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Roberts MD, McCarthy JJ, Hornberger TA, Phillips SM, Mackey AL, Nader GA, Boppart MD, Kavazis AN, Reidy PT, Ogasawara R, Libardi CA, Ugrinowitsch C, Booth FW, Esser KA. Mechanisms of mechanical overload-induced skeletal muscle hypertrophy: current understanding and future directions. Physiol Rev 2023; 103:2679-2757. [PMID: 37382939 PMCID: PMC10625844 DOI: 10.1152/physrev.00039.2022] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 06/12/2023] [Accepted: 06/21/2023] [Indexed: 06/30/2023] Open
Abstract
Mechanisms underlying mechanical overload-induced skeletal muscle hypertrophy have been extensively researched since the landmark report by Morpurgo (1897) of "work-induced hypertrophy" in dogs that were treadmill trained. Much of the preclinical rodent and human resistance training research to date supports that involved mechanisms include enhanced mammalian/mechanistic target of rapamycin complex 1 (mTORC1) signaling, an expansion in translational capacity through ribosome biogenesis, increased satellite cell abundance and myonuclear accretion, and postexercise elevations in muscle protein synthesis rates. However, several lines of past and emerging evidence suggest that additional mechanisms that feed into or are independent of these processes are also involved. This review first provides a historical account of how mechanistic research into skeletal muscle hypertrophy has progressed. A comprehensive list of mechanisms associated with skeletal muscle hypertrophy is then outlined, and areas of disagreement involving these mechanisms are presented. Finally, future research directions involving many of the discussed mechanisms are proposed.
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Affiliation(s)
- Michael D Roberts
- School of Kinesiology, Auburn University, Auburn, Alabama, United States
| | - John J McCarthy
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky, United States
| | - Troy A Hornberger
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin, United States
| | - Stuart M Phillips
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Abigail L Mackey
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery, Copenhagen University Hospital-Bispebjerg and Frederiksberg, and Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Gustavo A Nader
- Department of Kinesiology and Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, United States
| | - Marni D Boppart
- Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States
| | - Andreas N Kavazis
- School of Kinesiology, Auburn University, Auburn, Alabama, United States
| | - Paul T Reidy
- Department of Kinesiology, Nutrition and Health, Miami University, Oxford, Ohio, United States
| | - Riki Ogasawara
- Healthy Food Science Research Group, Cellular and Molecular Biotechnology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
| | - Cleiton A Libardi
- MUSCULAB-Laboratory of Neuromuscular Adaptations to Resistance Training, Department of Physical Education, Federal University of São Carlos, São Carlos, Brazil
| | - Carlos Ugrinowitsch
- School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
| | - Frank W Booth
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri, United States
| | - Karyn A Esser
- Department of Physiology and Aging, College of Medicine, University of Florida, Gainesville, Florida, United States
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Lundquist A, Lázár E, Han NS, Emanuelsson EB, Reitzner SM, Chapman MA, Shirokova V, Alkass K, Druid H, Petri S, Sundberg CJ, Bergmann O. FiNuTyper: Design and validation of an automated deep learning-based platform for simultaneous fiber and nucleus type analysis in human skeletal muscle. Acta Physiol (Oxf) 2023; 239:e13982. [PMID: 37097015 DOI: 10.1111/apha.13982] [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: 12/20/2022] [Revised: 03/30/2023] [Accepted: 04/21/2023] [Indexed: 04/26/2023]
Abstract
AIM While manual quantification is still considered the gold standard for skeletal muscle histological analysis, it is time-consuming and prone to investigator bias. To address this challenge, we assembled an automated image analysis pipeline, FiNuTyper (Fiber and Nucleus Typer). METHODS We integrated recently developed deep learning-based image segmentation methods, optimized for unbiased evaluation of fresh and postmortem human skeletal muscle, and utilized SERCA1 and SERCA2 as type-specific myonucleus and myofiber markers after validating them against the traditional use of MyHC isoforms. RESULTS Parameters including cross-sectional area, myonuclei per fiber, myonuclear domain, central myonuclei per fiber, and grouped myofiber ratio were determined in a fiber-type-specific manner, revealing that a large degree of sex- and muscle-related heterogeneity could be detected using the pipeline. Our platform was also tested on pathological muscle tissue (ALS and IBM) and adapted for the detection of other resident cell types (leucocytes, satellite cells, capillary endothelium). CONCLUSION In summary, we present an automated image analysis tool for the simultaneous quantification of myofiber and myonuclear types, to characterize the composition and structure of healthy and diseased human skeletal muscle.
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Affiliation(s)
- August Lundquist
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Enikő Lázár
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Nan S Han
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Eric B Emanuelsson
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Stefan M Reitzner
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
- Department for Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden
| | - Mark A Chapman
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
- Department of Integrated Engineering, University of San Diego, San Diego, USA
| | - Vera Shirokova
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Kanar Alkass
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
- Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden
| | - Henrik Druid
- Department of Oncology-Pathology, Karolinska Institutet, Stockholm, Sweden
| | - Susanne Petri
- Department of Neurology, Hanover Medical School, Hanover, Germany
| | - Carl J Sundberg
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
- Department of Learning, Informatics, Management, and Ethics, Karolinska Institutet, Stockholm, Sweden
| | - Olaf Bergmann
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
- Center for Regenerative Therapies Dresden, Technische Universität Dresden, Dresden, Germany
- Pharmacology and Toxicology, University Medical Center Göttingen (UMG), Göttingen, Germany
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Smith MA, Sexton CL, Smith KA, Osburn SC, Godwin JS, Beausejour JP, Ruple BA, Goodlett MD, Edison JL, Fruge AD, Robinson AT, Gladden LB, Young KC, Roberts MD. Molecular predictors of resistance training outcomes in young untrained female adults. J Appl Physiol (1985) 2023; 134:491-507. [PMID: 36633866 PMCID: PMC10190845 DOI: 10.1152/japplphysiol.00605.2022] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 01/10/2023] [Accepted: 01/10/2023] [Indexed: 01/13/2023] Open
Abstract
We sought to determine if the myofibrillar protein synthetic (MyoPS) response to a naïve resistance exercise (RE) bout, or chronic changes in satellite cell number and muscle ribosome content, were associated with hypertrophic outcomes in females or differed in those who classified as higher (HR) or lower (LR) responders to resistance training (RT). Thirty-four untrained college-aged females (23.4 ± 3.4 kg/m2) completed a 10-wk RT protocol (twice weekly). Body composition and leg imaging assessments, a right leg vastus lateralis biopsy, and strength testing occurred before and following the intervention. A composite score, which included changes in whole body lean/soft tissue mass (LSTM), vastus lateralis (VL) muscle cross-sectional area (mCSA), midthigh mCSA, and deadlift strength, was used to delineate upper and lower HR (n = 8) and LR (n = 8) quartiles. In all participants, training significantly (P < 0.05) increased LSTM, VL mCSA, midthigh mCSA, deadlift strength, mean muscle fiber cross-sectional area, satellite cell abundance, and myonuclear number. Increases in LSTM (P < 0.001), VL mCSA (P < 0.001), midthigh mCSA (P < 0.001), and deadlift strength (P = 0.001) were greater in HR vs. LR. The first-bout 24-hour MyoPS response was similar between HR and LR (P = 0.367). While no significant responder × time interaction existed for muscle total RNA concentrations (i.e., ribosome content) (P = 0.888), satellite cell abundance increased in HR (P = 0.026) but not LR (P = 0.628). Pretraining LSTM (P = 0.010), VL mCSA (P = 0.028), and midthigh mCSA (P < 0.001) were also greater in HR vs. LR. Female participants with an enhanced satellite cell response to RT, and more muscle mass before RT, exhibited favorable resistance training adaptations.NEW & NOTEWORTHY This study continues to delineate muscle biology differences between lower and higher responders to resistance training and is unique in that a female population was interrogated. As has been reported in prior studies, increases in satellite cell numbers are related to positive responses to resistance training. Satellite cell responsivity, rather than changes in muscle ribosome content per milligrams of tissue, may be a more important factor in delineating resistance-training responses in women.
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Affiliation(s)
- Morgan A Smith
- School of Kinesiology, Auburn University, Auburn, Alabama
| | - Casey L Sexton
- School of Kinesiology, Auburn University, Auburn, Alabama
| | - Kristen A Smith
- Department of Nutrition, Dietetics and Hospitality Management, Auburn University, Auburn, Alabama
| | | | | | | | | | - Michael D Goodlett
- Athletics Department, Auburn University, Auburn, Alabama
- Edward Via College of Osteopathic Medicine, Auburn, Alabama
| | - Joseph L Edison
- Athletics Department, Auburn University, Auburn, Alabama
- Edward Via College of Osteopathic Medicine, Auburn, Alabama
| | - Andrew D Fruge
- Department of Nutrition, Dietetics and Hospitality Management, Auburn University, Auburn, Alabama
- College of Nursing, Auburn University, Auburn, Alabama
| | | | | | - Kaelin C Young
- School of Kinesiology, Auburn University, Auburn, Alabama
- Edward Via College of Osteopathic Medicine, Auburn, Alabama
| | - Michael D Roberts
- School of Kinesiology, Auburn University, Auburn, Alabama
- Edward Via College of Osteopathic Medicine, Auburn, Alabama
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Dam TV, Dalgaard LB, Johansen FT, Bengtsen MB, Mose M, Lauritsen KM, Gravholt CH, Hansen M. Effects of transdermal estrogen therapy on satellite cell number and molecular markers for muscle hypertrophy in response to resistance training in early postmenopausal women. Eur J Appl Physiol 2023; 123:667-681. [PMID: 36585491 DOI: 10.1007/s00421-022-05093-0] [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: 10/06/2021] [Accepted: 03/31/2022] [Indexed: 01/01/2023]
Abstract
PURPOSE To investigate the effects of resistance training with or without transdermal estrogen therapy (ET) on satellite cell (SC) number and molecular markers for muscle hypertrophy in early postmenopausal women. METHODS Using a double-blinded randomized controlled design, we allocated healthy, untrained postmenopausal women to perform 12 weeks of resistance training with placebo (PLC, n = 16) or ET (n = 15). Muscle biopsies obtained before and after the intervention, and two hours after the last training session were analyzed for fiber type, SC number and molecular markers for muscle hypertrophy and degradation (real-time PCR, western blotting). RESULTS The analysis of SCs per Type I fiber showed a time x treatment interaction caused by a 47% decrease in PLC, and a 26% increase after ET after the training period. Also, SCs per Type II fiber area was lower after the intervention driven by a 57% decrease in PLC. Most molecular markers changed similarly in the two groups. CONCLUSION A decline in SC per muscle fiber was observed after the 12-week training period in postmenopausal women, which was counteracted when combined with use of transdermal ET. CLINICAL TRIAL REGISTRATION NUMBER nct03020953.
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Affiliation(s)
- Tine Vrist Dam
- Department of Public Health, Aarhus University, Dalgas Avenue 4, 8000, Aarhus C, Denmark
| | - Line Barner Dalgaard
- Department of Public Health, Aarhus University, Dalgas Avenue 4, 8000, Aarhus C, Denmark
| | - Frank Ted Johansen
- Department of Public Health, Aarhus University, Dalgas Avenue 4, 8000, Aarhus C, Denmark
| | - Mads Bisgaard Bengtsen
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Maike Mose
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Katrine Meyer Lauritsen
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Claus H Gravholt
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark.,Department of Molecular Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Mette Hansen
- Department of Public Health, Aarhus University, Dalgas Avenue 4, 8000, Aarhus C, Denmark.
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Mechanobiology-based physical therapy and rehabilitation after orthobiologic interventions: a narrative review. INTERNATIONAL ORTHOPAEDICS 2021; 46:179-188. [PMID: 34709429 DOI: 10.1007/s00264-021-05253-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Accepted: 10/19/2021] [Indexed: 10/20/2022]
Abstract
PURPOSE This review aims to summarize the evidence for the role of mechanotherapies and rehabilitation in supporting the synergy between regeneration and repair after an orthobiologic intervention. METHODS A selective literature search was performed using Web of Science, OVID, and PubMed to review research articles that discuss the effects of combining mechanotherapy with various forms of regenerative medicine. RESULTS Various mechanotherapies can encourage the healing process for patients at different stages. Taping, bracing, cold water immersion, and extracorporeal shockwave therapy can be used throughout the duration of acute inflammatory response. The regulation of angiogenesis can be sustained with blood flow restriction and resistance training, whereas heat therapy and tissue loading during exercise are recommended in the remodeling phase. CONCLUSION Combining mechanotherapy with various forms of regenerative medicine has shown promise for improving treatment outcomes. However, further studies that reveal a greater volume of evidence are needed to support clinical decisions.
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Murach KA, Fry CS, Dupont-Versteegden EE, McCarthy JJ, Peterson CA. Fusion and beyond: Satellite cell contributions to loading-induced skeletal muscle adaptation. FASEB J 2021; 35:e21893. [PMID: 34480776 PMCID: PMC9293230 DOI: 10.1096/fj.202101096r] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 08/13/2021] [Accepted: 08/17/2021] [Indexed: 12/14/2022]
Abstract
Satellite cells support adult skeletal muscle fiber adaptations to loading in numerous ways. The fusion of satellite cells, driven by cell-autonomous and/or extrinsic factors, contributes new myonuclei to muscle fibers, associates with load-induced hypertrophy, and may support focal membrane damage repair and long-term myonuclear transcriptional output. Recent studies have also revealed that satellite cells communicate within their niche to mediate muscle remodeling in response to resistance exercise, regulating the activity of numerous cell types through various mechanisms such as secretory signaling and cell-cell contact. Muscular adaptation to resistance and endurance activity can be initiated and sustained for a period of time in the absence of satellite cells, but satellite cell participation is ultimately required to achieve full adaptive potential, be it growth, function, or proprioceptive coordination. While significant progress has been made in understanding the roles of satellite cells in adult muscle over the last few decades, many conclusions have been extrapolated from regeneration studies. This review highlights our current understanding of satellite cell behavior and contributions to adaptation outside of regeneration in adult muscle, as well as the roles of satellite cells beyond fusion and myonuclear accretion, which are gaining broader recognition.
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Affiliation(s)
- Kevin A Murach
- The Center for Muscle Biology, University of Kentucky, Lexington, Kentucky, USA.,Molecular Muscle Mass Regulation Laboratory, Exercise Science Research Center, Department of Health, Human Performance, and Recreation, University of Arkansas, Fayetteville, Arkansas, USA.,Cell and Molecular Biology Program, University of Arkansas, Fayetteville, Arkansas, USA
| | - Christopher S Fry
- The Center for Muscle Biology, University of Kentucky, Lexington, Kentucky, USA.,Department of Athletic Training and Clinical Nutrition, College of Health Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - Esther E Dupont-Versteegden
- The Center for Muscle Biology, University of Kentucky, Lexington, Kentucky, USA.,Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - John J McCarthy
- The Center for Muscle Biology, University of Kentucky, Lexington, Kentucky, USA.,Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Charlotte A Peterson
- The Center for Muscle Biology, University of Kentucky, Lexington, Kentucky, USA.,Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, Kentucky, USA.,Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky, USA
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7
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LOPEZ PEDRO, RADAELLI RÉGIS, TAAFFE DENNISR, NEWTON ROBERTU, GALVÃO DANIELA, TRAJANO GABRIELS, TEODORO JULIANAL, KRAEMER WILLIAMJ, HÄKKINEN KEIJO, PINTO RONEIS. Resistance Training Load Effects on Muscle Hypertrophy and Strength Gain: Systematic Review and Network Meta-analysis. Med Sci Sports Exerc 2021; 53:1206-1216. [PMID: 33433148 PMCID: PMC8126497 DOI: 10.1249/mss.0000000000002585] [Citation(s) in RCA: 72] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
PURPOSE This study aimed to analyze the effect of resistance training (RT) performed until volitional failure with low, moderate, and high loads on muscle hypertrophy and muscle strength in healthy adults and to assess the possible participant-, design-, and training-related covariates that may affect the adaptations. METHODS Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, MEDLINE, CINAHL, EMBASE, SPORTDiscus, and Web of Science databases were searched. Including only studies that performed sets to volitional failure, the effects of low- (>15 repetitions maximum (RM)), moderate- (9-15 RM), and high-load (≤8 RM) RTs were examined in healthy adults. Network meta-analysis was undertaken to calculate the standardized mean difference (SMD) between RT loads in overall and subgroup analyses involving studies deemed of high quality. Associations between participant-, design-, and training-related covariates with SMD were assessed by univariate and multivariate network meta-regression analyses. RESULTS Twenty-eight studies involving 747 healthy adults were included. Although no differences in muscle hypertrophy between RT loads were found in overall (P = 0.113-0.469) or subgroup analysis (P = 0.871-0.995), greater effects were observed in untrained participants (P = 0.033) and participants with some training background who undertook more RT sessions (P = 0.031-0.045). Muscle strength improvement was superior for both high-load and moderate-load compared with low-load RT in overall and subgroup analysis (SMD, 0.60-0.63 and 0.34-0.35, respectively; P < 0.001-0.003), with a nonsignificant but superior effect for high compared with moderate load (SMD, 0.26-0.28, P = 0.068). CONCLUSIONS Although muscle hypertrophy improvements seem to be load independent, increases in muscle strength are superior in high-load RT programs. Untrained participants exhibit greater muscle hypertrophy, whereas undertaking more RT sessions provides superior gains in those with previous training experience.
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Affiliation(s)
- PEDRO LOPEZ
- Exercise Medicine Research Institute, Edith Cowan University, Joondalup, Western Australia, AUSTRALIA,School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, AUSTRALIA
| | - RÉGIS RADAELLI
- Exercise Research Laboratory, School of Physical Education, Physiotherapy and Dance, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, BRAZIL
| | - DENNIS R. TAAFFE
- Exercise Medicine Research Institute, Edith Cowan University, Joondalup, Western Australia, AUSTRALIA,School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, AUSTRALIA
| | - ROBERT U. NEWTON
- Exercise Medicine Research Institute, Edith Cowan University, Joondalup, Western Australia, AUSTRALIA,School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, AUSTRALIA,School of Human Movement and Nutrition Sciences, University of Queensland, Queensland, AUSTRALIA
| | - DANIEL A. GALVÃO
- Exercise Medicine Research Institute, Edith Cowan University, Joondalup, Western Australia, AUSTRALIA,School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, AUSTRALIA
| | - GABRIEL S. TRAJANO
- School of Exercise and Nutrition Sciences, Faculty of Health, Queensland University of Technology (QUT), Brisbane, Queensland, AUSTRALIA
| | - JULIANA L. TEODORO
- Exercise Research Laboratory, School of Physical Education, Physiotherapy and Dance, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, BRAZIL
| | | | - KEIJO HÄKKINEN
- Neuromuscular Research Center, Biology of Physical Activity, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, FINLAND
| | - RONEI S. PINTO
- Exercise Research Laboratory, School of Physical Education, Physiotherapy and Dance, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, BRAZIL
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Angleri V, Ugrinowitsch C, Libardi C. Are resistance training systems necessary to avoid a stagnation and maximize the gains muscle strength and hypertrophy? Sci Sports 2020. [DOI: 10.1016/j.scispo.2018.12.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Bjørnsen T, Wernbom M, Kirketeig A, Paulsen G, Samnøy L, Bækken L, Cameron-Smith D, Berntsen S, Raastad T. Type 1 Muscle Fiber Hypertrophy after Blood Flow-restricted Training in Powerlifters. Med Sci Sports Exerc 2019; 51:288-298. [PMID: 30188363 DOI: 10.1249/mss.0000000000001775] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
PURPOSE To investigate the effects of blood flow-restricted resistance exercise (BFRRE) on myofiber areas (MFA), number of myonuclei and satellite cells (SC), muscle size and strength in powerlifters. METHODS Seventeen national level powerlifters (25 ± 6 yr [mean ± SD], 15 men) were randomly assigned to either a BFRRE group (n = 9) performing two blocks (weeks 1 and 3) of five BFRRE front squat sessions within a 6.5-wk training period, or a conventional training group (Con; n = 8) performing front squats at 60%-85% of one-repetition maximum (1RM). The BFRRE consisted of four sets (first and last set to voluntary failure) at ~30% of 1RM. Muscle biopsies were obtained from m. vastus lateralis (VL) and analyzed for MFA, myonuclei, SC and capillaries. Cross-sectional areas (CSA) of VL and m. rectus femoris were measured by ultrasonography. Strength was evaluated by maximal voluntary isokinetic torque (MVIT) in knee extension and 1RM in front squat. RESULTS BFRRE induced selective increases in type I MFA (BFRRE: 12% vs Con: 0%, P < 0.01) and myonuclear number (BFRRE: 18% vs Con: 0%, P = 0.02). Type II MFA was unaltered in both groups. BFRRE induced greater changes in VL CSA (7.7% vs 0.5%, P = 0.04), which correlated with the increases in MFA of type I fibers (r = 0.81, P = 0.02). No group differences were observed in SC and strength changes, although MVIT increased with BFRRE (P = 0.04), whereas 1RM increased in Con (P = 0.02). CONCLUSIONS Two blocks of low-load BFRRE in the front squat exercise resulted in increased quadriceps CSA associated with preferential hypertrophy and myonuclear addition in type 1 fibers of national level powerlifters.
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Affiliation(s)
- Thomas Bjørnsen
- Department of Public Health, Sport and Nutrition, Faculty of Health and Sport Sciences, University of Agder, Kristiansand, NORWAY
| | - Mathias Wernbom
- Center for Health and Performance, Department of Food and Nutrition, and Sport Science, University of Gothenburg, Gothenburg, SWEDEN
| | | | | | - Lars Samnøy
- Norwegian Powerlifting Federation, Oslo, NORWAY
| | - Lasse Bækken
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, NORWAY
| | - David Cameron-Smith
- Liggins Institute, University of Auckland, Auckland, NEW ZEALAND.,Food and Bio-based Products Group, AgResearch, Palmerston North, NEW ZEALAND.,Riddet Institute, Palmerston North, NEW ZEALAND
| | - Sveinung Berntsen
- Department of Public Health, Sport and Nutrition, Faculty of Health and Sport Sciences, University of Agder, Kristiansand, NORWAY
| | - Truls Raastad
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, NORWAY
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CONCEIÇÃO MIGUELS, VECHIN FELIPEC, LIXANDRÃO MANOEL, DAMAS FELIPE, LIBARDI CLEITONA, TRICOLI VALMOR, ROSCHEL HAMILTON, CAMERA DONNY, UGRINOWITSCH CARLOS. Muscle Fiber Hypertrophy and Myonuclei Addition: A Systematic Review and Meta-analysis. Med Sci Sports Exerc 2018; 50:1385-1393. [DOI: 10.1249/mss.0000000000001593] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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11
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Murach KA, Englund DA, Dupont-Versteegden EE, McCarthy JJ, Peterson CA. Myonuclear Domain Flexibility Challenges Rigid Assumptions on Satellite Cell Contribution to Skeletal Muscle Fiber Hypertrophy. Front Physiol 2018; 9:635. [PMID: 29896117 PMCID: PMC5986879 DOI: 10.3389/fphys.2018.00635] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 05/11/2018] [Indexed: 12/29/2022] Open
Abstract
Satellite cell-mediated myonuclear accretion is thought to be required for skeletal muscle fiber hypertrophy, and even drive hypertrophy by preceding growth. Recent studies in humans and rodents provide evidence that challenge this axiom. Specifically, Type 2 muscle fibers reliably demonstrate a substantial capacity to hypertrophy in the absence of myonuclear accretion, challenging the notion of a tightly regulated myonuclear domain (i.e., area that each myonucleus transcriptionally governs). In fact, a “myonuclear domain ceiling”, or upper limit of transcriptional output per nucleus to support hypertrophy, has yet to be identified. Satellite cells respond to muscle damage, and also play an important role in extracellular matrix remodeling during loading-induced hypertrophy. We postulate that robust satellite cell activation and proliferation in response to mechanical loading is largely for these purposes. Future work will aim to elucidate the mechanisms by which Type 2 fibers can hypertrophy without additional myonuclei, the extent to which Type 1 fibers can grow without myonuclear accretion, and whether a true myonuclear domain ceiling exists.
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Affiliation(s)
- Kevin A Murach
- The Center for Muscle Biology, College of Health Sciences, University of Kentucky, Lexington, KY, United States.,Department of Rehabilitation Sciences, College of Health Sciences, University of Kentucky, Lexington, KY, United States
| | - Davis A Englund
- The Center for Muscle Biology, College of Health Sciences, University of Kentucky, Lexington, KY, United States.,Department of Rehabilitation Sciences, College of Health Sciences, University of Kentucky, Lexington, KY, United States
| | - Esther E Dupont-Versteegden
- The Center for Muscle Biology, College of Health Sciences, University of Kentucky, Lexington, KY, United States.,Department of Rehabilitation Sciences, College of Health Sciences, University of Kentucky, Lexington, KY, United States
| | - John J McCarthy
- The Center for Muscle Biology, College of Health Sciences, University of Kentucky, Lexington, KY, United States.,Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, United States
| | - Charlotte A Peterson
- The Center for Muscle Biology, College of Health Sciences, University of Kentucky, Lexington, KY, United States.,Department of Rehabilitation Sciences, College of Health Sciences, University of Kentucky, Lexington, KY, United States
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Murach KA, Fry CS, Kirby TJ, Jackson JR, Lee JD, White SH, Dupont-Versteegden EE, McCarthy JJ, Peterson CA. Starring or Supporting Role? Satellite Cells and Skeletal Muscle Fiber Size Regulation. Physiology (Bethesda) 2018; 33:26-38. [PMID: 29212890 PMCID: PMC5866409 DOI: 10.1152/physiol.00019.2017] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 09/18/2017] [Accepted: 09/18/2017] [Indexed: 12/22/2022] Open
Abstract
Recent loss-of-function studies show that satellite cell depletion does not promote sarcopenia or unloading-induced atrophy, and does not prevent regrowth. Although overload-induced muscle fiber hypertrophy is normally associated with satellite cell-mediated myonuclear accretion, hypertrophic adaptation proceeds in the absence of satellite cells in fully grown adult mice, but not in young growing mice. Emerging evidence also indicates that satellite cells play an important role in remodeling the extracellular matrix during hypertrophy.
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Affiliation(s)
- Kevin A Murach
- The Center for Muscle Biology, University of Kentucky, Lexington, Kentucky
- Department of Rehabilitation Sciences, College of Health Sciences, University of Kentucky, Lexington, Kentucky
| | - Christopher S Fry
- Department of Nutrition and Metabolism, School of Health Professions, University of Texas Medical Branch at Galveston, Galveston, Texas
| | - Tyler J Kirby
- The Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York
| | - Janna R Jackson
- The Center for Muscle Biology, University of Kentucky, Lexington, Kentucky
- Department of Rehabilitation Sciences, College of Health Sciences, University of Kentucky, Lexington, Kentucky
| | - Jonah D Lee
- Environment, Health, and Safety, University of Michigan, Ann Arbor, Michigan
| | - Sarah H White
- Department of Animal Science, Texas A&M University, College Station, Texas; and
| | - Esther E Dupont-Versteegden
- The Center for Muscle Biology, University of Kentucky, Lexington, Kentucky
- Department of Rehabilitation Sciences, College of Health Sciences, University of Kentucky, Lexington, Kentucky
| | - John J McCarthy
- The Center for Muscle Biology, University of Kentucky, Lexington, Kentucky
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky
| | - Charlotte A Peterson
- The Center for Muscle Biology, University of Kentucky, Lexington, Kentucky;
- Department of Rehabilitation Sciences, College of Health Sciences, University of Kentucky, Lexington, Kentucky
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Liu ZY, Deng W, Zhang RY, Huang JP, Wang XF, Qian DG, Xu J, Jin L, Wang XF. Anemia, Physical Function, and Mortality in Long-Lived Individuals Aged 95 and Older: A Population-Based Study. J Am Geriatr Soc 2016; 63:2202-4. [PMID: 26480990 DOI: 10.1111/jgs.13685] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Zu-yun Liu
- Unit of Epidemiology, State Key Laboratory of Genetic Engineering, Ministry of Education Key Laboratory of Contemporary Anthropology, School of Life Sciences, Institute of Biomedical Sciences, Fudan University, Shanghai, China
| | - Wan Deng
- Unit of Epidemiology, State Key Laboratory of Genetic Engineering, Ministry of Education Key Laboratory of Contemporary Anthropology, School of Life Sciences, Institute of Biomedical Sciences, Fudan University, Shanghai, China
| | - Ru-yue Zhang
- Unit of Epidemiology, State Key Laboratory of Genetic Engineering, Ministry of Education Key Laboratory of Contemporary Anthropology, School of Life Sciences, Institute of Biomedical Sciences, Fudan University, Shanghai, China
| | - Jia-pin Huang
- Unit of Epidemiology, State Key Laboratory of Genetic Engineering, Ministry of Education Key Laboratory of Contemporary Anthropology, School of Life Sciences, Institute of Biomedical Sciences, Fudan University, Shanghai, China
| | - Xiao-feng Wang
- Unit of Epidemiology, State Key Laboratory of Genetic Engineering, Ministry of Education Key Laboratory of Contemporary Anthropology, School of Life Sciences, Institute of Biomedical Sciences, Fudan University, Shanghai, China
| | - De-gui Qian
- Longevity Research Institute of Rugao, Rugao, Jiangsu, China
| | - Jun Xu
- Longevity Research Institute of Rugao, Rugao, Jiangsu, China
| | - Li Jin
- Unit of Epidemiology, State Key Laboratory of Genetic Engineering, Ministry of Education Key Laboratory of Contemporary Anthropology, School of Life Sciences, Institute of Biomedical Sciences, Fudan University, Shanghai, China
| | - Xiao-feng Wang
- Unit of Epidemiology, State Key Laboratory of Genetic Engineering, Ministry of Education Key Laboratory of Contemporary Anthropology, School of Life Sciences, Institute of Biomedical Sciences, Fudan University, Shanghai, China
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