis (TrA), which are responsible for the stabilization of the body. In addition, the TrA and IO are involved in abdominal pressure increase and play a role in stabilizing the trunk (De Troyer et al., 1990;Cresswell et al., 1992) and the LM in fine control of the lumbar spine (Bergmark, 1989). Trunk muscles have complex roles; however, changes in the activity of each muscle in different postures, including standing and sitting, have not been fully investigated. ...
The trunk muscles play a role in posture maintenance, but whether they are related to spinal alignment in different postures has only been investigated in young adults and not in the elderly who show age-related changes in the spine. This study aimed to determine the relationship between changes in spinal alignment and muscle thickness in three postures in healthy elderly subjects. Spinal mouse measurements of Spinal alignment and ultrasound measurements of the trunk muscles were performed in the standing, upright and slump sitting positions on healthy elderly individuals living in the community. Results showed significant differences in the sacral tilt, lumbar curvature, and overall tilt angles in the slump sitting position for spinal alignment, and significant differences were noted in muscle thickness between standing and upright sitting, standing and slump sitting, and standing and slump sitting, and upright and slump sitting for the spinal proprioceptive muscle (second lumbar level). In conclusion, there was no correlation between the two changes. It was suggested that the spine be viewed as a whole and not in parts, with muscle thickness changes. Keywords: Spine, postural difference, posture holding muscle.
... Thus, it is logical that if the expiratory musculature is weakened, due to its synergic action, the pelvic floor musculature could also be affected, which could be the cause of the UI. Moreover, the inspiratory act occurs most effectively when the diaphragm obtains support from the abdominal muscles in movement [54]; thus, lower values in inspiratory muscle strength would be obtained if the abdominal muscle strength is reduced. Therefore, we hypothesise that the strength of the expiratory muscles could mediate the weak and indirect association observed between inspiratory muscle strength and IU. ...
Purpose
Patients with multiple sclerosis (MS) with respiratory muscle weakness could have physical function impairments, given the functional/biomechanical link of the trunk stabilising system. Thus, clinicians could employ new treatment strategies targeting respiratory muscles to improve their physical function. This study pretends to evaluate the relationship between respiratory muscle strength, pulmonary function and pelvic floor function, and also to correlate these variables with physical function (gait function, disability and quality of life) in patients with MS.
Methods
41 patients participated in this descriptive cross-sectional study. Respiratory muscle strength [maximal respiratory pressures (MIP/MEP)], pulmonary function (forced spirometry), pelvic floor function [urinary incontinence (UI)], physical function [Timed Up & Go (TUG) test, Barthel index and health status questionnaire (SF-12)] were evaluated.
Results
Respiratory muscle strength and pulmonary function were moderately related to UI (MIP: rho = −0.312; MEP: rho = −0.559). MEP was moderately related to physical function (TUG: rho = −0.508; Barthel index: rho = 0.418). Patients with and without expiratory muscle weakness showed differences in UI, pulmonary and physical function.
Conclusion
Patients with MS with greater deterioration in pulmonary function and respiratory muscle strength, especially expiratory muscles, showed greater deterioration in UI and physical function. Expiratory muscle weakness had a negative impact on urinary, physical and pulmonary function.
•
Implications for rehabilitation
• Pulmonary function is associated with urinary incontinence and gait functionality in patients with multiple sclerosis (MS).
• Expiratory muscle weakness is associated with impaired urinary and physical function in patients with MS.
• The inclusion of respiratory muscle training to the rehabilitation programs of patients with MS could improve their pelvic floor disorders and physical function.
... Its action includes the support for the abdominal wall, role in maintenance of posture, trunk movement includes flexion, extension, lateral flexion, rises the intra-abdominal pressure in case of Forced Expiration, Defecation, Micturition, Parturition. The contraction of the transversus thoracic pulls the ribs caudally, and helps in the expiration and it is barely active in the supine lying position and while doing the stomach vacuum blow exercise[11]. ...
Background:
Smoking cigarettes which progressively impairs the lung functions is a leading risk factor for early death and disability worldwide. Alternate use of the tobacco products along with some exercise practicing behaviour help to prevent the impairment of lung function because most smokers fail to cease smoking. The objective of this research was to find out the effectiveness of the balloon blowing exercise among the young adult smokers using the peak expiratory flow meter.
Methods:
A quasi- experimental study in which 100 male participants were included according to inclusion and exclusion criteria. Pre-test and Post-test was taken using Peak expiratory flow meter, after intervention is provided.
Results:
The mean appraise of the Group A pre-test was 287.1 and the post-test was 283.2, and the mean appraise of the Group B pre-test was 279.7 and the post-test was 367.2. The significant appraise was .581 for Group A and .000 for the Group B since the p < 0.05. The study shows the significant result as the p appraise is less than 0.05.
Conclusion:
This study concludes that there was a significant increase in the peak expiratory flow rate in the post test of Group B.
... On the other hand, bilateral activation of the oblique abdominal muscles and transverse abdominal muscle during expiration will increase intraabdominal pressure and pleural pressure which assist lung deflation. In addition to assisting expiration, these muscles play a role in coughing and airway clearance preventing the development of atelectasis [26][27][28][29]. ...
Background:
Critical illness has detrimental effects on the diaphragm, but the impact of critical illness on other major muscles of the respiratory pump has been largely neglected. This study aimed to determine the impact of critical illness on the most important muscles of the respiratory muscle pump, especially on the expiratory muscles in children during mechanical ventilation. In addition, the correlation between changes in thickness of the expiratory muscles and the diaphragm was assessed.
Methods:
This longitudinal observational cohort study performed at a tertiary pediatric intensive care unit included 34 mechanical ventilated children (> 1 month- < 18 years). Thickness of the diaphragm and expiratory muscles (obliquus interna, obliquus externa, transversus abdominis and rectus abdominis) was assessed daily using ultrasound. Contractile activity was estimated from muscle thickening fraction during the respiratory cycle.
Results:
Over the first 4 days, both diaphragm and expiratory muscles thickness decreased (> 10%) in 44% of the children. Diaphragm and expiratory muscle thickness increased (> 10%) in 26% and 20% of the children, respectively. No correlation was found between contractile activity of the muscles and the development of atrophy. Furthermore, no correlation was found between changes in thickness of the diaphragm and the expiratory muscles (P = 0.537). Decrease in expiratory muscle thickness was significantly higher in patients failing extubation compared to successful extubation (- 34% vs - 4%, P = 0.014).
Conclusions:
Changes in diaphragm and expiratory muscles thickness develop rapidly after the initiation of mechanical ventilation. Changes in thickness of the diaphragm and expiratory muscles were not significantly correlated. These data provide a unique insight in the effects of critical illness on the respiratory muscle pump in children.
... 7,43 When respiration is challenged through increased chemical loading or during unstable postural conditions, the TrA muscle is the first abdominal muscle recruited to assist expiration. 8,44 It appears that individuals with CLBP were not able to activate the TrA muscle efficiently during an increased postural demand. In addition, the results revealed that individuals in the CLBP group showed a smaller muscle thickness change in all abdominal muscles, except the EO muscle, during both respiratory phases in position 4 (ie, difficult postural task). ...
Objective
The aim was to assess the abdominal muscle activities during inspiration and expiration at different sitting positions in individuals with and without chronic low back pain (CLBP).
Methods
This study was conducted on 36 participants (18 with CLBP and 18 healthy controls). Ultrasound imaging was used to assess thickness changes of the transverse abdominis, internal oblique, rectus abdominis, and external oblique muscles. Muscle thickness was measured during inspiration and expiration under 3 different stability levels: sitting on a chair, sitting on a gym ball, and sitting on a gym ball with lifting the left foot. The muscle thickness measured in these positions was normalized to the actual muscle thickness at rest in supine lying and presented as a percentage of thickness change.
Results
Both groups displayed greater abdominal muscle activities as the stability of the surface decreased during both respiratory phases. However, compared with the healthy controls, the CLBP group showed smaller muscle thickness changes in all abdominal muscles, except the external oblique, in both respiration phases while sitting on a gym ball with lifting the left foot. The CLBP group displayed overactivity of the rectus abdominis muscle relative to the healthy controls while sitting on a chair in both respiratory phases.
Conclusion
The findings of the study indicate that as the stability of the support surface decreases, individuals with CLBP had more difficulty activating all abdominal muscles in a similar manner compared to healthy controls in both respiratory phases, which might affect both respiration and postural stability.
... 16 When the workload increases, the abdominal muscles contract during expiration, with an initial recruitment of transversus abdominis muscle and subsequent recruitment of the other abdominal muscles. 17 Expiratory abdominal muscle contraction enhances inspiratory diaphragm performance (through its lengthtension relationship) and spring loads the thoracic cage to expand when the abdominal muscles relax, assisting with the inspiratory work of breathing. 18 The work of breathing during heavy loads is thus redistributed to accessory inspiratory muscles, abdominal muscles, and the diaphragm. ...
The diaphragm is vulnerable to injury during mechanical ventilation, and diaphragm dysfunction is both a marker of severity of illness and a predictor of poor patient outcome in the ICU. A combination of factors can result in diaphragm weakness. Both insufficient and excessive diaphragmatic contractile effort can cause atrophy or injury, and recent evidence suggests that targeting an appropriate amount of diaphragm activity during mechanical ventilation has the potential to mitigate diaphragm dysfunction. Several monitoring tools can be used to assess diaphragm activity and function during mechanical ventilation, including pressure-derived parameters, electromyography, and ultrasound. This review details these techniques and presents the rationale for a diaphragm-protective ventilation strategy.
... A decrease in EELV represents an increase in the elastic recoil of the chest and potentially more energy for inspiration, which may occur passively as a result of the potential energy of the chest wall at the end of expiration [4]. ; the results were the same for all patients, whether or not they perceived bene ts from the PLB [5][6][7]. ...
Introduction: Chronic Obstructive pulmonary disease (COPD) is characterized by airflow obstruction with breathing-related symptoms such as chronic cough, exertion dyspnoea, expectoration, and wheeze [1]. The Buteyko concept is a system of breathing exercises originally devised in the 1950s by Professor Konstantin Buteyko, a Russian physician and academic personality [2].
... Mean (SD) running distance per week was 39.7 (19.9) km. Mean (SD) training age (years of training at this load) was 11 (10) year. Twenty-five participants were right handed and five were left handed. ...
Objective
The transversus abdominis muscle (TrA) is active during running as a secondary respiratory muscle and acts, together with the multifidus, as trunk stabiliser. The purpose of this study was to determine size and symmetry of TrA and multifidus muscles at rest and with contraction in endurance runners without low back pain.
Design
Cross-sectional study.
Setting
A medical imaging centre in Melbourne, Australia.
Participants
Thirty middle-aged (43years±7) endurance-trained male (n=18) and female (n=12) runners without current or history of low back pain.
Outcome measures
MRI at rest and with the core engaged. The TrA and multifidus muscles were measured for thickness and length (TrA) and anteroposterior and mediolateral thickness (multifidus). Muscle activation was extrapolated from rest to contraction and compared with the same and contralateral side. Paired t-tests were performed to compare sides and contraction status.
Results
Left and right TrA and multifidus demonstrated similar parameters at rest (p>0.05). However, with contraction, the right TrA and multifidus (in mediolateral direction) were 9.2% (p=0.038) and 42% (p<0.001) thicker, respectively, than their counterparts on the left. There was no TrA thickness side difference with contraction in left-handed participants (p=0.985). When stratified by sex, the contracted TrA on the right side remained 8.4% thicker, but it was no longer statistically significant (p=0.134). The side difference with contraction of the TrA became less with increasing training age.
Conclusions
Right-handed long-term runners without low back pain exhibit a greater right side core muscle activation when performing an isometric contraction. This activation preference diminishes with increasing training age.
... Studies in human subjects reveal some eupneic activity in the standing posture, but minimal to none in supine subjects. The transversus abdominis appears to have the greatest respiratory-related activity, followed by the internal oblique, external oblique, and rectus abdominis (2,105,432). There are some differences, however. ...
This review is a comprehensive description of all muscles that assist lung inflation or deflation in any way. The developmental origin, anatomical orientation, mechanical action, innervation, and pattern of activation are described for each respiratory muscle fulfilling this broad definition. In addition, the circumstances in which each muscle is called upon to assist ventilation are discussed. The number of “respiratory” muscles is large, and the coordination of respiratory muscles with “nonrespiratory” muscles and in nonrespiratory activities is complex—commensurate with the diversity of activities that humans pursue, including sleep (8.27). The capacity for speech and adoption of the bipedal posture in human evolution has resulted in patterns of respiratory muscle activation that differ significantly from most other animals. A disproportionate number of respiratory muscles affect the nose, mouth, pharynx, and larynx, reflecting the vital importance of coordinated muscle activity to control upper airway patency during both wakefulness and sleep. The upright posture has freed the hands from locomotor functions, but the evolutionary history and ontogeny of forelimb muscles pervades the patterns of activation and the forces generated by these muscles during breathing. The distinction between respiratory and nonrespiratory muscles is artificial, as many “nonrespiratory” muscles can augment breathing under conditions of high ventilator demand. Understanding the ontogeny, innervation, activation patterns, and functions of respiratory muscles is clinically useful, particularly in sleep medicine. Detailed explorations of how the nervous system controls the multiple muscles required for successful completion of respiratory behaviors will continue to be a fruitful area of investigation. © 2019 American Physiological Society. Compr Physiol 9:1025‐1080, 2019.
... 6 Namely, the greater CSA of intraperitoneal tissue including visceral fat itself becomes a load during breathing and it may induce a greater percentage of CSA in respiratory muscles such as abdominal oblique muscle group. 25,26 In the present study, visceral fat CSA significantly decreased after the intervention. Therefore, reduced abdominal pressure may contribute to the decrease observed in abdominal oblique skeletal muscle CSA. ...
Background and objectives:
Limited information is available on how weight loss intervention programs affect skeletal muscle mass especially in trunk.
Methods and study design:
A total of 235 overweight Japanese men and women aged 40-64 years with a body mass index of 28.0 to 44.8 kg/m2 participated in this randomized controlled intervention study. They were randomly divided into a lifestyle intervention group and control group. Before and after the one-year lifestyle intervention for weight loss an abdominal transverse image was acquired by computed tomography. The cross-sectional areas (CSAs) of visceral fat, subcutaneous fat, and skeletal muscle of rectus abdominis, abdominal oblique, iliopsoas, and erector spinae muscle were calculated.
Results:
The body weight changed by approximately -5% in the intervention groups. The corresponding values for subcutaneous fat and visceral fat CSAs were -10.8 to -17.5% in both sexes. The reductions observed in skeletal muscle CSAs were significantly less (-6.0% and -7.2% in the men and women intervention groups respectively) than those in fat tissue CSAs. The CSA of each of the four skeletal muscle groups also significantly decreased; however, after adjustments for body weight at each time point, only reductions in the iliopsoas muscle in both sex and abdominal oblique muscles in men remained significant.
Conclusions:
The lifestyle weight loss intervention might reduce the relative amount of the abdominal skeletal muscles especially in iliopsoas muscle.
Introduction: Breathing and postural control is reported to be both neuromuscularly and mechanically
interdependent. To date, the effects of voluntary abdominal and thoracic breathing
(VAB and VTB) on the EMG activity of muscles involved in both respiratory and postural functions,
as well as gait biomechanics related to these breathing patterns, have not been investigated
in young, healthy adults. The aim of the study was to evaluate the EMG responses of neck and
trunk muscles, as well as the kinematic, stability, and kinetic parameters of gait induced by VAB
and VTB compared to involuntary breathing (INB).
Methods: Twenty-four healthy, physically active participants (12 men and 12 females) were
required to complete three two-minute walking sessions on an instrumented treadmill (e.g. devices
with capacitive sensors embedded beneath the running belt) at 5.0 km h 1, first with INB
and then alternatively with VAB and VTB. A respiratory inductive plethysmography unit was used
to provide real-time visual feedback of the breathing pattern performed by each participant. The
EMG activity of the sternocleidomastoid (SCM), upper trapezius (UT), thoracic and lumbar
erector spinae (TES and LES), as well as spatiotemporal (step width, stride length, stride time,
stance phase, swing phase, and cadence), stability (anteroposterior and mediolateral center of
pressure trajectory), and dynamic gait parameters (vertical ground reaction forces, vGRF) were
recorded during each testing condition.
Results: Our findings revealed that both voluntary breathing patterns significantly affected the
EMG activity of the SCM (p < 0.01) and UT (p < 0.05), with the activity between these muscles, as
expressed by the SCM:UT ratio, being more balanced during VAB (0.94) and VTB (1.05)
compared to INB (0.73). Additionally, VAB walking led to a narrower step width (p < 0.01) and
reduced vGRF over the forefoot (p < 0.01) compared to INB walking. Neither VAB nor VTB
influenced the activation levels of the LES and TES, nor did they affect other spatiotemporal,
stability, or dynamic gait parameters (p > 0.05).
Conclusions: Our findings suggest that certain gait parameters (e.g. step width, forefoot vGRFs) are
primarily influenced by VAB compared to INB, likely due to the more balanced activation of the
SCM and UT muscles. This balanced activation may enhance
The abdominal wall is a complex structure composed of layers of muscles, fascia, and other tissues that encase the abdominal cavity. Its anatomy is crucial for providing support, protection, and mobility to the abdominal organs. The anterior abdominal wall consists of skin, subcutaneous tissue, muscles (rectus abdominis, external oblique, internal oblique, and transversus abdominis), fascia, and peritoneum. Conversely, the posterior abdominal wall includes muscles such as the psoas major, quadratus lumborum, and iliacus, along with fascia, blood vessels (abdominal aorta and inferior vena cava), nerves, and retroperitoneal organs such as the kidneys and ureters. The abdominal fascial plane is a complex network of connective tissue layers that envelop and support the abdominal muscles and organs. Anteriorly composed of layers such as the superficial fascia, deep fascia, and transversalis fascia, the anterior abdominal fascial plane provides a sturdy framework that supports the abdominal wall and its contents. It acts as a barrier, compartmentalizing different regions of the abdomen and preventing the spread of infection or injury. The posterior abdominal fascial layers constitute a vital structural framework that supports and protects the abdominal cavity’s posterior aspect. The thoracolumbar fascia spans across the lumbar vertebrae, iliac crest, and ribs, serving as a robust anchor for the muscles of the back and abdomen. Its organization into multiple layers provides structural reinforcement, contributing to trunk stability and posture maintenance. Furthermore, the abdominal fascial plane serves as a conduit for blood vessels, lymphatics, and nerves, ensuring proper vascular supply and innervation to the abdominal organs and muscles.
Introduction
Weaning of patient from ventilator and finally extubation is a challenge, especially in critical care setup. Though many parameters are available, based on which, the decision of extubation is taken but still many times, there is failure of weaning.
Aim
We conducted a prospective observational study to look for diaphragm and abdominal muscle thickness, contraction, and lung ultrasound as indicator for weaning and extubation.
Material and Methods
Patients of either gender aged between 20-50 years, who were on invasive mechanical ventilation for more than 48 hrs. and put on spontaneous breathing trial. A bedside ultrasound examination was performed. Abdominal expiratory muscle thickness, diaphragmatic excursion (DE), diaphragmatic thickness fraction (DTF) and lung ultrasound score (LUS) were measured.
Results
12 patients had simple weaning pattern whereas 5 patients had difficult weaning and 8 patients had prolonged weaning. The mean value of DE was 1.97 cm, DTF- 2.3 mm. The mean value of SOFA score is significant between simple, difficult, prolonged weaning (2.24, 4.56, 7.33 respectively). The DE, which is 2.52, 1.26, 1.81 in simple difficult and prolonged weaning respectively is highly significant. The mean value of LUS was 8.34 and is significant in all weaning patterns. The highest sensitivity is found for SOFA score (84.62) with AUC of 0.88.
Conclusion
Evaluation of patient with diaphragm thickness fraction (mean DTF of 26%) and diaphragm excursion (2.52 cm) with mean LUS score of 4.67 opens a new dimension to predict weaning in critically ill patients who are put on spontaneous breathing trial. The sequence of thickness of abdominal expiratory muscles adds to accuracy in successful weaning. Larger muti-center trials are required to make these parameters as a standard practice for weaning patients in critical care setup.
Current technologies are unable to identify the simultaneous contraction of deep and superficialmuscles when the subject is in motion. In this contribution, we propose a method to identify the co-contraction patterns of four muscles of the abdominal wall, namely the rectus abdominis, obliquus externus, obliquus internus and transversus abdominis, with only two pairs of surface electrodes. Surface electromyography (EMG) signals are acquired from two bipolar leads placed on the lower abdomen of the volunteers. Following the extraction of features, a principal component analysis is conducted to optimize the data representation, and a random forest classifier is employed to classify the co-contraction patterns. Our method achieves up to 86.30% accuracy, which demonstrates the possibility of identifying fourteen co-contraction patterns of four different muscles of the abdominal wall, either surface or deep muscles. Conclusion: This method does not need to be adapted to a new patient, which is better suited to the physiotherapists’s practice. Moreover, it opens a field of research regarding the role of deep muscles in motion either during exercises or daily life tasks as well as in pathologies with complex etiology. EMG research will benefit from this method, which provides a better understanding of muscle co-contractions, but also reduces the number of sensors needed to acquire relevant information, while remaining non-invasive. The clinical interest lies in the improvement of the physiotherapeutic management. Indeed, a better knowledge of the patient’s co-contractions patterns makes it easier to adapt the physiotherapist’s treatment plan to the patient’s needs.
Background:
A variety of physical complaints have been related to chronic diastasis recti (DR), including back pain, pelvic pain, and urinary incontinence. However, its clinical significance is still subject of debate, leaving many patients to feel unheard when experiencing symptoms. This study aims to assess current knowledge on DR, its potential treatments, and the awareness of this condition amongst involved health care professionals.
Methods:
A literature review was performed to analyze current available knowledge on DR and its treatment. Then, a survey was conducted to investigate the awareness on DR amongst general practitioners, midwives, gynecologists, general surgeons, and plastic surgeons.
Results:
Over 500 health care professionals completed our survey, including 46 general practitioners, 39 midwives, 249 gynecologists, 33 general surgeons, and 74 plastic surgeons. Although the majority of respondents (>78% in all groups) reported to encounter DR in daily practice, opinions differed markedly on most significant symptoms, associated physical complaints, best first referral for treatment, and best treatment modality.
Conclusion:
Current literature is not unanimous on the relation between DR and physical complaints and on its most suitable treatment. This incongruity is corroborated by the variety of responses from involved health care professionals in our survey. More clinical data are needed to provide clarity on this issue.
Background
Respiratory muscle ultrasound is a widely available, highly feasible technique that can be used to study the contribution of the individual respiratory muscles related to respiratory dysfunction. Stroke disrupts multiple functions, and the respiratory function is often significantly decreased in stroke patients.
Method
A search of the MEDLINE, Web of Science, and PubMed databases was conducted. We identified studies measuring respiratory muscles in healthy and patients by ultrasonography. Two reviewers independently extracted and documented data regarding to the criteria. Data were extracted including participant demographics, ultrasonography evaluation protocol, subject population, reference values, etc.
Result
A total of 1954 participants from 39 studies were included. Among them, there were 1,135 participants from 19 studies on diaphragm, 259 participants from 6 studies on extra-diaphragmatic inspiratory muscles, and 560 participants from 14 studies on abdominal expiratory muscles. The ultrasonic evaluation of diaphragm and abdominal expiratory muscle thickness had a relatively typically approach, while, extra-diaphragmatic inspiratory muscles were mainly used in ICU that lack of a consistent paradigm.
Conclusion
Diaphragm and expiratory muscle ultrasound has been widely used in the assessment of respiratory muscle function. On the contrary, there is not enough evidence to assess extra-diaphragmatic inspiratory muscles by ultrasound. In addition, the thickness of the diaphragm on the hemiplegic side was lower than that on the non-hemiplegic side in stroke patients. For internal oblique muscle (IO), rectus abdominis muscle (RA), transversus abdominis muscle (TrA), and external oblique muscle (EO), most studies showed that the thickness on the hemiplegic side was lower than that on the non-hemiplegic side.
Clinical Trial Registration: The protocol of this review was registered in the PROSPERO database (CRD42022352901).
As a clinician, everyone undergoes a difficult time in clinical decision-making when attempting to apply a clinical prediction rule for manipulation (Flynn et al., 2002; Childs et al., 2004) to a patient with a history and physical examination consistent with clinical lumbar instability (Hicks et al., 2005). The effect on neural pathways associated with manipulation has been suggested as one possible mechanism that may improve muscle performance (Pickar, 2002) and patient symptoms. Support exists for an association between spinal manipulation and improved muscle function in the quadriceps (Suter et al., 1999), the erector spinae (Keller and Colloca, 2000), and the deep neck flexors (Sterling et al., 2001). Therefore, it is reasonable to hypothesize that spinal manipulation, by a reflexogenic mechanism, may improve the performance of the deep trunk stabilizers. In turn, improved relaxation and contractility of the lumbar multifidus and the transversus abdominis (TrA) theoretically could lead to improved functional stability of the spine through enhancement of the neurological and active subsystems as defined by Panjabi (1992a, b). This single case study describes changes observed in the TrA musculature pre- to post-manipulation in a patient that presented with a clinical paradox (symptoms suggestive of clinical lumbar instability but also meeting the clinical prediction rule to succeed with lumbar manipulation therapy). Real-time ultrasound imaging (USI) was used to describe the changes in the TrA musculature..
We investigated the effects of intentional breath-holding also known as a valsalava maneuver on the kinematics of the lumbar spine, pelvis, hips, and knees, as well as electromyographic (EMG) activity of the trunk muscle during patient transfer with and without knee flexion. The kinematics of the lumbar spine, pelvis, hip, and knee were recorded using a synchronized 3-D motion capture system. Surface EMG was used to assess the activity of the external oblique (EO), internal oblique (IO), erector spinae (ES), and rectus femoris (RF). There was a significant difference in the peak angle of the lumbar spine (η2 = 0.644–0.600), pelvis (η2 = 0.514–0.294), hips (η2 = 0.897–0.746), and knees (η2 = 0.977–0.870), as well as in normalized EMG activity of the EO (η2 = 0.543–0.501), IO (η2 = 0.619–0.460), ES (η2 = 0.567–0.195), and RF (η2 = 0.607–0.144) (except for the RF in the lowering phase, p = 0.10), between the different types of patient transfer, in both the lifting and lowering phases (p < 0.001). These findings suggest that intentional breath-holding during patient transfer contributes to decreased lumbar flexion and ES activity, thus potentially preventing low back injury. However, individuals with a history of heart and cardiovascular disease are advised to avoid the valsalava maneuver.
Sleep irregularities and respiratory events (apnea, O2 desaturation or a combination thereof) are often present in the infant population. While inspiration is the main active process in the act of breathing, expiration is generally thought to occur passively. Although commonly considered as quiet during sleep, expiratory abdominal muscles have been proposed to be recruited to promote ventilation, facilitate gas exchange, and reduce the work of breathing during conditions of increased respiratory drive, exercise, or airway obstruction. In this study, we investigated the occurrence of expiratory abdominal muscle activity in polysomnographic studies of subjects (aged 0–2 years) suspected of sleep disordered breathing. Our results indicate that abdominal muscle activation occurs during sleep, most frequently during non-rapid eye movement and rapid-eye movement states compared to slow-wave sleep. Furthermore, abdominal muscle activity was present during regular breathing or associated with respiratory events (apneas or O2 desaturation). In the latter case, abdominal muscle recruitment more frequently followed the onset of respiratory events and terminated with recovery from blood O2 desaturation events. We conclude that expiratory abdominal muscle activity contributes to the pattern of respiratory muscle recruitment during sleep in infants and given its temporal relationship with respiratory events, we propose that its recruitment could facilitate proper ventilation by counteracting airway resistance and O2 desaturation in infancy across different stages of sleep.
PhD thesis "Towards respiratory muscle-protective mechanical ventilation in the critically ill: technology to monitor and assist physiology"
Activity of the respiratory muscles is disturbed by virtually every respiratory disorder. Clinical manifestations of respiratory muscle involvement are subtle and commonly missed. The critical step in diagnosing problems is for a clinician to suspect a muscle problem when the presentation is camouflaged by obscuring features. This chapter provides a detailed discussion of methods to detect and monitor respiratory muscle function. Screening tools consist of physical examination, pulmonary function testing, and recordings of inspiratory and expiratory pressures. Precise quantification of diaphragmatic contractility is provided by recordings of transdiaphragmatic pressure in response to phrenic-nerve stimulation. Mechanical load on the respiratory muscles is best captured by computation of work of breathing and its subfractions. Electromyographic recordings of electrical activity of the diaphragm help in assessing neuromuscular coupling. Burgeoning reports on ultrasound and airway pressure recordings reflect a craving for easy-to-use noninvasive tools, but the techniques are beset by poor reproducibility and failure to validate proposed threshold values. The greatest challenge for improving patient care remains physician understanding of the basic physiology that underpins methods used to diagnose and monitor respiratory muscle pathology.
Background
Ultrasound may be useful to assess the structure, activity, and function of the abdominal muscles in mechanically ventilated patients.
Research Question
Does measurement of abdominal muscle thickening on ultrasound in mechanically ventilated patients provide clinically relevant information about abdominal muscle function and weaning outcomes?
Study Design and Methods
This study consisted of two parts, a physiological study conducted in healthy subjects and a prospective observational study in mechanically ventilated patients. Abdominal muscle thickness and thickening fraction (TF) were measured during cough and expiratory efforts in 20 healthy subjects and before and during a spontaneous breathing trial (SBT) in 57 ventilated patients.
Results
In healthy subjects, internal oblique and rectus abdominis thickening fraction correlated with pressure generated during expiratory efforts (p < 0.001). In ventilated patients, abdominal muscle thickness and thickening fraction were feasible to measure in all patients, and reproducibility was moderately acceptable. During a failed SBT, thickening fraction of transversus abdominis and internal oblique increased substantially (+13.2%, 95%CI 0.9 – 24.8 from baseline; +7.2%, 95%CI 2.2 – 13.2, respectively). The combined thickening fraction of transversus abdominis, internal oblique, and rectus abdominis measured during cough was associated with an increased risk of reintubation or reconnection to the ventilator after attempted liberation (odds ratio 2.1, 95% CI 1.1 – 4.4 per 10% decrease in thickening fraction).
Interpretation
Abdominal muscle thickening on ultrasound is correlated to the airway pressure generated by expiratory efforts. In mechanically ventilated patients, abdominal muscle ultrasound measurements are feasible and moderately reproducible. Among patients who pass a spontaneous breathing trial, reduced abdominal muscle thickening during cough is associated with a high risk of liberation failure.
Accurate measurements of pressure and flow rate are essential in respiratory mechanics researches [1, 2]. Apart from airway pressure displayed on the mechanical ventilator, additional sources of pressure measurements, such as tracheal pressure, gastric pressure, and esophageal pressure, are useful for differentiating the influence of the airway resistance and chest wall elastance on the lung mechanics [3–7]. Flow measurement is fundamental for lung volume evaluation during mechanical ventilation [1, 2, 8]. In this chapter, frequently used techniques and instruments for pressure and flow data acquisition are introduced.
En el campo del deporte y la educación física, el uso de diferentes ejercicios y métodos para fortalecer la musculatura del tronco carece de base científica. Por otro lado, los estudios electromiográficos sobre la musculatura del tronco muestran resultados contradictorios debido a diferencias metodológicas entre ellos. El planteamiento de esos problemas nos ha llevado a desarrollar un estudio sobre la participación de la musculatura del tronco en ejercicios de fortalecimiento abdominal, tratando de solucionar las diferencias metodológicas existentes. La participación de la musculatura del tronco en 33 ejercicios de fortalecimiento abdominal ha sido estudiada en una población de 46 sujetos voluntarios. Para este propósito, hemos utilizado electromiografía de superficie integrada (EMGi) en la segunda y tercera porción del músculo recto del abdomen (RA), obliquus externo (OE) y erector de la columna (ES) del lado derecho del cuerpo. Nuestros resultados indican diferencias en la activación del la musculatura del tronco durante los ejercicios de enrollamiento o encorvamiento (ejercicios de curl-up) e incorporacion (ejercicios de abdominales), según su ejecución mecánica. Los coeficientes de variación y correlación indican una mayor dispersión de la respuesta neural y una menor correlación entre los diferentes músculos, en los ejercicios agrupados como de incorporación, lo que demuestra que estos fueron los ejercicios más difíciles de desarrollar. La gradación de los ejercicios se ha determinado en cada músculo, según la intensidad de su contracción mediante el t-test. La significancia estadística se definió en el nivel p <0,05. El estudio de la influencia de las variables antropométricas y de sexo sobre la intensidad de la contracción muscular muestra que solo la variación de la curvatura dorso-lumbar afectó significativamente, o sea el grupo de sujetos con mayor variación en la curvatura dorso-lumbar, ya sea en hombres o mujer. Se ha comprobado una fuerte correlación entre la intensidad de contracción de la porción superior del músculo recto del abdomen, obtenida durante la ejecución de los ejercicios que mostró diferencias significativas entre ellos y los valores obtenidos con la escala de Borg en la percepción del esfuerzo.
This study investigated effects of cognitive dual-task interference and task prioritization instructions on task performance and trunk control during a dynamic balance task in persons with and without recurrent low back pain (rLBP). First, we tested the hypothesis that those with rLBP rely more on cognitive resources than back-healthy controls, and therefore trunk kinematics would be altered under dual-task interference conditions. Then, we tested participants’ ability to modulate task performance in accord with prioritization instructions. Persons with and without rLBP (n = 19/group) performed the Balance-Dexterity Task, which involved single-limb balance while compressing an unstable spring with the other limb, with and without a cognitive task engaging verbal working memory. Trunk coupling was quantified with the coefficient of determination (R2) of an angle–angle plot of thorax–pelvis frontal plane motion. Task performance was quantified using variability of spring compression force and of cognitive task errors. Trunk coupling in the rLBP group was lower than that of the back-healthy control group in the single-task condition (p = 0.024) and increased in the dual-task condition (p = 0.006), abolishing the difference between groups. Significant main effects of task prioritization instruction on performance were observed with no differences between groups, indicating similar performance modulation. Cognitive task error variability decreased with a switch from a single- to dual-task condition, exposing an unexpected facilitation effect. We interpret these findings in the context of movement-specific reinvestment and action-specific perception theories as they pertain to cognitive contributions to posture and how the dual-task interference paradigm may influence those contributions.
Low back pain is one of most common musculoskeletal disorders around the world. One major problem clinicians face is the lack of objective assessment modalities. Computed tomography and magnetic resonance imaging are commonly utilized but are unable to clearly distinguish patients with low back pain from healthy patients with respect to abnormalities. The reason may be the anisotropic nature of muscles, which is altered in function, and the scans provide only structural assessment. In view of this, ultrasound may be helpful in understanding the disease as it is performed in real-time and comprises different modes that measure thickness, blood flow and stiffness. By the use of ultrasound, patients with low back pain have been found to differ from healthy patients with respect to the thickness and stiffness of the transversus abdominis, thoracolumbar fascia and multifidus. The study results are currently still not conclusive, and further study is necessary to validate. Future work should focus on quantitative assessment of these tissues to provide textural, structural, hemodynamic and mechanical studies of low back pain. This review highlights the current understanding of how medical ultrasound has been used for diagnosis and study of low back pain and discusses potential new applications.
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 8th 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.
To assess the mechanical function of the abdominal muscles during eupnea in the dog, we have measured the electrical activity and the respiratory changes in length of the rectus abdominis, external oblique, and transversus abdominis muscles in eight supine, lightly anesthetized, spontaneously breathing animals. Seven animals had phasic expiratory electromyographic (EMG) activity in the transversus and showed expiratory shortening of the muscle below its in situ relaxation length (Lr). In contrast, only three animals had expiratory EMG activity and expiratory shortening of the external oblique, and no animal had expiratory EMG activity in the rectus. Seven animals, however, showed shortening of the rectus muscle during expiration. The amount of transversus expiratory shortening in the eight animals averaged (mean +/- SE) - 7.61 +/- 1.72% Lr and was significantly larger (P less than 0.005) than the amount of external oblique (-0.11 +/- 0.10% Lr) or rectus (-0.90 +/- 0.39% Lr) expiratory shortening. Hyperoxic hypercapnia amplified these differences. These data thus indicate that in supine anesthetized dogs (1) the transversus is, in real mechanical terms, the primary abdominal muscle of expiration; and (2) the abdominal compartment of the chest wall during eupnea moves both below and above its neutral position, and not exclusively above it.
Abdominal muscle activity was studied in eight normal subjects, while seated and supine, during inspiratory resistive and elastic mechanical loading. Electromyograms of the external oblique and rectus abdominis muscle were recorded using unipolar needle electrodes and changes in antero-posterior dimensions of the abdomen (Vab) were measured using linearized magnetometers. Elastic loading evoked abdominal muscle activity during expiration, especially in the rectus abdominis, in seven seated subjects while resistive loading did so in five. In four runs activity was also detectable throughout inspiration. Abdominal muscle activity was associated with a reduction in Vab throughout the respiratory cycle. When the subjects were supine loads did not evoke abdominal muscle activity. We conclude that abdominal muscle recruitment during inspiratory mechanical loading may facilitate inspiration by increasing diaphragmatic length.
Abdominal muscle activity was studied in 10 normal naive subjects during quiet breathing in different body positions. Electromyograms of the upper and lower portions of the external oblique and rectus abdominis were recorded with bipolar needle electrodes and changes in abdominal and rib cage displacements were measured using linearized magnetometers. The abdominal muscles were always silent in the supine posture. In contrast, 8 of the 10 subjects showed tonic abdominal muscle activity in the standing posture and 4 of the subjects did so also in the 45 degrees head-down position; when present, this activity was always greater in the dependent (where the hydrostatic pressure was greater) than in the non-dependent portion of the muscles. Tonic abdominal muscle activity was associated with a reduction of abdominal volume throughout the respiratory cycle and a reduction of the end-expiratory lung volume below the neutral position of the respiratory system. We conclude that (1) tonic activity is present in the abdominal muscles in most standing subjects, (2) this activity is primarily related to the magnitude of hydraulic pressure exerted by the abdominal contents on the abdominal wall, and (3) in most normal individuals standing at rest, the end-expiratory position is at least in part actively determined. Such an abdominal muscle use, although causing quiet breathing to depart from the relaxed abdominothoracic configuration, may be associated with minimum respiratory work.
It is established that during tidal breathing the rib cage expands more than the abdomen in the upright posture, whereas the reverse is usually true in the supine posture. To explore the reasons for this, we studied nine normal subjects in the supine, standing, and sitting postures, measuring thoracoabdominal movement with magnetometers and respiratory muscle activity via integrated electromyograms. In eight of the subjects, gastric and esophageal pressures and diaphragmatic electromyograms via esophageal electrodes were also measured. In the upright postures, there was generally more phasic and tonic activity in the scalene, sternocleidomastoid, and parasternal intercostal muscles. The diaphragm showed more phasic (but not more tonic) activity in the upright postures, and the abdominal oblique muscle showed more tonic (but not phasic) activity in the standing posture. Relative to the esophageal pressure change with inspiration, the inspiratory gastric pressure change was greater in the upright than in the supine posture. We conclude that the increased rib cage motion characteristic of the upright posture owes to a combination of increased activation of rib cage inspiratory muscles plus greater activation of the diaphragm that, together with a stiffened abdomen, acts to move the rib cage more effectively.
BANZETT, differences in humans. AND consumption, during 1977
- M A Pagel
1988. JR., M. A. PAGEL, flow, muscles 59: 43-50, R. B. BANZETT, differences in humans. AND consumption, during 1977. S. H. LORING, in abdominal J. Appl. Physiol. R. L. JOHNSON, JR. oxygen and work hyper- unobstructed Invest. AND P. dur- muscle activity 51: 1471-1476,