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Warneke K, Behm DG, Alizadeh S, Hillebrecht M, Konrad A, Wirth K. Discussing Conflicting Explanatory Approaches in Flexibility Training Under Consideration of Physiology: A Narrative Review. Sports Med 2024; 54:1785-1799. [PMID: 38819597 PMCID: PMC11258068 DOI: 10.1007/s40279-024-02043-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/01/2024] [Indexed: 06/01/2024]
Abstract
The mechanisms underlying range of motion enhancements via flexibility training discussed in the literature show high heterogeneity in research methodology and study findings. In addition, scientific conclusions are mostly based on functional observations while studies considering the underlying physiology are less common. However, understanding the underlying mechanisms that contribute to an improved range of motion through stretching is crucial for conducting comparable studies with sound designs, optimising training routines and accurately interpreting resulting outcomes. While there seems to be no evidence to attribute acute range of motion increases as well as changes in muscle and tendon stiffness and pain perception specifically to stretching or foam rolling, the role of general warm-up effects is discussed in this paper. Additionally, the role of mechanical tension applied to greater muscle lengths for range of motion improvement will be discussed. Thus, it is suggested that physical training stressors can be seen as external stimuli that control gene expression via the targeted stimulation of transcription factors, leading to structural adaptations due to enhanced protein synthesis. Hence, the possible role of serial sarcomerogenesis in altering pain perception, reducing muscle stiffness and passive torque, or changes in the optimal joint angle for force development is considered as well as alternative interventions with a potential impact on anabolic pathways. As there are limited possibilities to directly measure serial sarcomere number, longitudinal muscle hypertrophy remains without direct evidence. The available literature does not demonstrate the necessity of only using specific flexibility training routines such as stretching to enhance acute or chronic range of motion.
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Affiliation(s)
- Konstantin Warneke
- Institute of Human Movement Science, Sport and Health, University of Graz, Graz, Austria.
- Department of Movement Sciences, Institute of Sport Science, University of Klagenfurt, Universitatsstraße 65, 9020, Klagenfurt Am Wörthersee, Austria.
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, NL, Canada.
| | - David G Behm
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Shahab Alizadeh
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, NL, Canada
- Human Performance Lab, Department of Kinesiology, University of Calgary, Calgary, AB, Canada
| | - Martin Hillebrecht
- University Sports Center, Carl Von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Andreas Konrad
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, NL, Canada
- University Sports Center, Carl Von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Klaus Wirth
- University of Applied Sciences Wiener Neustadt, Vienna, Austria
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Shan C, Liu Y, Ma C, Li C, Liu Q, Liu S, Jiang G, Tian J. Dietary supplementation with Clostridium autoethanogenum protein improves growth performance and promotes muscle protein synthesis by activating the mTOR signaling pathway of the broiler. Front Vet Sci 2024; 11:1389738. [PMID: 38974336 PMCID: PMC11225622 DOI: 10.3389/fvets.2024.1389738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Accepted: 05/29/2024] [Indexed: 07/09/2024] Open
Abstract
The experiment aimed to evaluate the effects of different ratios of Clostridium autoethanogenum protein (CAP) used in the diets on the growth performance, muscle quality, serum indexes, and mTOR pathway of white feather broilers. Four hundred and eighty 1-day-old Arbor Acres (AA) broilers, comprising equal numbers of males and females, were randomly assigned to one of four treatments, and each treatment consisted of 12 replicates of 10 birds. Four diets were formulated based on isoenergetic and isonitrogenous principles. The control group (CAP 0) did not receive any CAP, while the experimental groups received 2% (CAP 2), 3% (CAP 3), and 4% (CAP 4) of CAP for six weeks. Compared with the CAP0, (1) The feed conversion ratio (FCR) was lower (p < 0.05), and the leg muscle yield was higher (p < 0.05) in the CAP3 and CAP4; (2) The serum levels of TP, ALB, T-AOC, and SOD were improved in the CAP3 (p < 0.05); (3) The expression of Lipin-1 gene was down-regulated and AMPKɑ2, Akt, and 4E-BP1 genes were up-regulated in the experiment group (p < 0.05); (4) The inclusion of 3% CAP in the diet increased the levels of 4E-BP1, S6K1, Akt, and AMPKɑ2 phosphorylation by modulating the mTOR signaling pathway (p < 0.05). In conclusion, broiler diets containing 3% CAP can activate the mTOR signaling pathway to promote muscle synthesis and improve growth performance.
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Affiliation(s)
- Chunqiao Shan
- School of Biological Engineering, Dalian Polytechnic University, Dalian, China
| | - Yan Liu
- Dalian Sanyi Biotechnology Research Institute, Dalian Sanyi Animal Medicine Co., Ltd., Dalian Liaoning, China
| | - Chaoxin Ma
- Research Quality Control Center, Jiangsu Sanyi Animal Nutrition Technology Co., Ltd., Xuzhou, China
| | - Chuang Li
- Research Quality Control Center, Jiangsu Sanyi Animal Nutrition Technology Co., Ltd., Xuzhou, China
| | - Qiuchen Liu
- Dalian Sanyi Biotechnology Research Institute, Dalian Sanyi Animal Medicine Co., Ltd., Dalian Liaoning, China
| | - Sisi Liu
- Harbin Academy of Agricultural Sciences, Harbin Heilongjiang, China
| | - Guotuo Jiang
- Dalian Sanyi Biotechnology Research Institute, Dalian Sanyi Animal Medicine Co., Ltd., Dalian Liaoning, China
| | - Jing Tian
- School of Biological Engineering, Dalian Polytechnic University, Dalian, China
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Fuchs CJ, Hermans WJH, Nyakayiru J, Weijzen MEG, Smeets JSJ, Aussieker T, Senden JM, Wodzig WKHW, Snijders T, Verdijk LB, van Loon LJC. Daily blood flow restriction does not preserve muscle mass and strength during 2 weeks of bed rest. J Physiol 2024. [PMID: 38411283 DOI: 10.1113/jp286065] [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: 11/29/2023] [Accepted: 02/08/2024] [Indexed: 02/28/2024] Open
Abstract
We measured the impact of blood flow restriction on muscle protein synthesis rates, muscle mass and strength during 2 weeks of strict bed rest. Twelve healthy, male adults (age: 24 ± 3 years, body mass index: 23.7 ± 3.1 kg/m2 ) were subjected to 14 days of strict bed rest with unilateral blood flow restriction performed three times daily in three 5 min cycles (200 mmHg). Participants consumed deuterium oxide and we collected blood and saliva samples throughout 2 weeks of bed rest. Before and immediately after bed rest, lean body mass (dual-energy X-ray absorptiometry scan) and thigh muscle volume (magnetic resonance imaging scan) were assessed in both the blood flow restricted (BFR) and control (CON) leg. Muscle biopsies were collected and unilateral muscle strength (one-repetition maximum; 1RM) was assessed for both legs before and after the bed rest period. Bed rest resulted in 1.8 ± 1.0 kg lean body mass loss (P < 0.001). Thigh muscle volume declined from 7.1 ± 1.1 to 6.7 ± 1.0 L in CON and from 7.0 ± 1.1 to 6.7 ± 1.0 L in BFR (P < 0.001), with no differences between treatments (P = 0.497). In addition, 1RM leg extension strength decreased from 60.2 ± 10.6 to 54.8 ± 10.9 kg in CON and from 59.2 ± 12.1 to 52.9 ± 12.0 kg in BFR (P = 0.014), with no differences between treatments (P = 0.594). Muscle protein synthesis rates during bed rest did not differ between the BFR and CON leg (1.11 ± 0.12 vs. 1.08 ± 0.13%/day, respectively; P = 0.302). Two weeks of bed rest substantially reduces skeletal muscle mass and strength. Blood flow restriction during bed rest does not modulate daily muscle protein synthesis rates and does not preserve muscle mass or strength. KEY POINTS: Bed rest, often necessary for recovery from illness or injury, leads to the loss of muscle mass and strength. It has been postulated that blood flow restriction may attenuate the loss of muscle mass and strength during bed rest. We investigated the effect of blood flow restriction on muscle protein synthesis rates, muscle mass and strength during 2 weeks of strict bed rest. Blood flow restriction applied during bed rest does not modulate daily muscle protein synthesis rates and does not preserve muscle mass or strength. Blood flow restriction is not effective in preventing muscle atrophy during a prolonged period of bed rest.
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Affiliation(s)
- Cas J Fuchs
- Department of Human Biology, Faculty of Health, Medicine and Life Sciences, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Wesley J H Hermans
- Department of Human Biology, Faculty of Health, Medicine and Life Sciences, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Jean Nyakayiru
- Department of Human Biology, Faculty of Health, Medicine and Life Sciences, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Michelle E G Weijzen
- Department of Human Biology, Faculty of Health, Medicine and Life Sciences, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Joey S J Smeets
- Department of Human Biology, Faculty of Health, Medicine and Life Sciences, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Thorben Aussieker
- Department of Human Biology, Faculty of Health, Medicine and Life Sciences, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Joan M Senden
- Department of Human Biology, Faculty of Health, Medicine and Life Sciences, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Will K H W Wodzig
- Central Diagnostic Laboratory, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Tim Snijders
- Department of Human Biology, Faculty of Health, Medicine and Life Sciences, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Lex B Verdijk
- Department of Human Biology, Faculty of Health, Medicine and Life Sciences, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Luc J C van Loon
- Department of Human Biology, Faculty of Health, Medicine and Life Sciences, School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University Medical Centre+, Maastricht, The Netherlands
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Guarente L, Sinclair DA, Kroemer G. Human trials exploring anti-aging medicines. Cell Metab 2024; 36:354-376. [PMID: 38181790 DOI: 10.1016/j.cmet.2023.12.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 11/01/2023] [Accepted: 12/05/2023] [Indexed: 01/07/2024]
Abstract
Here, we summarize the current knowledge on eight promising drugs and natural compounds that have been tested in the clinic: metformin, NAD+ precursors, glucagon-like peptide-1 receptor agonists, TORC1 inhibitors, spermidine, senolytics, probiotics, and anti-inflammatories. Multiple clinical trials have commenced to evaluate the efficacy of such agents against age-associated diseases including diabetes, cardiovascular disease, cancer, and neurodegenerative diseases. There are reasonable expectations that drugs able to decelerate or reverse aging processes will also exert broad disease-preventing or -attenuating effects. Hence, the outcome of past, ongoing, and future disease-specific trials may pave the way to the development of new anti-aging medicines. Drugs approved for specific disease indications may subsequently be repurposed for the treatment of organism-wide aging consequences.
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Affiliation(s)
- Leonard Guarente
- Department of Biology, Massachusetts Institute for Technology, Cambridge, MA 02139; Academy for Healthspan and Lifespan Research (AHLR), New York, NY, USA.
| | - David A Sinclair
- Academy for Healthspan and Lifespan Research (AHLR), New York, NY, USA; Blavatnik Institute, Genetics Department, Harvard Medical School, Boston, MA 02115, USA
| | - Guido Kroemer
- Academy for Healthspan and Lifespan Research (AHLR), New York, NY, USA; Centre de Recherche des Cordeliers, Equipe labellisée par la Ligue contre le cancer, Université Paris Cité, Sorbonne Université, Inserm U1138, Institut Universitaire de France, Paris, France; Metabolomics and Cell Biology Platforms, Institut Gustave Roussy, Villejuif, France; Institut du Cancer Paris CARPEM, Department of Biology, Hôpital Européen Georges Pompidou, AP-HP, Paris, France.
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Lee DJW, Hodzic Kuerec A, Maier AB. Targeting ageing with rapamycin and its derivatives in humans: a systematic review. THE LANCET. HEALTHY LONGEVITY 2024; 5:e152-e162. [PMID: 38310895 DOI: 10.1016/s2666-7568(23)00258-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 11/22/2023] [Accepted: 11/24/2023] [Indexed: 02/06/2024] Open
Abstract
Rapamycin and its derivatives (rapalogs) are inhibitors of mTOR, a major regulator of the ageing process. We aimed to summarise the effects of rapamycin and its derivatives on the severity of ageing-related physiological changes and disease in adults. A search across five databases yielded 18 400 unique articles, resulting in 19 included studies. Rapamycin and its derivatives improved physiological parameters associated with ageing in the immune, cardiovascular, and integumentary systems of healthy individuals or individuals with ageing-related diseases. Overall, no significant effects on the endocrine, muscular, or neurological systems were found. The effects of rapamycin or its derivatives on the respiratory, digestive, renal, and reproductive systems were not assessed. No serious adverse events attributed to rapamycin and its derivatives were reported in healthy individuals; however, there were increased numbers of infections and increases in total cholesterol, LDL cholesterol, and triglycerides in individuals with ageing-related diseases. Future studies should assess the remaining unexamined systems and test the effects of long-term exposure to rapamycin and its derivatives.
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Affiliation(s)
- Deborah J W Lee
- Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Ajla Hodzic Kuerec
- Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Centre for Healthy Longevity, @AgeSingapore National University Health System, Singapore
| | - Andrea B Maier
- Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Centre for Healthy Longevity, @AgeSingapore National University Health System, Singapore; Department of Human Movement Sciences, @AgeAmsterdam, Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, Netherlands.
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Elliehausen CJ, Anderson RM, Diffee GM, Rhoads TW, Lamming DW, Hornberger TA, Konopka AR. Geroprotector drugs and exercise: friends or foes on healthy longevity? BMC Biol 2023; 21:287. [PMID: 38066609 PMCID: PMC10709984 DOI: 10.1186/s12915-023-01779-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 11/23/2023] [Indexed: 12/18/2023] Open
Abstract
Physical activity and several pharmacological approaches individually combat age-associated conditions and extend healthy longevity in model systems. It is tantalizing to extrapolate that combining geroprotector drugs with exercise could extend healthy longevity beyond any individual treatment. However, the current dogma suggests that taking leading geroprotector drugs on the same day as exercise may limit several health benefits. Here, we review leading candidate geroprotector drugs and their interactions with exercise and highlight salient gaps in knowledge that need to be addressed to identify if geroprotector drugs can have a harmonious relationship with exercise.
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Affiliation(s)
- Christian J Elliehausen
- Division of Geriatrics and Gerontology, Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA
- Geriatric Research, Education, and Clinical Center, William S. Middleton Memorial Veterans Hospital, Madison, WI, USA
| | - Rozalyn M Anderson
- Division of Geriatrics and Gerontology, Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA
- Geriatric Research, Education, and Clinical Center, William S. Middleton Memorial Veterans Hospital, Madison, WI, USA
| | - Gary M Diffee
- Department of Kinesiology, University of Wisconsin-Madison, Madison, WI, USA
| | - Timothy W Rhoads
- Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, WI, USA
- Division of Endocrinology, Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Dudley W Lamming
- William S. Middleton Memorial Veterans Hospital, Madison, WI, USA
| | - Troy A Hornberger
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI, USA
| | - Adam R Konopka
- Division of Geriatrics and Gerontology, Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA.
- Geriatric Research, Education, and Clinical Center, William S. Middleton Memorial Veterans Hospital, Madison, WI, USA.
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Davids CJ, Roberts LA, Bjørnsen T, Peake JM, Coombes JS, Raastad T. Where Does Blood Flow Restriction Fit in the Toolbox of Athletic Development? A Narrative Review of the Proposed Mechanisms and Potential Applications. Sports Med 2023; 53:2077-2093. [PMID: 37578669 PMCID: PMC10587223 DOI: 10.1007/s40279-023-01900-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/24/2023] [Indexed: 08/15/2023]
Abstract
Blood flow-restricted exercise is currently used as a low-intensity time-efficient approach to reap many of the benefits of typical high-intensity training. Evidence continues to lend support to the notion that even highly trained individuals, such as athletes, still benefit from this mode of training. Both resistance and endurance exercise may be combined with blood flow restriction to provide a spectrum of adaptations in skeletal muscle, spanning from myofibrillar to mitochondrial adjustments. Such diverse adaptations would benefit both muscular strength and endurance qualities concurrently, which are demanded in athletic performance, most notably in team sports. Moreover, recent work indicates that when traditional high-load resistance training is supplemented with low-load, blood flow-restricted exercise, either in the same session or as a separate training block in a periodised programme, a synergistic and complementary effect on training adaptations may occur. Transient reductions in mechanical loading of tissues afforded by low-load, blood flow-restricted exercise may also serve a purpose during de-loading, tapering or rehabilitation of musculoskeletal injury. This narrative review aims to expand on the current scientific and practical understanding of how blood flow restriction methods may be applied by coaches and practitioners to enhance current athletic development models.
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Affiliation(s)
- Charlie J Davids
- Sport, Performance, and Nutrition Research Group, School of Allied Health, Human Services and Sport, La Trobe University, Melbourne, Australia.
- School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, QLD, Australia.
- Sport Performance Innovation and Knowledge Excellence (SPIKE), Queensland Academy of Sport, Brisbane, QLD, Australia.
| | - Llion A Roberts
- School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, QLD, Australia
- Sport Performance Innovation and Knowledge Excellence (SPIKE), Queensland Academy of Sport, Brisbane, QLD, Australia
- School of Health Sciences and Social Work, Griffith University, Gold Coast, QLD, Australia
| | - Thomas Bjørnsen
- Department of Sport Science and Physical Education, University of Agder, Kristiansand, Norway
- Norwegian Olympic and Paralympic Committee and Confederation of Sports, Oslo, Norway
| | - Jonathan M Peake
- Sport Performance Innovation and Knowledge Excellence (SPIKE), Queensland Academy of Sport, Brisbane, QLD, Australia
- School of Biomedical Science, Queensland University of Technology, Brisbane, QLD, Australia
| | - Jeff S Coombes
- School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Truls Raastad
- Norwegian Olympic and Paralympic Committee and Confederation of Sports, Oslo, Norway
- Department of Physical Performance, Norwegian School of Sport Science, Oslo, Norway
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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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Konopka AR, Lamming DW. Blazing a trail for the clinical use of rapamycin as a geroprotecTOR. GeroScience 2023; 45:2769-2783. [PMID: 37801202 PMCID: PMC10643772 DOI: 10.1007/s11357-023-00935-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 09/04/2023] [Indexed: 10/07/2023] Open
Abstract
Treatment with rapamycin, an inhibitor of the mechanistic Target Of Rapamycin Complex One (mTORC1) protein kinase, has been repeatedly demonstrated to extend lifespan and prevent or delay age-related diseases in diverse model systems. Concerns over the risk of potentially serious side effects in humans, including immunosuppression and metabolic disruptions, have cautiously limited the translation of rapamycin and its analogs as a treatment for aging associated conditions. During the last decade, we and others have developed a working model that suggests that while inhibition of mTORC1 promotes healthy aging, many of the negative side effects of rapamycin are associated with "off-target" inhibition of a second mTOR complex, mTORC2. Differences in the kinetics and molecular mechanisms by which rapamycin inhibits mTORC1 and mTORC2 suggest that a therapeutic window for rapamycin could be exploited using intermittent dosing schedules or alternative rapalogs that may enable more selective inhibition of mTORC1. However, the optimal dosing schedules and the long-term efficacy of such interventions in humans are unknown. Here, we highlight ongoing or upcoming clinical trials that will address outstanding questions regarding the safety, pharmacokinetics, pharmacodynamics, and efficacy of rapamycin and rapalogs on several clinically oriented outcomes. Results from these early phase studies will help guide the design of phase 3 clinical trials to determine whether rapamycin can be used safely to inhibit mTORC1 for the treatment and prevention of age-related diseases in humans.
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Affiliation(s)
- Adam R Konopka
- Division of Geriatrics, Department of Medicine, University of Wisconsin-Madison, Madison, WI, 53705, USA.
- William S. Middleton Memorial Veterans Hospital, Madison, WI, 53705, USA.
- Division of Geriatrics and Gerontology, Department of Medicine, Geriatric Research Education and Clinical Center (GRECC), William S. Middleton Memorial Veterans Hospital, University of Wisconsin-Madison, 2500 Overlook Terrace, Madison, WI, 53705, USA.
| | - Dudley W Lamming
- William S. Middleton Memorial Veterans Hospital, Madison, WI, 53705, USA
- Division of Endocrinology, Department of Medicine, University of Wisconsin-Madison, Madison, WI, 53705, USA
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10
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Mannozzi J, Al-Hassan MH, Kaur J, Lessanework B, Alvarez A, Massoud L, Aoun K, Spranger M, O'Leary DS. Blood flow restriction training activates the muscle metaboreflex during low-intensity sustained exercise. J Appl Physiol (1985) 2023; 135:260-270. [PMID: 37348015 PMCID: PMC10393340 DOI: 10.1152/japplphysiol.00274.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 06/09/2023] [Indexed: 06/24/2023] Open
Abstract
Blood flow restriction training (BFRT) employs partial vascular occlusion of exercising muscle and has been shown to increase muscle performance while using reduced workload and training time. Numerous studies have demonstrated that BFRT increases muscle hypertrophy, mitochondrial function, and beneficial vascular adaptations. However, changes in cardiovascular hemodynamics during the exercise protocol remain unknown, as most studies measured blood pressure before the onset and after the cessation of exercise. With reduced perfusion to the exercising muscle during BFRT, the resultant accumulation of metabolites within the ischemic muscle could potentially trigger a large reflex increase in blood pressure, termed the muscle metaboreflex. At low workloads, this pressor response occurs primarily via increases in cardiac output. However, when increases in cardiac output are limited (e.g., heart failure or during severe exercise), the reflex shifts to peripheral vasoconstriction as the primary mechanism to increase blood pressure, potentially increasing the risk of a cardiovascular event. Using our chronically instrumented conscious canine model, we utilized a 60% reduction in femoral blood pressure applied to the hindlimbs during steady-state treadmill exercise (3.2 km/h) to reproduce the ischemic environment observed during BFRT. We observed significant increases in heart rate (+19 ± 3 beats/min), stroke volume (+2.52 ± 1.2 mL), cardiac output (+1.21 ± 0.2 L/min), mean arterial pressure (+18.2 ± 2.4 mmHg), stroke work (+1.93 ± 0.2 L/mmHg), and nonischemic vascular conductance (+3.62 ± 1.7 mL/mmHg), indicating activation of the muscle metaboreflex.NEW & NOTEWORTHY Blood flow restriction training (BFRT) increases muscle mass, strength, and endurance. There has been minimal consideration of the reflex cardiovascular responses that could be elicited during BFRT sessions. We showed that during low-intensity exercise BFRT may trigger large reflex increases in blood pressure and sympathetic activity due to muscle metaboreflex activation. Thus, we urge caution when employing BFRT, especially in patients in whom exaggerated cardiovascular responses may occur that could cause sudden, adverse cardiovascular events.
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Affiliation(s)
- Joseph Mannozzi
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Mohamed-Hussein Al-Hassan
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Jasdeep Kaur
- Department of Kinesiology and Health Education, University of Texas at Austin, Austin, Texas, United States
| | - Beruk Lessanework
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Alberto Alvarez
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Louis Massoud
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Kamel Aoun
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Marty Spranger
- Department of Physiology, Michigan State University, East Lansing, Michigan, United States
| | - Donal S O'Leary
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, United States
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11
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Roy A, Narkar VA, Kumar A. Emerging role of TAK1 in the regulation of skeletal muscle mass. Bioessays 2023; 45:e2300003. [PMID: 36789559 PMCID: PMC10023406 DOI: 10.1002/bies.202300003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 01/02/2023] [Accepted: 02/02/2023] [Indexed: 02/16/2023]
Abstract
Maintenance of skeletal muscle mass and strength throughout life is crucial for heathy living and longevity. Several signaling pathways have been implicated in the regulation of skeletal muscle mass in adults. TGF-β-activated kinase 1 (TAK1) is a key protein, which coordinates the activation of multiple signaling pathways. Recently, it was discovered that TAK1 is essential for the maintenance of skeletal muscle mass and myofiber hypertrophy following mechanical overload. Forced activation of TAK1 in skeletal muscle causes hypertrophy and attenuates denervation-induced muscle atrophy. TAK1-mediated signaling in skeletal muscle promotes protein synthesis, redox homeostasis, mitochondrial health, and integrity of neuromuscular junctions. In this article, we have reviewed the role and potential mechanisms through which TAK1 regulates skeletal muscle mass and growth. We have also proposed future areas of research that could be instrumental in exploring TAK1 as therapeutic target for improving muscle mass in various catabolic conditions and diseases.
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Affiliation(s)
- Anirban Roy
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston College of Pharmacy, Houston, TX 77204, USA
| | - Vihang A. Narkar
- Brown Foundation Institute of Molecular Medicine, McGovern Medical School, The University of Texas Health Science Center, Houston, Texas, USA
| | - Ashok Kumar
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston College of Pharmacy, Houston, TX 77204, USA
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12
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Yuan J, Wu L, Xue Z, Xu G, Wu Y. Application and progress of blood flow restriction training in improving muscle mass and strength in the elderly. Front Physiol 2023; 14:1155314. [PMID: 37035674 PMCID: PMC10079911 DOI: 10.3389/fphys.2023.1155314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 03/17/2023] [Indexed: 04/11/2023] Open
Abstract
As an emerging training method, blood flow restriction training has been proved to promote the growth of muscle mass and strength. In recent years, it has been gradually applied in different populations. However, there are few studies on how blood flow restriction training affects muscle mass and strength in the elderly. The relevant literature is compiled and summarized in this study. Through the comparison of blood flow restriction training with traditional training methods and its application in the elderly, it shows that blood flow restriction training can effectively increase muscle mass and strength, prevent muscle atrophy, improve cardiopulmonary function, facilitate injury and postoperative rehabilitation, and intervene in related degenerative diseases as a training method suitable for the elderly,. The main mechanism of blood flow restriction training promoting muscle mass and strength growth is metabolic stress response, including muscle fiber recruitment, protein synthesis signal pathway activation, hormone secretion, etc., and is also related to cell swelling caused by pressure. At present, although the application of blood flow restriction training in the elderly population is increasing, there is a lack of personalized programs. In the future, more research on the dose effect and safety of blood flow restriction training is needed to develop more accurate personalized training programs.
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Affiliation(s)
| | | | | | - Guodong Xu
- *Correspondence: Guodong Xu, ; Yuxiang Wu,
| | - Yuxiang Wu
- *Correspondence: Guodong Xu, ; Yuxiang Wu,
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13
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Park HS, Song JS, Kim EK. Effects of low-intensity resistance exercise with blood flow restriction after high tibial osteotomy in middle-aged women. Medicine (Baltimore) 2022; 101:e32294. [PMID: 36595769 PMCID: PMC9794348 DOI: 10.1097/md.0000000000032294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND High tibial osteotomy (HTO) is an effective surgical method for treating medial compartment osteoarthritis. However, in most cases after surgery, muscle strength is decreased, and rapid muscle atrophy is observed. Therefore, the purpose of this study is to verify the effects of low-intensity resistance exercise (LIE) with blood flow restriction (BFR) on the cross-sectional area (CSA) of thigh muscles, knee extensor strength, pain, and knee joint function and investigate proper arterial occlusion pressure (AOP) in middle-aged women who underwent HTO. METHOD This study was designed as a prospective randomized controlled trial. Forty-two middle-aged women who underwent HTO were randomly divided into three groups and participated in LIE with (40% or 80% AOP applied) or without BFR. The main outcome was the measurement of the CSA of thigh muscles (at 30% and 50% distal length of the femur) before and 12 weeks after treatment. Additionally, knee extension muscle strength, pain, and joint function were evaluated before and 6 and 12 weeks after treatment. RESULTS CSA of thigh muscles at 30% and 50% distal length of the femur decreased in the AOP 40% and control groups and was the largest in the AOP 80% group 12 weeks after treatment. Knee extension strength increased in all groups and was the highest in the AOP 80% group 6 and 12 weeks after treatment. Pain improved in all groups, with no intergroup differences. Knee joint function improved in all groups and was superior in the 80% AOP group 12 weeks after treatment. CONCLUSION LIE with BFR at 80% AOP was effective in preventing atrophy of the thigh muscle, increasing muscle strength, and improving function. BFR at 40% AOP had no difference in the results when compared with the group in which BFR was not applied. Therefore, LIE with an AOP of 80% is recommended for patients undergoing HTO.
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Affiliation(s)
- Han-Soo Park
- Korean National Sports University, Songpa-gu, Seoul, Republic of Korea
| | - Jun-Seob Song
- Gangnam JS Hospital, Gangnam-gu, Seoul, Republic of Korea
| | - Eun-Kuk Kim
- SRC Hospital, Chowol-eup, Gwangju-si, Gyeonggi-do, Republic of Korea
- * Correspondence: Eun-Kuk Kim, SRC Hospital, 25, Gyeongsu-gil, Chowol-eup, Gwangju-si, Gyeonggi-do, Republic of Korea (e-mail: )
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14
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Ke J, Zhou X, Yang Y, Shen H, Luo X, Liu H, Gao L, He X, Zhang X. Blood flow restriction training promotes functional recovery of knee joint in patients after arthroscopic partial meniscectomy: A randomized clinical trial. Front Physiol 2022; 13:1015853. [PMID: 36311243 PMCID: PMC9611541 DOI: 10.3389/fphys.2022.1015853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 09/30/2022] [Indexed: 11/13/2022] Open
Abstract
Purpose: To explore the effect of blood flow restriction training (BFRT) on the recovery of knee function in patients after arthroscopic partial meniscectomy (APM). Methods: Forty patients undergoing APM surgery were included in this parallel group, two-arm, single-assessor blinded, randomized clinical trial. The subjects were randomly divided into two groups: routine rehabilitation group (RR Group, n = 20) and routine rehabilitation + blood flow restriction training group (RR + BFRT Group, n = 20). One subject in each group dropped out during the experiment. All patients received 8 weeks of routine rehabilitation starting from the second day after APM. In addition, patients in the RR + BFRT group required additional BFRT twice a week. Visual analogue scale (VAS) score, range of motion (ROM), one-leg standing test (OLST) score, Lysholm knee score, quadriceps muscle strength, quadriceps thickness, and thigh circumference were evaluated at preoperative, postoperative, 4 and 8 weeks after surgery. SPSS 25.0 software was used for statistical analysis of the data. Repeated measures ANOVA was used if the data were normally distributed and had homogeneity of variance. Generalized estimating equations were chosen if the data were not normally distributed or had homogeneity of variance. Results: There were no significant differences in VAS score, ROM, OLST score, Lysholm knee score, quadriceps muscle strength, quadriceps thickness, and thigh circumference between the two groups before surgery (p > 0.05). Compared with postoperative, VAS score, ROM, OLST score, Lysholm knee score, and thigh circumference were significantly improved in the RR group (p < 0.05), while quadriceps muscle strength and quadriceps thickness were not significantly enhanced at 8 weeks postoperatively (p > 0.05). However, VAS score, ROM, OLST score, Lysholm knee score, quadriceps muscle strength, quadriceps thickness, and thigh circumference were all significantly improved in the RR + BFRT group at 8 weeks postoperatively (p < 0.05). Furthermore, compared with the RR group, VAS score (50% vs. 86%), ROM (7.9% vs. 16.0%), OLST score (57.3% vs. 130.1%), Lysholm knee score (38.4% vs. 55.7%), relative peak torque (11.0% vs. 84.7%), mean power (20.6% vs. 88.1%), rectus femoris thickness (0.40% vs. 13.0%), vastus medialis (0.29% vs. 5.32%), vastus lateralis (0% vs. 6.2%), vastus internus (0% vs. 5.8%), and thigh circumference (2.7% vs. 5.8%) in the RR + BFRT group were significantly improved at 4 and 8 weeks postoperatively (p < 0.05). Conclusion: BFRT combined with routine rehabilitation training can better promote the recovery of knee joint function in patients after APM, especially the improvement of quadriceps muscle strength and thickness.
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Affiliation(s)
- Junjie Ke
- Sichuan Provincial Orthopedic Hospital, Chengdu, China
- School of Sports Medicine and Health, Chengdu Sport University, Chengdu, China
| | - Xuchang Zhou
- School of Sport Medicine and Rehabilitation, Beijing Sport University, Beijing, China
- National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital and Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen, China
| | - Yajing Yang
- National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital and Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen, China
| | - Hai Shen
- Sichuan Provincial Orthopedic Hospital, Chengdu, China
| | - Xiaobing Luo
- Sichuan Provincial Orthopedic Hospital, Chengdu, China
| | - Hui Liu
- Sichuan Provincial Orthopedic Hospital, Chengdu, China
| | - Lu Gao
- School of Sport Medicine and Rehabilitation, Beijing Sport University, Beijing, China
| | - Xin He
- Sichuan Provincial Orthopedic Hospital, Chengdu, China
| | - Xin Zhang
- Sichuan Provincial Orthopedic Hospital, Chengdu, China
- *Correspondence: Xin Zhang,
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15
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Damasceno SDO, Junior EP, Lemos LK, Biral TM, Cavina APDS, Vanderlei FM. Virtual reality-based therapy associated with blood flow restriction in older adults: A proposal for integration of techniques. Front Physiol 2022; 13:958823. [PMID: 36060703 PMCID: PMC9437243 DOI: 10.3389/fphys.2022.958823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 07/29/2022] [Indexed: 11/13/2022] Open
Affiliation(s)
- Silas de Oliveira Damasceno
- Postgraduate Program in Movement Sciences, Universidade Estadual Paulista (FCT/UNESP), Presidente Prudente, SP, Brazil
- *Correspondence: Silas de Oliveira Damasceno,
| | - Eduardo Pizzo Junior
- Postgraduate Program in Movement Sciences, Universidade Estadual Paulista (FCT/UNESP), Presidente Prudente, SP, Brazil
| | - Leonardo Kesrouani Lemos
- Postgraduate Program in Physiotherapy, Universidade Estadual Paulista (FCT/UNESP), Presidente Prudente, SP, Brazil
| | - Taíse Mendes Biral
- Postgraduate Program in Movement Sciences, Universidade Estadual Paulista (FCT/UNESP), Presidente Prudente, SP, Brazil
| | | | - Franciele Marques Vanderlei
- Postgraduate Program in Movement Sciences, Universidade Estadual Paulista (FCT/UNESP), Presidente Prudente, SP, Brazil
- Department of Physiotherapy, Universidade Estadual Paulista (FCT/UNESP), Presidente Prudente, SP, Brazil
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16
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Lin H, Salech F, Lim A, Vogrin S, Duque G. The effect of rapamycin and its analogues on age-related musculoskeletal diseases: a systematic review. Aging Clin Exp Res 2022; 34:2317-2333. [PMID: 35861940 DOI: 10.1007/s40520-022-02190-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 06/23/2022] [Indexed: 11/30/2022]
Abstract
BACKGROUND Preclinical studies have shown a therapeutic role of the mechanistic/mammalian target of rapamycin complex 1 (mTORC1) inhibition with rapamycin and its analogues (rapalogues) on several age-related musculoskeletal disorders (MSKD). However, the applicability to humans of these findings is unknown. OBJECTIVE To assess the efficacy of rapalogues on age-related MSKD in humans. METHODS We conducted a systematic review according to the PRISMA guidelines. MEDLINE, EMBase, EMCare, and Cochrane Central Registry of Controlled Trials were searched for original studies examining the effects of rapalogues on outcomes linked to the age-related MSKD in humans. This review is registered in the PROSPERO database (University of New York; registration number CRD42020208167). RESULTS Fourteen studies met the inclusion criteria and were analyzed. The effect of rapamycin and other rapalogues, including everolimus and temsirolimus, on bone, muscle and joints have been evaluated in humans; however, considerable variability concerning the subjects' age, inclusion criteria, and drug administration protocols was identified. In bone, the use of rapamycin is associated with a decrease in bone resorption markers dependent on osteoclastic activity. In muscle, rapamycin and rapalogues are associated with a reduction in muscle protein synthesis in response to exercise. In the context of rheumatoid arthritis, rapamycin and rapalogues have been associated with clinical improvement and a decrease in inflammatory activity. CONCLUSION Although there are studies that have evaluated the effect of rapamycin and rapalogues on MSKD in humans, the evidence supporting its use is still incipient, and the clinical implication of these results on the development of osteoporosis, sarcopenia, or osteosarcopenia has not been studied, opening an interesting field for future research.
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Affiliation(s)
- Hong Lin
- Australian Institute for Musculoskeletal Science (AIMSS), Geroscience and Osteosarcopenia Research Program, The University of Melbourne and Western Health, VIC, St. Albans, Australia.,Department of Medicine - Western Health, The University of Melbourne, VIC, St Albans, Australia.,Melbourne Medical School, The University of Melbourne, St Albans, VIC, Australia
| | - Felipe Salech
- Sección de Geriatría, Clínica de Caídas Y Fracturas, Hospital Clínico Universidad de Chile, Santiago, Chile.,Centro de Investigación Clínica Avanzada (CICA), Hospital Clínico Universidad de Chile, Santiago, Chile.,Centro de Gerociencia, Salud Mental Y Metabolismo (GERO), Santiago, Chile
| | - Anthony Lim
- Australian Institute for Musculoskeletal Science (AIMSS), Geroscience and Osteosarcopenia Research Program, The University of Melbourne and Western Health, VIC, St. Albans, Australia.,Department of Medicine - Western Health, The University of Melbourne, VIC, St Albans, Australia.,Melbourne Medical School, The University of Melbourne, St Albans, VIC, Australia
| | - Sara Vogrin
- Australian Institute for Musculoskeletal Science (AIMSS), Geroscience and Osteosarcopenia Research Program, The University of Melbourne and Western Health, VIC, St. Albans, Australia.,Melbourne Medical School, The University of Melbourne, St Albans, VIC, Australia
| | - Gustavo Duque
- Australian Institute for Musculoskeletal Science (AIMSS), Geroscience and Osteosarcopenia Research Program, The University of Melbourne and Western Health, VIC, St. Albans, Australia. .,Department of Medicine - Western Health, The University of Melbourne, VIC, St Albans, Australia. .,Melbourne Medical School, The University of Melbourne, St Albans, VIC, Australia.
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17
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Lees MJ, Hodson N, Tinline-Goodfellow CT, Fung HJW, Elia A, Moore DR. Challenges of rapamycin repurposing as a potential therapeutic candidate for COVID-19: implications for skeletal muscle metabolic health in older persons. Am J Physiol Endocrinol Metab 2022; 322:E551-E555. [PMID: 35521831 PMCID: PMC9169843 DOI: 10.1152/ajpendo.00064.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged as the causative agent of the ongoing coronavirus disease 2019 (COVID-19) pandemic that has spread worldwide, resulting in over 6 million deaths as of March 2022. Older people have been disproportionately affected by the disease, as they have a greater risk of hospitalization, are more vulnerable to severe infection, and have higher mortality than younger patients. Although effective vaccines have been rapidly developed and administered globally, several clinical trials are ongoing to repurpose existing drugs to combat severe infection. One such drug, rapamycin, is currently under study for this purpose, given its immunosuppressant effects that are mediated by its inhibition of the mechanistic target of rapamycin (mTOR), a master regulator of cell growth. Consistent with this premise, acute rapamycin administration in young healthy humans blocks or attenuates mTOR and its downstream effectors, leading to the inhibition of muscle protein synthesis (MPS). Skeletal muscle mass declines when MPS is chronically lower than muscle protein breakdown. This is consequential for older people who are more susceptible to anabolic resistance (i.e., the blunting of MPS) due to reduced activity, sedentariness, or bed rest such as that associated with COVID-19 hospitalization, and who have also demonstrated a delayed or blunted ability to regain inactivity-induced muscle loss. The lack of studies investigating rapamycin administration on skeletal muscle in older people, and the emergence of effective antiviral medications against severe infection, may indicate the reduced relevance of drug repurposing for present or future pandemics.
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Affiliation(s)
- Matthew J Lees
- Department of Exercise Sciences, Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, Canada
| | - Nathan Hodson
- Department of Sport and Exercise Sciences, Musculoskeletal Science and Sports Medicine Research Centre, Manchester Metropolitan University, Manchester, United Kingdom
| | - Cassidy T Tinline-Goodfellow
- Department of Exercise Sciences, Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, Canada
| | - Hugo J W Fung
- Department of Exercise Sciences, Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, Canada
| | - Antonis Elia
- Division of Environmental Physiology, School of Chemistry, Bioengineering and Health, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Daniel R Moore
- Department of Exercise Sciences, Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, Canada
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Bemben DA, Sherk VD, Buchanan SR, Kim S, Sherk K, Bemben MG. Acute and Chronic Bone Marker and Endocrine Responses to Resistance Exercise With and Without Blood Flow Restriction in Young Men. Front Physiol 2022; 13:837631. [PMID: 35370772 PMCID: PMC8969015 DOI: 10.3389/fphys.2022.837631] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 02/22/2022] [Indexed: 12/28/2022] Open
Abstract
In this study, we compared acute and chronic bone marker and hormone responses to 6 weeks of low intensity (20% 1RM) blood flow restriction (BFR20) resistance training to high intensity (70% 1RM) traditional resistance training (TR70) and moderate intensity (45% 1RM) traditional resistance training (TR45) in young men (18–35 years). Participants were randomized to one of the training groups or to a control group (CON). The following training programs were performed 3 days per week for 6 weeks for knee extension and knee flexion exercises: BFR20, 20%1RM, 4 sets (30, 15, 15, 15 reps) wearing blood flow restriction cuffs around the proximal thighs; TR70, 70% 1RM 3 sets 10 reps; and TR45, 45% 1RM 3 sets 15 reps. Muscle strength and thigh cross-sectional area were assessed at baseline, between week 3 and 6 of training. Acute bone marker (Bone ALP, CTX-I) and hormone (testosterone, IGF-1, IGFBP-3, cortisol) responses were assessed at weeks 1 and 6, with blood collection done in the morning after an overnight fast. The main findings were that the acute bone formation marker (Bone ALP) showed significant changes for TR70 and BFR20 but there was no difference between weeks 1 and 6. TR70 had acute increases in testosterone, IGF-1, and IGFBP-3 (weeks 1 and 6). BFR20 had significant acute increases in testosterone (weeks 1 and 6) and in IGF-1 at week 6, while TR45 had significant acute increases in testosterone (week 1), IGF-1 (week 6), and IGFBP-3 (week 6). Strength and muscle size gains were similar for the training groups. In conclusion, low intensity BFR resistance training was effective for stimulating acute bone formation marker and hormone responses, although TR70 showed the more consistent hormone responses than the other training groups.
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Affiliation(s)
- Debra A. Bemben
- Department of Health and Exercise Science, University of Oklahoma, Norman, OK, United States
- *Correspondence: Debra A. Bemben,
| | - Vanessa D. Sherk
- Department of Orthopedics, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Samuel R. Buchanan
- Department of Health and Human Performance, University of Texas Rio Grande Valley, Edinburg, TX, United States
| | - SoJung Kim
- Department of Health and Exercise Science, Rowan University, Glassboro, NJ, United States
| | - Kyle Sherk
- Hanger Clinic, Denver, CO, United States
| | - Michael G. Bemben
- Department of Health and Exercise Science, University of Oklahoma, Norman, OK, United States
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May AK, Russell AP, Della Gatta PA, Warmington SA. Muscle Adaptations to Heavy-Load and Blood Flow Restriction Resistance Training Methods. Front Physiol 2022; 13:837697. [PMID: 35185627 PMCID: PMC8850930 DOI: 10.3389/fphys.2022.837697] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 01/11/2022] [Indexed: 11/13/2022] Open
Abstract
Resistance-based blood flow restriction training (BFRT) improves skeletal muscle strength and size. Unlike heavy-load resistance training (HLRT), there is debate as to whether strength adaptations following BFRT interventions can be primarily attributed to concurrent muscle hypertrophy, as the magnitude of hypertrophy is often minor. The present study aimed to investigate the effect of 7 weeks of BFRT and HLRT on muscle strength and hypertrophy. The expression of protein growth markers from muscle biopsy samples was also measured. Male participants were allocated to moderately heavy-load training (HL; n = 9), low-load BFRT (LL + BFR; n = 8), or a control (CON; n = 9) group to control for the effect of time. HL and LL + BFR completed 21 training sessions (3 d.week−1) comprising bilateral knee extension and knee flexion exercises (HL = 70% one-repetition maximum (1-RM), LL + BFR = 20% 1-RM + blood flow restriction). Bilateral knee extension and flexion 1-RM strength were assessed, and leg muscle CSA was measured via peripheral quantitative computed tomography. Protein growth markers were measured in vastus lateralis biopsy samples taken pre- and post the first and last training sessions. Biopsy samples were also taken from CON at the same time intervals as HL and LL + BFR. Knee extension 1-RM strength increased in HL (19%) and LL + BFR (19%) but not CON (2%; p < 0.05). Knee flexion 1-RM strength increased similarly between all groups, as did muscle CSA (50% femur length; HL = 2.2%, LL + BFR = 3.0%, CON = 2.1%; TIME main effects). 4E-BP1 (Thr37/46) phosphorylation was lower in HL and LL + BFR immediately post-exercise compared with CON in both sessions (p < 0.05). Expression of other growth markers was similar between groups (p > 0.05). Overall, BFRT and HLRT improved muscle strength and size similarly, with comparable changes in intramuscular protein growth marker expression, both acutely and chronically, suggesting the activation of similar anabolic pathways. However, the low magnitude of muscle hypertrophy was not significantly different to the non-training control suggesting that strength adaptation following 7 weeks of BFRT is not driven by hypertrophy, but rather neurological adaptation.
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20
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Hughes L, Hackney KJ, Patterson SD. Optimization of Exercise Countermeasures to Spaceflight Using Blood Flow Restriction. Aerosp Med Hum Perform 2022; 93:32-45. [PMID: 35063054 DOI: 10.3357/amhp.5855.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
INTRODUCTION: During spaceflight missions, astronauts work in an extreme environment with several hazards to physical health and performance. Exposure to microgravity results in remarkable deconditioning of several physiological systems, leading to impaired physical condition and human performance, posing a major risk to overall mission success and crew safety. Physical exercise is the cornerstone of strategies to mitigate physical deconditioning during spaceflight. Decades of research have enabled development of more optimal exercise strategies and equipment onboard the International Space Station. However, the effects of microgravity cannot be completely ameliorated with current exercise countermeasures. Moreover, future spaceflight missions deeper into space require a new generation of spacecraft, which will place yet more constraints on the use of exercise by limiting the amount, size, and weight of exercise equipment and the time available for exercise. Space agencies are exploring ways to optimize exercise countermeasures for spaceflight, specifically exercise strategies that are more efficient, require less equipment, and are less time-consuming. Blood flow restriction exercise is a low intensity exercise strategy that requires minimal equipment and can elicit positive training benefits across multiple physiological systems. This method of exercise training has potential as a strategy to optimize exercise countermeasures during spaceflight and reconditioning in terrestrial and partial gravity environments. The possible applications of blood flow restriction exercise during spaceflight are discussed herein.Hughes L, Hackney KJ, Patterson SD. Optimization of exercise countermeasures to spaceflight using blood flow restriction. Aerosp Med Hum Perform. 2021; 93(1):32-45.
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21
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Active Women Across the Lifespan: Nutritional Ingredients to Support Health and Wellness. Sports Med 2022; 52:101-117. [PMID: 36173598 PMCID: PMC9521557 DOI: 10.1007/s40279-022-01755-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/17/2022] [Indexed: 12/15/2022]
Abstract
Women are the largest consumers of dietary supplements. Dietary supplements can play a role in health and performance, particularly for women. Growing evidence and innovations support the unique physiological and nutrient timing needs for women. Despite the need for more nutrition and exercise-specific research in women, initial data and known physiological differences between sexes related to the brain, respiration, bone, and muscle support new product development and evidence-based education for active women regarding the use of dietary supplements. In this narrative review, we discuss hormonal and metabolic considerations with the potential to impact nutritional recommendations for active women. We propose four potential areas of opportunity for ingredients to help support the health and well-being of active women, including: (1) body composition, (2) energy/fatigue, (3) mental health, and (4) physical health.
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22
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Hedt C, McCulloch PC, Harris JD, Lambert BS. Blood Flow Restriction Enhances Rehabilitation and Return to Sport: The Paradox of Proximal Performance. Arthrosc Sports Med Rehabil 2022; 4:e51-e63. [PMID: 35141536 PMCID: PMC8811501 DOI: 10.1016/j.asmr.2021.09.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 09/15/2021] [Indexed: 12/17/2022] Open
Abstract
The use of blood flow restriction (BFR) within rehabilitation is rapidly increasing as further research is performed elucidating purported benefits such as improved muscular strength and size, neuromuscular control, decreased pain, and increased bone mineral density. Interestingly, these benefits are not isolated to structures distal to the occlusive stimulus. Proximal gains are of high interest to rehabilitation professionals, especially those working with patients who are limited due to pain or postsurgical precautions. The review to follow will focus on current evidence and ongoing hypotheses regarding physiologic responses to BFR, current clinical applications, proximal responses to BFR training, potential practical applications for rehabilitation and injury prevention, and directions for future research. Interestingly, benefits have been found in musculature proximal to the occlusive stimulus, which may lend promise to a greater variety of patient populations and conditions. Furthermore, an increasing demand for BFR use in the sports world warrants further research for performance research and recovery. LEVEL OF EVIDENCE Level V, expert opinion.
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Affiliation(s)
- Corbin Hedt
- Houston Methodist Orthopedics & Sports Medicine, Houston, Texas, U.S.A
| | | | - Joshua D. Harris
- Houston Methodist Orthopedics & Sports Medicine, Houston, Texas, U.S.A
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Centner C, Jerger S, Lauber B, Seynnes O, Friedrich T, Lolli D, Gollhofer A, König D. Low-Load Blood Flow Restriction and High-Load Resistance Training Induce Comparable Changes in Patellar Tendon Properties. Med Sci Sports Exerc 2021; 54:582-589. [PMID: 34772900 DOI: 10.1249/mss.0000000000002824] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
INTRODUCTION Low-load resistance training with blood flow restriction (LL-BFR) has emerged as a viable alternative to conventional high-load (HL) resistance training regimens. Despite increasing evidence confirming comparable muscle adaptations between LL-BFR and HL resistance exercise, only very little is known about tendinous mechanical and morphological adaptations following LL-BFR. Therefore, the aim of the present study was to examine the effects of 14 weeks of LL-BFR and HL training on patellar tendon adaptations. METHODS N = 29 recreationally active male participants were randomly allocated into the following two groups: LL-BFR resistance training (20-35% one repetition maximum/1RM) or HL resistance training (70-85% 1RM). Both groups trained three times per week for 14 weeks. One week before and after the intervention, patellar tendon mechanical and morphological properties were assessed via ultrasound and magnetic resonance imaging (MRI). Additionally, changes in muscle cross-sectional area (CSA) were quantified by MRI and muscle strength via dynamic 1RM measurements. RESULTS The findings demonstrated that both LL-BFR and HL training resulted in comparable changes in patellar tendon stiffness (LL-BFR: + 25.2%, p = 0.003; HL: + 22.5%, p = 0.024) without significant differences between groups. Similar increases in tendon CSA were observed in HL and LL-BFR. Muscle mass and strength also significantly increased in both groups but were not statistically different between HL (+ 38%) and LL-BFR (+ 34%), except for knee extension 1RM where higher changes were seen in LL-BFR. CONCLUSION The present results support the notion that both HL and LL-BFR cause substantial changes in patellar tendon properties and the magnitude of changes are not significantly different between conditions. Further studies are needed which examine the physiological mechanisms underlying the altered tendon properties following LL-BFR training.
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Affiliation(s)
- Christoph Centner
- Department of Sport and Sport Science, University of Freiburg, Germany Praxisklinik Rennbahn, Muttenz, Switzerland Department of Neurosciences and Movement Sciences, Université de Fribourg, Switzerland Department of Physical Performance, Norwegian School of Sport Sciences, Norway Department of Sports Science, Institute for Nutrition, Sports and Health, University of Vienna, Vienna, Austria
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Rotator cuff strength is not augmented by blood flow restriction training. Phys Ther Sport 2021; 52:305-311. [PMID: 34742029 DOI: 10.1016/j.ptsp.2021.10.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 10/20/2021] [Accepted: 10/22/2021] [Indexed: 11/22/2022]
Abstract
OBJECTIVE Blood flow restriction (BFR) training utilizes a tourniquet applied to the upper or lower extremities (UE or LE) to occlude blood flow while exercising. BFR training may help augment strength in muscles that are proximal to BFR cuff application. However, prior studies have failed to demonstrate augmented strength gains in the rotator cuff when the tourniquet is applied to the UE. The purpose of this study was to evaluate if a protocol consisting of LE exercises, performed with BFR, followed by rotator cuff exercises was superior in augmenting strength, and cross-sectional area (CSA) of the rectus femoris, in untrained subjects when compared to a non-BFR training group. DESIGN Randomized controlled trial. SETTING University. PARTICIPANTS Thirty-five subjects (mean age 25.8 ± 1.6 y) randomized to a BFR or non-BFR group. MAIN OUTCOME MEASURES Muscular strength measured via hand held dynamometer and the CSA of the dominant rectus femoris was measured by diagnostic ultrasound. RESULTS Both groups experienced significant gains in LE and rotator cuff strength. Strength increased in the BFR group by 11.6% for the supraspinatus, 34.1% for shoulder ER, 23.4% for the quadriceps, and 17.1% for the hamstrings. Strength increased in the non-BFR group by 7.3% for the supraspinatus, 20% for shoulder ER, 12.8% for the quadriceps, and 10.7% for the hamstrings. However, there were no differences in strength gains between groups. Neither group experienced a significant increase in CSA for the rectus femoris. CONCLUSION The BFR protocol used in this study did not augment strength for the rotator cuff in subjects who also performed LE exercises under occlusion.
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Mesquita PHC, Vann CG, Phillips SM, McKendry J, Young KC, Kavazis AN, Roberts MD. Skeletal Muscle Ribosome and Mitochondrial Biogenesis in Response to Different Exercise Training Modalities. Front Physiol 2021; 12:725866. [PMID: 34646153 PMCID: PMC8504538 DOI: 10.3389/fphys.2021.725866] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 08/13/2021] [Indexed: 11/20/2022] Open
Abstract
Skeletal muscle adaptations to resistance and endurance training include increased ribosome and mitochondrial biogenesis, respectively. Such adaptations are believed to contribute to the notable increases in hypertrophy and aerobic capacity observed with each exercise mode. Data from multiple studies suggest the existence of a competition between ribosome and mitochondrial biogenesis, in which the first adaptation is prioritized with resistance training while the latter is prioritized with endurance training. In addition, reports have shown an interference effect when both exercise modes are performed concurrently. This prioritization/interference may be due to the interplay between the 5’ AMP-activated protein kinase (AMPK) and mechanistic target of rapamycin complex 1 (mTORC1) signaling cascades and/or the high skeletal muscle energy requirements for the synthesis and maintenance of cellular organelles. Negative associations between ribosomal DNA and mitochondrial DNA copy number in human blood cells also provide evidence of potential competition in skeletal muscle. However, several lines of evidence suggest that ribosome and mitochondrial biogenesis can occur simultaneously in response to different types of exercise and that the AMPK-mTORC1 interaction is more complex than initially thought. The purpose of this review is to provide in-depth discussions of these topics. We discuss whether a curious competition between mitochondrial and ribosome biogenesis exists and show the available evidence both in favor and against it. Finally, we provide future research avenues in this area of exercise physiology.
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Affiliation(s)
| | | | - Stuart M Phillips
- Department of Kinesiology, McMaster University, Hamilton, ON, Canada
| | - James McKendry
- Department of Kinesiology, McMaster University, Hamilton, ON, Canada
| | - Kaelin C Young
- School of Kinesiology, Auburn University, Auburn, AL, United States.,Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine, Auburn, AL, United States
| | | | - Michael D Roberts
- School of Kinesiology, Auburn University, Auburn, AL, United States.,Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine, Auburn, AL, United States
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Bejarano-Pineda L, Guss D, Waryasz G, DiGiovanni CW, Kwon JY. The Syndesmosis, Part I: Anatomy, Injury Mechanism, Classification, and Diagnosis. Orthop Clin North Am 2021; 52:403-415. [PMID: 34538351 DOI: 10.1016/j.ocl.2021.05.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Ankle fractures are common injuries to the lower extremity with approximately 20% sustaining a concomitant injury to the syndesmosis. Although the deltoid ligament is not formally included in the syndesmotic complex, it plays an important role in the mortise stability. Therefore, its integrity should be always evaluated when syndesmotic injury is suspected. Given the anatomic variability of the syndesmosis between individuals, bilateral ankle imaging is recommended, especially in cases of subtle instability. Diagnostic tests that allow dynamic assessment of the distal tibiofibular joint in the 3 planes are the most reliable in determining the presence of syndesmotic injury.
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Affiliation(s)
- Lorena Bejarano-Pineda
- Foot & Ankle Research and Innovation Laboratory - Harvard Medical School, Division of Foot and Ankle Surgery, Department of Orthopaedic Surgery, Massachusetts General Hospital - Newton-Wellesley Hospital, 40 2nd Avenue Building 52, Suite 1150, Waltham, MA 02451, USA; Foot & Ankle Service, Department of Orthopaedic Surgery, Massachusetts General Hospital, 40 2nd Avenue Building 52, Suite 1150, Waltham, MA 02451, USA
| | - Daniel Guss
- Foot & Ankle Research and Innovation Laboratory - Harvard Medical School, Division of Foot and Ankle Surgery, Department of Orthopaedic Surgery, Massachusetts General Hospital - Newton-Wellesley Hospital, 40 2nd Avenue Building 52, Suite 1150, Waltham, MA 02451, USA; Foot & Ankle Service, Department of Orthopaedic Surgery, Massachusetts General Hospital, 40 2nd Avenue Building 52, Suite 1150, Waltham, MA 02451, USA
| | - Gregory Waryasz
- Foot & Ankle Research and Innovation Laboratory - Harvard Medical School, Division of Foot and Ankle Surgery, Department of Orthopaedic Surgery, Massachusetts General Hospital - Newton-Wellesley Hospital, 40 2nd Avenue Building 52, Suite 1150, Waltham, MA 02451, USA; Foot & Ankle Service, Department of Orthopaedic Surgery, Massachusetts General Hospital, 40 2nd Avenue Building 52, Suite 1150, Waltham, MA 02451, USA
| | - Christopher W DiGiovanni
- Foot & Ankle Research and Innovation Laboratory - Harvard Medical School, Division of Foot and Ankle Surgery, Department of Orthopaedic Surgery, Massachusetts General Hospital - Newton-Wellesley Hospital, 40 2nd Avenue Building 52, Suite 1150, Waltham, MA 02451, USA; Foot & Ankle Service, Department of Orthopaedic Surgery, Massachusetts General Hospital, 40 2nd Avenue Building 52, Suite 1150, Waltham, MA 02451, USA
| | - John Y Kwon
- Foot & Ankle Research and Innovation Laboratory - Harvard Medical School, Division of Foot and Ankle Surgery, Department of Orthopaedic Surgery, Massachusetts General Hospital - Newton-Wellesley Hospital, 40 2nd Avenue Building 52, Suite 1150, Waltham, MA 02451, USA; Foot & Ankle Service, Department of Orthopaedic Surgery, Massachusetts General Hospital, 40 2nd Avenue Building 52, Suite 1150, Waltham, MA 02451, USA.
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Przkora R, Sibille K, Victor S, Meroney M, Leeuwenburgh C, Gardner A, Vasilopoulos T, Parvataneni HK. Blood flow restriction exercise to attenuate postoperative loss of function after total knee replacement: a randomized pilot study. Eur J Transl Myol 2021; 31. [PMID: 34459574 PMCID: PMC8495367 DOI: 10.4081/ejtm.2021.9932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 07/16/2021] [Indexed: 11/22/2022] Open
Abstract
Aging well is directly associated with a healthy lifestyle. The focus of this paper is to relate that attenuation of postoperative loss of muscle function after a total knee arthroplasty (TKA) is an important consideration. Because patients usually do not tolerate standard high-resistance exercise in the preoperative or postoperative period, they often experience a decline in strength and function. Therefore, we tested the feasibility and acceptability of an alternative low-resistance exercise protocol with blood flow restriction (BFR) using a tourniquet in the preoperative period for patients awaiting TKA. We recruited patients undergoing a TKA and randomized six to the BFR exercise for 4 weeks prior to surgery and four to standard of care (no exercise). We measured physical function using the Short Physical Performance Battery (SPPB), the 6-Minute Walk Test (6MWT), leg strength (peak torque), and pain (numerical pain score) 4 to 5 weeks preoperatively and 2 weeks postoperatively. The clinical management, e.g., anesthetic management, did not differ between groups. No complications were observed. Our findings demonstrate the feasibility and acceptability of the BFR intervention. Although preliminary and not powered for comparison, the BFR group demonstrated less decline in SPPB following surgery (−2.2, 95%CI:−4.4,0.1) compared to the no exercise group (−4.8, 95%CI:−7.8,−1.7). No differences were noted for the 6MWT, leg strength, and pain measurements. We conclude that preoperative low-resistance exercise using the BFR is feasible and acceptable, and this test warrants investigation as an intervention to potentially attenuate the postoperative loss of physical function after TKA.
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Affiliation(s)
- Rene Przkora
- Department of Anesthesiology, University of Florida College of Medicine, Gainesville, Florida.
| | - Kimberly Sibille
- Department of Anesthesiology, University of Florida College of Medicine, Gainesville, Florida, USA; Department of Aging and Geriatric Research, University of Florida College of Medicine, Gainesville, Florida.
| | - Sandra Victor
- Department of Anesthesiology, University of Florida College of Medicine, Gainesville, Florida.
| | - Matthew Meroney
- Department of Anesthesiology, University of Florida College of Medicine, Gainesville, Florida.
| | - Christiaan Leeuwenburgh
- Department of Aging and Geriatric Research, University of Florida College of Medicine, Gainesville, Florida, USA; Department of Anatomy and Cell Biology, University of Florida College of Medicine, Gainesville, Florida.
| | - Anna Gardner
- Department of Applied Physiology and Kinesiology, University of Florida College of Health and Human Performance, Gainesville, Florida.
| | - Terrie Vasilopoulos
- Department of Anesthesiology, University of Florida College of Medicine, Gainesville, Florida, USA; Department of Orthopaedics and Rehabilitation, University of Florida College of Medicine, Gainesville, Florida.
| | - Hari K Parvataneni
- Department of Orthopaedics and Rehabilitation, University of Florida College of Medicine, Gainesville, Florida.
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Teixeira EL, de Salles Painelli V, Silva-Batista C, de Souza Barros T, Longo AR, Lasevicius T, Schoenfeld BJ, Aihara AY, de Almeida Peres B. Blood Flow Restriction Does Not Attenuate Short-Term Detraining-Induced Muscle Size and Strength Losses After Resistance Training With Blood Flow Restriction. J Strength Cond Res 2021; 35:2082-2088. [DOI: 10.1519/jsc.0000000000003148] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Lambert B, Hedt C, Daum J, Taft C, Chaliki K, Epner E, McCulloch P. Blood Flow Restriction Training for the Shoulder: A Case for Proximal Benefit. Am J Sports Med 2021; 49:2716-2728. [PMID: 34110960 DOI: 10.1177/03635465211017524] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Although blood flow restriction (BFR) is becoming increasingly popular in physical therapy and athletic training settings, little is known about the effects of BFR combined with low-intensity exercise (LIX) on muscles proximal to the site of occlusion. HYPOTHESIS/PURPOSE Determine whether LIX combined with BFR applied distally to the shoulder on the brachial region of the arm (BFR-LIX) promotes greater increases in shoulder lean mass, rotator cuff strength, endurance, and acute increases in shoulder muscle activation compared with LIX alone. We hypothesized that BFR-LIX would elicit greater increases in rotator cuff strength, endurance, and muscle mass. We also hypothesized that the application of BFR would increase EMG amplitude in the shoulder muscles during acute exercise. STUDY DESIGN Controlled laboratory study. METHODS 32 healthy adults were randomized into 2 groups (BFR group, 13 men, 3 women; No-BFR group, 10 men, 6 women) who performed 8 weeks of shoulder LIX (2 times per week; 4 sets [30/15/15/fatigue]; 20% maximum) using common rotator cuff exercises (cable external rotation [ER], cable internal rotation [IR], dumbbell scaption, and side-lying dumbbell ER). The BFR group also trained with an automated tourniquet placed at the proximal arm (50% occlusion). Regional lean mass (dual-energy x-ray absorptiometry), isometric strength, and muscular endurance (repetitions to fatigue [RTF]; 20% maximum; with and without 50% occlusion) were measured before and after training. Electromyographic amplitude (EMGa) was recorded from target shoulder muscles during endurance testing. A mixed-model analysis of covariance (covaried on baseline measures) was used to detect within-group and between-group differences in primary outcome measures (α = .05). RESULTS The BFR group had greater increases in lean mass in the arm (mean ± 95% CI: BFR, 175 ± 54 g; No BFR, -17 ± 77 g; P < .01) and shoulder (mean ± 95% CI: BFR, 278 ± 90 g; No BFR, 96 ± 61 g; P < .01), isometric IR strength (mean ± 95% CI: BFR, 2.9 ± 1.3 kg; No BFR, 0.1 ± 1.3 kg; P < .01), single-set RTF volume (repetitions × resistance) for IR (~1.7- to 2.1-fold higher; P < .01), and weekly training volume (weeks 4, 6-8, ~5%-22%; P < .05). Acute occlusion (independent of group or timepoint) yielded increases in EMGa during RTF (~10%-20%; P < .05). CONCLUSION Combined BFR-LIX may yield greater increases in shoulder and arm lean mass, strength, and muscular endurance compared with fatiguing LIX alone during rotator cuff exercises. These findings may be due, in part, to a greater activation of shoulder muscles while using BFR. CLINICAL RELEVANCE The present study demonstrates that BFR-LIX may be a suitable candidate for augmenting preventive training or rehabilitation outcomes for the shoulder.
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Affiliation(s)
- Bradley Lambert
- Orthopedic Biomechanics Research Laboratory, Department of Orthopedics and Sports Medicine, Houston Methodist Hospital, Houston, Texas, USA
| | - Corbin Hedt
- Orthopedic Biomechanics Research Laboratory, Department of Orthopedics and Sports Medicine, Houston Methodist Hospital, Houston, Texas, USA
| | - Joshua Daum
- Orthopedic Biomechanics Research Laboratory, Department of Orthopedics and Sports Medicine, Houston Methodist Hospital, Houston, Texas, USA
| | - Carter Taft
- Department of Kinesiology, Rice University, Houston, Texas, USA
| | - Kalyan Chaliki
- Department of Kinesiology, Rice University, Houston, Texas, USA
| | - Eden Epner
- Orthopedic Biomechanics Research Laboratory, Department of Orthopedics and Sports Medicine, Houston Methodist Hospital, Houston, Texas, USA
| | - Patrick McCulloch
- Orthopedic Biomechanics Research Laboratory, Department of Orthopedics and Sports Medicine, Houston Methodist Hospital, Houston, Texas, USA
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Goldsmith JA, Ennasr AN, Farkas GJ, Gater DR, Gorgey AS. Role of exercise on visceral adiposity after spinal cord injury: a cardiometabolic risk factor. Eur J Appl Physiol 2021; 121:2143-2163. [PMID: 33891156 DOI: 10.1007/s00421-021-04688-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 04/10/2021] [Indexed: 12/30/2022]
Abstract
PURPOSE Visceral adipose tissue (VAT) is associated with cardiometabolic disease risk in able-bodied (AB) populations. However, the underlying mechanisms of VAT-induced disease risk are unknown in persons with spinal cord injury (SCI). Potential mechanisms of VAT-induced cardiometabolic dysfunction in persons with SCI include systemic inflammation, liver adiposity, mitochondrial dysfunction, and anabolic deficiency. Moreover, how exercise interventions impact these mechanisms associated with VAT-induced cardiometabolic dysfunction are still being explored. METHODS A search for relevant scientific literature about the effects of exercise on VAT and cardiometabolic health was conducted on the PubMed database. Literature from reference lists was also included when appropriate. RESULTS Both aerobic and resistance exercise training beneficially impact health and VAT mass via improving mitochondrial function, glucose effectiveness, and inflammatory signaling in SCI and AB populations. Specifically, aerobic exercise appears to also modulate cellular senescence in AB populations and animal models, while resistance exercise seems to augment anabolic signaling in persons with SCI. CONCLUSIONS The current evidence supports regular engagement in exercise to reduce VAT mass and the adverse effects on cardiometabolic health in persons with SCI. Future research is needed to further elucidate the precise mechanisms by which VAT negatively impacts health following SCI. This will likely facilitate the development of rehabilitation protocols that target VAT reduction in persons with SCI.
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Affiliation(s)
- Jacob A Goldsmith
- Spinal Cord Injury and Disorders Center, Central Virginia VA Health Care System, 1201 Broad Rock Boulevard, Richmond, VA, 23249, USA
| | - Areej N Ennasr
- Spinal Cord Injury and Disorders Center, Central Virginia VA Health Care System, 1201 Broad Rock Boulevard, Richmond, VA, 23249, USA
| | - Gary J Farkas
- Department of Physical Medicine and Rehabilitation, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - David R Gater
- Department of Physical Medicine and Rehabilitation, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Ashraf S Gorgey
- Spinal Cord Injury and Disorders Center, Central Virginia VA Health Care System, 1201 Broad Rock Boulevard, Richmond, VA, 23249, USA. .,Department of Physical Medicine and Rehabilitation, Virginia Commonwealth University, Richmond, VA, 23298, USA.
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Dadon-Freiberg M, Chapnik N, Froy O. REV-ERBα alters circadian rhythms by modulating mTOR signaling. Mol Cell Endocrinol 2021; 521:111108. [PMID: 33285244 DOI: 10.1016/j.mce.2020.111108] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 11/22/2020] [Accepted: 11/30/2020] [Indexed: 11/21/2022]
Abstract
REV-ERBα is a nuclear receptor that inhibits Bmal1 transcription as part of the circadian clock molecular mechanism. Mammalian target of rapamycin (mTOR) complex 1 (mTORC1) is a master regulator of cell and whole-body energy homeostasis, that serves as an important link between metabolism and circadian clock, in part, by regulating BMAL1 activity. While the connection of REV-ERBα to the circadian clock molecular mechanism is well characterized, the interaction between mTORC1, REV-ERBα and the circadian clock machinery is not very clear. We used leucine and rapamycin to modulate mTORC1 activation and evaluate this effect on circadian rhythms. In the liver, mTORC1 was inhibited by leucine. REV-ERBα overexpression activated the mTORC1 signaling pathway via transcription inhibition of mTORC1 inhibitor, Tsc1, antagonizing the effect of leucine, while its silencing downregulated mTORC1 signaling. Activation of mTORC1 led to increased BMAL1 phosphorylation. Activation as well as inhibition of mTORC1 led to altered circadian rhythms in mouse muscle. Inhibition of liver mTORC1 by leucine or rapamycin led to low-amplitude circadian rhythms. In summary, our study shows that leucine inhibits liver mTORC1 pathway leading to dampened circadian rhythms. REV-ERBα activates the mTORC1 pathway, leading to phosphorylation of the clock protein BMAL1.
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Affiliation(s)
- Maayan Dadon-Freiberg
- Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
| | - Nava Chapnik
- Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
| | - Oren Froy
- Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel.
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IN-SEASON REHABILITATION PROGRAM USING BLOOD FLOW RESTRICTION THERAPY FOR TWO DECATHLETES WITH PATELLAR TENDINOPATHY: A CASE REPORT. Int J Sports Phys Ther 2020; 15:1184-1195. [PMID: 33344034 DOI: 10.26603/ijspt20201184] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Background and Purpose Patellar tendinopathy is an overuse injury experienced primarily by athletes; especially athletes who participate in sports that involve frequent jumping. Therapeutic exercise is the primary conservative treatment for patients with this condition. However, some patients with patellar tendinopathy may be unable to tolerate the loading that occurs during exercise. The use of blood flow restriction (BFR) therapy for patients with patellar tendinopathy may allow the athlete to exercise with a lower load while still experiencing the physiological benefits associated with training at a higher intensity. The purpose of this case report was to detail the outcomes from a rehabilitation program utilizing BFR for two collegiate decathletes with patellar tendinopathy. Study Design Case ReportCase Descriptions and Interventions: Two NCAA Division III freshmen collegiate decathletes with a history of left knee pain prior to college and who had been complaining of increasing pain during the initial month of track practices. Findings from the musculoskeletal examinations included left sided lower extremity weakness, pain during functional testing, pain when palpating the left patellar tendon, and VISA-P scores less than 80. Ultrasound imaging at baseline revealed thickened tendons on the left with hypoechoic regions. Both athletes participated in 20 therapy sessions consisting of therapeutic exercises performed with BFR. Outcomes Both athletes experienced improvements in pain scores, increases in lower extremity strength, improved functional test performance, higher VISA-P scores, and improvements in tendon size and appearance as measured by diagnostic ultrasound. Conclusion Both athletes experienced improvements with the BFR-based therapeutic exercise program and were able to compete throughout the track season. The use of BFR may allow patients who are unable to tolerate exercise due to pain an alternative approach during rehabilitation. Future research should compare therapeutic exercise programs for this condition with and without BFR. Level of Evidence Level V.
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Humes C, Aguero S, Chahla J, Foad A. Blood Flow Restriction and Its Function in Post-Operative Anterior Cruciate Ligament Reconstruction Therapy: Expert Opinion. THE ARCHIVES OF BONE AND JOINT SURGERY 2020; 8:570-574. [PMID: 33088857 DOI: 10.22038/abjs.2020.42068.2145] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
An increasingly popular method for post-operative rehabilitation of an ACL reconstruction, as a substitute for traditional therapy, is blood flow restriction therapy (BFR). BFR therapy utilizes a pneumatic cuff to simulate strenuous exercise in an effort to stimulate muscle recruitment, mitigate atrophy, and promote hypertrophy in patients with load-bearing limitations. Because this is a relatively new form of therapy, there is a lack of established literature and protocol that is preventing widespread use of the therapy. This article will seek to confirm the value and validity of the utilization of BFR therapy. In order to validate the utilization of BFR, an evaluation of the science underlying BFR will be discussed as well as the technique and exercises preformed during therapy. Furthermore, analysis of other BFR literature will be utilized to lend further credence to the obtained conclusions. Based on the literature, BFR therapy mitigates atrophy through type II muscle recruitment while also stimulating hypertrophy in patients, supporting its use post-operatively. Moreover, positive results from BFR case series also lend credence to its value as a substitute for traditional therapy in patients who have weight-bearing limitations, specifically those who are recovering from anterior cruciate ligament reconstructions.
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Rolnick N, Schoenfeld BJ. Can Blood Flow Restriction Used During Aerobic Training Enhance Body Composition in Physique Athletes? Strength Cond J 2020. [DOI: 10.1519/ssc.0000000000000585] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Liegnell R, Apró W, Danielsson S, Ekblom B, van Hall G, Holmberg HC, Moberg M. Elevated plasma lactate levels via exogenous lactate infusion do not alter resistance exercise-induced signaling or protein synthesis in human skeletal muscle. Am J Physiol Endocrinol Metab 2020; 319:E792-E804. [PMID: 32830552 DOI: 10.1152/ajpendo.00291.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Lactate has been implicated as a potential signaling molecule. In myotubes, lactate incubation increases mechanistic target of rapamycin complex 1 (mTORC1)- and ERK-signaling and induces hypertrophy, indicating that lactate could be a mediator of muscle adaptations to resistance exercise. However, the potential signaling properties of lactate, at rest or with exercise, have not been explored in human tissue. In a crossover design study, 8 men and 8 women performed one-legged resistance exercise while receiving venous infusion of saline or sodium lactate. Blood was sampled repeatedly, and muscle biopsies were collected at rest and at 0, 90, and 180 min and 24 h after exercise. The primary outcomes examined were intracellular signaling, fractional protein synthesis rate (FSR), and blood/muscle levels of lactate and pH. Postexercise blood lactate concentrations were 130% higher in the Lactate trial (3.0 vs. 7.0 mmol/L, P < 0.001), whereas muscle levels were only marginally higher (27 vs. 32 mmol/kg dry wt, P = 0.003) compared with the Saline trial. Postexercise blood pH was higher in the Lactate trial (7.34 vs. 7.44, P < 0.001), with no differences in intramuscular pH. Exercise increased the phosphorylation of mTORS2448 (∼40%), S6K1T389 (∼3-fold), and p44T202/T204 (∼80%) during recovery, without any differences between trials. FSR over the 24-h recovery period did not differ between the Saline (0.067%/h) and Lactate (0.062%/h) trials. This study does not support the hypothesis that blood lactate levels can modulate anabolic signaling in contracted human muscle. Further in vivo research investigating the impact of exercised versus rested muscle and the role of intramuscular lactate is needed to elucidate its potential signaling properties.
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Affiliation(s)
- Rasmus Liegnell
- Department of Physiology, Nutrition and Biomechaniscs, Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - William Apró
- Department of Physiology, Nutrition and Biomechaniscs, Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Sebastian Danielsson
- Department of Physiology, Nutrition and Biomechaniscs, Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Björn Ekblom
- Department of Physiology, Nutrition and Biomechaniscs, Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Gerrit van Hall
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
- Clinical Metabolomics Core Facility, Clinical Biochemistry, Rigshospitalet, Copenhagen, Denmark
| | - Hans-Christer Holmberg
- Swedish Winter Sports Research Centre, Department of Health Sciences, Mid Sweden University, Östersund, Sweden
- Department of Physiology and Pharmacology, Biomedicum C5, Karolinska Institute, Stockholm, Sweden
| | - Marcus Moberg
- Department of Physiology, Nutrition and Biomechaniscs, Swedish School of Sport and Health Sciences, Stockholm, Sweden
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Rolnick N, Schoenfeld BJ. Blood Flow Restriction Training and the Physique Athlete: A Practical Research-Based Guide to Maximizing Muscle Size. Strength Cond J 2020. [DOI: 10.1519/ssc.0000000000000553] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Da Silva-Grigoletto ME, Neto EP, Behm DG, Loenneke JP, La Scala Teixeira CV. Functional Training and Blood Flow Restriction: A Perspective View on the Integration of Techniques. Front Physiol 2020; 11:817. [PMID: 32848818 PMCID: PMC7412632 DOI: 10.3389/fphys.2020.00817] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 06/18/2020] [Indexed: 11/13/2022] Open
Affiliation(s)
- Marzo E. Da Silva-Grigoletto
- Functional Training Group, Federal University of Sergipe, Aracajú, Brazil
- *Correspondence: Marzo E. Da Silva-Grigoletto
| | | | - David George Behm
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Jeremy P. Loenneke
- Department of Health, Exercise Science, and Recreation Management, University of Mississippi, Oxford, MS, United States
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Bodine SC. Edward F. Adolph Distinguished Lecture. Skeletal muscle atrophy: Multiple pathways leading to a common outcome. J Appl Physiol (1985) 2020; 129:272-282. [PMID: 32644910 DOI: 10.1152/japplphysiol.00381.2020] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Skeletal muscle atrophy continues to be a serious consequence of many diseases and conditions for which there is no treatment. Our understanding of the mechanisms regulating skeletal muscle mass has improved considerably over the past two decades. For many years it was known that skeletal muscle atrophy resulted from an imbalance between protein synthesis and protein breakdown, with the net balance shifting toward protein breakdown. However, the molecular and cellular mechanisms underlying the increased breakdown of myofibrils was unknown. Over the past two decades, numerous reports have identified novel genes and signaling pathways that are upregulated and activated in response to stimuli such as disuse, inflammation, metabolic stress, starvation and others that induce muscle atrophy. This review summarizes the discovery efforts performed in the identification of several pathways involved in the regulation of skeletal muscle mass: the mammalian target of rapamycin (mTORC1) and the ubiquitin proteasome pathway and the E3 ligases, MuRF1 and MAFbx. While muscle atrophy is a common outcome of many diseases, it is doubtful that a single gene or pathway initiates or mediates the breakdown of myofibrils. Interestingly, however, is the observation that upregulation of the E3 ligases, MuRF1 and MAFbx, is a common feature of many divergent atrophy conditions. The challenge for the field of muscle biology is to understand how all of the various molecules, transcription factors, and signaling pathways interact to produce muscle atrophy and to identify the critical factors for intervention.
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Affiliation(s)
- Sue C Bodine
- Department of Internal Medicine/Endocrinology and Metabolism, University of Iowa Carver College of Medicine, Iowa City, Iowa
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39
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Gorgey AS, Graham ZA, Chen Q, Rivers J, Adler RA, Lesnefsky EJ, Cardozo CP. Sixteen weeks of testosterone with or without evoked resistance training on protein expression, fiber hypertrophy and mitochondrial health after spinal cord injury. J Appl Physiol (1985) 2020; 128:1487-1496. [PMID: 32352341 DOI: 10.1152/japplphysiol.00865.2019] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
We investigated the effects of testosterone replacement therapy (TRT) with and without evoked resistance training (RT) on protein expression of key metabolic and hypertrophy regulators, muscle fiber cross-sectional area (CSA), and markers of mitochondrial health after spinal cord injury (SCI). Twenty-two men with chronic motor complete SCI were randomly assigned to either TRT + RT (n = 11) or TRT (n = 11) for 16 wk. TRT + RT men underwent twice weekly progressive RT using electrical stimulation with ankle weights. TRT was administered via testosterone patches (2-6 mg/day). Muscle biopsies were obtained before and after 16 wk from the right vastus lateralis. Expression of proteins associated with oxidative muscles and mechanical loading (PGC-1α and FAK), muscle hypertrophy (total and phosphorylated Akt, total and phosphorylated mTOR), and cellular metabolism (total and phosphorylated AMPK and GLUT4) were evaluated. Immunohistochemistry analysis was performed to measure fiber CSA and succinate dehydrogenase (SDH) activity as well as mitochondrial citrate synthase (CS) activity and complex III (CIII) activities. TRT + RT demonstrated a robust 27.5% increase in average fiber CSA compared with a -9% decrease following TRT only (P = 0.01). GLUT4 protein expression was elevated in the TRT + RT group compared with TRT only (P = 0.005). Total Akt (P = 0.06) and phosphorylated Akt Ser389 (P = 0.049) were also elevated in the TRT + RT group. Mitochondrial activity of SDH (P = 0.03) and CS (P = 0.006) increased in the TRT + RT group, with no changes in the TRT-only group. Sixteen weeks of TRT with RT resulted in fiber hypertrophy and beneficial changes in markers of skeletal muscle health and function.NEW & NOTEWORTHY Fiber cross-sectional area (CSA), protein expression, mitochondrial citrate synthase (CS), and succinate dehydrogenase (SDH) were measured following 16 wk of low-dose testosterone replacement therapy (TRT) with and without electrically evoked resistance training (RT) in men with spinal cord injury (SCI). Fiber CSA and protein expression of total GLUT4, total Akt, and phosphorylated Akt increased following TRT + RT but not in the TRT-only group. Mitochondrial CS and SDH increased after TRT + RT but not in TRT-only group.
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Affiliation(s)
- Ashraf S Gorgey
- Spinal Cord Injury and Disorders Center, Hunter Holmes McGuire Veterans Affairs Medical Center, Richmond, Virginia.,Virginia Commonwealth University, Department of Physical Medicine and Rehabilitation, Richmond, Virginia
| | - Zachary A Graham
- Birmingham Veterans Affairs Medical Center, Birmingham, Alabama.,Department of Cell, Developmental, and Integrative Biology, University of Alabama-Birmingham, Birmingham, Alabama
| | - Qun Chen
- Medical Service, Hunter Holmes McGuire Veterans Affairs Medical Center, Richmond, Virginia.,Division of Cardiology, Department of Internal Medicine, Pauley Heart Center Virginia Commonwealth University, Richmond, Virginia
| | - Jeannie Rivers
- Surgery Service, Hunter Holmes McGuire Veterans Affairs Medical Center, Richmond, Virginia
| | - Robert A Adler
- Endocrinology Service, Hunter Holmes McGuire Veterans Affairs Medical Center, Richmond, Virginia.,Endocrine Division, Virginia Commonwealth University School of Medicine¸ Richmond, Virginia
| | - Edward J Lesnefsky
- Medical Service, Hunter Holmes McGuire Veterans Affairs Medical Center, Richmond, Virginia.,Division of Cardiology, Department of Internal Medicine, Pauley Heart Center Virginia Commonwealth University, Richmond, Virginia
| | - Christopher P Cardozo
- Center for the Medical Consequences of Spinal Cord Injury, James J. Peters Veterans Affairs Medical Center, Bronx, New York.,Icahn School of Medicine at Mt. Sinai, New York, New York
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40
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Khoubi M, Habibi A, Ghanbarzadeh M, Shakerian S, Mirzaii B. Acute interval waking with blood flow restriction could not increase ERK, p38 and decrease myostatin. J Sports Med Phys Fitness 2020; 60:32-36. [PMID: 32008310 DOI: 10.23736/s0022-4707.18.09200-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND There is mounting evidence that moderate to high intensity exercise training has a key role in skeletal muscle adaption. Blood flow restriction (BFR) low intensity exercise training associated with unique effect on muscle hypertrophy. The purpose of the study was to investigate of effect of acute interval walking with blood flow restriction on phosphorylation of 4EBP1, P38, ERK and myostatin (MSTN) of skeletal muscle in inactive men. METHODS Five healthy inactive men were participated in 2 sessions with 14 days interspersed. Session one was including BFR by 5 intervals 3-min walking at 55%Maximum heart rate (MHR) and 1 min at rest. Session two was including 5 intervals 3-min walking at 55% MHRand 1 min at rest without BFR. All samples were collected at 30 min and 3 h after exercise test. Concentration of P38, ERK and MSTN skeletal muscle were evaluated by Western blotting. Dependent t-test and Independent t-test was used to analyze the data after subtracting the post-test score from the pre-test. However, there was a significant difference between the pre and post-test for 4EBP1 (P=0.001) and ERK (P=0.049) in the blood flow restriction group. RESULTS There was no significant difference between pre and post-test of P38 (P=0/452). Significant difference was observed for ERK (P=0.012) in acute interval walking (P=0.049). There was no significant difference between pre and post-test of 4EBP1 (P=0.064) and P38 (P=0/122). No significant difference was found between two group for concentration of 4EBP1 (P=0.068), P38 (P-0.091) and ERK (P=0.827), (P≥0.05). CONCLUSIONS This study has shown that acute interval walking with blood flow restriction does not activate MAPK pathway signaling in inactive men.
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Affiliation(s)
- Mehdi Khoubi
- Department of Exercise Physiology, Faculty of Sport Sciences, Shahid Chamran University of Ahvaz, Ahvaz, Iran -
| | - Abdolhamid Habibi
- Department of Exercise Physiology, Faculty of Sport Sciences, Shahid Chamran University of Ahvaz, Ahvaz, Iran
| | - Mohsen Ghanbarzadeh
- Department of Exercise Physiology, Faculty of Sport Sciences, Shahid Chamran University of Ahvaz, Ahvaz, Iran
| | - Saeed Shakerian
- Department of Exercise Physiology, Faculty of Sport Sciences, Shahid Chamran University of Ahvaz-Iran, Ahvaz, Iran
| | - Bahman Mirzaii
- Department of Physiology, University of Gilan, Rasht, Iran
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41
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Pignanelli C, Petrick HL, Keyvani F, Heigenhauser GJF, Quadrilatero J, Holloway GP, Burr JF. Low-load resistance training to task failure with and without blood flow restriction: muscular functional and structural adaptations. Am J Physiol Regul Integr Comp Physiol 2020; 318:R284-R295. [PMID: 31823670 DOI: 10.1152/ajpregu.00243.2019] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The application of blood flow restriction (BFR) during resistance exercise is increasingly recognized for its ability to improve rehabilitation and for its effectiveness in increasing muscle hypertrophy and strength among healthy populations. However, direct comparison of the skeletal muscle adaptations to low-load resistance exercise (LL-RE) and low-load BFR resistance exercise (LL-BFR) performed to task failure is lacking. Using a within-subject design, we examined whole muscle group and skeletal muscle adaptations to 6 wk of LL-RE and LL-BFR training to repetition failure. Muscle strength and size outcomes were similar for both types of training, despite ~33% lower total exercise volume (load × repetition) with LL-BFR than LL-RE (28,544 ± 1,771 vs. 18,949 ± 1,541 kg, P = 0.004). After training, only LL-BFR improved the average power output throughout the midportion of a voluntary muscle endurance task. Specifically, LL-BFR training sustained an 18% greater power output from baseline and resulted in a greater change from baseline than LL-RE (19 ± 3 vs. 3 ± 4 W, P = 0.008). This improvement occurred despite histological analysis revealing similar increases in capillary content of type I muscle fibers following LL-RE and LL-BFR training, which was primarily driven by increased capillary contacts (4.53 ± 0.23 before training vs. 5.33 ± 0.27 and 5.17 ± 0.25 after LL-RE and LL-BFR, respectively, both P < 0.05). Moreover, maximally supported mitochondrial respiratory capacity increased only in the LL-RE leg by 30% from baseline (P = 0.006). Overall, low-load resistance training increased indexes of muscle oxidative capacity and strength, which were not further augmented with the application of BFR. However, performance on a muscle endurance test was improved following BFR training.
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Affiliation(s)
- Christopher Pignanelli
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Heather L Petrick
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Fatemeh Keyvani
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | | | - Joe Quadrilatero
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Graham P Holloway
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Jamie F Burr
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
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42
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Nyakayiru J, Fuchs CJ, Trommelen J, Smeets JSJ, Senden JM, Gijsen AP, Zorenc AH, VAN Loon LJC, Verdijk LB. Blood Flow Restriction Only Increases Myofibrillar Protein Synthesis with Exercise. Med Sci Sports Exerc 2019; 51:1137-1145. [PMID: 30694972 PMCID: PMC6553970 DOI: 10.1249/mss.0000000000001899] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Supplemental digital content is available in the text. Purpose Combining blood flow restriction (BFR) with exercise can stimulate skeletal muscle hypertrophy. Recent observations in an animal model suggest that BFR performed without exercise can also induce anabolic effects. We assessed the effect of BFR performed both with and without low-load resistance-type exercise (LLRE) on in vivo myofibrillar protein synthesis rates in young men. Methods Twenty healthy young men (age = 24 ± 1 yr, body mass index = 22.9 ± 0.6 kg·m−2) were randomly assigned to remain in resting condition (REST ± BFR; n = 10) or to perform LLRE (LLRE ± BFR at 20% one-repetition maximum; n = 10), combined with two 5-min cycles of single leg BFR. Myofibrillar protein synthesis rates were assessed during a 5-h post-BFR period by combining a primed continuous L-[ring-13C6]phenylalanine infusion with the collection of blood samples, and muscle biopsies from the BFR leg and the contralateral control leg. The phosphorylation status of anabolic signaling (mammalian target of rapamycin pathway) and metabolic stress (acetyl-CoA carboxylase)–related proteins, as well as the mRNA expression of genes associated with skeletal muscle mass regulation, was assessed in the collected muscle samples. Results Under resting conditions, no differences in anabolic signaling or myofibrillar protein synthesis rates were observed between REST + BFR and REST (0.044% ± 0.004% vs 0.043% ± 0.004% per hour, respectively; P = 0.683). By contrast, LLRE + BFR increased myofibrillar protein synthesis rates by 10% ± 5% compared with LLRE (0.048% ± 0.005% vs 0.043% ± 0.004% per hour, respectively; P = 0.042). Furthermore, compared with LLRE, LLRE + BFR showed higher phosphorylation status of acetyl-CoA carboxylase and 4E-BP1 as well as the elevated mRNA expression of MuRF1 (all P < 0.05). Conclusion BFR does not increase myofibrillar protein synthesis rates in healthy young men under resting conditions. When combined with LLRE, BFR increases postexercise myofibrillar protein synthesis rates in vivo in humans.
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Affiliation(s)
- Jean Nyakayiru
- NUTRIM, School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, THE NETHERLANDS
| | - Cas J Fuchs
- NUTRIM, School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, THE NETHERLANDS
| | - Jorn Trommelen
- NUTRIM, School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, THE NETHERLANDS
| | - Joey S J Smeets
- NUTRIM, School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, THE NETHERLANDS
| | - Joan M Senden
- NUTRIM, School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, THE NETHERLANDS
| | - Annemie P Gijsen
- NUTRIM, School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, THE NETHERLANDS
| | - Antoine H Zorenc
- NUTRIM, School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, THE NETHERLANDS
| | - Luc J C VAN Loon
- NUTRIM, School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, THE NETHERLANDS.,Institute of Sports and Exercise Studies, HAN University of Applied Sciences, Nijmegen, THE NETHERLANDS
| | - Lex B Verdijk
- NUTRIM, School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, THE NETHERLANDS
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43
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Anderson AB, Owens JG, Patterson SD, Dickens JF, LeClere LE. Blood Flow Restriction Therapy: From Development to Applications. Sports Med Arthrosc Rev 2019; 27:119-123. [PMID: 31361722 DOI: 10.1097/jsa.0000000000000240] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Blood flow restriction (BFR) has been shown to produce beneficial adaptations to skeletal muscle. These adaptations have been documented in the civilian and military populations. BFR therapy may provide patients a safe method to begin strength training at earlier stages of rehabilitation to allow for earlier and more effective return to activity and improved military readiness. The purpose was to review BFR therapy physiology, complications, side effects, standardized treatment algorithms, and long-term patient outcomes.
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Affiliation(s)
- Ashley B Anderson
- Walter Reed National Military Medical Center.,Uniformed Services University of the Health Sciences, Bethesda
| | | | | | - Jonathan F Dickens
- Walter Reed National Military Medical Center.,Uniformed Services University of the Health Sciences, Bethesda.,John A. Feagin Jr. Sports Medicine Fellowship, West Point, NY
| | - Lance E LeClere
- Uniformed Services University of the Health Sciences, Bethesda.,United States Naval Academy, Annapolis, MD
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44
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Wong V, Abe T, Chatakondi RN, Bell ZW, Spitz RW, Dankel SJ, Loenneke JP. The influence of biological sex and cuff width on muscle swelling, echo intensity, and the fatigue response to blood flow restricted exercise. J Sports Sci 2019; 37:1865-1873. [PMID: 30945606 DOI: 10.1080/02640414.2019.1599316] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The purpose was to determine if the muscle swelling, echo intensity, and fatigue responses to blood flow restriction differs based on cuff width (Experiment 1), applied pressure (Experiment 2), and sex. Ultrasound of muscle was taken before and after exercise. In Experiment 1 (n = 96), men swelled more than women and more with a narrow cuff than a wide cuff (0.60 cm vs. 0.52 cm). Expressed as a percentage change, there were no longer differences between cuffs (Narrow: 15% vs. Wide: 14%) or sex (Men: 14% vs. Women: 15%). Echo intensity remained unchanged. Women required more repetitions to reach task failure in sets 2, 3, and 4. In Experiment 2 (n = 87), men swelled more than women (Men: 0.46 cm vs. Women: 0.31 cm). Expressed as a percentage change, there were no differences. Echo intensity decreased in both conditions and to a greater extent with a higher applied pressure. If the acute muscle swelling response is important for initiating long term adaptation, then our results indicate that neither cuff width, sex, nor applied pressure will differentially impact the adaptation observed via this mechanism. Changes in echo intensity were inconsistent and the utility of this measurement may need to be reconsidered.
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Affiliation(s)
- Vickie Wong
- a Department of Health, Exercise Science, and Recreation Management, Kevser Ermin Applied Physiology Laboratory , The University of Mississippi , University , MS , USA
| | - Takashi Abe
- a Department of Health, Exercise Science, and Recreation Management, Kevser Ermin Applied Physiology Laboratory , The University of Mississippi , University , MS , USA
| | - Raksha N Chatakondi
- a Department of Health, Exercise Science, and Recreation Management, Kevser Ermin Applied Physiology Laboratory , The University of Mississippi , University , MS , USA
| | - Zachary W Bell
- a Department of Health, Exercise Science, and Recreation Management, Kevser Ermin Applied Physiology Laboratory , The University of Mississippi , University , MS , USA
| | - Robert W Spitz
- a Department of Health, Exercise Science, and Recreation Management, Kevser Ermin Applied Physiology Laboratory , The University of Mississippi , University , MS , USA
| | - Scott J Dankel
- a Department of Health, Exercise Science, and Recreation Management, Kevser Ermin Applied Physiology Laboratory , The University of Mississippi , University , MS , USA
| | - Jeremy P Loenneke
- a Department of Health, Exercise Science, and Recreation Management, Kevser Ermin Applied Physiology Laboratory , The University of Mississippi , University , MS , USA
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45
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Haun CT, Vann CG, Mobley CB, Osburn SC, Mumford PW, Roberson PA, Romero MA, Fox CD, Parry HA, Kavazis AN, Moon JR, Young KC, Roberts MD. Pre-training Skeletal Muscle Fiber Size and Predominant Fiber Type Best Predict Hypertrophic Responses to 6 Weeks of Resistance Training in Previously Trained Young Men. Front Physiol 2019; 10:297. [PMID: 30971942 PMCID: PMC6445136 DOI: 10.3389/fphys.2019.00297] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 03/06/2019] [Indexed: 12/24/2022] Open
Abstract
Limited evidence exists regarding differentially expressed biomarkers between previously-trained low versus high hypertrophic responders in response to resistance training. Herein, 30 college-aged males (training age 5 ± 3 years; mean ± SD) partook in 6 weeks of high-volume resistance training. Body composition, right leg vastus lateralis (VL) biopsies, and blood were obtained prior to training (PRE) and at the 3-week (W3) and 6-week time points (W6). The 10 lowest (LOW) and 10 highest (HIGH) hypertrophic responders were clustered based upon a composite hypertrophy score of PRE-to-W6 changes in right leg VL mean muscle fiber cross-sectional area (fCSA), VL thickness assessed via ultrasound, upper right leg lean soft tissue mass assessed via dual x-ray absorptiometry (DXA), and mid-thigh circumference. Two-way ANOVAs were used to compare biomarker differences between the LOW and HIGH clusters over time, and stepwise linear regression was performed to elucidate biomarkers that explained significant variation in the composite hypertrophy score from PRE to W3, W3 to W6, and PRE to W6 in all 30 participants. PRE-to-W6 HIGH and LOW responders exhibited a composite hypertrophy change of +10.7 ± 3.2 and -2.1 ± 1.6%, respectively (p < 0.001). Compared to HIGH responders, LOW responders exhibited greater PRE type II fCSA (+18%, p = 0.022). Time effects (p < 0.05) existed for total RNA/mg muscle (W6 > W3 > PRE), phospho (p)-4EBP1 (PRE > W3&W6), pan-mTOR (PRE > W3 < W6), p-mTOR (PRE > W3 < W6), pan-AMPKα (PRE > W3 < W6), pan-p70s6k (PRE > W3), muscle ubiquitin-labeled proteins (PRE > W6), mechano growth factor mRNA (W6 > W3&PRE), 45S rRNA (PRE > W6), and muscle citrate synthase activity (PRE > W3&W6). No interactions existed for the aforementioned biomarkers and/or other assayed targets (muscle 20S proteasome activity, serum total testosterone, muscle androgen receptor protein levels, muscle glycogen, or serum creatine kinase). Regression analysis indicated PRE type II fiber percentage (R2 = 0.152, β = 0.390, p = 0.033) and PRE type II fCSA (R2 = 0.207, β = -0.455, p = 0.019) best predicted the PRE-to-W6 change in the composite hypertrophy score. While our sample size is limited, these data suggest: (a) HIGH responders may exhibit more growth potential given that they possessed lower PRE type II fCSA values and (b) possessing a greater type II fiber percentage as a trained individual may be advantageous for hypertrophy in response to resistance training.
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Affiliation(s)
- Cody T Haun
- School of Kinesiology, Auburn University, Auburn, AL, United States.,Department of Exercise Science, LaGrange College, LaGrange, GA, United States
| | | | - C Brooks Mobley
- School of Kinesiology, Auburn University, Auburn, AL, United States
| | - Shelby C Osburn
- School of Kinesiology, Auburn University, Auburn, AL, United States
| | - Petey W Mumford
- School of Kinesiology, Auburn University, Auburn, AL, United States
| | - Paul A Roberson
- School of Kinesiology, Auburn University, Auburn, AL, United States
| | - Matthew A Romero
- School of Kinesiology, Auburn University, Auburn, AL, United States
| | - Carlton D Fox
- School of Kinesiology, Auburn University, Auburn, AL, United States
| | - Hailey A Parry
- School of Kinesiology, Auburn University, Auburn, AL, United States
| | | | | | - Kaelin C Young
- School of Kinesiology, Auburn University, Auburn, AL, United States.,Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine - Auburn Campus, Auburn, AL, United States
| | - Michael D Roberts
- School of Kinesiology, Auburn University, Auburn, AL, United States.,Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine - Auburn Campus, Auburn, AL, United States
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46
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Bjørnsen T, Wernbom M, Løvstad A, Paulsen G, D’Souza RF, Cameron-Smith D, Flesche A, Hisdal J, Berntsen S, Raastad T. Delayed myonuclear addition, myofiber hypertrophy, and increases in strength with high-frequency low-load blood flow restricted training to volitional failure. J Appl Physiol (1985) 2019; 126:578-592. [DOI: 10.1152/japplphysiol.00397.2018] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The purpose of the present study was to investigate muscle hypertrophy, strength, and myonuclear and satellite cell (SC) responses to high-frequency blood flow-restricted resistance exercise (BFRRE). Thirteen individuals [24 ± 2 yr (mean ± SD), 9 men] completed two 5-day blocks of 7 BFRRE sessions, separated by a 10-day rest period. Four sets of unilateral knee extensions to voluntary failure at 20% of one repetition maximum (1RM) were conducted with partial blood flow restriction (90–100 mmHg). Muscle samples obtained before, during, 3 days, and 10 days after training were analyzed for muscle fiber area (MFA), myonuclei, SC, and mRNA and miRNA expression. Muscle size was measured by ultrasonography and magnetic resonance imaging and strength with 1RM knee extension. With the first block of BFRRE, SC number increased in both fiber types (70%–80%, P < 0.05), whereas type I and II MFA decreased by 6 ± 7% and 15 ± 11% ( P < 0.05), respectively. With the second block of training, muscle size increased by 6%–8%, whereas the number of SCs (type I: 80 ± 63%, type II: 147 ± 95%), myonuclei (type I: 30 ± 24%, type II: 31 ± 28%), and MFA (type I: 19 ± 19%, type II: 11 ± 19%) peaked 10 days after the second block of BFRRE, whereas strength peaked after 20 days of detraining (6 ± 6%, P < 0.05). Pax7- and p21 mRNA expression were elevated during the intervention, whereas myostatin, IGF1R, MyoD, myogenin, cyclinD1 and -D2 mRNA did not change until 3–10 days postintervention. High-frequency low-load BFRRE induced robust increases in SC, myonuclei, and muscle size but modest strength gains. Intriguingly, the responses were delayed and peaked 10–20 days after the training intervention, indicating overreaching. NEW & NOTEWORTHY In line with previous studies, we demonstrate that high-frequency low-load blood flow-restricted resistance exercise (HF-BFRRE) can elicit robust increases in satellite cell and myonuclei numbers, along with gains in muscle size and strength. However, our results also suggest that these processes can be delayed and that with very strenuous HF-BFRRE, there may even be transient muscle fiber atrophy, presumably because of accumulated stress responses. Our findings have implications for the prescription of BFR exercise.
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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
- Department of Food and Nutrition, and Sport Science, University of Gothenburg, Sweden
- Department of Health and Rehabilitation, Unit of Physiotherapy, Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden
| | - Amund Løvstad
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
| | | | | | - David Cameron-Smith
- Liggins Institute, University of Auckland, New Zealand
- Food & Bio-based Products Group, AgResearch, Palmerston North, New Zealand
- Riddet Institute, Palmerston North, New Zealand
| | - Alexander Flesche
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
| | - Jonny Hisdal
- Department of Vascular Surgery, Oslo University Hospital, Oslo, Norway
| | - 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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You JS, McNally RM, Jacobs BL, Privett RE, Gundermann DM, Lin KH, Steinert ND, Goodman CA, Hornberger TA. The role of raptor in the mechanical load-induced regulation of mTOR signaling, protein synthesis, and skeletal muscle hypertrophy. FASEB J 2019; 33:4021-4034. [PMID: 30509128 PMCID: PMC6404572 DOI: 10.1096/fj.201801653rr] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 11/05/2018] [Indexed: 12/21/2022]
Abstract
It is well known that an increase in mechanical loading can induce skeletal muscle hypertrophy, and a long standing model in the field indicates that mechanical loads induce hypertrophy via a mechanism that requires signaling through the mechanistic target of rapamycin complex 1 (mTORC1). Specifically, it has been widely proposed that mechanical loads activate signaling through mTORC1 and that this, in turn, promotes an increase in the rate of protein synthesis and the subsequent hypertrophic response. However, this model is based on a number of important assumptions that have not been rigorously tested. In this study, we created skeletal muscle specific and inducible raptor knockout mice to eliminate signaling by mTORC1, and with these mice we were able to directly demonstrate that mechanical stimuli can activate signaling by mTORC1, and that mTORC1 is necessary for mechanical load-induced hypertrophy. Surprisingly, however, we also obtained multiple lines of evidence that indicate that mTORC1 is not required for a mechanical load-induced increase in the rate of protein synthesis. This observation highlights an important shortcoming in our understanding of how mechanical loads induce hypertrophy and illustrates that additional mTORC1-independent mechanisms play a critical role in this process.-You, J.-S., McNally, R. M., Jacobs, B. L., Privett, R. E., Gundermann, D. M., Lin, K.-H., Steinert, N. D., Goodman, C. A., Hornberger, T. A. The role of raptor in the mechanical load-induced regulation of mTOR signaling, protein synthesis, and skeletal muscle hypertrophy.
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Affiliation(s)
- Jae-Sung You
- Department of Comparative Biosciences, University of Wisconsin–Madison, Madison, Wisconsin, USA
- School of Veterinary Medicine, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Rachel M. McNally
- Department of Comparative Biosciences, University of Wisconsin–Madison, Madison, Wisconsin, USA
- School of Veterinary Medicine, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Brittany L. Jacobs
- Department of Comparative Biosciences, University of Wisconsin–Madison, Madison, Wisconsin, USA
- School of Veterinary Medicine, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Rachel E. Privett
- Department of Comparative Biosciences, University of Wisconsin–Madison, Madison, Wisconsin, USA
- School of Veterinary Medicine, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - David M. Gundermann
- Department of Comparative Biosciences, University of Wisconsin–Madison, Madison, Wisconsin, USA
- School of Veterinary Medicine, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Kuan-Hung Lin
- Department of Comparative Biosciences, University of Wisconsin–Madison, Madison, Wisconsin, USA
- School of Veterinary Medicine, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Nate D. Steinert
- Department of Comparative Biosciences, University of Wisconsin–Madison, Madison, Wisconsin, USA
- School of Veterinary Medicine, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Craig A. Goodman
- Department of Comparative Biosciences, University of Wisconsin–Madison, Madison, Wisconsin, USA
- School of Veterinary Medicine, University of Wisconsin–Madison, Madison, Wisconsin, USA
- Institute of Health and Sport, Victoria University, Melbourne, Victoria, Australia
- Australian Institute for Musculoskeletal Science, Victoria University, St. Albans, Victoria, Australia
| | - Troy A. Hornberger
- Department of Comparative Biosciences, University of Wisconsin–Madison, Madison, Wisconsin, USA
- School of Veterinary Medicine, University of Wisconsin–Madison, Madison, Wisconsin, USA
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Goodman CA. Role of mTORC1 in mechanically induced increases in translation and skeletal muscle mass. J Appl Physiol (1985) 2019; 127:581-590. [PMID: 30676865 DOI: 10.1152/japplphysiol.01011.2018] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Skeletal muscle mass is, in part, regulated by the rate of mRNA translation (i.e., protein synthesis). The conserved serine/threonine kinase, mTOR (the mammalian/mechanistic target of rapamycin), found in the multiprotein complex, mTOR complex 1 (mTORC1), is a major positive regulator of protein synthesis. The purpose of this review is to describe some of the critical steps in translation initiation, mTORC1 and its potential direct and indirect roles in regulating translation, and evidence that mTORC1 regulates protein synthesis and muscle mass, with a particular focus on basal conditions and the response to mechanical stimuli. Current evidence suggests that for acute contraction models of mechanical stimuli, there is an emerging pattern suggesting that there is an early increase in protein synthesis governed by a rapamycin-sensitive mTORC1-dependent mechanism, while at later poststimulation time points, the mechanism may change to a rapamycin-insensitive mTORC1-dependent or even an mTORC1-independent mechanism. Furthermore, evidence suggests that mTORC1 appears to be absolutely necessary for muscle fiber hypertrophy induced by chronic mechanical loading but may only play a partial role in the hypertrophy induced by more intermittent types of acute resistance exercise, with the possibility of mTORC1-independent mechanisms also playing a role. Despite the progress that has been made, many questions about the activation of mTORC1, and its downstream targets, remain to be answered. Further research will hopefully provide novel insights into the regulation of skeletal muscle mTORC1 that may eventually be translated into novel exercise programing and/or targeted pharmacological therapies aimed at preventing muscle wasting and/or increasing muscle mass.
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Affiliation(s)
- Craig A Goodman
- Institute of Health and Sport; Victoria University, Melbourne, Australia.,Australian Institute for Musculoskeletal Science (AIMSS), Victoria University, St. Albans, Victoria, Australia
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Blood Flow Restriction Resistance Exercise as a Rehabilitation Modality Following Orthopaedic Surgery: A Review of Venous Thromboembolism Risk. J Orthop Sports Phys Ther 2019; 49:17-27. [PMID: 30208794 DOI: 10.2519/jospt.2019.8375] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Synopsis Restoration of skeletal muscle mass and strength is critical to successful outcomes following orthopaedic surgery. Blood flow restriction (BFR) resistance exercise has emerged as a promising means of augmenting traditional low-intensity physical rehabilitation exercise and has yielded successful outcomes in a wide range of applications. Though BFR is well tolerated and safe for most individuals, patients who have undergone orthopaedic surgery may be an exception, due to their heightened risk for venous thromboembolism (VTE). While the pathogenesis of VTE is multifactorial and specific to the individual, it is commonly described as a combination of blood stasis, endothelial injury, and alterations in the constituents of the blood leading to hypercoagulability. The collective literature suggests that, given the pathogenic mechanisms of VTE, limited use of a wide, partially occluding cuff during resistance exercise should be low risk, and the likelihood that BFR would directly cause a VTE event is remote. Alternatively, it is plausible that BFR may enhance blood flow and promote fibrinolysis. Of greater concern is the individual with pre-existing asymptomatic VTE, which could be dislodged during BFR. However, it is unknown whether the direct risk associated with BFR is greater than the risk accompanying traditional exercise alone. Presently, there are no universally agreed-upon standards indicating which postsurgical orthopaedic patients may perform BFR safely. While excluding all these patients from BFR may be overly cautious, clinicians need to thoroughly screen for VTE signs and symptoms, be cognizant of each patient's risk factors, and use proper equipment and prescription methods prior to initiating BFR. J Orthop Sports Phys Ther 2019;49(1):17-27. Epub 12 Sep 2018. doi:10.2519/jospt.2019.8375.
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Natsume T, Yoshihara T, Naito H. Electromyostimulation with blood flow restriction enhances activation of mTOR and MAPK signaling pathways in rat gastrocnemius muscles. Appl Physiol Nutr Metab 2018; 44:637-644. [PMID: 30398900 DOI: 10.1139/apnm-2018-0384] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Neuromuscular electrical stimulation (NMES) combined with blood flow restriction (BFR) induces muscle hypertrophy. However, cellular mechanisms underlying the muscle hypertrophy induced by NMES combined with BFR remain unclear. We tested the hypothesis that NMES combined with BFR would enhance the mechanistic target of rapamycin (mTOR) and mitogen-activated protein kinase (MAPK) signaling pathways. Age-matched male Wistar rats (6 months old, n = 7 per group) were assigned randomly to control, BFR alone (BFR), NMES alone (NMES), and NMES combined with BFR (NMES/BFR) groups. NMES induced 25 isometric contractions lasting 8 s with 4-s resting periods between contractions in the gastrocnemius muscle. Four sets in total were performed, with 1-min intervals between sets. A latex cuff was placed on the proximal portion of the hind limb and BFR at 200 mm Hg was conducted in 4 sets (each set 5 min) with 1-min rest intervals between sets. Venous blood was collected from the lateral tail vein to determine pH, H+ concentration, and lactate concentration before and immediately after the treatments. Expression levels of proteins related to muscle hypertrophy were determined by Western blot analysis. The application of NMES/BFR promoted muscle fatigue more than NMES alone. NMES/BFR induced greater changes in accumulation of metabolites and increase in gastrocnemius muscle weight. The phosphorylation of mTOR and MAPK signaling-related proteins was also enhanced following NMES/BFR, compared with other conditions. Thus, NMES enhanced the activation of mTOR and MAPK signaling pathways when combined with BFR.
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Affiliation(s)
- Toshiharu Natsume
- a Institute of Health and Sports Science & Medicine, Juntendo University, 1-1 Hirakagakuendai, Inzai, Chiba 270-1695, Japan
| | - Toshinori Yoshihara
- b Graduate School of Health and Sports Science, Juntendo University, 1-1 Hirakagakuendai, Inzai, Chiba 270-1695, Japan
| | - Hisashi Naito
- b Graduate School of Health and Sports Science, Juntendo University, 1-1 Hirakagakuendai, Inzai, Chiba 270-1695, Japan
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