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Kliszczewicz B, Markert CD, Bechke E, Williamson C, Clemons KN, Snarr RL, McKenzie MJ. Acute Effect of Popular High-Intensity Functional Training Exercise on Physiologic Markers of Growth. J Strength Cond Res 2021; 35:1677-1684. [PMID: 30399116 DOI: 10.1519/jsc.0000000000002933] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
ABSTRACT Kliszczewicz, B, Markert, CD, Bechke, E, Williamson, C, Clemons, KN, Snarr, RL, and McKenzie, MJ. Acute effect of popular high-intensity functional training exercise on physiologic markers of growth. J Strength Cond Res 35(6): 1677-1684, 2021-Constantly evolving, high-intensity functional training (HIFT) exercise consists of various modalities, orders, weights, and repetition schemes. High-intensity functional training has gained popularity among the general population, but lacks empirical evidence regarding acute adaptive responses. The purpose of this study was to describe the acute effects of 2 representative bouts of HIFT on physiologic markers of growth. For convenience, the bouts are designated "short" (<5 minutes) and "long" (∼15 minutes), although duration was not the only difference between bouts. Ten apparently healthy men (28.1 ± 5 years) performed 2 HIFT bouts in a randomized crossover design. Blood was collected at 5 time points (Pre, Post, 1, 3, and 6 hours) to examine growth hormone (GH), insulin-like growth factor (IGF-1), insulin-like growth factor binding proteins 1 and 2 (IGFBP-1 and IGFBP-2), and vascular endothelial growth factor (VEGF). Blood lactate concentration ([La]) was analyzed at the Pre and Post time points. A repeated-measures analysis of variance (ANOVA) revealed no trial differences among the markers (IGF-1, IGFBP-1, IGFBP-2, and VEGF) except GH at Post, where the long bout produced a greater effect (p = 0.005). Mean GH levels (pg·ml-1) in the short bout increased from 68.4 to 106.5, and in the long bout, mean GH levels increased from 38.5 to 286.4. The repeated-measures ANOVA revealed a main time effect in GH (p = 0.037), while a post hoc t-test demonstrated elevated GH at 1 hour (p = 0.018) when compared with Pre. No time-dependent change (p > 0.05) was observed in IGF-1, IGFBP-1, IGFBP-2, or VEGF. Mean blood [lactate] increased more than tenfold in both bouts. The findings of this descriptive study suggest that, other than GH, there are no acute differences in markers of skeletal muscle or vascular growth between these 2 specific HIFT bouts.
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Affiliation(s)
- Brian Kliszczewicz
- Department of Exercise Science and Sport Management, Kennesaw State University WellStar College of Health and Human Services, Kennesaw, Georgia
| | - Chad D Markert
- Department of Exercise Physiology, Anderson Conference Center, School of Health Sciences, Winston-Salem State University, Winston-Salem, North Carolina
| | - Emily Bechke
- Department of Exercise Science and Sport Management, Kennesaw State University WellStar College of Health and Human Services, Kennesaw, Georgia
| | - Cassie Williamson
- Department of Exercise Science and Sport Management, Kennesaw State University WellStar College of Health and Human Services, Kennesaw, Georgia
| | - Khala N Clemons
- Department of Exercise Physiology, Anderson Conference Center, School of Health Sciences, Winston-Salem State University, Winston-Salem, North Carolina
| | - Ronald L Snarr
- Department of Health Sciences and Kinesiology, School of Health and Kinesiology, Georgia Southern University, Statesboro, Georgia; and
| | - Michael J McKenzie
- Department of Health and Exercise Science, Beaver College of Health Sciences, Appalachian State University, Boone North Carolina
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Kliszczewicz B, Markert CD, Bechke E, Williamson C, Clemons KN, Snarr RL, Mckenzie MJ. Acute inflammatory responses to high-intensity functional training programming: An observational study. jhse 2019. [DOI: 10.14198/jhse.2019.144.18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Markert CD, Clemons KN, Bechke EE, Williamson CM, McKenzie MJ, Kliszczewicz BM. Biomarkers of Inflammation and Angiogenesis Following Short Vs. Long Bouts of High-Intensity Training. Med Sci Sports Exerc 2018. [DOI: 10.1249/01.mss.0000538525.14197.c3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Brown JM, Guy BS, Henderson DX, Ebert CE, Harp J, Markert CD. Regenerative medicine: a vehicle to infuse laboratory-bench modules into an exercise physiology curriculum. Adv Physiol Educ 2018; 42:32-42. [PMID: 29341813 DOI: 10.1152/advan.00070.2017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Regenerative medicine is a novel discipline that both excites undergraduates and may be used as a vehicle to expose students to scientific concepts and opportunities. The goal of this article is to describe the implementation of a National Science Foundation-funded Targeted Infusion Project in which underrepresented minority undergraduates are exposed to laboratory-bench skills and summer research opportunities that they may not have encountered otherwise. A 3-wk infusion of laboratory-bench and data presentation skills, in the context of a regenerative medicine/bioengineering project, aimed to engage students and expose them to opportunities as summer researchers and teaching assistants. The infusion aimed to assess the extent to which students improved 1) attitudes toward laboratory-bench-based techniques, using attitudes toward science as a proxy; 2) perceptions of scientific inquiry; 3) intentions to engage in undergraduate research; and 4) intentions to persist in science, technology, engineering, and mathematics (STEM)-related fields. Results indicate that the 3-wk infusion had no effect on science attitudes, but transcribed responses to structured interviews administered after the summer research experience indicated that students who completed summer research projects had positive experiences. Differences in intentions to engage in research were detected between groups of students in different STEM majors, in addition to differences in intentions to pursue a career in science. We describe the implementation of the infusion and briefly discuss quantitative outcomes. We conclude that infusion of laboratory-bench modules in the context of a regenerative medicine/bioengineering project may play a small but important role in increasing (minority) participation and persistence in the STEM pipeline.
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Affiliation(s)
- Jason M Brown
- Department of Psychological Sciences, Winston-Salem State University , Winston-Salem, North Carolina
- Department of Exercise Physiology, Winston-Salem State University , Winston-Salem, North Carolina
| | - Breonte S Guy
- Department of Psychological Sciences, Winston-Salem State University , Winston-Salem, North Carolina
| | - Dawn X Henderson
- Department of Psychology, North Carolina Agricultural and Technical State University , Greensboro, North Carolina
| | - C Edward Ebert
- Department of Chemistry, Winston-Salem State University , Winston-Salem, North Carolina
| | - Jill Harp
- Department of Biological Sciences, Winston-Salem State University , Winston-Salem, North Carolina
| | - Chad D Markert
- Department of Exercise Physiology, Winston-Salem State University , Winston-Salem, North Carolina
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Markert CD, Guo X, Skardal A, Wang Z, Bharadwaj S, Zhang Y, Bonin K, Guthold M. Characterizing the micro-scale elastic modulus of hydrogels for use in regenerative medicine. J Mech Behav Biomed Mater 2013; 27:115-27. [DOI: 10.1016/j.jmbbm.2013.07.008] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Revised: 06/29/2013] [Accepted: 07/03/2013] [Indexed: 12/23/2022]
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Markert CD, Guo X, Skardal A, Bharadwaj S, Zhang Y, Bonin K, Guthold M. How Stiff Is It? Characterizing the micro‐scale elastic modulus of hydrogels for use in regenerative medicine. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.1217.21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Chad D. Markert
- Regenerative MedicineWake Forest Health SciencesWinston‐ SalemNC
| | - Xinyi Guo
- Department of PhysicsWake Forest UniversityWinston‐SalemNC
| | | | | | - Yuanyuan Zhang
- Regenerative MedicineWake Forest Health SciencesWinston‐ SalemNC
| | - Keith Bonin
- Department of PhysicsWake Forest UniversityWinston‐SalemNC
| | - Martin Guthold
- Department of PhysicsWake Forest UniversityWinston‐SalemNC
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Markert CD, Case LE, Carter GT, Furlong PA, Grange RW. Exercise and duchenne muscular dystrophy: Where we have been and where we need to go. Muscle Nerve 2012; 45:746-51. [DOI: 10.1002/mus.23244] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Davoodi J, Markert CD, Voelker KA, Hutson SM, Grange RW. Nutrition strategies to improve physical capabilities in Duchenne muscular dystrophy. Phys Med Rehabil Clin N Am 2011; 23:187-99, xii-xiii. [PMID: 22239883 DOI: 10.1016/j.pmr.2011.11.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
There is no current cure for Duchenne muscular dystrophy (DMD), and palliative and prophylactic interventions to improve the quality of life of patients remain limited, with the exception of corticosteroids. This article describes 2 potential nutritional interventions for the treatment of DMD, green tea extract (GTE) and the branched-chain amino acid leucine, and their positive effects on physical activity. Both GTE and leucine are suitable for human consumption, are easily tolerated with no side effects, and, with appropriate preclinical data, could be brought forward to clinical trials rapidly.
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Affiliation(s)
- J Davoodi
- Department of Human Nutrition, Foods and Exercise, Virginia Tech, Blacksburg, VA 24061, USA
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Abstract
To develop a rational framework for answering questions about the role of exercise in Duchenne muscular dystrophy (DMD), we focused on five pathophysiological mechanisms and offer brief hypotheses regarding how exercise may beneficially modulate pertinent cellular and molecular pathways. We aimed to provide an integrative overview of mechanisms of DMD pathology that may improve or worsen as a result of exercise. We also sought to stimulate discussion of what outcomes/dependent variables most appropriately measure these mechanisms, with the purpose of defining criteria for well-designed, controlled studies of exercise in DMD. The five mechanisms include pathways that are both intrinsic and extrinsic to the diseased muscle cells.
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Affiliation(s)
- Chad D Markert
- Wake Forest Institute for Regenerative Medicine, Medical Center Boulevard, Winston-Salem, North Carolina 27157, USA.
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Markert CD, Kim E, Gifondorwa DJ, Childers MK, Milligan CE. A single-dose resveratrol treatment in a mouse model of amyotrophic lateral sclerosis. J Med Food 2011; 13:1081-5. [PMID: 20626250 DOI: 10.1089/jmf.2009.0243] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The underlying causes of denervation of the neuromuscular junction and eventual motor neuron death in amyotrophic lateral sclerosis (ALS) have not been resolved. The superoxide dismutase 1 (SOD1)(G93A) mutant mouse is a frequently used animal model of ALS. We hypothesized that resveratrol (RSV), a polyphenolic molecule that enhances mammalian NAD(+)-dependent SIRT1 deacetylases and may increase life span, would improve motor function and survival in the SOD1 mouse model via modulation of p53 acetylation. Data were collected for mean survival times, neuromuscular performance on the ROTOR-ROD™ (San Diego Instruments, San Diego, CA, USA), body weight, and p53 acetylation. Mean survival times were not statistically different (P=.23) between control and experimental (RSV-fed) groups (mean +/- SD, control [n=11] 138 +/- 6 days vs. experimental [n=10] 135 +/- 8 days). Performance was not significantly different between groups at time points corresponding to 50%, 80%, and 90% mean life span (P=.46), nor did RSV treatment attenuate body weight loss. Thus although manipulation of SIRT1 deacetylase activity has effects at the protein level in healthy aging organisms, we conclude that RSV treatment does not lead to functional improvement or increased longevity in a mouse model of ALS. We speculate that RSV-mediated modulation of p53 acetylation is either incapable of increasing or insufficient to increase motor performance and longevity in this model of ALS.
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Affiliation(s)
- Chad D Markert
- Department of Neurology, Wake Forest University, Winston-Salem, North Carolina 27157, USA.
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Markert CD, Ambrosio F, Call J, Grange RW. Exercise and Duchenne Muscular Dystrophy: Towards Evidence-Based Exercise Prescription. Med Sci Sports Exerc 2010. [DOI: 10.1249/01.mss.0000389544.46046.0a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Tegeler CJ, Grange RW, Bogan DJ, Markert CD, Case D, Kornegay JN, Childers MK. Eccentric contractions induce rapid isometric torque drop in dystrophin-deficient dogs. Muscle Nerve 2010; 42:130-2. [PMID: 20544944 DOI: 10.1002/mus.21699] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We tested the hypothesis that eccentric contractions (ECCs) rapidly induce greater-than-normal isometric torque drop in dystrophin-deficient golden retriever muscular dystrophy (GRMD) muscles. ECCs were imposed by forcibly stretching activated muscles. The results indicate that isometric torque drop was greater in GRMD versus controls (P < 0.0001). Our findings support the hypothesis that ECCs induce greater-than-normal isometric torque drop in GRMD muscles. The magnitude of ECC-induced isometric torque loss may be an ideal clinical endpoint in the GRMD model.
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Affiliation(s)
- Christopher J Tegeler
- Wake Forest University Health Sciences, Institute for Regenerative Medicine, 391 Technology Way, Winston-Salem, North Carolina 27101, USA
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Markert CD, Meaney MP, Voelker KA, Grange RW, Dalley HW, Cann JK, Ahmed M, Bishwokarma B, Walker SJ, Yu SX, Brown M, Lawlor MW, Beggs AH, Childers MK. Functional muscle analysis of the Tcap knockout mouse. Hum Mol Genet 2010; 19:2268-83. [PMID: 20233748 DOI: 10.1093/hmg/ddq105] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Autosomal recessive limb-girdle muscular dystrophy type 2G (LGMD2G) is an adult-onset myopathy characterized by distal lower limb weakness, calf hypertrophy and progressive decline in ambulation. The disease is caused by mutations in Tcap, a z-disc protein of skeletal muscle, although the precise mechanisms resulting in clinical symptoms are unknown. To provide a model for preclinical trials and for mechanistic studies, we generated knockout (KO) mice carrying a null mutation in the Tcap gene. Here we present the first report of a Tcap KO mouse model for LGMD2G and the results of an investigation into the effects of Tcap deficiency on skeletal muscle function in 4- and 12-month-old mice. Muscle histology of Tcap-null mice revealed abnormal myofiber size variation with central nucleation, similar to findings in the muscles of LGMD2G patients. An analysis of a Tcap binding protein, myostatin, showed that deletion of Tcap was accompanied by increased protein levels of myostatin. Our Tcap-null mice exhibited a decline in the ability to maintain balance on a rotating rod, relative to wild-type controls. No differences were detected in force or fatigue assays of isolated extensor digitorum longus (EDL) and soleus (SOL) muscles. Finally, a mechanical investigation of EDL and SOL indicated an increase in muscle stiffness in KO animals. We are the first to establish a viable KO mouse model of Tcap deficiency and our model mice demonstrate a dystrophic phenotype comparable to humans with LGMD2G.
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Affiliation(s)
- C D Markert
- Department of Neurology, Wake Forest University, Winston-Salem, NC 27101, USA
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Markert CD, Bharadwaj S, Zhang Y, Childers MK, Furth ME. Immunofluorescence microscopy for imaging of nuclear p63 in human primary keratinocytes: A comparison of antibodies and fixation methods. J Immunol Methods 2010; 352:174-7. [DOI: 10.1016/j.jim.2009.11.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2009] [Revised: 11/10/2009] [Accepted: 11/10/2009] [Indexed: 01/25/2023]
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Markert CD, Atala A, Cann JK, Christ G, Furth M, Ambrosio F, Childers MK. Mesenchymal stem cells: emerging therapy for Duchenne muscular dystrophy. PM R 2009; 1:547-59. [PMID: 19627945 DOI: 10.1016/j.pmrj.2009.02.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2008] [Revised: 02/20/2009] [Accepted: 02/25/2009] [Indexed: 12/31/2022]
Abstract
Multipotent cells that can give rise to bone, cartilage, fat, connective tissue, and skeletal and cardiac muscle are termed mesenchymal stem cells. These cells were first identified in the bone marrow, distinct from blood-forming stem cells. Based on the embryologic derivation, availability, and various pro-regenerative characteristics, research exploring their use in cell therapy shows great promise for patients with degenerative muscle diseases and a number of other conditions. In this review, the authors explore the potential for mesenchymal stem cell therapy in the emerging field of regenerative medicine with a focus on treatment for Duchenne muscular dystrophy.
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Affiliation(s)
- Chad D Markert
- Department of Neurology, School of Medicine, and Wake Forest Institute for Regenerative Medicine, Wake Forest University Health Sciences, Winston-Salem, NC, USA
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Markert CD, Childers MK. Physiological Effects of Botulinum Neurotoxin A on in vitro Contractile Properties of Skeletal Muscle. Med Sci Sports Exerc 2006. [DOI: 10.1249/00005768-200605001-02454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Abstract
OBJECTIVE To determine whether continuous nonthermal therapeutic ultrasound (US) and low-intensity exercise (Ex) influence skeletal muscle regeneration after a standardized contusion injury in an animal model. DESIGN Randomized controlled trial with blinded comparisons in a 2 x 2 factorial (US by Ex) design. SETTING Animal care facility and exercise physiology biochemistry laboratory. ANIMALS Twenty male Wistar rats (age, 8 mo) received a reproducible bilateral contusion injury to the gastrocnemius muscles. Ten gastrocnemius muscles from 5 noninjured, nontreated rats provided baseline control data. INTERVENTIONS US (continuous duty cycle, 3 MHz; intensity, 0.1 W/cm2 ; transducer, 1cm2 ; duration, 5 min/d; duty cycle, 100%) and exercise (20 min/d of low-intensity treadmill walking at 14 m/min). Gastrocnemius muscles from injured rats received exercise treatment alone (Ex + NoUS), exercise and US treatment (Ex + US), US treatment alone (NoEx + US), and no treatment (NoEx + NoUS). MAIN OUTCOME MEASURES Ninety-six-hour postinjury muscle mass, contractile protein concentration, fiber cross-sectional area, number of nuclei per fiber, and myonuclear density. RESULTS Myonuclei per fiber were statistically greater in injured than in noninjured gastrocnemius muscle (P < .05). There were no statistical differences (P > .01) among the 4 injured treatment groups for any of the outcome measures chosen as biomarkers of skeletal muscle regeneration. CONCLUSIONS There is no evidence that the specific continuous US and Ex protocols investigated enhanced skeletal muscle regeneration after contusion injury.
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Affiliation(s)
- Chad D Markert
- Sport and Excercise Science Program, Ohio State University, Columbus, OH 43210-1284, USA
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Kim JS, Hinchcliff KW, Yamaguchi M, Beard LA, Markert CD, Devor ST. Age-related changes in metabolic properties of equine skeletal muscle associated with muscle plasticity. Vet J 2005; 169:397-403. [PMID: 15848782 DOI: 10.1016/j.tvjl.2004.03.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/20/2004] [Indexed: 12/25/2022]
Abstract
The purpose of the present study was to determine the age-related changes in myosin heavy chain (MHC) composition and muscle oxidative and glycolytic capacity in 18 horses ranging in age from two to 30 years. Muscle samples were collected by excisional biopsy of the semimebranosus muscle. MHC expression and the key enzymatic activities were measured. There was no significant correlation between horse age and the proportions of type-IIA and type-IIX MHC isoforms. The percentage of type-I MHC isoforms decreased with advancing age. Muscle citrate synthase activity decreased, whereas lactate dehydrogenase activity increased with increasing age. Muscle 3-OH acyl CoA dehydrogenase activity did not change with ageing. The results suggest that, similar to humans, the oxidative capacity of equine skeletal muscle decreases with age. The age-related changes in muscle metabolic properties appear to be consistent with an age-related transition in MHC isoforms of equine skeletal muscle that shifts toward more glycolytic isoforms with age.
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Affiliation(s)
- Jeong-su Kim
- Section of Sport and Exercise Sciences, The Ohio State University, Columbus, OH 43210-1284, USA
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Kim JS, Hinchcliff KW, Yamaguchi M, Beard LA, Markert CD, Devor ST. Exercise training increases oxidative capacity and attenuates exercise-induced ultrastructural damage in skeletal muscle of aged horses. J Appl Physiol (1985) 2005; 98:334-42. [PMID: 15377646 DOI: 10.1152/japplphysiol.00172.2003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Exercise training improves functional capacity in aged individuals. Whether such training reduces the severity of exercise-induced muscle damage is unknown. The purpose of the present study was to determine the effect of 10 wk of treadmill exercise training on skeletal muscle oxidative capacity and exercise-induced ultrastructural damage in six aged female Quarter horses (>23 yr of age). The magnitude of ultrastructural muscle damage induced by an incremental exercise test before and after training was determined by electron microscopic examination of samples of triceps, semimembranosus, and masseter (control) muscles. Maximal aerobic capacity increased 22% after 10 wk of exercise training. The percentage of type IIa myosin heavy chain increased in semimembranosus muscle, whereas the percentage of type IIx myosin heavy chain decreased in triceps muscle. After training, triceps muscle showed significant increases in activities of both citrate synthase and 3-hydroxyacyl-CoA-dehydrogenase. Attenuation of exercise-induced ultrastructural muscle damage occurred in the semimembranosus muscle at both the same absolute and the same relative workloads after the 10-wk conditioning period. We conclude that aged horses adapt readily to intense aerobic exercise training with improvements in endurance, whole body aerobic capacity, and muscle oxidative capacity, and heightened resistance to exercise-induced ultrastructural muscle cell damage. However, adaptations may be muscle-group specific.
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Affiliation(s)
- Jeong-su Kim
- Sport and Exercise Science Program, The Ohio State University, 129C Larkins Hall, 337 West Seventeenth Ave., Columbus, OH 43210-1284, USA
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Markert CD, Merrick MA, Kirby TE, Devor ST. Exercise and Therapeutic Ultrasound in Skeletal Muscle Regeneration. Med Sci Sports Exerc 2004. [DOI: 10.1249/00005768-200405001-00065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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