Muscle fascia and force transmission

Ultrasound in Obstetrics & Gynecology

Objectives To assess change in levator hiatal dimensions between pregnancy and different timepoints after vaginal delivery, and map recovery of the hiatus in order to contribute to secondary prevention of symptoms of pelvic floor disorders. Methods Twenty nulliparous women with a singleton pregnancy underwent ultrasound assessment of the pelvic floor at rest, on maximum pelvic floor muscle contraction (PFMC) and on Valsalva maneuver at 12 weeks' gestation and at 1 day and 1, 2, 3, 4, 6, 12, 18 and 24 weeks after vaginal delivery. Dimensions of the levator hiatus were measured and contractility and distensibility were calculated. The Wilcoxon signed rank test was used to compare each postpartum value with that at 12 weeks' gestation. Results Levator hiatal area at rest, on PFMC and on Valsalva maneuver was significantly increased at 1 day and at 1 and 2 weeks after vaginal delivery compared with measurements at 12 weeks' gestation. Hiatal area at rest and on PFMC from 3 weeks postpartum onward, as well as contractility from 6 weeks onward, were comparable to values at 12 weeks' gestation, whereas, a significant difference remained on Valsalva maneuver until 24 weeks after delivery. Moreover, distensibility was still increased at 24 weeks postpartum compared with measurements at 12 weeks' gestation. Conclusion The puborectalis muscle has the ability to recover anatomically from a first vaginal delivery, and recovery occurs mainly during the first 3 weeks after delivery. Stretching of the puborectalis muscle, as reflected by distensibility, persisted 24 weeks after the first vaginal delivery. The data provide a better understanding of the early 'normal' regeneration process and we hypothesize

Biomechanics and Modeling in Mechanobiology, 2019

A micromechanical muscle model for determining the impact of motor unit fiber clustering on force transmission in aging skeletal muscle. Biomechanics and Modeling in Mechanobiology.

2021

Introduction Mechanical neck pain (MNP) is a commonly occurring musculoskeletal condition that is usually managed using electrical modalities, joint mobilization techniques, and therapeutic exercises, but has limited evidence of their efficacy. Pathology (densification) of the deep cervical fascia that occurs due to the increased viscosity of hyaluronic acid (HA) may induce neck pain and associated painful symptoms of the upper quarter region. Fascial manipulation (FM) and yoga poses are considered to reduce the thixotropy of the ground substances of the deep fascia and improve muscle function. The purpose of this study is to investigate the effect of FM and sequential yoga poses (SYP) when compared to the usual care on pain, function, and oculomotor control in MNP. Methods This FaCe-Man trial will recruit 160 patients with subacute and chronic mechanical neck pain diagnosed using predefined criteria. Participants will be randomized to either the intervention group or the usual care...

Complementary therapies in clinical practice, 2020

Mental imagery (MI) research has mainly focused to date on mechanisms of effect and performance gains associated with muscle and neural tissues. MI's potential to affect fascia has rarely been considered. This paper conceptualizes ways in which MI might mutually interact with fascial tissue to support performance and cognitive functions. Such ways acknowledge, among others, MI's positive effect on proprioception, body schema, and pain. Drawing on cellular, physiological, and functional similarities and associations between muscle and fascial tissues, we propose that MI has the potential to affect and be affected by fascial tissue. We suggest that fascia-targeted MI (fascial mental imagery; FMI) can therefore be a useful approach for scientific as well as clinical purposes. We use the example of fascial dynamic neuro-cognitive imagery (FDNI) as a codified FMI method available for scientific and therapeutic explorations into rehabilitation and prevention of fascia-related disa...

2021

In Duchenne muscular dystrophy (DMD), diaphragm muscle dysfunction results in respiratory insufficiency, a leading cause of death in patients. Increased muscle stiffness occurs with buildup of fibrotic tissue, characterized by excessive accumulation of extracellular matrix (ECM) components such as collagen. However, changes in mechanical properties are not explained by collagen amount alone and we must consider the complex structure and mechanics of fibrotic tissue. The goals of our study were to (1) determine if and how collagen organization changes with the progression of DMD in diaphragm muscle tissue, and (2) predict how collagen organization influences the mechanical properties of ECM. We first visualized collagen structure with scanning electron microscopy (SEM) images and then developed an analysis framework to quantify collagen organization and generate image-based finite-element models. The image analysis revealed significant age- and disease-dependent increases in collagen...

Biomechanics and modeling in mechanobiology, 2016

Mechanical behavior of skeletal muscles is commonly modeled under the assumption of mechanical independence between individual muscles within a muscle group. Epimuscular myofascial force transmission via the connective tissue network surrounding a muscle challenges this assumption as it alters the force distributed to the tendons of individual muscles. This study aimed to derive a lumped estimate of stiffness of the intermuscular and extramuscular connective tissues and to assess changes in such stiffness in response to a manipulation of the interface between adjacent muscles. Based on in situ measurements of force transmission in the rat plantar flexors, before and after resection of their connective tissue network, a nonlinear estimate of epimuscular myofascial stiffness was quantified and included in a multi-muscle model with lumped parameters which allows for force transmission depending on the relative position between the muscles in the group. Such stiffness estimate was asses...

Surgical and Radiologic Anatomy, 2018

Purpose The thoracolumbar fascia (TLF) and the erector spinae aponeurosis (ESA) play significant roles in the biomechanics of the spine and could be a source of low back pain. Attachment, collagen fiber direction, size and biomechanical properties of the TLF have been well documented. However, questions remain about the attachment of the TLF and ESA in relation to adjoining tissues in the lumbosacral region. Moreover, quantitative data in relation to the ESA have rarely been examined. The aim of this study was to further investigate the anatomical features of the TLF and ESA and to determine the attachments and sliding areas of the paraspinal compartment through dissection. Materials and methods In 10 fresh cadavers (6 females, 4 males, mean age: 77 ± 10 years), we determined (1) the gross anatomy of the ESA and the TLF (attachments and sliding areas) and (2) the structure of the ESA and the TLF (thickness, width, orientation of collagen fibers). The pennation angle between the axis of the ES muscle fibers and the axis of the collagen fibers of the ESA were also measured. Results The TLF is an irregular dense connective tissue with a mean thickness of 0.95 mm. The distance between the spinous processes line and the site where the neurovascular bundles pierced the TLF, depending on the vertebral level, ranged from 29 mm at L1 to 75 mm at L3. The ESA constituted a band of regular longitudinally oriented connective fibers (mean thickness: 1.85 mm). Muscles fibers of the ES were strongly diagonally attached to the ESA (mean pennation angle 8° for the iliocostalis and 14° for the longissimus). To a lesser extent, the superficial multifidi were attached to the ESA at the lumbar level close to the midline and at the sacral level. Conclusion The ESA, at twice the thickness of the pTLF, was the thickest dense connective tissue of the paraspinal compartment. The ESA and the TLF circumscribed subcompartments and sliding areas between the TFL and the lumbar paraspinal muscles, between the ES and the multifidus, and between the longissimus and the iliocostalis.

Scientific Reports, 2020

The central nervous system (CNS) controls skeletal muscles by the recruitment of motor units (MUs). Understanding MU function is critical in the diagnosis of neuromuscular diseases, exercise physiology and sports, and rehabilitation medicine. Recording and analyzing the MUs’ electrical depolarization is the basis for state-of-the-art methods. Ultrafast ultrasound is a method that has the potential to study MUs because of the electrical depolarizations and consequent mechanical twitches. In this study, we evaluate if single MUs and their mechanical twitches can be identified using ultrafast ultrasound imaging of voluntary contractions. We compared decomposed spatio-temporal components of ultrasound image sequences against the gold standard needle electromyography. We found that 31% of the MUs could be successfully located and their firing pattern extracted. This method allows new non-invasive opportunities to study mechanical properties of MUs and the CNS control in neuromuscular phy...

Journal of Anatomy, 2015

Different authors have modelled myofascial tissue connectivity over a distance using cadaveric models, but in vivo models are scarce. The aim of this study was to evaluate the relationship between pelvic motion and deep fascia displacement in the medial gastrocnemius (MG). Deep fascia displacement of the MG was evaluated through automatic tracking with an ultrasound. Angular variation of the pelvis was determined by 2D kinematic analysis. The average maximum fascia displacement and pelvic motion were 1.501 AE 0.78 mm and 6.55 AE 2.47°, respectively. The result of a simple linear regression between fascia displacement and pelvic motion for three task executions by 17 individuals was r = 0.791 (P < 0.001). Moreover, hamstring flexibility was related to a lower anterior tilt of the pelvis (r = 0.544, P < 0.024) and a lower deep fascia displacement of the MG (r = 0.449, P < 0.042). These results support the concept of myofascial tissue connectivity over a distance in an in vivo model, reinforce the functional concept of force transmission through synergistic muscle groups, and grant new perspectives for the role of fasciae in restricting movement in remote zones.

Journal of the Mechanical Behavior of Biomedical Materials, 2021

Skeletal muscle is an anisotropic soft biological tissue composed of muscle fibres embedded in a structurally complex, hierarchically organised extracellular matrix. In a recent work (Kuravi et al., 2021) we have developed 3D finite element models from series of histological sections. Moreover, based on decellularisation of fresh tissue samples, a novel set of experimental data on the direction dependent mechanical properties of collagenous ECM was established (Kohn et al., 2021). Together with existing information on the material properties of single muscle fibres, the combination of these techniques allows computing predictions of the composite tissue response. To this end, an inverse finite element procedure is proposed in the present work to calibrate a constitutive model of the extracellular matrix, and supplementary biaxial tensile tests on fresh and decellularised tissues are performed for model validation. The results of this rigorously predictive and thus unforgiving strategy suggest that the prediction of the tissue response from the individual characteristics of muscle cells and decellularised tissue is only possible within clear limits. While orders of magnitude are well matched, and the qualitative behaviour in a wide range of load cases is largely captured, the existing deviations point at potentially missing components of the model and highlight the incomplete experimental information in bottom-up multiscale approaches to model skeletal muscle tissue.

Research Square (Research Square), 2022

The myotonometry is a noninvasive method capable to quantify linear elastic and viscoelastic properties of the myofascial tissue. However, this super cial layer contains different structures that have different distribution and organization of structural components. Myotonometric measurements of dynamic stiffness, logarithmic decrement and creep and ultrasonographic measurements of cutaneous tissue, subcutaneous tissue, thoracolumbar fascia and lumbar multi dus muscle thickness and echogenicity were obtained from 50 healthy individuals in the resting prone position and during contralateral arm lift. The most important ndings were that, both in the relaxed and contracted lumbar multi dus state, the dynamic stiffness strongly negatively (r=-0.69; p<0.001 in relaxation, r=-0.83; p<0.001 in contraction) and creep strongly positively (r=0.79; p<0.001 in relaxation, r=0.85; p<0.001 in contraction) correlated with thicknesses of subcutaneous tissue. With lumbar multi dus contraction, the relative increase in dynamic stiffness was negatively correlated with relative decrease in dermis (r=-0.51; p<0.001) and subcutaneous tissue (r=-0.47; p=0.001), as well as positively correlated with relative increase in lumbar multi dus (r=0.36; p=0.010) thickness. Concluding, the amount of dynamic stiffness and creep of super cial soft tissues in the lumbar region predominantly depends on subcutaneous tissue thickness regardless of muscle state. Elasticity is barely affected by soft tissue morphometry. Mechanical parameters do not depend on the echogenicity (density) of soft tissues.

Journal of Tissue Engineering and Regenerative Medicine, 2012

Scaffoldless engineered 3D skeletal muscle tissue created from satellite cells offers the potential to replace muscle tissue that is lost due to severe trauma or disease. Transforming growth factor-beta 1 (TGF-b1) plays a vital role in mediating migration and differentiation of satellite cells during the early stages of muscle development. Additionally, TGF-b1 promotes collagen type I synthesis in the extracellular matrix (ECM) of skeletal muscle, which provides a passive elastic substrate to support myofibres and facilitate the transmission of force. To determine the role of TGF-b1 in skeletal muscle construct formation and contractile function in vitro, we created tissue-engineered 3D skeletal muscle constructs with varying levels of recombinant TGF-b1 added to the cell culture medium. Prior to the addition of TGF-b1, the primary cell population was composed of 75% Pax7-positive cells. The peak force for twitch, tetanus and spontaneous force were significantly increased in the presence of 2.0 ng/ml TGF-b1 when compared to 0, 0.5 and 1.0 ng/ml TGF-b1. Visualization of the cellular structure with H&E and with immunofluorescence staining for sarcomeric myosin heavy chains and collagen type I showed denser regions of better organized myofibres in the presence of 2.0 ng/ml TGF-b1 versus 0, 0.5 and 1.0 ng/ml. The addition of 2.0 ng/ml TGF-b1 to the culture medium of engineered 3D skeletal muscle constructs enhanced contractility and extracellular matrix organization.

Current Geriatrics Reports, 2018

Purpose of Review To define the unique effects of age on the pelvic floor muscle and to outline current treatments of pelvic floor dysfunction in the older population. Recent Findings Aging has muscular, hormonal, and neurological effects on the pelvic floor that may lead to pelvic floor dysfunction. Muscular changes lead to decreased force output and weakness on clinical examination. Hormonal effects exacerbate pelvic tissue changes, most notably in the postmenopausal woman. Neurological changes are less well-defined, but gradual denervation of the pelvic floor, especially noted in parous women, has been implicated as a possible cause of pelvic floor weakness and dysfunction. Medical treatments include pessaries, medications, implanted electrical stimulation, and surgery. Pelvic floor physical therapy, including strength training and coordination training, as well as pain-relieving modalities at the level of the pelvic floor muscle, is an effective conservative management option for older adults with pelvic floor dysfunction. The literature available regarding treatment of pelvic floor dysfunction is more robust for older females compared to males. Summary There are numerous unique considerations in the treatment of the older adult with pelvic floor dysfunction, due to muscular, hormonal, and neurological changes with age. Conservative management, including physical therapy, should be considered prior to surgical intervention. Further research is especially needed regarding the effects of age and the treatment of age-related pelvic dysfunction in the older male.

Life, 2021

The female pelvis is a complex anatomical region comprising the pelvic organs, muscles, neurovascular supplies, and fasciae. The anatomy of the pelvic floor and its fascial components are currently poorly described and misunderstood. This systematic search and review aimed to explore and summarize the current state of knowledge on the fascial anatomy of the pelvic floor in women. Methods: A systematic search was performed using Medline and Scopus databases. A synthesis of the findings with a critical appraisal was subsequently carried out. The risk of bias was assessed with the Anatomical Quality Assurance Tool. Results: A total of 39 articles, involving 1192 women, were included in the review. Although the perineal membrane, tendinous arch of pelvic fascia, pubourethral ligaments, rectovaginal fascia, and perineal body were the most frequently described structures, uncertainties were identified in micro- and macro-anatomy. The risk of bias was scored as low in 16 studies (41%), unc...

Journal of Electromyography and Kinesiology, 2022

During a voluntary contraction, motor units (MUs) fire a train of action potentials, causing summation of the twitch forces, resulting in fused or unfused tetanus. Twitches have been important in studying whole-muscle contractile properties and differentiation between MU types. However, there are still knowledge gaps concerning the voluntary force generation mechanisms. Current methods rely on the spike-triggered averaging technique, which cannot track changes in successive twitches' properties in response to individual neural firings. This study proposes a method that estimates successive twitches contractile parameters of single MUs during low force voluntary isometric contractions in human biceps brachii. We used a previously developed ultrafast ultrasound imaging method to estimate unfused tetanic activity signals of single MUs. A twitch decomposition model was used to decompose unfused tetanic activity signals into individual twitches. This study found that the contractile parameters varied within and across MUs. There was an association between the inter-spike interval and the contraction time (r = 0.49, p < 0.001) and the half-relaxation time (r = 0.58, p < 0.001), respectively. The method shows the proof-of-concept to study MU contractile properties of individual twitches in vivo, which can provide further insights into the force generation mechanisms of voluntary contractions and response to individual neural discharges.

Scientific Reports, 2023

Kinesio taping (KT) is widely used in sports for performance improvement and injury prevention. However, little is known of the behavior of the muscle region beneath the KT with movement, particularly when the muscle is fatigued. Accordingly, this study investigated the changes in the medial gastrocnemius muscle architecture and fascia thickness when using KT during maximum isometric plantar flexion (MVIC) and badminton lunges following heel rise exercises performed to exhaustion. Eleven healthy collegiate badminton players (4 males and 7 females) were recruited. All of the participants performed two tasks (MVIC and badminton lunge) with a randomized sequence of no taping, KT and sham taping and repeated following exhaustive repetitive heel rise exercise. In the MVIC task, the fascia thickness with the medial gastrocnemius muscle at rest significantly decreased following fatigue induction both without taping and with KT and sham taping (p = 0.036, p = 0.028 and p = 0.025, respectively). In the lunge task, the fascia thickness reduced after fatigue induction in the no taping and sham taping trials; however, no significant change in the fascia thickness occurred in the KT trials. Overall, the results indicate that KT provides a better effect during dynamic movement than in isometric contraction. As one of the world's fastest racket sports 1 , badminton requires players to reach the shuttlecock as fast as possible and with the minimal effort within the physical constraints of the court 2 . In order to meet this requirement, badminton players must master a range of specific footwork strategies. Among these strategies, one of the most important is the forward lunge, which accounts for up to 17.86 ± 4.83% of the movements performed during a singles match 3 . Due to the rapid, repetitive, and stop-and-go nature of the lunge movement, the leg muscles may easily become fatigued and painful, particularly in long rallies. Fatigued muscles not only harm athletic performance, but also increase the risk of injury 4 . Thus, athletes (including badminton players) commonly apply kinesio tape (KT) to the muscle region after suffering muscle fatigue during training or competition . According to the inventor of KT, Dr. Kenzo Kase's report, KT exerts five main physiological effects: skin, circulatory/lymphatic, fascia, muscle, and joint 7 , where these effects are induced through a recoil action produced by the wave-pattern elastic nature of the tape, which leads to skin convolutions of the involved region. For example, by lifting the skin, the tape creates space in the muscle fascia-a soft connective tissue wrapping the muscle fibers, which contains nerves, blood and lymphatic vessels . The study in rabbit hind leg by Shim et al. resulted that the tape induces lymphatic drainage during passive exercise and hastened blood flow to the taped area 10 , thereby helping reduce swelling and speeding up the self-healing process. Thus, as described above, athletes often make use of adjuncts such as braces and taping techniques to speed the muscle recovery process following intensive training or tournament play 11 . Many studies have examined the effects of KT on ability enhancement in vertical jumping 12 , or in improving the medial gastrocnemius muscle strength and push-off force in healthy inactive individuals . It has been shown that KT provides an effective means of enhancing the recovery from