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Scientific Reports Sep 2021The passive elastic modulus of muscle fiber appears to be size-dependent. The objectives of this study were to determine whether this size effect was evident in the...
The passive elastic modulus of muscle fiber appears to be size-dependent. The objectives of this study were to determine whether this size effect was evident in the mechanical testing of muscle fiber bundles and to examine whether the muscle fiber bundle cross-section is circular. Muscle fibers and fiber bundles were extracted from lumbar spine multifidus and longissimus of three cohorts: group one (G1) and two (G2) included 13 (330 ± 14 g) and 6 (452 ± 28 g) rats, while Group 3 (G3) comprised 9 degenerative spine patients. A minimum of six muscle fibers and six muscle fiber bundles from each muscle underwent cumulative stretches, each of 10% strain followed by 4 minutes relaxation. For all specimens, top and side diameters were measured. Elastic modulus was calculated as tangent at 30% strain from the stress-strain curve. Linear correlations between the sample cross sectional area (CSA) and elastic moduli in each group were performed. The correlations showed that increasing specimen CSA resulted in lower elastic modulus for both rats and humans, muscle fibers and fiber bundles. The median ratio of major to minor axis exceeded 1.0 for all groups, ranging between 1.15-1.29 for fibers and 1.27-1.44 for bundles. The lower elastic moduli with increasing size can be explained by relatively less collagenous extracellular matrix in the large fiber bundles. Future studies of passive property measurement should aim for consistent bundle sizes and measuring diameters of two orthogonal axes of the muscle specimens.
Topics: Animals; Biomechanical Phenomena; Elastic Modulus; Humans; Male; Muscle Fibers, Skeletal; Paraspinal Muscles; Rats; Rats, Sprague-Dawley
PubMed: 34535711
DOI: 10.1038/s41598-021-97895-z -
Anatomical Record (Hoboken, N.J. : 2007) Jun 2022Kangaroo rats (Dipodomys spp.) use specialized bipedal hopping like that of kangaroos. In contrast to kangaroos that have elastic tendons capable of storing energy,...
Kangaroo rats (Dipodomys spp.) use specialized bipedal hopping like that of kangaroos. In contrast to kangaroos that have elastic tendons capable of storing energy, kangaroo rats have inelastic tendons that are unable to store large amounts of energy. Thus, the musculature of the ankle joint provides the greatest power contribution to kangaroo rat hopping. Skeletal muscle can be characterized by several fiber types, including slow twitch (Type I) and fast twitch (Type II) fibers. Fast fibers are found in higher concentration in muscles that perform quick, dynamic movements, whereas slow fibers are found in higher proportion in muscles that perform slow, endurant movements. Using fiber type specific antibodies, we identified four pure (Types I, IIA, IIB, and IIX) and two hybrid (Types I/IIA and IIA/IIX) fiber types in six hindlimb muscles from three kangaroo rats (Dipodomys merriami) to investigate the relationship between fiber composition and hindlimb muscle function. Hindlimb muscles (except soleus) were dominated by Type IIB fibers, which were largest in cross-sectional area, and are known to be best suited for rapid and explosive movements. Oxidative Type IIA and Type IIX fibers were found at moderate concentrations and likely function in maintaining continual saltatory locomotion. Thus, kangaroo rats can use these two fiber type populations as "gears" for both endurant and explosive behaviors.
Topics: Animals; Dipodomys; Hindlimb; Immunohistochemistry; Locomotion; Muscle Fibers, Fast-Twitch; Muscle Fibers, Skeletal; Muscle Fibers, Slow-Twitch; Muscle, Skeletal; Potoroidae
PubMed: 34605198
DOI: 10.1002/ar.24791 -
The Journal of Experimental Biology Jan 2016Stretching of an activated skeletal muscle induces a transient tension increase followed by a period during which the tension remains elevated well above the isometric... (Review)
Review
Stretching of an activated skeletal muscle induces a transient tension increase followed by a period during which the tension remains elevated well above the isometric level at an almost constant value. This excess of tension in response to stretching has been called 'static tension' and attributed to an increase in fibre stiffness above the resting value, named 'static stiffness'. This observation was originally made, by our group, in frog intact muscle fibres and has been confirmed more recently, by us, in mammalian intact fibres. Following stimulation, fibre stiffness starts to increase during the latent period well before crossbridge force generation and it is present throughout the whole contraction in both single twitches and tetani. Static stiffness is dependent on sarcomere length in a different way from crossbridge force and is independent of stretching amplitude and velocity. Static stiffness follows a time course which is distinct from that of active force and very similar to the myoplasmic calcium concentration time course. We therefore hypothesize that static stiffness is due to a calcium-dependent stiffening of a non-crossbridge sarcomere structure, such as the titin filament. According to this hypothesis, titin, in addition to its well-recognized role in determining the muscle passive tension, could have a role during muscle activity.
Topics: Animals; Biomechanical Phenomena; Connectin; Humans; Isometric Contraction; Muscle Fibers, Skeletal; Sarcomeres; Time Factors
PubMed: 26792325
DOI: 10.1242/jeb.124370 -
Acta Biomaterialia May 2022Skeletal muscle tissue shows a clear asymmetry with regard to the passive stresses under tensile and compressive deformation, referred to as tension-compression...
Skeletal muscle tissue shows a clear asymmetry with regard to the passive stresses under tensile and compressive deformation, referred to as tension-compression asymmetry (TCA). The present study is the first one reporting on TCA at different length scales, associated with muscle tissue and muscle fibres, respectively. This allows for the first time the comparison of TCA between the tissue and one of its individual components, and thus to identify the length scale at which this phenomenon originates. Not only the passive stress-stretch characteristics were recorded, but also the volume changes during the axial tension and compression experiments. The study reveals clear differences in the characteristics of TCA between fibres and tissue. At tissue level TCA increases non-linearly with increasing deformation and the ratio of tensile to compressive stresses at the same magnitude of strain reaches a value of approximately 130 at 13.5% deformation. At fibre level instead it initially drops to a value of 6 and then rises again to a TCA of 14. At a deformation of 13.5%, the tensile stress is about 6 times higher. Thus, TCA is about 22 times more expressed at tissue than fibre scale. Moreover, the analysis of volume changes revealed little compressibility at tissue scale whereas at fibre level, especially under compressive stress, the volume decreases significantly. The data collected in this study suggests that the extracellular matrix has a distinct role in amplifying the TCA, and leads to more incompressible tissue behaviour. STATEMENT OF SIGNIFICANCE: This article analyses and compares for the first time the tension-compression asymmetry (TCA) displayed by skeletal muscle at tissue and fibre scale. In addition, the volume changes of tissue and fibre specimens with application of passive tensile and compressive loads are studied. The study identifies a key role of the extracellular matrix in establishing the mechanical response of skeletal muscle tissue: It contributes significantly to the passive stress, it is responsible for the major part of tissue-scale TCA and, most probably, prevents/balances the volume changes of muscle fibres during deformation. These new results thus shed light on the origin of TCA and provide new information to be used in microstructure-based approaches to model and simulate skeletal muscle tissue.
Topics: Biomechanical Phenomena; Muscle Fibers, Skeletal; Muscle, Skeletal; Pressure; Stress, Mechanical
PubMed: 35339701
DOI: 10.1016/j.actbio.2022.03.034 -
Meat Science Jan 2024Goat meat is popular with consumers for its rich nutritional content. Muscle fiber characteristics have been shown to play a crucial role in determining the quantity and...
Goat meat is popular with consumers for its rich nutritional content. Muscle fiber characteristics have been shown to play a crucial role in determining the quantity and quality of meat. However, little is known about the temporal changes in muscle fiber characteristics and meat quality during growth in goats. In this study, muscle fiber type, fiber diameter, fiber cross-sectional area (CSA), glycolytic potential (GP), meat pH, and meat color were analyzed in the gastrocnemius (GAS), gluteus medius (GM), biceps brachii (BB), longissimus lumborum (LL) muscles from newborn (NHMG) and adult (AHMG) Haimen goats. The distribution of type I and type Π fiber in goats is not consistent across the four muscles and undergoes alterations with age. The diameter and CSA of the muscle fibers were similar among the four NHMG muscles. However, in AHMG, the LL muscle had the largest fiber in terms of both diameter and CSA, followed by BB, GM, and GAS muscles. Moreover, the CSA of type Π fibers was higher than that of type I fibers in both NHMG and AHMG. GP values ranged from 90 to 140 umol/g across the muscle and no significant differences were observed. AHMG had a higher pH level and a* value, but lower L* and b* values than NHMG. Overall, our findings enhance our understanding of the changes in muscle fiber type and meat quality during the growth in Haimen goats and provide a basis for future research on the development and transformation of muscle fibers in goats.
Topics: Animals; Goats; Muscle Fibers, Skeletal; Muscle, Skeletal; Glycolysis; Meat
PubMed: 37857027
DOI: 10.1016/j.meatsci.2023.109361 -
Poultry Science Jul 2021The aim of this study was to compare the histochemical and meat quality characteristics between the normal and white-striping (WS) pectoralis major muscles....
The aim of this study was to compare the histochemical and meat quality characteristics between the normal and white-striping (WS) pectoralis major muscles. Additionally, this study investigated the effects of oven cooking (OV) and sous-vide (SV) cooking methods on objective texture parameters and sensory quality characteristics of the normal and WS chicken breast meats. Results showed that the WS condition broilers had higher body and breast weights (P < 0.001), and a greater area of muscle fiber than the normal broilers (P < 0.001). The WS fresh fillets exhibited a lower preference of visual appearance compared to the normal fillets (P < 0.05), although no differences were detected in the characteristics of meat quality between the groups (P > 0.05). After cooking, there was greater cooking loss, Warner-Bratzler shear force, and texture parameter analysis-hardness values for breast fillets cooked by OV treatment at 180°C for reached core temperature to 71°C compared to the fillets cooked by SV treatment at 60°C for 2 h (P < 0.05), whereas the normal and WS groups were exhibited similar values within each cooking methods (P > 0.05). Regarding sensory quality characteristics, WS breast fillets cooked by SV (SV+WS) were rated as tenderer and juicier, and given a higher overall acceptability score compared to normal and WS fillets cooked by OV (P < 0.05). However, owing to a lesser developed flavor in SV+WS fillets, the panelists assigned a lower overall acceptability rating in these fillets compared to SV+Normal fillets (P < 0.05). Overall, the SV cooking can be an effective method for improving the sensory quality characteristics of WS and normal chicken breast.
Topics: Animals; Chickens; Cooking; Meat; Muscle Fibers, Skeletal; Pectoralis Muscles
PubMed: 34102482
DOI: 10.1016/j.psj.2021.101177 -
Journal of Clinical Neurophysiology :... Aug 2015Needle electromyography is an important tool in the diagnosis of neuromuscular diseases and has also been applied successfully in the evaluation of the vocal cord... (Review)
Review
Needle electromyography is an important tool in the diagnosis of neuromuscular diseases and has also been applied successfully in the evaluation of the vocal cord paralysis. Laryngeal electromyography, initially described by Weddell, is used to determine the cause of vocal cord paralysis and to differentiate organic from nonorganic causes of speech disorders. This test allows the diagnosis of lower motor neuron and nerve paralysis as well as myopathies. Laryngeal electromyography also helps to determine the prognosis of paralysis caused by traumatic injury of the laryngeal nerves and is used for guidance during botulinum toxin injection in spasmodic dysphonias. Single fiber electromyography is used to diagnose abnormalities of neuromuscular transmission and is applied in the study the architecture of the motor unit in muscles. This article reviews the techniques of laryngeal muscles single fiber electromyography, provides limited informative data, and discusses its potential value in the evaluation of patients with dysphonia.
Topics: Adult; Electromyography; Female; Humans; Laryngeal Diseases; Laryngeal Muscles; Male; Muscle Fibers, Skeletal; Young Adult
PubMed: 26241239
DOI: 10.1097/WNP.0000000000000176 -
Methods in Molecular Biology (Clifton,... 2024Unlike in the Cnidaria, where muscle cells are coupled together into an epithelium, ctenophore muscles are single, elongated, intramesogleal structures resembling...
Unlike in the Cnidaria, where muscle cells are coupled together into an epithelium, ctenophore muscles are single, elongated, intramesogleal structures resembling vertebrate smooth muscle. Under voltage-clamp, these fibers can be separated into different classes with different sets of membrane ion channels. The ion channel makeup is related to the muscle's anatomical position and specific function. For example, Beroe ovata radial fibers, which are responsible for maintaining the rigidity of the body wall, generate sequences of brief action potentials whereas longitudinal fibers, which are concerned with mouth opening and body flexions, often produce single longer duration action potentials.Beroe muscle contractions depend on the influx of Ca. During an action potential the inward current is carried by Ca, and the increase in intracellular Ca concentration generated can be monitored in FLUO-3-loaded cells. Confocal microscopy in line scan mode shows that the Ca spreads from the outer membrane into the core of the fiber and is cleared from there relatively slowly. The rise in intracellular Ca is linked to an increase in a Ca-activated K conductance (K), which can also be elicited by iontophoretic Ca injection. Near the cell membrane, Ca clearance monitored using FLUO3, matches the decline in the K conductance. For light loads, Ca is cleared rapidly, but this fast system is insufficient when Ca influx is maintained. Action potential frequency may be regulated by the slowly developing K conductance.
Topics: Animals; Muscle, Smooth; Calcium; Ctenophora; Patch-Clamp Techniques; Action Potentials; Muscle Contraction; Electrophysiological Phenomena; Electrophysiology; Microscopy, Confocal
PubMed: 38668975
DOI: 10.1007/978-1-0716-3642-8_15 -
Journal of Biomechanics Feb 2022Skeletal muscle design studies, based on anatomical structure, extend back several hundred years. Accurate anatomical drawings show that many muscle fibers are oriented...
Skeletal muscle design studies, based on anatomical structure, extend back several hundred years. Accurate anatomical drawings show that many muscle fibers are oriented at an angle relative to a muscle's axis of force generation. This pennation angle has been reported in the skeletal muscle biomechanics literature, primarily in the context of trying to understand muscle force generation. In this perspective, I will describe several discoveries that changed my understanding of pennation and I will suggest that muscle pennation has little if any functional significance. I believe that the correct view of pennation is that it represents a packing strategy whereby short fibers can be packed into a limited volume. While surface pennation angle is easily measured, is very descriptive, and changes during force generation, I believe it has no functional significance.
Topics: Biomechanical Phenomena; Muscle Fibers, Skeletal; Muscle, Skeletal
PubMed: 35074689
DOI: 10.1016/j.jbiomech.2022.110954 -
Biological Reviews of the Cambridge... Aug 2022The size and arrangement of fibres play a determinate role in the kinetic and energetic performance of muscles. Extrapolations between fibre architecture and performance... (Review)
Review
The size and arrangement of fibres play a determinate role in the kinetic and energetic performance of muscles. Extrapolations between fibre architecture and performance underpin our understanding of how muscles function and how they are adapted to power specific motions within and across species. Here we provide a synopsis of how this 'fibre to function' paradigm has been applied to understand muscle design, performance and adaptation in animals. Our review highlights the widespread application of the fibre to function paradigm across a diverse breadth of biological disciplines but also reveals a potential and highly prevalent limitation running through past studies. Specifically, we find that quantification of muscle architectural properties is almost universally based on an extremely small number of fibre measurements. Despite the volume of research into muscle properties, across a diverse breadth of research disciplines, the fundamental assumption that a small proportion of fibre measurements can accurately represent the architectural properties of a muscle has never been quantitatively tested. Subsequently, we use a combination of medical imaging, statistical analysis, and physics-based computer simulation to address this issue for the first time. By combining diffusion tensor imaging (DTI) and deterministic fibre tractography we generated a large number of fibre measurements (>3000) rapidly for individual human lower limb muscles. Through statistical subsampling simulations of these measurements, we demonstrate that analysing a small number of fibres (n < 25) typically used in previous studies may lead to extremely large errors in the characterisation of overall muscle architectural properties such as mean fibre length and physiological cross-sectional area. Through dynamic musculoskeletal simulations of human walking and jumping, we demonstrate that recovered errors in fibre architecture characterisation have significant implications for quantitative predictions of in-vivo dynamics and muscle fibre function within a species. Furthermore, by applying data-subsampling simulations to comparisons of muscle function in humans and chimpanzees, we demonstrate that error magnitudes significantly impact both qualitative and quantitative assessment of muscle specialisation, potentially generating highly erroneous conclusions about the absolute and relative adaption of muscles across species and evolutionary transitions. Our findings have profound implications for how a broad diversity of research fields quantify muscle architecture and interpret muscle function.
Topics: Animals; Computer Simulation; Diffusion Tensor Imaging; Muscle Fibers, Skeletal; Muscle, Skeletal; Running
PubMed: 35388613
DOI: 10.1111/brv.12856