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Spadoni S, Todros S, Reggiani C, Marcucci L, Pavan PG. The role of the extracellular matrix in the reduction of lateral force transmission in muscle bundles: A finite element analysis. Comput Biol Med 2024; 175:108488. [PMID: 38653066 DOI: 10.1016/j.compbiomed.2024.108488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 03/28/2024] [Accepted: 04/15/2024] [Indexed: 04/25/2024]
Abstract
BACKGROUND AND OBJECTIVE Aging is associated with a reduction in muscle performance, but muscle weakness is characterized by a much greater loss of force loss compared to mass loss. The aim of this work is to assess the contribution of the extracellular matrix (ECM) to the lateral transmission of force in humans and the loss of transmitted force due to age-related modifications. METHODS Finite element models of muscle bundles are developed for young and elderly human subjects, by considering a few fibers connected through an ECM layer. Bundles of young and elderly subjects are assumed to differ in terms of ECM thickness, as observed experimentally. A three-element-based Hill model is adopted to describe the active behavior of muscle fibers, while the ECM is modeled assuming an isotropic hyperelastic neo-Hookean constitutive formulation. Numerical analyses are carried out by mimicking, at the scale of a bundle, two experimental protocols from the literature. RESULTS When comparing numerical results obtained for bundles of young and elderly subjects, a greater reduction in the total transmitted force is observed in the latter. The loss of transmitted force is 22 % for the elderly subjects, while it is limited to 7.5 % for the young subjects. The result for the elderly subjects is in line with literature studies on animal models, showing a reduction in the range of 20-34 %. This can be explained by an alteration in the mechanism of lateral force transmission due to the lower shear stiffness of the ECM in elderly subjects, related to its higher thickness. CONCLUSIONS Computational modeling allows to evaluate at the bundle level how the age-related increase of the ECM amount between fibers affects the lateral transmission of force. The results suggest that the observed increase in ECM thickness in aging alone can explain the reduction of the total transmitted force, due to the impaired lateral transmission of force of each fiber.
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Affiliation(s)
- Silvia Spadoni
- Department of Industrial Engineering, University of Padova, Padova, Italy
| | - Silvia Todros
- Department of Industrial Engineering, University of Padova, Padova, Italy.
| | - Carlo Reggiani
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Lorenzo Marcucci
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Piero G Pavan
- Department of Industrial Engineering, University of Padova, Padova, Italy; Fondazione Istituto di Ricerca Pediatrica Città Della Speranza, Padova, Italy
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2
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Lloyd EM, Pinniger GJ, Murphy RM, Grounds MD. Slow or fast: Implications of myofibre type and associated differences for manifestation of neuromuscular disorders. Acta Physiol (Oxf) 2023; 238:e14012. [PMID: 37306196 DOI: 10.1111/apha.14012] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 05/30/2023] [Accepted: 06/06/2023] [Indexed: 06/13/2023]
Abstract
Many neuromuscular disorders can have a differential impact on a specific myofibre type, forming the central premise of this review. The many different skeletal muscles in mammals contain a spectrum of slow- to fast-twitch myofibres with varying levels of protein isoforms that determine their distinctive contractile, metabolic, and other properties. The variations in functional properties across the range of classic 'slow' to 'fast' myofibres are outlined, combined with exemplars of the predominantly slow-twitch soleus and fast-twitch extensor digitorum longus muscles, species comparisons, and techniques used to study these properties. Other intrinsic and extrinsic differences are discussed in the context of slow and fast myofibres. These include inherent susceptibility to damage, myonecrosis, and regeneration, plus extrinsic nerves, extracellular matrix, and vasculature, examined in the context of growth, ageing, metabolic syndrome, and sexual dimorphism. These many differences emphasise the importance of carefully considering the influence of myofibre-type composition on manifestation of various neuromuscular disorders across the lifespan for both sexes. Equally, understanding the different responses of slow and fast myofibres due to intrinsic and extrinsic factors can provide deep insight into the precise molecular mechanisms that initiate and exacerbate various neuromuscular disorders. This focus on the influence of different myofibre types is of fundamental importance to enhance translation for clinical management and therapies for many skeletal muscle disorders.
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Affiliation(s)
- Erin M Lloyd
- Department of Anatomy, Physiology and Human Biology, School of Human Sciences, The University of Western Australia, Perth, Western Australia, Australia
- Curtin Health Innovation Research Institute, Curtin Medical School, Curtin University, Bentley, Western Australia, Australia
| | - Gavin J Pinniger
- Department of Anatomy, Physiology and Human Biology, School of Human Sciences, The University of Western Australia, Perth, Western Australia, Australia
| | - Robyn M Murphy
- Department of Biochemistry and Chemistry, School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, Victoria, Australia
| | - Miranda D Grounds
- Department of Anatomy, Physiology and Human Biology, School of Human Sciences, The University of Western Australia, Perth, Western Australia, Australia
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3
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A cell-based framework for modeling cardiac mechanics. Biomech Model Mechanobiol 2023; 22:515-539. [PMID: 36602715 PMCID: PMC10097778 DOI: 10.1007/s10237-022-01660-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 11/19/2022] [Indexed: 01/06/2023]
Abstract
Cardiomyocytes are the functional building blocks of the heart-yet most models developed to simulate cardiac mechanics do not represent the individual cells and their surrounding matrix. Instead, they work on a homogenized tissue level, assuming that cellular and subcellular structures and processes scale uniformly. Here we present a mathematical and numerical framework for exploring tissue-level cardiac mechanics on a microscale given an explicit three-dimensional geometrical representation of cells embedded in a matrix. We defined a mathematical model over such a geometry and parametrized our model using publicly available data from tissue stretching and shearing experiments. We then used the model to explore mechanical differences between the extracellular and the intracellular space. Through sensitivity analysis, we found the stiffness in the extracellular matrix to be most important for the intracellular stress values under contraction. Strain and stress values were observed to follow a normal-tangential pattern concentrated along the membrane, with substantial spatial variations both under contraction and stretching. We also examined how it scales to larger size simulations, considering multicellular domains. Our work extends existing continuum models, providing a new geometrical-based framework for exploring complex cell-cell and cell-matrix interactions.
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4
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Willingham TB, Kim Y, Lindberg E, Bleck CKE, Glancy B. The unified myofibrillar matrix for force generation in muscle. Nat Commun 2020; 11:3722. [PMID: 32709902 PMCID: PMC7381600 DOI: 10.1038/s41467-020-17579-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 07/07/2020] [Indexed: 12/15/2022] Open
Abstract
Human movement occurs through contraction of the basic unit of the muscle cell, the sarcomere. Sarcomeres have long been considered to be arranged end-to-end in series along the length of the muscle into tube-like myofibrils with many individual, parallel myofibrils comprising the bulk of the muscle cell volume. Here, we demonstrate that striated muscle cells form a continuous myofibrillar matrix linked together by frequently branching sarcomeres. We find that all muscle cells contain highly connected myofibrillar networks though the frequency of sarcomere branching goes down from early to late postnatal development and is higher in slow-twitch than fast-twitch mature muscles. Moreover, we show that the myofibrillar matrix is united across the entire width of the muscle cell both at birth and in mature muscle. We propose that striated muscle force is generated by a singular, mesh-like myofibrillar network rather than many individual, parallel myofibrils. Skeletal muscle cells have long been considered to be made primarily of many individual, parallel myofibrils. Here, the authors show that the striated muscle contractile machinery forms a highly branched, mesh-like myofibrillar matrix connected across the entire length and width of the muscle cell.
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Affiliation(s)
- T Bradley Willingham
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Yuho Kim
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Eric Lindberg
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Christopher K E Bleck
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Brian Glancy
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA. .,National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, 20892, USA.
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5
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Marcucci L, Reggiani C. Increase of resting muscle stiffness, a less considered component of age-related skeletal muscle impairment. Eur J Transl Myol 2020. [DOI: 10.4081/ejtm.2020.8982] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Elderly people perform more slowly movements of everyday life as rising from a chair, walking, and climbing stairs. This is in the first place due to the loss of muscle contractile force which is even more pronounced than the loss of muscle mass. In addition, a secondary, but not negligible, component is the rigidity or increased stiffness which requires greater effort to produce the same movement and limits the range of motion of the joints. In this short review, we discuss the possible determinants of the limitations of joint mobility in healthy elderly, starting with the age-dependent alterations of the articular structure and focusing on the increased stiffness of the skeletal muscles. Thereafter, the possible mechanisms of the increased stiffness of the muscle-tendon complex are considered, among them changes in the muscle fibers, alterations of the connective components (extracellular matrix or ECM, aponeurosis, fascia and tendon) and remodeling of the neural pattern of muscle activation with increased of antagonist co-activation.
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6
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Marcucci L, Reggiani C. Increase of resting muscle stiffness, a less considered component of age-related skeletal muscle impairment. Eur J Transl Myol 2020; 30:8982. [PMID: 32782762 PMCID: PMC7385684 DOI: 10.4081/ejtm.2019.8982] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 04/06/2020] [Indexed: 12/13/2022] Open
Abstract
Elderly people perform more slowly movements of everyday life as rising from a chair, walking, and climbing stairs. This is in the first place due to the loss of muscle contractile force which is even more pronounced than the loss of muscle mass. In addition, a secondary, but not negligible, component is the rigidity or increased stiffness which requires greater effort to produce the same movement and limits the range of motion of the joints. In this short review, we discuss the possible determinants of the limitations of joint mobility in healthy elderly, starting with the age-dependent alterations of the articular structure and focusing on the increased stiffness of the skeletal muscles. Thereafter, the possible mechanisms of the increased stiffness of the muscle-tendon complex are considered, among them changes in the muscle fibers, alterations of the connective tissue components, i.e., extracellular matrix (ECM), aponeurosis, tendon and fascia, and remodeling of the neural pattern of muscle activation that increases antagonist co-activation.
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Affiliation(s)
- Lorenzo Marcucci
- Department of Biomedical Sciences, Padova University, Padova, Italy.,Center for Mechanics of Biological Materials, Padova University, Padova, Italy.,Center for Biosystems Dynamics Research, RIKEN, Suita, Osaka, 565-0874, Japan
| | - Carlo Reggiani
- Department of Biomedical Sciences, Padova University, Padova, Italy.,Center for Mechanics of Biological Materials, Padova University, Padova, Italy.,Science and Research Centre Koper, Institute for Kinesiology Research, Koper, Slovenia
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7
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Alterations of Extracellular Matrix Mechanical Properties Contribute to Age-Related Functional Impairment of Human Skeletal Muscles. Int J Mol Sci 2020; 21:ijms21113992. [PMID: 32498422 PMCID: PMC7312402 DOI: 10.3390/ijms21113992] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/29/2020] [Accepted: 05/29/2020] [Indexed: 12/30/2022] Open
Abstract
Aging of human skeletal muscles is associated with increased passive stiffness, but it is still debated whether muscle fibers or extracellular matrix (ECM) are the determinants of such change. To answer this question, we compared the passive stress generated by elongation of fibers alone and arranged in small bundles in young healthy (Y: 21 years) and elderly (E: 67 years) subjects. The physiological range of sarcomere length (SL) 2.5-3.3 μm was explored. The area of ECM between muscle fibers was determined on transversal sections with picrosirius red, a staining specific for collagen fibers. The passive tension of fiber bundles was significantly higher in E compared to Y at all SL. However, the resistance to elongation of fibers alone was not different between the two groups, while the ECM contribution was significantly increased in E compared to Y. The proportion of muscle area occupied by ECM increased from 3.3% in Y to 8.2% in E. When the contribution of ECM to bundle tension was normalized to the fraction of area occupied by ECM, the difference disappeared. We conclude that, in human skeletal muscles, the age-related reduced compliance is due to an increased stiffness of ECM, mainly caused by collagen accumulation.
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8
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Purslow PP. The Structure and Role of Intramuscular Connective Tissue in Muscle Function. Front Physiol 2020; 11:495. [PMID: 32508678 PMCID: PMC7248366 DOI: 10.3389/fphys.2020.00495] [Citation(s) in RCA: 83] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 04/23/2020] [Indexed: 12/12/2022] Open
Abstract
Extracellular matrix (ECM) structures within skeletal muscle play an important, but under-appreciated, role in muscle development, function and adaptation. Each individual muscle is surrounded by epimysial connective tissue and within the muscle there are two distinct extracellular matrix (ECM) structures, the perimysium and endomysium. Together, these three ECM structures make up the intramuscular connective tissue (IMCT). There are large variations in the amount and composition of IMCT between functionally different muscles. Although IMCT acts as a scaffold for muscle fiber development and growth and acts as a carrier for blood vessels and nerves to the muscle cells, the variability in IMCT between different muscles points to a role in the variations in active and passive mechanical properties of muscles. Some traditional measures of the contribution of endomysial IMCT to passive muscle elasticity relied upon tensile measurements on single fiber preparations. These types of measurements may now be thought to be missing the important point that endomysial IMCT networks within a muscle fascicle coordinate forces and displacements between adjacent muscle cells by shear and that active contractile forces can be transmitted by this route (myofascial force transmission). The amount and geometry of the perimysial ECM network separating muscle fascicles varies more between different muscle than does the amount of endomysium. While there is some evidence for myofascial force transmission between fascicles via the perimysium, the variations in this ECM network appears to be linked to the amount of shear displacements between fascicles that must necessarily occur when the whole muscle contracts and changes shape. Fast growth of muscle by fiber hypertrophy is not always associated with a high turnover of ECM components, but slower rates of growth and muscle wasting may be associated with IMCT remodeling. A hypothesis arising from this observation is that the level of cell signaling via shear between integrin and dystroglycan linkages on the surface of the muscle cells and the overlying endomysium may be the controlling factor for IMCT turnover, although this idea is yet to be tested.
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Affiliation(s)
- Peter P Purslow
- Centro de Investigacion Veterinaria de Tandil, Facultad de Ciencias Veterinarias, Universidad Nacional del Centro de la Provincia de Buenos Aires, Tandil, Argentina
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9
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Csapo R, Gumpenberger M, Wessner B. Skeletal Muscle Extracellular Matrix - What Do We Know About Its Composition, Regulation, and Physiological Roles? A Narrative Review. Front Physiol 2020; 11:253. [PMID: 32265741 PMCID: PMC7096581 DOI: 10.3389/fphys.2020.00253] [Citation(s) in RCA: 200] [Impact Index Per Article: 50.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 03/05/2020] [Indexed: 12/20/2022] Open
Abstract
Skeletal muscle represents the largest body-composition component in humans. In addition to its primary function in the maintenance of upright posture and the production of movement, it also plays important roles in many other physiological processes, including thermogenesis, metabolism and the secretion of peptides for communication with other tissues. Research attempting to unveil these processes has traditionally focused on muscle fibers, i.e., the contractile muscle cells. However, it is a frequently overlooked fact that muscle fibers reside in a three-dimensional scaffolding that consists of various collagens, glycoproteins, proteoglycans, and elastin, and is commonly referred to as extracellular matrix (ECM). While initially believed to be relatively inert, current research reveals the involvement of ECM cells in numerous important physiological processes. In interaction with other cells, such as fibroblasts or cells of the immune system, the ECM regulates muscle development, growth and repair and is essential for effective muscle contraction and force transmission. Since muscle ECM is highly malleable, its texture and, consequently, physiological roles may be affected by physical training and disuse, aging or various diseases, such as diabetes. With the aim to stimulate increased efforts to study this still poorly understood tissue, this narrative review summarizes the current body of knowledge on (i) the composition and structure of the ECM, (ii) molecular pathways involved in ECM remodeling, (iii) the physiological roles of muscle ECM, (iv) dysregulations of ECM with aging and disease as well as (v) the adaptations of muscle ECM to training and disuse.
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Affiliation(s)
- Robert Csapo
- Research Unit for Orthopaedic Sports Medicine and Injury Prevention, Institute for Sports Medicine, Alpine Medicine & Health Tourism, UMIT - Private University for Health Sciences, Medical Informatics and Technology, Hall, Austria
| | - Matthias Gumpenberger
- Research Unit for Orthopaedic Sports Medicine and Injury Prevention, Institute for Sports Medicine, Alpine Medicine & Health Tourism, UMIT - Private University for Health Sciences, Medical Informatics and Technology, Hall, Austria
| | - Barbara Wessner
- Department of Sports Medicine, Exercise Physiology and Prevention, Centre for Sport Science and University Sports, University of Vienna, Vienna, Austria
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10
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Kim H, Kim MC, Asada HH. Extracellular matrix remodelling induced by alternating electrical and mechanical stimulations increases the contraction of engineered skeletal muscle tissues. Sci Rep 2019; 9:2732. [PMID: 30804393 PMCID: PMC6389954 DOI: 10.1038/s41598-019-39522-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 01/28/2019] [Indexed: 12/22/2022] Open
Abstract
Engineered skeletal muscles are inferior to natural muscles in terms of contractile force, hampering their potential use in practical applications. One major limitation is that the extracellular matrix (ECM) not only impedes the contraction but also ineffectively transmits the forces generated by myotubes to the load. In the present study, ECM remodelling improves contractile force in a short time, and a coordinated, combined electrical and mechanical stimulation induces the desired ECM remodelling. Notably, the application of single and combined stimulations to the engineered muscles remodels the structure of their ECM networks, which determines the mechanical properties of the ECM. Myotubes in the tissues are connected in parallel and in series to the ECM. The stiffness of the parallel ECM must be low not to impede contraction, while the stiffness of the serial ECM must be high to transmit the forces to the load. Both the experimental results and the mechanistic model suggest that the combined stimulation through coordination reorients the ECM fibres in such a way that the parallel ECM stiffness is reduced, while the serial ECM stiffness is increased. In particular, 3 and 20 minutes of alternating electrical and mechanical stimulations increase the force by 18% and 31%, respectively.
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Affiliation(s)
- Hyeonyu Kim
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
| | - Min-Cheol Kim
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - H Harry Asada
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- BioSystem and Micromechanics IRG, Singapore-MIT Alliance for Research and Technology, National University of Singapore, Singapore, 117543, Singapore
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11
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Almeida H, DE Souza RF, Aidar FJ, DA Silva AG, Regi RP, Bastos AA. Global Active Stretching (SGA®) Practice for Judo Practitioners' Physical Performance Enhancement. INTERNATIONAL JOURNAL OF EXERCISE SCIENCE 2018; 11:364-374. [PMID: 29795746 PMCID: PMC5955326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In order to analyze the Global Active Stretching (SGA®) practice on the physical performance enhancement in judo-practitioner competitors, 12 male athletes from Judo Federation of Sergipe (Federação Sergipana de Judô), were divided into two groups: Experimental Group (EG) and Control Group (CG). For 10 weeks, the EG practiced SGA® self-postures and the CG practiced assorted calisthenic exercises. All of them were submitted to a variety of tests (before and after): handgrip strength, flexibility, upper limbs' muscle power, isometric pull-up force, lower limbs' muscle power (squat-jump - SJ and countermovement jump - CMJ) and Tokui Waza test. Due to the small number of people in the sample, the data were considered non-parametric and then we applied the Wilcoxon test using the software R version 3.3.2 (R Development Core Team, Austria). The effect size was calculated and considered statistically significant the values p ≤ 0.05. Concerning the results, the EG statistical differences were highlighted in flexibility, upper limbs' muscle power and lower limbs' muscle power (CMJ), with a gain of 3.00 ± (1.09) cm, 0,42 ± (0,51) m and 2.49 ± (0.63) cm, respectively. The CG only presented statistical difference in the lower limbs' test (CMJ), with a gain of 0,55 ± 2,28 cm. Thus, the main results pointed out statistical differences before and after in the EG in the flexibility, upper limbs and lower limbs' muscle power (CMJ), with a gain of 3.00 ± 1.09 cm, 0.42 ± 0.51 m 2.49 ± 0.63 cm, respectively. On the other hand, the CG presented a statistical difference only the lower limbs' CMJ test, with a gain of 0.55 ± 2.28 cm. The regular 10-week practice of SGA® self-postures increased judoka practitioners' posterior chain flexibility and vertical jumping (CMJ) performance.
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Affiliation(s)
- Heleno Almeida
- Graduate Program in Master's level in Physical Education, Federal University of Sergipe -UFS, São Cristovão, Sergipe, BRAZIL
| | - Raphael F DE Souza
- Graduate Program in Master's level in Physical Education, Federal University of Sergipe -UFS, São Cristovão, Sergipe, BRAZIL
| | - Felipe J Aidar
- Graduate Program in Master's level in Physical Education, Federal University of Sergipe -UFS, São Cristovão, Sergipe, BRAZIL
| | - Alisson G DA Silva
- Preparatory School of Air Cadets - EPCAR, Barbacena, Minas Gerais, BRAZIL
| | - Ricardo P Regi
- Clinic of Rehabilitation - ReabFisio, Barueri, São Paulo, BRAZIL
| | - Afrânio A Bastos
- Graduate Program in Master's level in Physical Education, Federal University of Sergipe -UFS, São Cristovão, Sergipe, BRAZIL
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12
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Bernabei M, Maas H, van Dieën JH. A lumped stiffness model of intermuscular and extramuscular myofascial pathways of force transmission. Biomech Model Mechanobiol 2016; 15:1747-1763. [PMID: 27193153 PMCID: PMC5106516 DOI: 10.1007/s10237-016-0795-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 05/03/2016] [Indexed: 12/02/2022]
Abstract
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 assessed for a group with normal intermuscular connective tissues and for a group with increased connectivity, mimicking scar tissue development. The model was able to successfully predict the amount of epimuscular force transmission for different experimental conditions than those used to obtain the model parameters. The proposed nonlinear stiffness estimates of epimuscular pathways could be integrated in larger musculoskeletal models, to provide more accurate predictions of force when effects of mechanical interaction or altered epimuscular connections, e.g. after surgery or injury, are substantial.
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Affiliation(s)
- Michel Bernabei
- Department of Human Movement Sciences, Vrije Universiteit Amsterdam, MOVE Research Institute Amsterdam, Van der Boechorststraat 9, 1081, Amsterdam, The Netherlands
| | - Huub Maas
- Department of Human Movement Sciences, Vrije Universiteit Amsterdam, MOVE Research Institute Amsterdam, Van der Boechorststraat 9, 1081, Amsterdam, The Netherlands.
| | - Jaap H van Dieën
- Department of Human Movement Sciences, Vrije Universiteit Amsterdam, MOVE Research Institute Amsterdam, Van der Boechorststraat 9, 1081, Amsterdam, The Netherlands
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13
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Leineweber M, Gao Y, Stouffer JR. Quantifying skeletal muscle recovery in a rat injury model using ultrasound imaging. J Biomech 2015; 48:379-82. [PMID: 25529138 DOI: 10.1016/j.jbiomech.2014.11.050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 11/26/2014] [Accepted: 11/28/2014] [Indexed: 11/18/2022]
Abstract
Monitoring skeletal muscle health during recovery or degeneration is of great interest both clinically and in research settings. This type of monitoring requires health measurements be taken at multiple time points. Contraction strength is a commonly used metric for quantifying muscle health, but it requires invasive in vitro or in situ procedures that may further damage the tissue. Ultrasound imaging can be used to visualize muscle damage, and semi-quantitative grading scales have been shown to be effective at characterizing abnormalities. Using an established functional testing procedure in a rat model as a baseline measurement of muscle strength, we show that ultrasound imaging combined with a semi-quantitative grading scale can be used to monitor recovery after contusion injury. Although additional work is needed to refine the imaging and grading procedures, ultrasound promises a fast and non-invasive alternative to functional testing for characterizing skeletal muscle health.
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Affiliation(s)
- Matt Leineweber
- Cornell University, Mechanical and Aerospace Engineering, 220 Upson Hall, Cornell University, Ithaca, NY 14853, USA
| | - Yingxin Gao
- Cornell University, Mechanical and Aerospace Engineering, 220 Upson Hall, Cornell University, Ithaca, NY 14853, USA.
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14
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Examining the feasibility of applying principal component analysis to detecting localized changes in mechanical properties. J Biomech 2015; 48:262-8. [DOI: 10.1016/j.jbiomech.2014.11.037] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 11/03/2014] [Accepted: 11/24/2014] [Indexed: 11/23/2022]
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15
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Zhang C, Gao Y. The role of transmembrane proteins on force transmission in skeletal muscle. J Biomech 2014; 47:3232-6. [PMID: 25113807 DOI: 10.1016/j.jbiomech.2014.07.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 06/24/2014] [Accepted: 07/16/2014] [Indexed: 10/25/2022]
Abstract
Lateral transmission of force from myofibers laterally to the surrounding extracellular matrix (ECM) via the transmembrane proteins between them is impaired in old muscles. Changes in geometrical and mechanical properties of ECM of skeletal muscle do not fully explain the impaired lateral transmission with aging. The objective of this study was to determine the role of transmembrane proteins on force transmission in skeletal muscle. In this study, a 2D finite element model of single muscle fiber composed of myofiber, ECM, and the transmembrane proteins between them was developed to determine how changes in spatial density and mechanical properties of transmembrane proteins affect the force transmission in skeletal muscle. We found that force transmission and stress distribution are not affected by mechanical stiffness of the transmembrane proteins due to its non-linear stress-strain relationship. Results also showed that the muscle fiber with insufficient transmembrane proteins near the end of muscle fiber transmitted less force than that with more proteins does. Higher stress was observed in myofiber, ECM, and proteins in the muscle fiber with fewer proteins.
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Affiliation(s)
- Chi Zhang
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, 220 Upson Hall, Ithaca, NY 14853, USA
| | - Yingxin Gao
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, 220 Upson Hall, Ithaca, NY 14853, USA.
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16
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Zhang C, Gao Y. Effects of aging on the lateral transmission of force in rat skeletal muscle. J Biomech 2014; 47:944-8. [PMID: 24507947 DOI: 10.1016/j.jbiomech.2014.01.026] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 01/09/2014] [Accepted: 01/14/2014] [Indexed: 10/25/2022]
Abstract
The age-related reduction in muscle force cannot be fully explained by the loss of muscle fiber mass or degeneration of myofibers. Our previous study showed that changes in lateral transmission of force could affect the total force transmitted to the tendon. The extracellular matrix (ECM) of skeletal muscle plays an important role in lateral transmission of force. The objective of this study was to define the effects of aging on lateral transmission of force in skeletal muscles, and explore possible underlying mechanisms. In vitro contractile tests were performed on extensor digitorum longus (EDL) muscle of young and old rats with series of tenotomy and myotomy. We concluded that lateral transmission of force was impaired in the old rats, and this deficit could be partly due to increased thickness of the ECM induced by aging.
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Affiliation(s)
- Chi Zhang
- Sibley School of Mechanical and Aerospace Engineering, 220 Upson Hall, Cornell University, Ithaca, NY 14853, USA
| | - Yingxin Gao
- Sibley School of Mechanical and Aerospace Engineering, 220 Upson Hall, Cornell University, Ithaca, NY 14853, USA.
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17
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Fry CS, Lee JD, Jackson JR, Kirby TJ, Stasko SA, Liu H, Dupont-Versteegden EE, McCarthy JJ, Peterson CA. Regulation of the muscle fiber microenvironment by activated satellite cells during hypertrophy. FASEB J 2013; 28:1654-65. [PMID: 24376025 DOI: 10.1096/fj.13-239426] [Citation(s) in RCA: 197] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Our aim in the current study was to determine the necessity of satellite cells for long-term muscle growth and maintenance. We utilized a transgenic Pax7-DTA mouse model, allowing for the conditional depletion of > 90% of satellite cells with tamoxifen treatment. Synergist ablation surgery, where removal of synergist muscles places functional overload on the plantaris, was used to stimulate robust hypertrophy. Following 8 wk of overload, satellite cell-depleted muscle demonstrated an accumulation of extracellular matrix (ECM) and fibroblast expansion that resulted in reduced specific force of the plantaris. Although the early growth response was normal, an attenuation of hypertrophy measured by both muscle wet weight and fiber cross-sectional area occurred in satellite cell-depleted muscle. Isolated primary myogenic progenitor cells (MPCs) negatively regulated fibroblast ECM mRNA expression in vitro, suggesting a novel role for activated satellite cells/MPCs in muscle adaptation. These results provide evidence that satellite cells regulate the muscle environment during growth.
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Affiliation(s)
- Christopher S Fry
- 1900 S. Limestone, CTW 105, University of Kentucky, Lexington, KY 40536, USA.
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