Transversus abdominis muscle function in humans

1990 ◽  
Vol 68 (3) ◽  
pp. 1010-1016 ◽  
Author(s):  
A. De Troyer ◽  
M. Estenne ◽  
V. Ninane ◽  
D. Van Gansbeke ◽  
M. Gorini
Keyword(s):  
Normal Subjects ◽  
Muscle Layer ◽  
Abdominal Muscle ◽  
Rectus Abdominis ◽  
Transversus Abdominis ◽  
Residual Capacity ◽  
Elastic Loading ◽  
External Oblique ◽  
Superficial Muscle ◽  
Transversus Abdominis Muscle

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.

Abdominal muscle activity during hypercapnia in awake dogs

1994 ◽  
Vol 77 (3) ◽  
pp. 1393-1398 ◽  
Author(s):  
A. M. Leevers ◽  
J. D. Road
Keyword(s):  
Tidal Volume ◽  
Muscle Layer ◽  
Abdominal Muscle ◽  
Rectus Abdominis ◽  
Transversus Abdominis ◽  
Emg Activity ◽  
Abdominal Muscles ◽  
Co2 Rebreathing ◽  
External Oblique ◽  
Internal Oblique

We previously found the internal abdominal muscle layer to be preferentially recruited during expiratory threshold loading in anesthetized and awake dogs. Expiratory threshold loading increases end-expiratory lung volume and hence can activate reflex pathways such as tonic vagal reflexes, which could influence abdominal muscle recruitment. Our objectives in the present study were to determine the effects of hypercapnia on abdominal muscle activation and the pattern of recruitment in awake dogs. Five tracheotomized dogs were chronically implanted with sonomicrometer transducers and fine-wire electromyogram (EMG) electrodes in each of the four abdominal muscles: transversus abdominis, internal oblique, external oblique, and rectus abdominis. Muscle length changes and EMG activity were studied in the awake dog at rest and during CO2 rebreathing. CO2 rebreathing produced a tripling of tidal volume and activation of the abdominal muscles. Despite the increase in tidal volume, there was no significant change in abdominal muscle end-inspiratory length. Both tonic and phasic expiratory shortening were greater in the internal muscle layer (transversus abdominis and internal oblique) than in the external muscle layer (external oblique and rectus abdominis). We conclude that the internal abdominal muscles are preferentially recruited by hypercapnia and vagal reflexes probably do not contribute to this differential recruitment but that segmental reflexes may be involved. The mechanical consequences of this recruitment are discussed.

Triangularis sterni muscle use in supine humans

1987 ◽  
Vol 62 (3) ◽  
pp. 919-925 ◽  
Author(s):  
A. De Troyer ◽  
V. Ninane ◽  
J. J. Gilmartin ◽  
C. Lemerre ◽  
M. Estenne
Keyword(s):  
Normal Subjects ◽  
Abdominal Muscle ◽  
Abdominal Muscles ◽  
Neural Activation ◽  
Trained Subjects ◽  
Rib Cage ◽  
Residual Capacity ◽  
External Oblique ◽  
Head Flexion ◽  
Static Head

The electrical activity of the triangularis sterni (transversus thoracis) muscle was studied in supine humans during resting breathing and a variety of respiratory and nonrespiratory maneuvers known to bring the abdominal muscles into action. Twelve normal subjects, of whom seven were uninformed and untrained, were investigated. The electromyogram of the triangularis sterni was recorded using a concentric needle electrode, and it was compared with the electromyograms of the abdominal (external oblique and rectus abdominis) muscles. The triangularis sterni was usually silent during resting breathing. In contrast, the muscle was invariably activated during expiration from functional residual capacity, expulsive maneuvers, “belly-in” isovolume maneuvers, static head flexion and trunk rotation, and spontaneous events such as speech, coughing, and laughter. When three trained subjects expired voluntarily with considerable recruitment of the triangularis sterni and no abdominal muscle activity, rib cage volume decreased and abdominal volume increased. These results indicate that unlike in the dog, spontaneous quiet expiration in supine humans is essentially a passive process; the human triangularis sterni, however, is a primary muscle of expiration; and its neural activation is largely coupled with that of the abdominals. The triangularis sterni probably contributes to the deflation of the rib cage during active expiration.

Mechanical response to hyperinflation of the two abdominal muscle layers

1989 ◽  
Vol 66 (5) ◽  
pp. 2189-2195 ◽  
Author(s):  
A. M. Leevers ◽  
J. D. Road
Keyword(s):  
Functional Residual Capacity ◽  
Muscle Length ◽  
Abdominal Muscle ◽  
Transversus Abdominis ◽  
Abdominal Muscles ◽  
Lung Inflation ◽  
Residual Capacity ◽  
Length Changes ◽  
External Oblique ◽  
Internal Oblique

Abdominal muscle length changes and activity were directly examined in vivo with the use of the techniques of sonomicrometry and electromyography, respectively, in nine supine anesthetized dogs. Expiratory threshold loading was utilized to stimulate recruitment of the abdominal muscles, and lung inflations produced the passive relationships. The internal layer, consisting of the internal oblique and transversus abdominis, shortened more in expiration than the external layer, consisting of the external oblique and rectus abdominis. The internal oblique shortened to approximately 83% of its length at functional residual capacity vs. 98% for the external oblique (P less than 0.05). The results obtained during passive lung inflation indicate these internal muscles are also more influenced by changes in lung volume. The internal oblique lengthened to 115% of its length at functional residual capacity vs. 103% for external oblique at total lung capacity (P less than 0.05). The results suggest that anatomic division of the abdominal muscles into external and internal layers corresponds to functional differences in terms of both passive lengthening and active shortening during ventilation and that these differences imply variable functions of the two layers.

Abdominal muscle use during breathing in unanesthetized dogs

1989 ◽  
Vol 66 (1) ◽  
pp. 20-27 ◽  
Author(s):  
A. De Troyer ◽  
J. J. Gilmartin ◽  
V. Ninane
Keyword(s):  
Respiratory Muscle ◽  
Abdominal Muscle ◽  
Rectus Abdominis ◽  
Transversus Abdominis ◽  
Abdominal Muscles ◽  
Quiet Breathing ◽  
Sitting Posture ◽  
Cervical Vagotomy ◽  
External Oblique ◽  
Conscious Animals

The pattern of abdominal muscle use during breathing in unanesthetized dogs is unknown. Therefore, we have recorded the electromyograms of the rectus abdominis, external oblique, and transversus abdominis in eight conscious animals breathing quietly in the sitting, standing, and prone postures. During quiet breathing in the sitting posture, all animals invariably had a large amount of phasic expiratory activity in the transversus abdominis. In contrast, only four animals showed some expiratory activity in the external oblique, and only one animal had expiratory activity in the rectus abdominis. A similar pattern was observed when the animals were standing or lying prone, although the amount of expiratory activity was less in this posture. Bilateral cervical vagotomy in four animals did not affect the degree of transversus abdominis expiratory activation or the influence of posture. We conclude that in conscious dogs 1) the abdominal muscles play an important role during breathing and make spontaneous quiet expiration a very active process, 2) the transversus abdominis is the primary respiratory muscle of the abdomen, and 3) unlike in anesthetized animals, extrapulmonary receptors play a major role in promoting abdominal expiratory contraction.

Responses of the anterolateral abdominal muscles during cough and expiratory threshold loading in the cat

2000 ◽  
Vol 88 (4) ◽  
pp. 1207-1214 ◽  
Author(s):  
Donald C. Bolser ◽  
Paul J. Reier ◽  
Paul W. Davenport
Keyword(s):  
Abdominal Muscle ◽  
Rectus Abdominis ◽  
Transversus Abdominis ◽  
Emg Activity ◽  
Abdominal Muscles ◽  
Cough Reflex ◽  
Gastric Pressure ◽  
Simultaneous Activation ◽  
External Oblique ◽  
Internal Oblique

The present study was conducted to determine the pattern of activation of the anterolateral abdominal muscles during the cough reflex. Electromyograms (EMGs) of the rectus abdominis, external oblique, internal oblique, transversus abdominis, and parasternal muscles were recorded along with gastric pressure in anesthetized cats. Cough was produced by mechanical stimulation of the lumen of the intrathoracic trachea or larynx. The pattern of EMG activation of these muscles during cough was compared with that during graded expiratory threshold loading (ETL; 1–30 cmH2O). ETL elicited differential recruitment of abdominal muscle EMG activity (transversus abdominis > internal oblique > rectus abdominis ≅ external oblique). In contrast, both laryngeal and tracheobronchial cough resulted in simultaneous activation of all four anterolateral abdominal muscles with peak EMG amplitudes 3- to 10-fold greater than those observed during the largest ETL. Gastric pressures during laryngeal and tracheobronchial cough were at least eightfold greater than those produced by the largest ETL. These results suggest that, unlike their behavior during expiratory loading, the anterolateral abdominal muscles act as a unit during cough.

Effects of posture on abdominal muscle shortening in awake dogs

1993 ◽  
Vol 75 (4) ◽  
pp. 1452-1459 ◽  
Author(s):  
A. M. Leevers ◽  
J. D. Road
Keyword(s):  
Respiratory Activity ◽  
Abdominal Muscle ◽  
Rectus Abdominis ◽  
Transversus Abdominis ◽  
Abdominal Muscles ◽  
Muscle Shortening ◽  
Lateral Decubitus ◽  
Length Changes ◽  
External Oblique ◽  
Internal Oblique

The objective of this study was to examine the effects of posture on tonic and phasic expiratory activity of the abdominal muscles in awake dogs. Six tracheostomized dogs were chronically instrumented with sonomicrometer transducers and bipolar electromyographic electrodes placed in each of the four abdominal muscles. To determine the effects of posture on tonic and phasic activity of individual abdominal muscles, muscle resting length (Lr) and tidal length changes (%Lr), respectively, were measured in awake dogs in the left lateral decubitus (LLD), sitting, and standing (STAND) positions. The transversus abdominis Lr consistently shortened when the dog was moved from LLD to STAND and lengthened when the dog was moved from LLD to the sitting position, and the external oblique Lr consistently lengthened when the dog went from LLD to STAND. The internal oblique and rectus abdominis had no consistent changes in Lr with a change in position. All four abdominal muscles actively shortened (%Lr) more in the upright positions. In addition, the internal layer (transversus abdominis and internal oblique) actively shortened more than the external layer (rectus abdominis and external oblique). In conclusion, both tonic and phasic respiratory activity of the abdominal muscles, reflected by changes in Lr and %Lr, respectively, were affected by changes in posture.

scholarly journals Core Muscle Activity during Physical Fitness Exercises: A Systematic Review

2020 ◽  
Vol 17 (12) ◽  
pp. 4306 ◽  
Author(s):  
José M. Oliva-Lozano ◽  
José M. Muyor
Keyword(s):  
Systematic Review ◽  
Physical Fitness ◽  
Rectus Abdominis ◽  
Core Stability ◽  
Erector Spinae ◽  
Transversus Abdominis ◽  
Emg Activity ◽  
Electromyographic Activity ◽  
Lumbar Multifidus ◽  
External Oblique

The aim of this study was to systematically review the current literature on the electromyographic (EMG) activity of six core muscles (the rectus abdominis, the internal and external oblique, the transversus abdominis, the lumbar multifidus, and the erector spinae) during core physical fitness exercises in healthy adults. A systematic review of the literature was conducted on the Cochrane, EBSCO, PubMed, Scopus, and Web of Science electronic databases for studies from January 2012 to March 2020. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were used. The inclusion criteria were as follows: (a) the full text available in English; (b) a cross-sectional or longitudinal (experimental or cohorts) study design; (c) the reporting of electromyographic activity as a percentage of maximum voluntary contraction (% MVIC), millivolts or microvolts; (d) an analysis of the rectus abdominis (RA), transversus abdominis (TA), lumbar multifidus (MUL), erector spinae (ES), and the internal (IO) or external oblique (EO); (e) an analysis of physical fitness exercises for core training; and (f) healthy adult participants. The main findings indicate that the greatest activity of the RA, EO, and ES muscles was found in free-weight exercises. The greatest IO activity was observed in core stability exercises, while traditional exercises showed the greatest MUL activation. However, a lack of research regarding TA activation during core physical fitness exercises was revealed, in addition to a lack of consistency between the studies when applying methods to measure EMG activity.

Changes in the neural drive to abdominal expiratory muscles in hemorrhagic hypotension

1994 ◽  
Vol 266 (6) ◽  
pp. H2423-H2429 ◽  
Author(s):  
R. F. Fregosi
Keyword(s):  
Pulmonary Ventilation ◽  
Respiratory Rhythm ◽  
Abdominal Muscle ◽  
Rectus Abdominis ◽  
Abdominal Muscles ◽  
Neural Drive ◽  
Hemorrhagic Hypotension ◽  
Severe Hypotension ◽  
Expiratory Muscles ◽  
External Oblique

The purpose of this study was to test the hypothesis that hemorrhage-induced hypotension increases the neural drive to the abdominal expiratory muscles in chloralose-urethan-anesthetized cats that are studied under conditions of constant arterial PCO2 (PaCO2) and hyperoxia. A secondary aim was to describe in detail the concomitant changes in inspired pulmonary ventilation (VI) and the pattern of breathing under these conditions. The rectified and integrated electromyogram (EMG) of the external oblique and rectus abdominis muscles and VI were recorded in moderate and severe hemorrhagic hypotension, leading to reductions in mean blood pressure of approximately 30 and 60%, respectively. The PaCO2 was prevented from falling, and the arterial PO2 was maintained at a hyperoxic level (> 200 mmHg) by adding CO2 and O2 to the inspired gas mixture. VI increased by 2.5- and 5-fold in moderate and severe hypotension (P < 0.05). The changes in VI were mediated exclusively by changes in tidal volume, indicating that the reflex did not alter the activity of respiratory rhythm-generating structures. The EMG of external oblique muscles averaged 2, 44, and 100% in control conditions and in moderate and severe hypotension, respectively; corresponding values in rectus abdominis muscles were 10, 28, and 100% (P < 0.05 for both muscles). Bilateral cervical vagotomy caused a one- to three-fold decrease in the ventilatory response to hemorrhage and abolished the increase in abdominal muscle EMG activities. In conclusion, hemorrhagic hypotension reflexly increases pulmonary ventilation and the neural drive to the abdominal muscles. The reflex is vagally mediated, but the location of the receptors was not identified.

scholarly journals Quantification of the Differences in Electromyographic Activity Magnitude Between the Upper and Lower Portions of the Rectus Abdominis Muscle During Selected Trunk Exercises

2001 ◽  
Vol 81 (5) ◽  
pp. 1096-1101 ◽  
Author(s):  
Gregory J Lehman ◽  
Stuart M McGill
Keyword(s):  
Muscle Activity ◽  
Abdominal Muscle ◽  
Rectus Abdominis ◽  
Oblique Muscle ◽  
Emg Activity ◽  
Electromyographic Activity ◽  
Rectus Abdominis Muscle ◽  
Emg Signal ◽  
External Oblique Muscle ◽  
External Oblique

Abstract Background and Purpose. Controversy exists around exercises and clinical tests that attempt to differentially activate the upper or lower portions of the rectus abdominis muscle. The purpose of this study was to assess the activation of the upper and lower portions of the rectus abdominis muscle during a variety of abdominal muscle contractions. Subjects. Subjects (N=11) were selected from a university population for athletic ability and low subcutaneous fat to optimize electromyographic (EMG) signal collection. Methods. Controlling for spine curvature, range of motion, and posture (and, therefore, muscle length), EMG activity of the external oblique muscle and upper and lower portions of rectus abdominis muscle was measured during the isometric portion of curl-ups, abdominal muscle lifts, leg raises, and restricted or attempted leg raises and curl-ups. A one-way repeated-measures analysis of variance was used to test for differences in activity between exercises in the external oblique and rectus abdominis muscles as well as between the portions of the rectus abdominis muscle. Results. No differences in muscle activity were found between the upper and lower portions of the rectus abdominis muscle within and between exercises. External oblique muscle activity, however, showed differences between exercises. Discussion and Conclusion. Normalizing the EMG signal led the authors to believe that the differences between the portions of the rectus abdominis muscle are small and may lack clinical or therapeutic relevance.

Action of abdominal muscles on rib cage in humans

1985 ◽  
Vol 58 (5) ◽  
pp. 1438-1443 ◽  
Author(s):  
A. Mier ◽  
C. Brophy ◽  
M. Estenne ◽  
J. Moxham ◽  
M. Green ◽  
...  
Keyword(s):  
Rectus Abdominis ◽  
Abdominal Muscles ◽  
Transverse Diameter ◽  
Transdiaphragmatic Pressure ◽  
Rib Cage ◽  
X Ray ◽  
Surface Electrodes ◽  
Residual Capacity ◽  
External Oblique ◽  
Stimulation Of

To assess the actions of the rectus abdominis and external oblique muscles on the rib cage in humans, these two muscles were stimulated with surface electrodes in four normal supine subjects at functional residual capacity. Changes in anteroposterior and transverse rib cage diameters and changes in xiphipubic distance were measured with pairs of magnetometers. Stimulation of rectus abdominis produced a marked decrease in the xiphipubic distance and in the anteroposterior diameter, thus making the rib cage more elliptic. In contrast, stimulation of the external oblique caused a decrease in the transverse diameter, making the rib cage more cylindrical. When both muscles were stimulated simultaneously, the resultant rib cage distortion depended on the relative voltage at which each muscle was stimulated. Electromyogram recordings showed that there was no cross contamination or activity of the diaphragm during the muscle stimulations. Transdiaphragmatic pressure increased with the voltage of stimulation, suggesting passive lengthening of the diaphragm. X-ray studies were performed in two subjects and confirmed the main magnetometer findings. These studies thus confirm that the rib cage in humans is more easily distortable than conventionally thought. The abdominal muscles can distort it in either direction depending on which muscles are contracting.

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