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Langley JO, Ng SC, Todd EE, Porter MS. V ˙ La max: determining the optimal test duration for maximal lactate formation rate during all-out sprint cycle ergometry. Eur J Appl Physiol 2024:10.1007/s00421-024-05456-9. [PMID: 38555335 DOI: 10.1007/s00421-024-05456-9] [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: 11/15/2023] [Accepted: 02/28/2024] [Indexed: 04/02/2024]
Abstract
PURPOSE This study aimed to ascertain the optimal test duration to elicit the highest maximal lactate formation rate ( V ˙ Lamax), whilst exploring the underpinning energetics, and identifying the optimal blood lactate sampling period. METHODS Fifteen trained to well-trained males (age 27 ± 6 years; peak power: 1134 ± 174 W) participated in a randomised cross-over design completing three all-out sprint cycling tests of differing test durations (10, 15, and 30 s). Peak and mean power output (W and W.kg-1), oxygen uptake, and blood lactate concentrations were measured. V ˙ Lamax and energetic contributions (phosphagen, glycolytic, and oxidative) were determined using these parameters. RESULTS The shortest test duration of 10 s elicited a significantly (p = 0.003; p < 0.001) higher V ˙ Lamax (0.86 ± 0.17 mmol.L-1.s-1; 95% CI 0.802-0.974) compared with both 15 s (0.68 ± 0.18 mmol.L-1.s-1; 95% CI 0.596-0.794) and 30 s (0.45 ± 0.07 mmol.L-1.s-1; 95% CI 0.410-0.487). Differences in V ˙ Lamax were associated with large effect sizes (d = 1.07, d = 3.15). We observed 81% of the PCr and 53% of the glycolytic work completed over the 30 s sprint duration was attained after 10 s. BLamaxpost were achieved at 5 ± 2 min (ttest 10 s), 6 ± 2 min (ttest 15 s), and 7 ± 2 min (ttest 30 s), respectively. CONCLUSION Our findings demonstrated a 10 s test duration elicited the highest V ˙ Lamax. Furthermore, the 10 s test duration mitigated the influence of the oxidative metabolism during all-out cycling. The optimal sample time to determine peak blood lactate concentration following 10 s was 5 ± 2 min.
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Affiliation(s)
- J O Langley
- Department of Higher Education Sport, Loughborough College, Radmoor Road, Loughborough, Leicestershire, LE11 3BT, UK.
| | - S C Ng
- Department of Higher Education Sport, Loughborough College, Radmoor Road, Loughborough, Leicestershire, LE11 3BT, UK
| | - E E Todd
- Department of Higher Education Sport, Loughborough College, Radmoor Road, Loughborough, Leicestershire, LE11 3BT, UK
| | - M S Porter
- Department of Higher Education Sport, Loughborough College, Radmoor Road, Loughborough, Leicestershire, LE11 3BT, UK
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2
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Vigh-Larsen JF, Mohr M. The physiology of ice hockey performance: An update. Scand J Med Sci Sports 2024; 34:e14284. [PMID: 36517860 DOI: 10.1111/sms.14284] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 11/11/2022] [Accepted: 12/10/2022] [Indexed: 12/23/2022]
Abstract
Ice hockey is an intense team sport characterized by repeated bursts of fast-paced skating, rapid changes in speed and direction and frequent physical encounters. These are performed in on-ice shifts of ~30-80 s interspersed with longer sequences of passive recovery, resulting in about 15-25 min on-ice time per player. Nearly 50% of the distance is covered at high-intensity skating speeds and with an accentuated intense activity pattern in forwards compared to defensemen. During ice hockey match-play, both aerobic and anaerobic energy systems are significantly challenged, with the heart rate increasing toward maximum levels during each shift, and with great reliance on both glycolytic and phosphagen ATP provision. The high-intensity activity pattern favors muscle glycogen as fuel, leading to pronounced reductions despite the relatively brief playing time, including severe depletion of a substantial proportion of individual fast- and slow-twitch fibers. Player-tracking suggests that the ability to perform high-intensity skating is compromised in the final stages of a game, which is supported by post-game reductions in repeated-sprint ability. Muscle glycogen degradation, in particular in individual fibers, as well as potential dehydration and hyperthermia, may be prime candidates implicated in exacerbated fatigue during the final stages of a game, whereas multiple factors likely interact to impair exercise tolerance during each shift. This includes pronounced PCr degradation, with potential inadequate resynthesis in a proportion of fast-twitch fibers in situations of repeated intense actions. Finally, the recovery pattern is inadequately described, but seems less long-lasting than in other team sports.
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Affiliation(s)
- Jeppe F Vigh-Larsen
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Magni Mohr
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
- Centre of Health Sciences, University of the Faroe Islands, Tórshavn, Faroe Islands
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3
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Han H, Zhao Y, Du J, Wang S, Yang X, Li W, Song J, Zhang S, Zhang Z, Tan Y, Hatch GM, Zhang M, Chen L. Exercise improves cognitive dysfunction and neuroinflammation in mice through Histone H3 lactylation in microglia. Immun Ageing 2023; 20:63. [PMID: 37978517 PMCID: PMC10655345 DOI: 10.1186/s12979-023-00390-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 11/07/2023] [Indexed: 11/19/2023]
Abstract
BACKGROUND Exercise is postulated to be a promising non-pharmacological intervention for the improvement of neurodegenerative disease pathology. However, the mechanism of beneficial effects of exercise on the brain remains to be further explored. In this study, we investigated the effect of an exercise-induced metabolite, lactate, on the microglia phenotype and its association with learning and memory. RESULTS Microglia were hyperactivated in the brains of AlCl3/D-gal-treated mice, which was associated with cognitive decline. Running exercise ameliorated the hyperactivation and increased the anti-inflammatory/reparative phenotype of microglia and improved cognition. Mice were injected intraperitoneally with sodium lactate (NaLA) had similar beneficial effects as that of exercise training. Exogenous NaLA addition to cultured BV2 cells promoted their transition from a pro-inflammatory to a reparative phenotype. CONCLUSION The elevated lactate acted as an "accelerator" of the endogenous "lactate timer" in microglia promoting this transition of microglia polarization balance through lactylation. These findings demonstrate that exercise-induced lactate accelerates the phenotypic transition of microglia, which plays a key role in reducing neuroinflammation and improving cognitive function.
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Affiliation(s)
- Hao Han
- Key Laboratory of Pathobiology, Ministry of Education, College of Basic Medical Sciences, Jilin University, Changchun, 130021, China
- Department of Pharmacology, College of Basic Medical Sciences, Jilin University, 126 Xin Min Street, Changchun, 130021, Jilin, China
| | - Yawei Zhao
- Key Laboratory of Pathobiology, Ministry of Education, College of Basic Medical Sciences, Jilin University, Changchun, 130021, China
- Department of Pharmacology, College of Basic Medical Sciences, Jilin University, 126 Xin Min Street, Changchun, 130021, Jilin, China
| | - Junda Du
- School of Pharmaceutical Sciences, Jilin University, Changchun, 130021, China
| | - Sushan Wang
- Key Laboratory of Pathobiology, Ministry of Education, College of Basic Medical Sciences, Jilin University, Changchun, 130021, China
- Department of Pharmacology, College of Basic Medical Sciences, Jilin University, 126 Xin Min Street, Changchun, 130021, Jilin, China
| | - Xuehan Yang
- Key Laboratory of Pathobiology, Ministry of Education, College of Basic Medical Sciences, Jilin University, Changchun, 130021, China
- Department of Pharmacology, College of Basic Medical Sciences, Jilin University, 126 Xin Min Street, Changchun, 130021, Jilin, China
| | - Weijie Li
- Key Laboratory of Pathobiology, Ministry of Education, College of Basic Medical Sciences, Jilin University, Changchun, 130021, China
- Department of Pharmacology, College of Basic Medical Sciences, Jilin University, 126 Xin Min Street, Changchun, 130021, Jilin, China
| | - Jiayi Song
- Key Laboratory of Pathobiology, Ministry of Education, College of Basic Medical Sciences, Jilin University, Changchun, 130021, China
- Department of Pharmacology, College of Basic Medical Sciences, Jilin University, 126 Xin Min Street, Changchun, 130021, Jilin, China
| | - Siwei Zhang
- Key Laboratory of Pathobiology, Ministry of Education, College of Basic Medical Sciences, Jilin University, Changchun, 130021, China
- Department of Pharmacology, College of Basic Medical Sciences, Jilin University, 126 Xin Min Street, Changchun, 130021, Jilin, China
| | - Ziyi Zhang
- The Second Hospital of Jilin University, Changchun, 130041, China
| | - Yongfei Tan
- South China Institute of Collaborative Innovation, Dongguan, 523808, China
| | - Grant M Hatch
- Departments of Pharmacology and Therapeutics, Biochemistry and Medical Genetics, Center for Research and Treatment of Atherosclerosis, DREAM Children's Hospital Research Institute of Manitoba, University of Manitoba, Winnipeg, MB, R3E0T6, Canada
| | - Ming Zhang
- Key Laboratory of Pathobiology, Ministry of Education, College of Basic Medical Sciences, Jilin University, Changchun, 130021, China.
- Department of Pharmacology, College of Basic Medical Sciences, Jilin University, 126 Xin Min Street, Changchun, 130021, Jilin, China.
| | - Li Chen
- Key Laboratory of Pathobiology, Ministry of Education, College of Basic Medical Sciences, Jilin University, Changchun, 130021, China.
- Department of Pharmacology, College of Basic Medical Sciences, Jilin University, 126 Xin Min Street, Changchun, 130021, Jilin, China.
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4
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Rubenstein AB, Smith GR, Zhang Z, Chen X, Chambers TL, Ruf-Zamojski F, Mendelev N, Cheng WS, Zamojski M, Amper MAS, Nair VD, Marderstein AR, Montgomery SB, Troyanskaya OG, Zaslavsky E, Trappe T, Trappe S, Sealfon SC. Integrated single-cell multiome analysis reveals muscle fiber-type gene regulatory circuitry modulated by endurance exercise. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.26.558914. [PMID: 37808658 PMCID: PMC10557702 DOI: 10.1101/2023.09.26.558914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Endurance exercise is an important health modifier. We studied cell-type specific adaptations of human skeletal muscle to acute endurance exercise using single-nucleus (sn) multiome sequencing in human vastus lateralis samples collected before and 3.5 hours after 40 min exercise at 70% VO2max in four subjects, as well as in matched time of day samples from two supine resting circadian controls. High quality same-cell RNA-seq and ATAC-seq data were obtained from 37,154 nuclei comprising 14 cell types. Among muscle fiber types, both shared and fiber-type specific regulatory programs were identified. Single-cell circuit analysis identified distinct adaptations in fast, slow and intermediate fibers as well as LUM-expressing FAP cells, involving a total of 328 transcription factors (TFs) acting at altered accessibility sites regulating 2,025 genes. These data and circuit mapping provide single-cell insight into the processes underlying tissue and metabolic remodeling responses to exercise.
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Affiliation(s)
- Aliza B. Rubenstein
- Department of Neurology, Icahn School of Medicine at Mount Sinai (ISMMS), New York, NY 10029, USA
| | - Gregory R. Smith
- Department of Neurology, Icahn School of Medicine at Mount Sinai (ISMMS), New York, NY 10029, USA
| | - Zidong Zhang
- Department of Neurology, Icahn School of Medicine at Mount Sinai (ISMMS), New York, NY 10029, USA
- Lewis-Sigler Institute of Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Xi Chen
- Center for Computational Biology, Flatiron Institute, Simons Foundation, New York, NY 10010, USA
| | - Toby L. Chambers
- Human Performance Laboratory, Ball State University, Muncie, IN 47306, USA
| | - Frederique Ruf-Zamojski
- Department of Neurology, Icahn School of Medicine at Mount Sinai (ISMMS), New York, NY 10029, USA
- Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Natalia Mendelev
- Department of Neurology, Icahn School of Medicine at Mount Sinai (ISMMS), New York, NY 10029, USA
| | - Wan Sze Cheng
- Department of Neurology, Icahn School of Medicine at Mount Sinai (ISMMS), New York, NY 10029, USA
| | - Michel Zamojski
- Department of Neurology, Icahn School of Medicine at Mount Sinai (ISMMS), New York, NY 10029, USA
- Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Mary Anne S. Amper
- Department of Neurology, Icahn School of Medicine at Mount Sinai (ISMMS), New York, NY 10029, USA
| | - Venugopalan D. Nair
- Department of Neurology, Icahn School of Medicine at Mount Sinai (ISMMS), New York, NY 10029, USA
| | - Andrew R. Marderstein
- Department of Genetics, Stanford University, Stanford, CA 94305, USA
- Department of Pathology, Stanford University, Stanford, CA 94305, USA
| | - Stephen B. Montgomery
- Department of Genetics, Stanford University, Stanford, CA 94305, USA
- Department of Pathology, Stanford University, Stanford, CA 94305, USA
| | - Olga G. Troyanskaya
- Lewis-Sigler Institute of Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
- Center for Computational Biology, Flatiron Institute, Simons Foundation, New York, NY 10010, USA
- Department of Computer Science, Princeton University, Princeton, NJ 08544, USA
| | - Elena Zaslavsky
- Department of Neurology, Icahn School of Medicine at Mount Sinai (ISMMS), New York, NY 10029, USA
| | - Todd Trappe
- Human Performance Laboratory, Ball State University, Muncie, IN 47306, USA
| | - Scott Trappe
- Human Performance Laboratory, Ball State University, Muncie, IN 47306, USA
- Senior author
| | - Stuart C. Sealfon
- Department of Neurology, Icahn School of Medicine at Mount Sinai (ISMMS), New York, NY 10029, USA
- Department of Computer Science, Princeton University, Princeton, NJ 08544, USA
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5
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Smith JAB, Murach KA, Dyar KA, Zierath JR. Exercise metabolism and adaptation in skeletal muscle. Nat Rev Mol Cell Biol 2023; 24:607-632. [PMID: 37225892 PMCID: PMC10527431 DOI: 10.1038/s41580-023-00606-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/30/2023] [Indexed: 05/26/2023]
Abstract
Viewing metabolism through the lens of exercise biology has proven an accessible and practical strategy to gain new insights into local and systemic metabolic regulation. Recent methodological developments have advanced understanding of the central role of skeletal muscle in many exercise-associated health benefits and have uncovered the molecular underpinnings driving adaptive responses to training regimens. In this Review, we provide a contemporary view of the metabolic flexibility and functional plasticity of skeletal muscle in response to exercise. First, we provide background on the macrostructure and ultrastructure of skeletal muscle fibres, highlighting the current understanding of sarcomeric networks and mitochondrial subpopulations. Next, we discuss acute exercise skeletal muscle metabolism and the signalling, transcriptional and epigenetic regulation of adaptations to exercise training. We address knowledge gaps throughout and propose future directions for the field. This Review contextualizes recent research of skeletal muscle exercise metabolism, framing further advances and translation into practice.
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Affiliation(s)
- Jonathon A B Smith
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Kevin A Murach
- Molecular Mass Regulation Laboratory, Exercise Science Research Center, Department of Health, Human Performance and Recreation, University of Arkansas, Fayetteville, AR, USA
| | - Kenneth A Dyar
- Metabolic Physiology, Institute for Diabetes and Cancer, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Juleen R Zierath
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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6
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Cholak S, Saville JW, Zhu X, Berezuk AM, Tuttle KS, Haji-Ghassemi O, Alvarado FJ, Van Petegem F, Subramaniam S. Allosteric modulation of ryanodine receptor RyR1 by nucleotide derivatives. Structure 2023; 31:790-800.e4. [PMID: 37192614 PMCID: PMC10569317 DOI: 10.1016/j.str.2023.04.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 02/22/2023] [Accepted: 04/19/2023] [Indexed: 05/18/2023]
Abstract
The coordinated release of Ca2+ from the sarcoplasmic reticulum (SR) is critical for excitation-contraction coupling. This release is facilitated by ryanodine receptors (RyRs) that are embedded in the SR membrane. In skeletal muscle, activity of RyR1 is regulated by metabolites such as ATP, which upon binding increase channel open probability (Po). To obtain structural insights into the mechanism of RyR1 priming by ATP, we determined several cryo-EM structures of RyR1 bound individually to ATP-γ-S, ADP, AMP, adenosine, adenine, and cAMP. We demonstrate that adenine and adenosine bind RyR1, but AMP is the smallest ATP derivative capable of inducing long-range (>170 Å) structural rearrangements associated with channel activation, establishing a structural basis for key binding site interactions that are the threshold for triggering quaternary structural changes. Our finding that cAMP also induces these structural changes and results in increased channel opening suggests its potential role as an endogenous modulator of RyR1 conductance.
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Affiliation(s)
- Spencer Cholak
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - James W Saville
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Xing Zhu
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Alison M Berezuk
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Katharine S Tuttle
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Omid Haji-Ghassemi
- Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Francisco J Alvarado
- Department of Medicine and Cardiovascular Research Center, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, USA
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
| | - Sriram Subramaniam
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
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7
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A Novel Approach to Determining the Alactic Time Span in Connection with Assessment of the Maximal Rate of Lactate Accumulation in Elite Track Cyclists. Int J Sports Physiol Perform 2023; 18:157-163. [PMID: 36596309 DOI: 10.1123/ijspp.2021-0464] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 09/05/2022] [Accepted: 10/06/2022] [Indexed: 01/05/2023]
Abstract
PURPOSE Following short-term all-out exercise, the maximal rate of glycolysis is frequently assessed on the basis of the maximal rate of lactate accumulation in the blood. Since the end of the interval without significant accumulation (talac) is 1 of 2 denominators in the calculation employed, accurate determination of this parameter is crucial. Although the very existence and definition of talac, as well as the validity of its determination as time-to-peak power (tPpeak), remain controversial, this parameter plays a key role in anaerobic diagnostics. Here, we describe a novel approach to determination of talac and compare it to the current standard. METHODS Twelve elite track cyclists performed 3 maximal sprints (3, 8, and 12 s) and a high-rate, low-resistance pedaling test on an ergometer with monitoring of crank force and pedaling rate. Before and after each sprint, capillary blood samples were taken for determination of lactate accumulation. Fatigue-free force-velocity and power-velocity profiles were generated. talac was determined as tPpeak and as the time point of the first systematic deviation from the force-velocity profile (tFf). RESULTS Accumulation of lactate after the 3-second sprint was significant (0.58 [0.19] mmol L-1; P < .001, d = 1.982). tFf was <3 seconds and tPpeak was ≥3 seconds during all sprints (P < .001, d = - 2.111). Peak power output was lower than maximal power output (P < .001, d = -0.937). Blood lactate accumulation increased linearly with increasing duration of exercise (R2 ≥ .99) and intercepted the x-axis at ∼tFf. CONCLUSION Definition of talac as tPpeak can lead to incorrect conclusions. We propose determination of talac based on tFf, the end of the fatigue-free state that may reflect the beginning of blood lactate accumulation.
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8
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Vigh‐Larsen JF, Ørtenblad N, Emil Andersen O, Thorsteinsson H, Kristiansen TH, Bilde S, Mikkelsen MS, Nielsen J, Mohr M, Overgaard K. Fibre type- and localisation-specific muscle glycogen utilisation during repeated high-intensity intermittent exercise. J Physiol 2022; 600:4713-4730. [PMID: 36030498 PMCID: PMC9825866 DOI: 10.1113/jp283225] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 08/24/2022] [Indexed: 01/11/2023] Open
Abstract
Glycogen particles are situated in key areas of the muscle cell in the vicinity of the main energy-consumption sites and may be utilised heterogeneously dependent on the nature of the metabolic demands. The present study aimed to investigate the time course of fibre type-specific utilisation of muscle glycogen in three distinct subcellular fractions (intermyofibrillar, IMF; intramyofibrillar, Intra; and subsarcolemmal, SS) during repeated high-intensity intermittent exercise. Eighteen moderately to well-trained male participants performed three periods of 10 × 45 s cycling at ∼105% watt max (EX1-EX3) coupled with 5 × 6 s maximal sprints at baseline and after each period. Muscle biopsies were sampled at baseline and after EX1 and EX3. A higher glycogen breakdown rate in type 2 compared to type 1 fibres was found during EX1 for the Intra (-72 vs. -45%) and IMF (-59 vs. -35%) glycogen fractions (P < 0.001) but with no differences for SS glycogen (-52 vs. -40%). In contrast, no fibre type differences were observed during EX2-EX3, where the utilisation of Intra and IMF glycogen in type 2 fibres was reduced, resulting in depletion of all three subcellular fractions to very low levels post-exercise within both fibre types. Importantly, large heterogeneity in single-fibre glycogen utilisation was present with an early depletion of especially Intra glycogen in individual type 2 fibres. In conclusion, there is a clear fibre type- and localisation-specific glycogen utilisation during high-intensity intermittent exercise, which varies with time course of exercise and is characterised by exacerbated pool-specific glycogen depletion at the single-fibre level. KEY POINTS: Muscle glycogen is the major fuel during high-intensity exercise and is stored in distinct subcellular areas of the muscle cell in close vicinity to the main energy consumption sites. In the present study quantitative electron microscopy imaging was used to investigate the utilisation pattern of three distinct subcellular muscle glycogen fractions during repeated high-intensity intermittent exercise. It is shown that the utilisation differs dependent on fibre type, subcellular localisation and time course of exercise and with large single-fibre heterogeneity. These findings expand on our understanding of subcellular muscle glycogen metabolism during exercise and may help us explain how reductions in muscle glycogen can attenuate muscle function even at only moderately lowered whole-muscle glycogen concentrations.
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Affiliation(s)
- Jeppe F. Vigh‐Larsen
- Department of Public HealthResearch Unit in Exercise BiologyAarhus UniversityAarhusDenmark
| | - Niels Ørtenblad
- Department of Sports Science and Clinical BiomechanicsUniversity of Southern DenmarkOdenseDenmark
| | - Ole Emil Andersen
- Department of Public HealthResearch Unit in Exercise BiologyAarhus UniversityAarhusDenmark,Steno Diabetes Center AarhusAarhus University HospitalAarhusDenmark
| | - Hallur Thorsteinsson
- Department of Sports Science and Clinical BiomechanicsUniversity of Southern DenmarkOdenseDenmark
| | - Thea H. Kristiansen
- Department of Public HealthResearch Unit in Exercise BiologyAarhus UniversityAarhusDenmark
| | - Stine Bilde
- Department of Public HealthResearch Unit in Exercise BiologyAarhus UniversityAarhusDenmark
| | - Mads S. Mikkelsen
- Department of Public HealthResearch Unit in Exercise BiologyAarhus UniversityAarhusDenmark
| | - Joachim Nielsen
- Department of Sports Science and Clinical BiomechanicsUniversity of Southern DenmarkOdenseDenmark
| | - Magni Mohr
- Department of Sports Science and Clinical BiomechanicsUniversity of Southern DenmarkOdenseDenmark,Centre of Health ScienceUniversity of the Faroe IslandsTórshavnFaroe Islands
| | - Kristian Overgaard
- Department of Public HealthResearch Unit in Exercise BiologyAarhus UniversityAarhusDenmark
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9
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Tripp TR, Frankish BP, Lun V, Wiley JP, Shearer J, Murphy RM, MacInnis MJ. Time course and fibre type-dependent nature of calcium-handling protein responses to sprint interval exercise in human skeletal muscle. J Physiol 2022; 600:2897-2917. [PMID: 35556249 DOI: 10.1113/jp282739] [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: 01/05/2022] [Accepted: 04/22/2022] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Sprint interval training (SIT) has been shown to cause fragmentation of the sarcoplasmic reticulum calcium-release channel, ryanodine receptor 1 (RyR1) 24 hours post-exercise, which may act as a signal for mitochondrial biogenesis. In this study, we examined the time course of RyR1 fragmentation in human whole muscle and pooled type I and type II skeletal muscle fibres following a single session of SIT. Full-length RyR1 protein content was significantly lower than pre-exercise by 6 h post-SIT in whole muscle, and fragmentation was detectable in type II but not type I fibres, though to a lesser extent than in whole muscle. The peak in PGC1A mRNA expression occurred earlier than RyR1 fragmentation. The increased temporal resolution and fibre type-specific responses for RyR1 fragmentation provide insights into its importance to mitochondrial biogenesis in humans. ABSTRACT Sprint interval training (SIT) causes fragmentation of the skeletal muscle sarcoplasmic reticulum Ca2+ release channel, ryanodine receptor 1 (RyR1), 24h post-exercise, potentially signaling mitochondrial biogenesis by increasing cytosolic [Ca2+ ]. Yet, the time course and skeletal muscle fibre type-specific patterns of RyR1 fragmentation following a session of SIT remain unknown. Ten participants (n = 4 females; n = 6 males) performed a session of SIT (6 × 30 s "all-out" with 4.5 min rest after each sprint) with vastus lateralis muscle biopsy samples collected before and 3, 6, and 24h after exercise. In whole muscle, full-length RyR1 protein content was significantly reduced 6 h (mean [SD]; -38 [38]%; p<0.05) and 24 h post-SIT (-30 [48]%; p<0.05) compared to pre-exercise. Examining each participant's largest response in pooled samples, full-length RyR1 protein content was reduced in type II (-26 [30]%; p<0.05) but not type I fibres (-11 [40]%; p>0.05). 3h post-SIT, there was also a decrease in SERCA1 in type II fibres (-23 [17]%; p<0.05) and SERCA2a in type I fibres (-19 [21]%; p<0.05), despite no time effect for either protein in whole muscle samples (p>0.05). PGC1A mRNA content was elevated 3h and 6h post-SIT (5.3- and 3.7-fold change from pre, respectively; p<0.05 for both), but peak PGC1A mRNA expression was not significantly correlated with peak RyR1 fragmentation (r2 = 0.10; p>0.05). In summary, altered Ca2+ -handling protein expression, which occurs primarily in type II muscle fibres, may influence signals for mitochondrial biogenesis as early as 3-6 h post-SIT in humans. Abstract figure legend Western blotting was performed on whole muscle and pooled type I and II muscle fibre preparations derived from human vastus lateralis muscle biopsy samples collected before and after a single session of sprint interval training (SIT). Full-length ryanodine receptor 1 (RyR1) protein content was reduced 6 and 24 h post-exercise in whole muscle samples compared to baseline, despite a heterogeneous time course among individuals. This RyR1 fragmentation proceeded and outlasted the increase in peroxisome proliferator-activated γ receptor coactivator 1α (PGC1A) mRNA expression. When examining the time point of each individual's peak response, RyR1 fragmentation was evident in type II, but not type I, muscle fibres. These findings suggest that, in humans, mitochondrial biogenesis could be influenced by RyR1 fragmentation 3-6 h post-SIT in a fibre type-dependent manner. Created with BioRender.com. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Thomas R Tripp
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Barnaby P Frankish
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, Melbourne, Australia
| | - Victor Lun
- University of Calgary Sport Medicine Centre, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - J Preston Wiley
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,University of Calgary Sport Medicine Centre, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Jane Shearer
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Department of Biochemistry & Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Robyn M Murphy
- Department of Physiology, Anatomy and Microbiology, School of Life Sciences, La Trobe University, Melbourne, Australia
| | - Martin J MacInnis
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
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10
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A century of exercise physiology: key concepts in regulation of glycogen metabolism in skeletal muscle. Eur J Appl Physiol 2022; 122:1751-1772. [PMID: 35355125 PMCID: PMC9287217 DOI: 10.1007/s00421-022-04935-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 03/15/2022] [Indexed: 01/20/2023]
Abstract
Glycogen is a branched, glucose polymer and the storage form of glucose in cells. Glycogen has traditionally been viewed as a key substrate for muscle ATP production during conditions of high energy demand and considered to be limiting for work capacity and force generation under defined conditions. Glycogenolysis is catalyzed by phosphorylase, while glycogenesis is catalyzed by glycogen synthase. For many years, it was believed that a primer was required for de novo glycogen synthesis and the protein considered responsible for this process was ultimately discovered and named glycogenin. However, the subsequent observation of glycogen storage in the absence of functional glycogenin raises questions about the true role of the protein. In resting muscle, phosphorylase is generally considered to be present in two forms: non-phosphorylated and inactive (phosphorylase b) and phosphorylated and constitutively active (phosphorylase a). Initially, it was believed that activation of phosphorylase during intense muscle contraction was primarily accounted for by phosphorylation of phosphorylase b (activated by increases in AMP) to a, and that glycogen synthesis during recovery from exercise occurred solely through mechanisms controlled by glucose transport and glycogen synthase. However, it now appears that these views require modifications. Moreover, the traditional roles of glycogen in muscle function have been extended in recent years and in some instances, the original concepts have undergone revision. Thus, despite the extensive amount of knowledge accrued during the past 100 years, several critical questions remain regarding the regulation of glycogen metabolism and its role in living muscle.
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11
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Wang Z, Xia T, Jin S, Liu X, Pan R, Yan M, Chang Q. Chronic Restraint Stress-Induced Muscle Atrophy Leads to Fatigue in Mice by Inhibiting the AMPK Signaling Pathway. Biomedicines 2021; 9:biomedicines9101321. [PMID: 34680438 PMCID: PMC8533263 DOI: 10.3390/biomedicines9101321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 09/16/2021] [Accepted: 09/23/2021] [Indexed: 11/16/2022] Open
Abstract
Currently, an increasing number of people are suffering from fatigue due to the state of their lifestyles, such as sedentary work in a relatively small space, irregular sleep patterns, or the lack of movement and exercise. The present study was designed to simulate the occurrence of fatigue in the above populations through a chronic restraint stress (CRS) model, and to reveal its dynamic processes and potential underlying molecular mechanisms. ICR mice were subjected to 8 h of restraint stress each day for 5, 10, or 15 days. It was found that the weight-loaded swimming performance, grip strength, and locomotor activity of the mice all decreased under CRS treatment, and that up to 15 days of CRS induced notable fatigue. Gastrocnemius muscle atrophy and some abnormal biochemical parameters related to fatigue under CRS were observed. Furthermore, transcriptome data showed that the changes in muscle cell metabolism and mitochondrial dysfunction were associated with the AMPK signaling pathway in CRS-treated mice. Western blotting analysis of the AMPK/PGC-1α signaling pathway revealed that CRS could decrease mitochondrial biogenesis and reduce the numbers of type I skeletal muscle fibers in the gastrocnemius of mice. CRS could also block the protective mitophagic flux to inhibit the abnormal clearance of damaged mitochondria. Our study suggests a critical link between muscle atrophy and CRS-induced fatigue in mice, suggesting that the pharmacological promotion of muscle and mitochondrial function can be used as a treatment for stress-induced fatigue.
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Affiliation(s)
| | | | | | | | | | - Mingzhu Yan
- Correspondence: (M.Y.); (Q.C.); Tel.: +86-10-5783-3468 (M.Y.); +86-10-5783-3224 (Q.C.)
| | - Qi Chang
- Correspondence: (M.Y.); (Q.C.); Tel.: +86-10-5783-3468 (M.Y.); +86-10-5783-3224 (Q.C.)
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12
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Hostrup M, Cairns SP, Bangsbo J. Muscle Ionic Shifts During Exercise: Implications for Fatigue and Exercise Performance. Compr Physiol 2021; 11:1895-1959. [PMID: 34190344 DOI: 10.1002/cphy.c190024] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Exercise causes major shifts in multiple ions (e.g., K+ , Na+ , H+ , lactate- , Ca2+ , and Cl- ) during muscle activity that contributes to development of muscle fatigue. Sarcolemmal processes can be impaired by the trans-sarcolemmal rundown of ion gradients for K+ , Na+ , and Ca2+ during fatiguing exercise, while changes in gradients for Cl- and Cl- conductance may exert either protective or detrimental effects on fatigue. Myocellular H+ accumulation may also contribute to fatigue development by lowering glycolytic rate and has been shown to act synergistically with inorganic phosphate (Pi) to compromise cross-bridge function. In addition, sarcoplasmic reticulum Ca2+ release function is severely affected by fatiguing exercise. Skeletal muscle has a multitude of ion transport systems that counter exercise-related ionic shifts of which the Na+ /K+ -ATPase is of major importance. Metabolic perturbations occurring during exercise can exacerbate trans-sarcolemmal ionic shifts, in particular for K+ and Cl- , respectively via metabolic regulation of the ATP-sensitive K+ channel (KATP ) and the chloride channel isoform 1 (ClC-1). Ion transport systems are highly adaptable to exercise training resulting in an enhanced ability to counter ionic disturbances to delay fatigue and improve exercise performance. In this article, we discuss (i) the ionic shifts occurring during exercise, (ii) the role of ion transport systems in skeletal muscle for ionic regulation, (iii) how ionic disturbances affect sarcolemmal processes and muscle fatigue, (iv) how metabolic perturbations exacerbate ionic shifts during exercise, and (v) how pharmacological manipulation and exercise training regulate ion transport systems to influence exercise performance in humans. © 2021 American Physiological Society. Compr Physiol 11:1895-1959, 2021.
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Affiliation(s)
- Morten Hostrup
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Simeon Peter Cairns
- SPRINZ, School of Sport and Recreation, Auckland University of Technology, Auckland, New Zealand.,Health and Rehabilitation Research Institute, Auckland University of Technology, Auckland, New Zealand
| | - Jens Bangsbo
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
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13
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Muscle Glycogen Metabolism and High-Intensity Exercise Performance: A Narrative Review. Sports Med 2021; 51:1855-1874. [PMID: 33900579 DOI: 10.1007/s40279-021-01475-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/08/2021] [Indexed: 02/06/2023]
Abstract
Muscle glycogen is the main substrate during high-intensity exercise and large reductions can occur after relatively short durations. Moreover, muscle glycogen is stored heterogeneously and similarly displays a heterogeneous and fiber-type specific depletion pattern with utilization in both fast- and slow-twitch fibers during high-intensity exercise, with a higher degradation rate in the former. Thus, depletion of individual fast- and slow-twitch fibers has been demonstrated despite muscle glycogen at the whole-muscle level only being moderately lowered. In addition, muscle glycogen is stored in specific subcellular compartments, which have been demonstrated to be important for muscle function and should be considered as well as global muscle glycogen availability. In the present review, we discuss the importance of glycogen metabolism for single and intermittent bouts of high-intensity exercise and outline possible underlying mechanisms for a relationship between muscle glycogen and fatigue during these types of exercise. Traditionally this relationship has been attributed to a decreased ATP resynthesis rate due to inadequate substrate availability at the whole-muscle level, but emerging evidence points to a direct coupling between muscle glycogen and steps in the excitation-contraction coupling including altered muscle excitability and calcium kinetics.
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14
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Ruiz-Iglesias A, Mañes S. The Importance of Mitochondrial Pyruvate Carrier in Cancer Cell Metabolism and Tumorigenesis. Cancers (Basel) 2021; 13:cancers13071488. [PMID: 33804985 PMCID: PMC8037430 DOI: 10.3390/cancers13071488] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 03/16/2021] [Accepted: 03/19/2021] [Indexed: 02/06/2023] Open
Abstract
Simple Summary The characteristic metabolic hallmark of cancer cells is the massive catabolism of glucose by glycolysis, even under aerobic conditions—the so-called Warburg effect. Although energetically unfavorable, glycolysis provides “building blocks” to sustain the unlimited growth of malignant cells. Aberrant glycolysis is also responsible for lactate accumulation and acidosis in the tumor milieu, which fosters hypoxia and immunosuppression. One of the mechanisms used by cancer cells to increase glycolytic flow is the negative regulation of the proteins that conform the mitochondrial pyruvate carrier (MPC) complex, which transports pyruvate into the mitochondrial matrix to be metabolized in the tricarboxylic acid (TCA) cycle. Evidence suggests that MPC downregulation in tumor cells impacts many aspects of tumorigenesis, including cancer cell-intrinsic (proliferation, invasiveness, stemness, resistance to therapy) and -extrinsic (angiogenesis, anti-tumor immune activity) properties. In many cancers, but not in all, MPC downregulation is associated with poor survival. MPC regulation is therefore central to tackling glycolysis in tumors. Abstract Pyruvate is a key molecule in the metabolic fate of mammalian cells; it is the crossroads from where metabolism proceeds either oxidatively or ends with the production of lactic acid. Pyruvate metabolism is regulated by many enzymes that together control carbon flux. Mitochondrial pyruvate carrier (MPC) is responsible for importing pyruvate from the cytosol to the mitochondrial matrix, where it is oxidatively phosphorylated to produce adenosine triphosphate (ATP) and to generate intermediates used in multiple biosynthetic pathways. MPC activity has an important role in glucose homeostasis, and its alteration is associated with diabetes, heart failure, and neurodegeneration. In cancer, however, controversy surrounds MPC function. In some cancers, MPC upregulation appears to be associated with a poor prognosis. However, most transformed cells undergo a switch from oxidative to glycolytic metabolism, the so-called Warburg effect, which, amongst other possibilities, is induced by MPC malfunction or downregulation. Consequently, impaired MPC function might induce tumors with strong proliferative, migratory, and invasive capabilities. Moreover, glycolytic cancer cells secrete lactate, acidifying the microenvironment, which in turn induces angiogenesis, immunosuppression, and the expansion of stromal cell populations supporting tumor growth. This review examines the latest findings regarding the tumorigenic processes affected by MPC.
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15
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The role of AMPK in regulation of Na +,K +-ATPase in skeletal muscle: does the gauge always plug the sink? J Muscle Res Cell Motil 2021; 42:77-97. [PMID: 33398789 DOI: 10.1007/s10974-020-09594-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 12/14/2020] [Indexed: 12/14/2022]
Abstract
AMP-activated protein kinase (AMPK) is a cellular energy gauge and a major regulator of cellular energy homeostasis. Once activated, AMPK stimulates nutrient uptake and the ATP-producing catabolic pathways, while it suppresses the ATP-consuming anabolic pathways, thus helping to maintain the cellular energy balance under energy-deprived conditions. As much as ~ 20-25% of the whole-body ATP consumption occurs due to a reaction catalysed by Na+,K+-ATPase (NKA). Being the single most important sink of energy, NKA might seem to be an essential target of the AMPK-mediated energy saving measures, yet NKA is vital for maintenance of transmembrane Na+ and K+ gradients, water homeostasis, cellular excitability, and the Na+-coupled transport of nutrients and ions. Consistent with the model that AMPK regulates ATP consumption by NKA, activation of AMPK in the lung alveolar cells stimulates endocytosis of NKA, thus suppressing the transepithelial ion transport and the absorption of the alveolar fluid. In skeletal muscles, contractions activate NKA, which opposes a rundown of transmembrane ion gradients, as well as AMPK, which plays an important role in adaptations to exercise. Inhibition of NKA in contracting skeletal muscle accentuates perturbations in ion concentrations and accelerates development of fatigue. However, different models suggest that AMPK does not inhibit or even stimulates NKA in skeletal muscle, which appears to contradict the idea that AMPK maintains the cellular energy balance by always suppressing ATP-consuming processes. In this short review, we examine the role of AMPK in regulation of NKA in skeletal muscle and discuss the apparent paradox of AMPK-stimulated ATP consumption.
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16
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Effect of New Zealand Blackcurrant Extract on Isometric Contraction-Induced Fatigue and Recovery: Potential Muscle-Fiber Specific Effects. Sports (Basel) 2020; 8:sports8100135. [PMID: 33076273 PMCID: PMC7602451 DOI: 10.3390/sports8100135] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 09/24/2020] [Accepted: 10/14/2020] [Indexed: 11/26/2022] Open
Abstract
New Zealand blackcurrant (NZBC) extract has shown performance-enhancing effects during cycling, running and sport climbing. We examined effects of NZBC extract on (1) voluntary and twitch force of the quadriceps femoris muscles during repeated isometric contraction-induced fatigue, (2) twitch force during recovery and (3) muscle fiber-specific effects. Familiarized recreationally active males (n = 12, age: 24 ± 5 yrs; height: 180 ± 5 cm; body mass: 89 ± 11 kg) performed sixteen, 5-s voluntary maximal isometric contractions (iMVC) separated by 3-s rest. Twitch force was recorded before, during the 3-s rests and 5-min recovery. Supplementation consisted of 7-days intake of NZBC extract (600 mg∙day−1 containing 210 mg anthocyanin) in a double-blind, randomized, placebo-controlled crossover design with a 14-days washout. NZBC extract allowed for greater force in the first quartile of the iMVCs. Twitch force at baseline was 12% higher with NZBC extract (p = 0.05). However, there was no effect of NZBC for twitch force during the 16-iMVCs and recovery. Based on the maximum post-activation potentiation during the placebo 16-iMVCs, four subjects were classified of having a predominant type I or II muscle fiber typology. In type II, NZBC extract provided a trend for increased MVC force (~14%) in the first quartile and for type I in the fourth quartile (~10%). In type I, NZBC extract seemed to have higher twitch forces during the fatiguing exercise protocol and recovery, indicating increased fatigue resistance. New Zealand blackcurrant extract affects force during repeated maximal isometric contractions. Future work on mechanisms by NZBC extract for muscle fiber-specific fatigue-induced force responses is warranted.
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17
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Hargreaves M, Spriet LL. Skeletal muscle energy metabolism during exercise. Nat Metab 2020; 2:817-828. [PMID: 32747792 DOI: 10.1038/s42255-020-0251-4] [Citation(s) in RCA: 396] [Impact Index Per Article: 99.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 06/25/2020] [Indexed: 12/12/2022]
Abstract
The continual supply of ATP to the fundamental cellular processes that underpin skeletal muscle contraction during exercise is essential for sports performance in events lasting seconds to several hours. Because the muscle stores of ATP are small, metabolic pathways must be activated to maintain the required rates of ATP resynthesis. These pathways include phosphocreatine and muscle glycogen breakdown, thus enabling substrate-level phosphorylation ('anaerobic') and oxidative phosphorylation by using reducing equivalents from carbohydrate and fat metabolism ('aerobic'). The relative contribution of these metabolic pathways is primarily determined by the intensity and duration of exercise. For most events at the Olympics, carbohydrate is the primary fuel for anaerobic and aerobic metabolism. Here, we provide an overview of exercise metabolism and the key regulatory mechanisms ensuring that ATP resynthesis is closely matched to the ATP demand of exercise. We also summarize various interventions that target muscle metabolism for ergogenic benefit in athletic events.
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Affiliation(s)
- Mark Hargreaves
- Department of Physiology, University of Melbourne, Melbourne, Victoria, Australia.
| | - Lawrence L Spriet
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada.
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18
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Wernbom M, Aagaard P. Muscle fibre activation and fatigue with low-load blood flow restricted resistance exercise-An integrative physiology review. Acta Physiol (Oxf) 2020; 228:e13302. [PMID: 31108025 DOI: 10.1111/apha.13302] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 05/12/2019] [Accepted: 05/17/2019] [Indexed: 12/13/2022]
Abstract
Blood flow-restricted resistance exercise (BFRRE) has been shown to induce increases in muscle size and strength, and continues to generate interest from both clinical and basic research points of view. The low loads employed, typically 20%-50% of the one repetition maximum, make BFRRE an attractive training modality for individuals who may not tolerate high musculoskeletal forces (eg, selected clinical patient groups such as frail old adults and patients recovering from sports injury) and/or for highly trained athletes who have reached a plateau in muscle mass and strength. It has been proposed that achieving a high degree of muscle fibre recruitment is important for inducing muscle hypertrophy with BFRRE, and the available evidence suggest that fatiguing low-load exercise during ischemic conditions can recruit both slow (type I) and fast (type II) muscle fibres. Nevertheless, closer scrutiny reveals that type II fibre activation in BFRRE has to date largely been inferred using indirect methods such as electromyography and magnetic resonance spectroscopy, while only rarely addressed using more direct methods such as measurements of glycogen stores and phosphocreatine levels in muscle fibres. Hence, considerable uncertainity exists about the specific pattern of muscle fibre activation during BFRRE. Therefore, the purpose of this narrative review was (1) to summarize the evidence on muscle fibre recruitment during BFRRE as revealed by various methods employed for determining muscle fibre usage during exercise, and (2) to discuss reported findings in light of the specific advantages and limitations associated with these methods.
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Affiliation(s)
- Mathias Wernbom
- Center for Health and Performance, Department of Food and Nutrition and Sport Science University of Gothenburg Gothenburg Sweden
- Department of Health and Rehabilitation, Institute of Neuroscience and Physiology, Sahlgrenska Academy University of Gothenburg Gothenburg Sweden
| | - Per Aagaard
- Department of Sports Sciences and Clinical Biomechanics, SDU Muscle Research Cluster (SMRC) University of Southern Denmark Odense M Denmark
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19
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Morris-Paterson TE, Stimpson SA, Miller RR, Barton ME, Leonard MS, Carmichael O, van Someren KA, Harridge SDR. Total body skeletal muscle mass estimated by magnetic resonance imaging and creatine (methyl-d 3 ) dilution in athletes. Scand J Med Sci Sports 2019; 30:421-428. [PMID: 31715651 DOI: 10.1111/sms.13585] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 10/15/2019] [Accepted: 10/21/2019] [Indexed: 01/07/2023]
Abstract
Creatine dilution (D3 -cr) is a technique for estimating total skeletal muscle mass (SMM) with practical utility, but has not been applied in athletic populations where body composition may differ to that in the normal population. This study aimed to assess the agreement between SMM derived from both D3 -cr and that obtained from whole-body magnetic resonance imaging (MRI) in 15 male and 5 female national level kayakers (stature: 182.0 ± 13.1 and 170.0 ± 9.0 cm; body mass: 80.6 ± 9.9 and 66.4 ± 6.0 kg; V̇O2 peak: 56.5 ± 7.0 and 49.6 ± 4.4 mL kg-1 min-1 , mean ± SD). SMM was determined following 60 mg of dosed D3 -cr and analysis of expelled urine collected on four subsequent days for creatine, creatinine, D3 -cr, and D3 -creatinine using liquid chromatography/mass spectroscopy. SMM was then estimated by assuming a creatine pool size of 4.3 g/kg. During the same time period, a whole-body MRI was undertaken to derive SMM from the analysis of multiple slices taken across the body. A strong positive correlation (F = 74.32; R = 0.90; P < .0001) between the two methods was observed, but the D3 -cr SMM was found to be significantly higher (43.3 ± 6.8 kg) when compared with MRI (36.3 ± 5.8 kg, P < .0001). However, the difference between the methods was removed when a higher intramuscular creatine pool (5.1 g/kg) was assumed. These data show that D3 -cr has potential utility in athletes, as referenced against MRI, but show that assumptions regarding creatine pool size need to be carefully considered.
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Affiliation(s)
- Tessa E Morris-Paterson
- Centre for Human & Applied Physiological Sciences, Faculty of Life Sciences & Medicine, King's College London, London, UK
| | - Stephen A Stimpson
- Muscle Metabolism Discovery Performance Unit, GSK, Research Triangle Park, NC, USA
| | - Ram R Miller
- Muscle Metabolism Discovery Performance Unit, GSK, Research Triangle Park, NC, USA.,Novartis Institutes for Biomedical Research, Cambridge, MA, USA
| | - Matthew E Barton
- Muscle Metabolism Discovery Performance Unit, GSK, Research Triangle Park, NC, USA.,Global Clinical Development, Gan & Lee Pharmaceuticals USA Corporation, Bridgewater, NJ, USA
| | - Michael S Leonard
- Muscle Metabolism Discovery Performance Unit, GSK, Research Triangle Park, NC, USA.,United Therapeutics, Research Triangle Park, NC, USA
| | - Owen Carmichael
- Biomedical Imaging Center, Pennington Biomedical Research Center, Baton Rouge, LA, USA
| | | | - Stephen D R Harridge
- Centre for Human & Applied Physiological Sciences, Faculty of Life Sciences & Medicine, King's College London, London, UK
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20
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Bin Naharudin MN, Yusof A, Shaw H, Stockton M, Clayton DJ, James LJ. Breakfast Omission Reduces Subsequent Resistance Exercise Performance. J Strength Cond Res 2019; 33:1766-1772. [DOI: 10.1519/jsc.0000000000003054] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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21
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Edman S, Söderlund K, Moberg M, Apró W, Blomstrand E. mTORC1 Signaling in Individual Human Muscle Fibers Following Resistance Exercise in Combination With Intake of Essential Amino Acids. Front Nutr 2019; 6:96. [PMID: 31294029 PMCID: PMC6603157 DOI: 10.3389/fnut.2019.00096] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 06/10/2019] [Indexed: 11/13/2022] Open
Abstract
Human muscles contain a mixture of type I and type II fibers with different contractile and metabolic properties. Little is presently known about the effect of anabolic stimuli, in particular nutrition, on the molecular responses of these different fiber types. Here, we examine the effect of resistance exercise in combination with intake of essential amino acids (EAA) on mTORC1 signaling in individual type I and type II human muscle fibers. Five strength-trained men performed two sessions of heavy leg press exercise. During exercise and recovery, the subjects ingested an aqueous solution of EAA (290 mg/kg) or flavored water (placebo). Muscle biopsies were taken from the vastus lateralis before and 90 min after exercise. The biopsies were freeze-dried and single fibers dissected out and weighed (range 0.95-8.1 μg). The fibers were homogenized individually and identified as type I or II by incubation with antibodies against the different isoforms of myosin. They were also analyzed for both the levels of protein as well as phosphorylation of proteins in the mTORC1 pathway using Western blotting. The levels of the S6K1 and eEF2 proteins were ~50% higher in type II than in type I fibers (P < 0.05), but no difference was found between fiber types with respect to the level of mTOR protein. Resistance exercise led to non-significant increases (2-3-fold) in mTOR and S6K1 phosphorylation as well as a 50% decrease (P < 0.05) in eEF2 phosphorylation in both fiber types. Intake of EAA caused a 2 and 6-fold higher (P < 0.05) elevation of mTOR and S6K1 phosphorylation, respectively, in both type I and type II fibers compared to placebo, with no effect on phosphorylation of eEF2. In conclusion, protein levels of S6K1 and eEF2 were significantly higher in type II than type I fibers suggesting higher capacity of the mTOR pathway in type II fibers. Ingestion of EAA enhanced the effect of resistance exercise on phosphorylation of mTOR and S6K1 in both fiber types, but with considerable variation between single fibers of both types.
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Affiliation(s)
- Sebastian Edman
- The Åstrand Laboratory, the Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Karin Söderlund
- The Åstrand Laboratory, the Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Marcus Moberg
- The Åstrand Laboratory, the Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - William Apró
- The Åstrand Laboratory, the Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Eva Blomstrand
- The Åstrand Laboratory, the Swedish School of Sport and Health Sciences, Stockholm, Sweden.,Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
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22
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Christiansen D, MacInnis MJ, Zacharewicz E, Xu H, Frankish BP, Murphy RM. A fast, reliable and sample-sparing method to identify fibre types of single muscle fibres. Sci Rep 2019; 9:6473. [PMID: 31019216 PMCID: PMC6482153 DOI: 10.1038/s41598-019-42168-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 03/08/2019] [Indexed: 11/30/2022] Open
Abstract
Many skeletal muscle proteins are present in a cell-specific or fibre-type dependent manner. Stimuli such as exercise, aging, and disease have been reported to result in fibre-specific responses in protein abundances. Thus, fibre-type-specific determination of the content of specific proteins provides enhanced mechanistic understanding of muscle physiology and biochemistry compared with typically performed whole-muscle homogenate analyses. This analysis, however, is laborious and typically not performed. We present a novel dot blotting method for easy and rapid determination of skeletal muscle fibre type based on myosin heavy chain (MHC) isoform presence. Requiring only small amounts of starting muscle tissue (i.e., 2–10 mg wet weight), muscle fibre type is determined in one-tenth of a 1–3-mm fibre segment, with the remainder of each segment pooled with fibre segments of the same type (I or II) for subsequent protein quantification by western blotting. This method, which we validated using standard western blotting, is much simpler and cheaper than previous methods and is adaptable for laboratories routinely performing biochemical analyses. Use of dot blotting for fibre typing will facilitate investigations of fibre-specific responses to diverse stimuli, which will advance our understanding of skeletal muscle physiology and biochemistry.
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Affiliation(s)
- Danny Christiansen
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, 3086, Australia.,Institute for Health and Sport (IHES), Victoria University, Melbourne, Australia
| | - Martin J MacInnis
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, 3086, Australia.,Faculty of Kinesiology, University of Calgary, Calgary, Canada
| | - Evelyn Zacharewicz
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, 3086, Australia
| | - Hongyang Xu
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, 3086, Australia
| | - Barnaby P Frankish
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, 3086, Australia
| | - Robyn M Murphy
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, 3086, Australia.
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23
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Fairman CM, Kendall KL, Hart NH, Taaffe DR, Galvão DA, Newton RU. The potential therapeutic effects of creatine supplementation on body composition and muscle function in cancer. Crit Rev Oncol Hematol 2018; 133:46-57. [PMID: 30661658 DOI: 10.1016/j.critrevonc.2018.11.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 11/07/2018] [Accepted: 11/07/2018] [Indexed: 12/16/2022] Open
Abstract
Low muscle mass in individuals with cancer has a profound impact on quality of life and independence and is associated with greater treatment toxicity and poorer prognosis. Exercise interventions are regularly being investigated as a means to ameliorate treatment-related adverse effects, and nutritional/supplementation strategies to augment adaptations to exercise are highly valuable. Creatine (Cr) is a naturally-occurring substance in the human body that plays a critical role in energy provision during muscle contraction. Given the beneficial effects of Cr supplementation on lean body mass, strength, and physical function in a variety of clinical populations, there is therapeutic potential in individuals with cancer at heightened risk for muscle loss. Here, we provide an overview of Cr physiology, summarize the evidence on the use of Cr supplementation in various aging/clinical populations, explore mechanisms of action, and provide perspectives on the potential therapeutic role of Cr in the exercise oncology setting.
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Affiliation(s)
- C M Fairman
- Exercise Medicine Research Institute, Edith Cowan University, Perth, Western Australia, Australia; School of Medical and Health Sciences, Edith Cowan University, Perth, Western Australia, Australia.
| | - K L Kendall
- School of Medical and Health Sciences, Edith Cowan University, Perth, Western Australia, Australia
| | - N H Hart
- Exercise Medicine Research Institute, Edith Cowan University, Perth, Western Australia, Australia; School of Medical and Health Sciences, Edith Cowan University, Perth, Western Australia, Australia; Institute for Health Research, University of Notre Dame Australia, Perth, Western Australia, Australia
| | - D R Taaffe
- Exercise Medicine Research Institute, Edith Cowan University, Perth, Western Australia, Australia; School of Medical and Health Sciences, Edith Cowan University, Perth, Western Australia, Australia; School of Human Movement and Nutrition Sciences, University of Queensland, Brisbane, Queensland, Australia
| | - D A Galvão
- Exercise Medicine Research Institute, Edith Cowan University, Perth, Western Australia, Australia; School of Medical and Health Sciences, Edith Cowan University, Perth, Western Australia, Australia
| | - R U Newton
- Exercise Medicine Research Institute, Edith Cowan University, Perth, Western Australia, Australia; School of Medical and Health Sciences, Edith Cowan University, Perth, Western Australia, Australia; School of Human Movement and Nutrition Sciences, University of Queensland, Brisbane, Queensland, Australia
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Rodríguez-Fernández A, Sánchez-Sánchez J, Ramirez-Campillo R, Rodríguez-Marroyo JA, Villa Vicente JG, Nakamura FY. Effects of short-term in-season break detraining on repeated-sprint ability and intermittent endurance according to initial performance of soccer player. PLoS One 2018; 13:e0201111. [PMID: 30110374 PMCID: PMC6093601 DOI: 10.1371/journal.pone.0201111] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 06/11/2018] [Indexed: 11/19/2022] Open
Abstract
To better understand the detraining effects in soccer, the purpose of the study was to analyse if performance level of soccer players modulate repeated-sprint ability (RSA) and intermittent endurance changes during 2-weeks of detraining (i.e., in-season break). Seventeen professional and sixteen young elite soccer players of two different teams performed, before and after 2-weeks of detraining, the RSA test and the Yo-Yo Intermittent Recovery Test, level 1 (YYIR1). Before detraining, professional players perform better (p < 0.05) RSA best time (RSAbest) than young players. A decrease (p < 0.05) in RSAbest, RSA total time (RSAtotal) and mean time (RSAmean) performance was observed in both teams, without changes in RSA fatigue index (Sdec). No significant changes in distance covered during YYIR1 was observed in any team. Before detraining, faster players from both teams (FG) (following the median split technique, soccer players with RSAbest ≤ 3.95 s) performed better (p < 0.01) in RSAtotal, RSAmean and RSAbest, but worse (p < 0.01) in Sdec. Although FG and the slower players (SG, RSAbest > 3.95 s) showed a worse (p < 0.05) RSAtotal, RSAbest and RSAmean performance after detraining (ES = 1.5, 1.4 and 2.9; ES = 0.6, 1.2 and 0.6; for FG and SG, respectively), the deterioration was greater in the FG for RSAbest (p < 0.05) and RSAtotal (ES = 1.46). After detraining, FG improved (p < 0.05) Sdec performance. In conclusion, a 2-week in-season break (detraining) period induced a worse RSA, with no effect on intermittent endurance in professional and elite young soccer players, with greater detrimental effects on RSAtotal and RSAbest in FG. In addition, Sdec does not seem to be sensitive to changes in RSA after a 2-week in-season break.
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Affiliation(s)
- Alejandro Rodríguez-Fernández
- Institute of Biomedicine (IBIOMED), Department of Physical Education and Sports, University of León, León, Spain
- Faculty of Physical Activity Sciences and Sports, University Isabel I, Burgos, Spain
- Unit Assessment and Planning of Sports Training, Faculty of Education, Pontifical University of Salamanca, Salamanca, Spain
| | - Javier Sánchez-Sánchez
- Institute of Biomedicine (IBIOMED), Department of Physical Education and Sports, University of León, León, Spain
- Unit Assessment and Planning of Sports Training, Faculty of Education, Pontifical University of Salamanca, Salamanca, Spain
| | - Rodrigo Ramirez-Campillo
- Unit Assessment and Planning of Sports Training, Faculty of Education, Pontifical University of Salamanca, Salamanca, Spain
- Department of Physical Activity Sciences, Universidad de Los Lagos, Osorno, Chile
| | | | - José Gerardo Villa Vicente
- Institute of Biomedicine (IBIOMED), Department of Physical Education and Sports, University of León, León, Spain
- Unit Assessment and Planning of Sports Training, Faculty of Education, Pontifical University of Salamanca, Salamanca, Spain
| | - Fabio Yuzo Nakamura
- Unit Assessment and Planning of Sports Training, Faculty of Education, Pontifical University of Salamanca, Salamanca, Spain
- Department of Medicine and Aging Sciences “G. d´Annunzio” University of Chieti-Pescara, Chieti, Italy
- The College of Healthcare Sciences, James Cook University, Townsville, Queensland, Australia
- * E-mail:
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Abstract
Many sports involve repeated bouts of high-intensity exercise. High-intensity exercise is compromised, however, by the early onset of exercise-induced fatigue. Metabolic by-products, ion dysbalance and amount of phosphocreatine are considered the main peripheral causes of fatigue during high-intensity exercise. Intake of nutritional ergogenic aids is commonplace to enhance performance of high-intensity exercise by offsetting the potential mechanisms of fatigue. Creatine, probably one of the best known nutritional aids to enhance performance of high-intensity exercise, has convincingly substantiated its ergogenic potential. Although multi-ingredient supplements are now common, the justification for effectiveness is mostly based on observations with single intake of those ingredients. In this narrative review, the main focus is on the evidence of the effect of co-ingestion of ergogenic aids on performance of high intensity exercise for which the single intake has shown beneficial effects on high-intensity performance.
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Sousa FAB, Vasque RE, Gobatto CA. Anaerobic metabolism during short all-out efforts in tethered running: Comparison of energy expenditure and mechanical parameters between different sprint durations for testing. PLoS One 2017; 12:e0179378. [PMID: 28599009 PMCID: PMC5466345 DOI: 10.1371/journal.pone.0179378] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 05/30/2017] [Indexed: 11/19/2022] Open
Abstract
This study's aims to verify the energy expenditure, metabolic distress and usefulness to evaluate the anaerobic constructs for different all-out durations in running efforts. Twelve active male underwent four testing sessions, one for familiarization and three performing one all-out (AO) tethered running sprint lasting 30s, 20s or 10s. Oxygen consumption, excess post exercise oxygen consumption, and lactate production were retained to analyse metabolic function, together with mechanical power and work as performance parameters. Paired results were compared via one-way ANOVA for repeated measures (Tukey-HSD post-hoc), effect sizes and ICC for absolute agreement. Statistical significance was accepted at p ≤ 0.05. Despite total and energy expenditure from oxidative pathway being significantly higher for longer durations (p < 0.001; ES > 0.7), glycolytic energy expenditure presented an agreement between AO30s and AO20s (ICC-A = 0.63*), while the paired comparisons to AO10s have presented significant differences (p < 0.01; ES > 1.0). Phosphagen energy expenditure were similar between all-out durations (p = 0.12; ICC-A = 0.62*; ES < 0.5). Maximum mechanical power was higher in AO10s than in AO30s (p = 0.03; ES = 0.6), not being different between AO10s and AO20s (p = 0.67; ICC-A = 0.88*; ES = 0.2) and between AO20s and AO30s (p = 0.18; ICC-A = 0.56*; ES = 0.4). In addition, agreement between work in the first ten seconds was confirmed via ICC only between AO10s and AO20s (p = 0.50; ICC-A = 0.86*; ES = 0.3), but not for the other paired comparisons (p < 0.1; ICC < 0.45; ES > 0.5). AO20s is a better alternative to estimate anaerobic power and capacity in one single test, with similar oxidative demand than AO30s.
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Affiliation(s)
- Filipe Antônio Barros Sousa
- School of Applied Sciences, University of Campinas, Limeira, Sao Paulo, Brazil
- Einstein Integrated Faculties of Limeira, Limeira, Brazil
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Thompson C, Vanhatalo A, Jell H, Fulford J, Carter J, Nyman L, Bailey SJ, Jones AM. Dietary nitrate supplementation improves sprint and high-intensity intermittent running performance. Nitric Oxide 2016; 61:55-61. [PMID: 27777094 DOI: 10.1016/j.niox.2016.10.006] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 10/19/2016] [Accepted: 10/20/2016] [Indexed: 12/30/2022]
Abstract
The influence of dietary nitrate (NO3-) supplementation on indices of maximal sprint and intermittent exercise performance is unclear. PURPOSE To investigate the effects of NO3- supplementation on sprint running performance, and cognitive function and exercise performance during the sport-specific Yo-Yo Intermittent Recovery level 1 test (IR1). METHODS In a double-blind, randomized, crossover study, 36 male team-sport players received NO3--rich (BR; 70 mL·day-1; 6.4 mmol of NO3-), and NO3--depleted (PL; 70 mL·day-1; 0.04 mmol NO3-) beetroot juice for 5 days. On day 5 of supplementation, subjects completed a series of maximal 20-m sprints followed by the Yo-Yo IR1. Cognitive tasks were completed prior to, during and immediately following the Yo-Yo IR1. RESULTS BR improved sprint split times relative to PL at 20 m (1.2%; BR 3.98 ± 0.18 vs. PL 4.03 ± 0.19 s; P < 0.05), 10 m (1.6%; BR 2.53 ± 0.12 vs. PL 2.57 ± 0.19 s; P < 0.05) and 5 m (2.3%; BR 1.73 ± 0.09 vs. PL 1.77 ± 0.09 s; P < 0.05). The distance covered in the Yo-Yo IR1 test improved by 3.9% (BR 1422 ± 502 vs. PL 1369 ± 505 m; P < 0.05). The reaction time to the cognitive tasks was shorter in BR (615 ± 98 ms) than PL (645 ± 120 ms; P < 0.05) at rest but not during the Yo-Yo IR1. There was no difference in response accuracy. CONCLUSIONS Dietary NO3- supplementation enhances maximal sprint and high-intensity intermittent running performance in competitive team sport players. Our findings suggest that NO3- supplementation has the potential to improve performance in single-sprint or multiple-sprint (team) sports.
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Affiliation(s)
| | - Anni Vanhatalo
- Sport and Health Sciences, University of Exeter, Heavitree Road, Exeter, UK
| | - Harry Jell
- Sport and Health Sciences, University of Exeter, Heavitree Road, Exeter, UK
| | - Jonathan Fulford
- NIHR Exeter Clinical Research Facility, University of Exeter, Heavitree Road, Exeter, UK
| | - James Carter
- Gatorade Sports Science Institute, PepsiCo R&D, Barrington, IL, USA
| | - Lara Nyman
- Gatorade Sports Science Institute, PepsiCo R&D, Barrington, IL, USA
| | - Stephen J Bailey
- Sport and Health Sciences, University of Exeter, Heavitree Road, Exeter, UK
| | - Andrew M Jones
- Sport and Health Sciences, University of Exeter, Heavitree Road, Exeter, UK.
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Ingestion of High Molecular Weight Carbohydrate Enhances Subsequent Repeated Maximal Power: A Randomized Controlled Trial. PLoS One 2016; 11:e0163009. [PMID: 27636206 PMCID: PMC5026365 DOI: 10.1371/journal.pone.0163009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 09/01/2016] [Indexed: 12/25/2022] Open
Abstract
Athletes in sports demanding repeat maximal work outputs frequently train concurrently utilizing sequential bouts of intense endurance and resistance training sessions. On a daily basis, maximal work within subsequent bouts may be limited by muscle glycogen availability. Recently, the ingestion of a unique high molecular weight (HMW) carbohydrate was found to increase glycogen re-synthesis rate and enhance work output during subsequent endurance exercise, relative to low molecular weight (LMW) carbohydrate ingestion. The effect of the HMW carbohydrate, however, on the performance of intense resistance exercise following prolonged-intense endurance training is unknown. Sixteen resistance trained men (23±3 years; 176.7±9.8 cm; 88.2±8.6 kg) participated in a double-blind, placebo-controlled, randomized 3-way crossover design comprising a muscle-glycogen depleting cycling exercise followed by ingestion of placebo (PLA), or 1.2 g•kg•bw-1 of LMW or HMW carbohydrate solution (10%) with blood sampling for 2-h post-ingestion. Thereafter, participants performed 5 sets of 10 maximal explosive repetitions of back squat (75% of 1RM). Compared to PLA, ingestion of HMW (4.9%, 90%CI 3.8%, 5.9%) and LMW (1.9%, 90%CI 0.8%, 3.0%) carbohydrate solutions substantially increased power output during resistance exercise, with the 3.1% (90% CI 4.3, 2.0%) almost certain additional gain in power after HMW-LMW ingestion attributed to higher movement velocity after force kinematic analysis (HMW-LMW 2.5%, 90%CI 1.4, 3.7%). Both carbohydrate solutions increased post-exercise plasma glucose, glucoregulatory and gut hormones compared to PLA, but differences between carbohydrates were unclear; thus, the underlying mechanism remains to be elucidated. Ingestion of a HMW carbohydrate following prolonged intense endurance exercise provides superior benefits to movement velocity and power output during subsequent repeated maximal explosive resistance exercise. This study was registered with clinicaltrials.gov (NCT02778373).
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29
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Kalsen A, Hostrup M, Söderlund K, Karlsson S, Backer V, Bangsbo J. Inhaled Beta2-Agonist Increases Power Output and Glycolysis during Sprinting in Men. Med Sci Sports Exerc 2016. [PMID: 26197029 DOI: 10.1249/mss.0000000000000732] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE The aim of the present study was to investigate the effects of the beta2-agonist terbutaline (TER) on power output and muscle metabolism during maximal sprint cycling. METHODS In a randomized double-blind cross-over design, nine moderately trained men (VO2max = 4.6 ± 0.2 L · min(-1)) conducted a 10-s cycle sprint after inhalation of either 15 mg of TER or placebo (PLA). A muscle biopsy sample was collected before and <10 s after the sprint and was analyzed for metabolites. RESULTS The mean power and peak power during the sprint were 8.3% ± 1.1% and 7.8% ± 2.5% higher (P < 0.05) with TER than with PLA, respectively. Moreover, the net rates of glycogenolysis (6.5 ± 0.8 vs 3.1 ± 0.7 mmol glucosyl units · kg dry weight(-1) · s(-1)) and glycolysis (2.4 ± 0.2 vs 1.6 ± 0.2 mmol glucosyl units · kg dry weight(-1) · s(-1)) were higher (P < 0.05) with TER than with PLA. After the sprint, adenosine triphosphate (ATP) was reduced with PLA (P < 0.05) but not with TER. During the sprint, there was no difference in the breakdown of phosphocreatine (PCr) between treatments. Estimated anaerobic ATP utilization was 9.2% ± 4.0% higher (P < 0.05) with TER than with PLA. After the sprint, ATP in Type II fibers was lowered (P < 0.05) by 25.7% ± 7.3% with PLA but was not reduced with TER. Before the sprint, PCr in Type II fibers was 24.5% ± 7.2% lower (P < 0.05) with TER than with PLA. With PLA, breakdown of PCr was 50.2% ± 24.8% higher (P < 0.05) in Type II fibers (vs Type I fibers), whereas no difference was observed between fiber types with TER. CONCLUSION The present study shows that a TER-induced increase in power output is associated with increased rates of glycogenolysis and glycolysis in skeletal muscles. Furthermore, as TER counteracts a reduction in ATP in Type II fibers, TER may postpone fatigue development in these fibers.
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Affiliation(s)
- Anders Kalsen
- 1Respiratory Research Unit, Bispebjerg University Hospital, Copenhagen, DENMARK; 2Section of Integrated Physiology, Department of Nutrition, Exercise, and Sports, University of Copenhagen, Copenhagen, DENMARK; and 3The Swedish School of Sport and Health Sciences, Stockholm, SWEDEN
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Proia P, Di Liegro CM, Schiera G, Fricano A, Di Liegro I. Lactate as a Metabolite and a Regulator in the Central Nervous System. Int J Mol Sci 2016; 17:E1450. [PMID: 27598136 PMCID: PMC5037729 DOI: 10.3390/ijms17091450] [Citation(s) in RCA: 152] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 08/22/2016] [Accepted: 08/25/2016] [Indexed: 12/21/2022] Open
Abstract
More than two hundred years after its discovery, lactate still remains an intriguing molecule. Considered for a long time as a waste product of metabolism and the culprit behind muscular fatigue, it was then recognized as an important fuel for many cells. In particular, in the nervous system, it has been proposed that lactate, released by astrocytes in response to neuronal activation, is taken up by neurons, oxidized to pyruvate and used for synthesizing acetyl-CoA to be used for the tricarboxylic acid cycle. More recently, in addition to this metabolic role, the discovery of a specific receptor prompted a reconsideration of its role, and lactate is now seen as a sort of hormone, even involved in processes as complex as memory formation and neuroprotection. As a matter of fact, exercise offers many benefits for our organisms, and seems to delay brain aging and neurodegeneration. Now, exercise induces the production and release of lactate into the blood which can reach the liver, the heart, and also the brain. Can lactate be a beneficial molecule produced during exercise, and offer neuroprotection? In this review, we summarize what we have known on lactate, discussing the roles that have been attributed to this molecule over time.
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Affiliation(s)
- Patrizia Proia
- Department of Psychological, Pedagogical and Educational Sciences, Sport and Exercise Sciences Research Unit, University of Palermo, Palermo I-90128, Italy.
| | - Carlo Maria Di Liegro
- Department of Biological Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo (UNIPA), Palermo I-90128, Italy.
| | - Gabriella Schiera
- Department of Biological Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo (UNIPA), Palermo I-90128, Italy.
| | - Anna Fricano
- Department of Biological Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo (UNIPA), Palermo I-90128, Italy.
| | - Italia Di Liegro
- Department of Experimental Biomedicine and Clinical Neurosciences (BIONEC), University of Palermo, Palermo I-90127, Italy.
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Ferguson SK, Holdsworth CT, Colburn TD, Wright JL, Craig JC, Fees A, Jones AM, Allen JD, Musch TI, Poole DC. Dietary nitrate supplementation: impact on skeletal muscle vascular control in exercising rats with chronic heart failure. J Appl Physiol (1985) 2016; 121:661-9. [PMID: 27445296 DOI: 10.1152/japplphysiol.00014.2016] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 07/15/2016] [Indexed: 01/14/2023] Open
Abstract
Chronic heart failure (CHF) results in central and peripheral derangements that ultimately reduce skeletal muscle O2 delivery and impair exercise tolerance. Dietary nitrate (NO3 (-)) supplementation improves skeletal muscle vascular function and tolerance to exercise. We tested the hypothesis that NO3 (-) supplementation would elevate exercising skeletal muscle blood flow (BF) and vascular conductance (VC) in CHF rats. Myocardial infarction (MI) was induced (coronary artery ligation) in young adult male rats. After 21 days of recovery, rats randomly received 5 days of NO3 (-)-rich beetroot juice (CHF + BR, n = 10) or a placebo (CHF, n = 10). Mean arterial pressure (carotid artery catheter) and skeletal muscle BF (radiolabeled microspheres) were measured during treadmill exercise (20 m/min, 5% grade). CHF-induced dysfunction, as determined by myocardial infarction size (29 ± 3% and 33 ± 4% in CHF and CHF + BR, respectively) and left ventricular end-diastolic pressure (18 ± 2 and 18 ± 2 mmHg in CHF and CHF + BR, respectively), and exercising mean arterial pressure (131 ± 3 and 128 ± 4 mmHg in CHF and CHF + BR, respectively) were not different (P > 0.05) between groups. Total exercising hindlimb skeletal muscle BF (95 ± 5 and 116 ± 9 ml·min(-1)·100 g(-1) in CHF and CHF + BR, respectively) and VC (0.75 ± 0.05 and 0.90 ± 0.05 ml·min(-1)·100 g(-1)·mmHg(-1) in CHF and CHF + BR, respectively) were 22% and 20% greater in BR-supplemented rats, respectively (P < 0.05). During exercise, BF in 9 and VC in 10 hindlimb muscles and muscle portions were significantly greater in the CHF + BR group. These results provide strong evidence that dietary NO3 (-) supplementation improves skeletal muscle vascular function during exercise in rats with CHF and, thus, support the use of BR as a novel therapeutic modality for the treatment of CHF.
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Affiliation(s)
- Scott K Ferguson
- Department of Anatomy and Physiology, Kansas State University, Manhattan, Kansas; Cardiovascular and Pulmonary Research Laboratory, Department of Medicine, University of Colorado Denver, Anschutz Medical Campus, Aurora, Colorado
| | - Clark T Holdsworth
- Department of Anatomy and Physiology, Kansas State University, Manhattan, Kansas
| | - Trenton D Colburn
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Jennifer L Wright
- Department of Anatomy and Physiology, Kansas State University, Manhattan, Kansas
| | - Jesse C Craig
- Department of Anatomy and Physiology, Kansas State University, Manhattan, Kansas; Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Alex Fees
- Department of Anatomy and Physiology, Kansas State University, Manhattan, Kansas
| | - Andrew M Jones
- Sport and Health Sciences, University of Exeter, St. Luke's Campus, Exeter, United Kingdom; and
| | - Jason D Allen
- Institute of Sport Exercise and Active Living, Victoria University, Melbourne, Victoria, Australia
| | - Timothy I Musch
- Department of Anatomy and Physiology, Kansas State University, Manhattan, Kansas; Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - David C Poole
- Department of Anatomy and Physiology, Kansas State University, Manhattan, Kansas; Department of Kinesiology, Kansas State University, Manhattan, Kansas
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Taylor CW, Ingham SA, Hunt JEA, Martin NRW, Pringle JSM, Ferguson RA. Exercise duration-matched interval and continuous sprint cycling induce similar increases in AMPK phosphorylation, PGC-1α and VEGF mRNA expression in trained individuals. Eur J Appl Physiol 2016; 116:1445-54. [PMID: 27251406 PMCID: PMC4943987 DOI: 10.1007/s00421-016-3402-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 05/19/2016] [Indexed: 01/19/2023]
Abstract
Purpose The effects of low-volume interval and continuous ‘all-out’ cycling, matched for total exercise duration, on mitochondrial and angiogenic cell signalling was investigated in trained individuals. Methods In a repeated measures design, 8 trained males (\documentclass[12pt]{minimal}
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\begin{document}$$\dot{V}{\text{O}}_{{2{\text{peak}}}}$$\end{document}V˙O2peak, 57 ± 7 ml kg−1 min−1) performed two cycling exercise protocols; interval (INT, 4 × 30 s maximal sprints interspersed by 4 min passive recovery) or continuous (CON, 2 min continuous maximal sprint). Muscle biopsies were obtained before, immediately after and 3 h post-exercise. Results Total work was 53 % greater (P = 0.01) in INT compared to CON (71.2 ± 7.3 vs. 46.3 ± 2.7 kJ, respectively). Phosphorylation of AMPKThr172 increased by a similar magnitude (P = 0.347) immediately post INT and CON (1.6 ± 0.2 and 1.3 ± 0.3 fold, respectively; P = 0.011), before returning to resting values at 3 h post-exercise. mRNA expression of PGC-1α (7.1 ± 2.1 vs. 5.5 ± 1.8 fold; P = 0.007), VEGF (3.5 ± 1.2 vs. 4.3 ± 1.8 fold; P = 0.02) and HIF-1α (2.0 ± 0.5 vs. 1.5 ± 0.3 fold; P = 0.04) increased at 3 h post-exercise in response to INT and CON, respectively; the magnitude of which were not different between protocols. Conclusions Despite differences in total work done, low-volume INT and CON ‘all-out’ cycling, matched for exercise duration, provides a similar stimulus for the induction of mitochondrial and angiogenic cell signalling pathways in trained skeletal muscle.
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Affiliation(s)
- Conor W Taylor
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK.,English Institute of Sport, EIS Performance Centre, Loughborough University, Loughborough, LE11 3TU, UK.,English Institute of Sport, Manchester Institute of Health and Performance, 299 Alan Turing Way, Manchester, M11 3BS, UK
| | - Stephen A Ingham
- English Institute of Sport, EIS Performance Centre, Loughborough University, Loughborough, LE11 3TU, UK
| | - Julie E A Hunt
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK.,Faculty of Health and Medical Sciences, School of Biosciences and Medicine, University of Surrey, Guildford, GU2 7YW, UK
| | - Neil R W Martin
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK
| | - Jamie S M Pringle
- English Institute of Sport, EIS Performance Centre, Loughborough University, Loughborough, LE11 3TU, UK.,British Athletics, National Performance Institute, Loughborough University, Loughborough, LE11 3TU, UK
| | - Richard A Ferguson
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK.
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33
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Vanhatalo A, Black MI, DiMenna FJ, Blackwell JR, Schmidt JF, Thompson C, Wylie LJ, Mohr M, Bangsbo J, Krustrup P, Jones AM. The mechanistic bases of the power-time relationship: muscle metabolic responses and relationships to muscle fibre type. J Physiol 2016; 594:4407-23. [PMID: 26940850 DOI: 10.1113/jp271879] [Citation(s) in RCA: 121] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 03/01/2016] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS The power-asymptote (critical power; CP) of the hyperbolic power-time relationship for high-intensity exercise defines a threshold between steady-state and non-steady-state exercise intensities and the curvature constant (W') indicates a fixed capacity for work >CP that is related to a loss of muscular efficiency. The present study reports novel evidence on the muscle metabolic underpinnings of CP and W' during whole-body exercise and their relationships to muscle fibre type. We show that the W' is not correlated with muscle fibre type distribution and that it represents an elevated energy contribution from both oxidative and glycolytic/glycogenolytic metabolism. We show that there is a positive correlation between CP and highly oxidative type I muscle fibres and that muscle metabolic steady-state is attainable <CP but not >CP. Our findings indicate a mechanistic link between the bioenergetic characteristics of muscle fibre types and the power-time relationship for high-intensity exercise. ABSTRACT We hypothesized that: (1) the critical power (CP) will represent a boundary separating steady-state from non-steady-state muscle metabolic responses during whole-body exercise and (2) that the CP and the curvature constant (W') of the power-time relationship for high-intensity exercise will be correlated with type I and type IIx muscle fibre distributions, respectively. Four men and four women performed a 3 min all-out cycling test for the estimation of CP and constant work rate (CWR) tests slightly >CP until exhaustion (Tlim ), slightly <CP for 24 min and until the >CP Tlim isotime to test the first hypothesis. Eleven men performed 3 min all-out tests and donated muscle biopsies to test the second hypothesis. Below CP, muscle [PCr] [42.6 ± 7.1 vs. 49.4 ± 6.9 mmol (kg d.w.)(-1) ], [La(-) ] [34.8 ± 12.6 vs. 35.5 ± 13.2 mmol (kg d.w.)(-1) ] and pH (7.11 ± 0.08 vs. 7.10 ± 0.11) remained stable between ∼12 and 24 min (P > 0.05 for all), whereas these variables changed with time >CP such that they were greater [[La(-) ] 95.6 ± 14.1 mmol (kg d.w.)(-1) ] and lower [[PCr] 24.2 ± 3.9 mmol (kg d.w.)(-1) ; pH 6.84 ± 0.06] (P < 0.05) at Tlim (740 ± 186 s) than during the <CP trial. The CP (234 ± 53 W) was correlated with muscle type I (r = 0.67, P = 0.025) and inversely correlated with muscle type IIx fibre proportion (r = -0.76, P = 0.01). There was no relationship between W' (19.4 ± 6.3 kJ) and muscle fibre type. These data indicate a mechanistic link between the bioenergetic characteristics of different muscle fibre types and the power-duration relationship. The CP reflects the bioenergetic characteristics of highly oxidative type I muscle fibres, such that a muscle metabolic steady-state is attainable below and not above CP.
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Affiliation(s)
- Anni Vanhatalo
- College of Life and Environmental Sciences, St Luke's Campus, University of Exeter, Exeter, UK
| | - Matthew I Black
- College of Life and Environmental Sciences, St Luke's Campus, University of Exeter, Exeter, UK
| | - Fred J DiMenna
- Teachers College, Department of Biobehavioral Sciences, Columbia University, New York, NY, USA
| | - Jamie R Blackwell
- College of Life and Environmental Sciences, St Luke's Campus, University of Exeter, Exeter, UK
| | - Jakob Friis Schmidt
- Department of Nutrition, Exercise and Sports, The August Krogh Building, University of Copenhagen, Copenhagen, Denmark
| | - Christopher Thompson
- College of Life and Environmental Sciences, St Luke's Campus, University of Exeter, Exeter, UK
| | - Lee J Wylie
- College of Life and Environmental Sciences, St Luke's Campus, University of Exeter, Exeter, UK
| | - Magni Mohr
- Faculty of Natural and Health Sciences, University of the Faroe Islands, Tórshavn, Faroe Islands.,Center of Health and Human Performance, Department of Food and Nutrition, and Sport Science, University of Gothenburg, Gothenburg, Sweden
| | - Jens Bangsbo
- Department of Nutrition, Exercise and Sports, The August Krogh Building, University of Copenhagen, Copenhagen, Denmark
| | - Peter Krustrup
- College of Life and Environmental Sciences, St Luke's Campus, University of Exeter, Exeter, UK.,Department of Nutrition, Exercise and Sports, The August Krogh Building, University of Copenhagen, Copenhagen, Denmark
| | - Andrew M Jones
- College of Life and Environmental Sciences, St Luke's Campus, University of Exeter, Exeter, UK
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Liu SZ, Jemiolo B, Lavin KM, Lester BE, Trappe SW, Trappe TA. Prostaglandin E2/cyclooxygenase pathway in human skeletal muscle: influence of muscle fiber type and age. J Appl Physiol (1985) 2015; 120:546-51. [PMID: 26607246 DOI: 10.1152/japplphysiol.00396.2015] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 11/22/2015] [Indexed: 01/04/2023] Open
Abstract
Prostaglandin E2 (PGE2) produced by the cyclooxygenase (COX) pathway regulates skeletal muscle protein turnover and exercise training adaptations. The purpose of this study was twofold: 1) define the PGE2/COX pathway enzymes and receptors in human skeletal muscle, with a focus on type I and II muscle fibers; and 2) examine the influence of aging on this pathway. Muscle biopsies were obtained from the soleus (primarily type I fibers) and vastus lateralis (proportionally more type II fibers than soleus) of young men and women (n = 8; 26 ± 2 yr), and from the vastus lateralis of young (n = 8; 25 ± 1 yr) and old (n = 12; 79 ± 2 yr) men and women. PGE2/COX pathway proteins [COX enzymes (COX-1 and COX-2), PGE2 synthases (cPGES, mPGES-1, and mPGES-2), and PGE2 receptors (EP1, EP2, EP3, and EP4)] were quantified via Western blot. COX-1, cPGES, mPGES-2, and all four PGE2 receptors were detected in all skeletal muscle samples examined. COX-1 (P < 0.1) and mPGES-2 were ∼20% higher, while EP3 was 99% higher and EP4 57% lower in soleus compared with vastus lateralis (P < 0.05). Aging did not change the level of skeletal muscle COX-1, while cPGES increased 45% and EP1 (P < 0.1), EP3, and EP4 decreased ∼33% (P < 0.05). In summary, PGE2 production capacity and receptor levels are different in human skeletal muscles with markedly different type I and II muscle fiber composition. In aging skeletal muscle, PGE2 production capacity is elevated and receptor levels are downregulated. These findings have implications for understanding the regulation of skeletal muscle adaptations to exercise and aging by the PGE2/COX pathway and related inhibitors.
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Affiliation(s)
- Sophia Z Liu
- Human Performance Laboratory, Ball State University, Muncie, Indiana
| | - Bozena Jemiolo
- Human Performance Laboratory, Ball State University, Muncie, Indiana
| | - Kaleen M Lavin
- Human Performance Laboratory, Ball State University, Muncie, Indiana
| | - Bridget E Lester
- Human Performance Laboratory, Ball State University, Muncie, Indiana
| | - Scott W Trappe
- Human Performance Laboratory, Ball State University, Muncie, Indiana
| | - Todd A Trappe
- Human Performance Laboratory, Ball State University, Muncie, Indiana
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Taylor CW, Ingham SA, Ferguson RA. Acute and chronic effect of sprint interval training combined with postexercise blood-flow restriction in trained individuals. Exp Physiol 2015; 101:143-54. [PMID: 26391312 DOI: 10.1113/ep085293] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 09/16/2015] [Indexed: 12/25/2022]
Abstract
This investigation assessed the efficacy of sprint interval training (SIT) combined with postexercise blood-flow restriction as a novel approach to enhance maximal aerobic physiology and performance. In study 1, a between-groups design was used to determine whether 4 weeks (2 days per week) of SIT (repeated 30 s maximal sprint cycling) combined with postexercise blood-flow restriction (BFR) enhanced maximal oxygen uptake (V̇(O2max)) and 15 km cycling time-trial performance (15 km TT) compared with SIT alone (CON) in trained individuals. The V̇(O2max) increased after BFR by 4.5% (P = 0.01) but was unchanged after CON. There was no difference in 15 km TT performance after CON or BFR. In study 2, using a repeated-measures design, participants performed an acute bout of either BFR or CON. Muscle biopsies were taken before and after exercise to examine the activation of signalling pathways regulating angiogenesis and mitochondrial biogenesis. Phosphorylation of p38MAPK(Thr180/Tyr182) increased by a similar extent after CON and BFR. There was no difference in the magnitude of increase in PGC-1α, VEGF and VEGFR-2 mRNA expression between protocols; however, HIF-1α mRNA expression increased (P = 0.04) at 3 h only after BFR. We have demonstrated the potency of combining BFR with SIT in increasing V̇(O2max) in trained individuals, but this did not translate to an enhanced exercise performance. Sprint interval training alone did not induce any observable adaptation. Although the mechanisms are not fully understood, we present preliminary evidence that BFR leads to enhanced HIF-1α-mediated cell signalling.
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Affiliation(s)
- Conor W Taylor
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK.,English Institute of Sport, Performance Centre, Loughborough University, Loughborough, UK
| | - Stephen A Ingham
- English Institute of Sport, Performance Centre, Loughborough University, Loughborough, UK
| | - Richard A Ferguson
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
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Baker LB, Rollo I, Stein KW, Jeukendrup AE. Acute Effects of Carbohydrate Supplementation on Intermittent Sports Performance. Nutrients 2015; 7:5733-63. [PMID: 26184303 PMCID: PMC4517026 DOI: 10.3390/nu7075249] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 06/26/2015] [Accepted: 06/30/2015] [Indexed: 12/24/2022] Open
Abstract
Intermittent sports (e.g., team sports) are diverse in their rules and regulations but similar in the pattern of play; that is, intermittent high-intensity movements and the execution of sport-specific skills over a prolonged period of time (~1–2 h). Performance during intermittent sports is dependent upon a combination of anaerobic and aerobic energy systems, both of which rely on muscle glycogen and/or blood glucose as an important substrate for energy production. The aims of this paper are to review: (1) potential biological mechanisms by which carbohydrate may impact intermittent sport performance; (2) the acute effects of carbohydrate ingestion on intermittent sport performance, including intermittent high-intensity exercise capacity, sprinting, jumping, skill, change of direction speed, and cognition; and (3) what recommendations can be derived for carbohydrate intake before/during exercise in intermittent sports based on the available evidence. The most researched intermittent sport is soccer but some sport-specific studies have also been conducted in other sports (e.g., rugby, field hockey, basketball, American football, and racquet sports). Carbohydrate ingestion before/during exercise has been shown in most studies to enhance intermittent high-intensity exercise capacity. However, studies have shown mixed results with regards to the acute effects of carbohydrate intake on sprinting, jumping, skill, change of direction speed, and cognition. In most of these studies the amount of carbohydrate consumed was ~30–60 g/h in the form of a 6%–7% carbohydrate solution comprised of sucrose, glucose, and/or maltodextrin. The magnitude of the impact that carbohydrate ingestion has on intermittent sport performance is likely dependent on the carbohydrate status of the individual; that is, carbohydrate ingestion has the greatest impact on performance under circumstances eliciting fatigue and/or hypoglycemia. Accordingly, carbohydrate ingestion before and during a game seems to have the greatest impact on intermittent sports performance towards the end of the game.
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Affiliation(s)
- Lindsay B Baker
- Gatorade Sports Science Institute, Barrington, IL 60010, USA.
| | - Ian Rollo
- Gatorade Sports Science Institute, Beaumont Park, Leicester LE3 9QH, UK.
| | | | - Asker E Jeukendrup
- School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire LE11 3TU, UK.
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Abstract
Skeletal muscle has the capacity to increase energy turnover by ∼1000 times its resting rate when contracting at the maximum force/power output. Since ATP is not stored in any appreciable quantity, the muscle requires a coordinated metabolic response to maintain an adequate supply of ATP to sustain contractile activity. The integration of intracellular metabolic pathways is dependent upon the cross-bridge cycling rate of myosin and actin, substrate availability and the accumulation of metabolic byproducts, all of which can influence the maintenance of contractile activity or result in the onset of fatigue. In addition, the mobilisation of extracellular substrates is dependent upon the integration of both the autonomic nervous system and endocrine systems to coordinate an increase in both carbohydrate and fat availability. The current review examines the evidence for skeletal muscle to generate power over short and long durations and discusses the metabolic response to sustain these processes. The review also considers the endocrine response from the perspective of the sympathoadrenal system to integrate extracellular substrate availability with the increased energy demands made by contracting skeletal muscle. Finally, the review briefly discusses the evidence that muscle acts in an endocrine manner during exercise and what role this might play in mobilising extracellular substrates to augment the effects of the sympathoadrenal system.
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Affiliation(s)
- Derek Ball
- School of Life SciencesHeriot-Watt University, Edinburgh EH14 4AS, UK
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38
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Ferguson SK, Holdsworth CT, Wright JL, Fees AJ, Allen JD, Jones AM, Musch TI, Poole DC. Microvascular oxygen pressures in muscles comprised of different fiber types: Impact of dietary nitrate supplementation. Nitric Oxide 2014; 48:38-43. [PMID: 25280991 DOI: 10.1016/j.niox.2014.09.157] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 09/08/2014] [Accepted: 09/15/2014] [Indexed: 10/24/2022]
Abstract
Nitrate (NO3(-)) supplementation via beetroot juice (BR) preferentially improves vascular conductance and O2 delivery to contracting skeletal muscles comprised predominantly of type IIb + d/x (i.e. highly glycolytic) fibers following its reduction to nitrite and nitric oxide (NO). To address the mechanistic basis for NO3(-) to improve metabolic control we tested the hypothesis that BR supplementation would elevate microvascular PO2 (PO2mv) in fast twitch but not slow twitch muscle. Twelve young adult male Sprague-Dawley rats were administered BR ([NO3(-)] 1 mmol/kg/day, n = 6) or water (control, n = 6) for 5 days. PO2mv (phosphorescence quenching) was measured at rest and during 180 s of electrically-induced 1-Hz twitch contractions (6-8 V) of the soleus (9% type IIb +d/x) and mixed portion of the gastrocnemius (MG, 91% type IIb + d/x) muscles. In the MG, but not the soleus, BR elevated contracting steady state PO2mv by ~43% (control: 14 ± 1, BR: 19 ± 2 mmHg (P < 0.05)). This higher PO2mv represents a greater blood-myocyte O2 driving force during muscle contractions thus providing a potential mechanism by which NO3(-) supplementation via BR improves metabolic control in fast twitch muscle. Recruitment of higher order type II muscle fibers is thought to play a role in the development of the VO2 slow component which is inextricably linked to the fatigue process. These data therefore provide a putative mechanism for the BR-induced improvements in high-intensity exercise performance seen in humans.
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Affiliation(s)
- Scott K Ferguson
- Department of Anatomy and Physiology, Kansas State University, Manhattan, KS 66506, USA
| | - Clark T Holdsworth
- Department of Anatomy and Physiology, Kansas State University, Manhattan, KS 66506, USA
| | - Jennifer L Wright
- Department of Anatomy and Physiology, Kansas State University, Manhattan, KS 66506, USA
| | - Alex J Fees
- Department of Anatomy and Physiology, Kansas State University, Manhattan, KS 66506, USA
| | - Jason D Allen
- Department of Community and Family Medicine, Department of Medicine, Duke University, Durham, NC 27710, USA
| | - Andrew M Jones
- Sport and Health Sciences, University of Exeter, St. Luke's Campus, Exeter EX12LU, UK
| | - Timothy I Musch
- Department of Anatomy and Physiology, Kansas State University, Manhattan, KS 66506, USA; Department of Kinesiology, Kansas State University, Manhattan, KS 66506, USA
| | - David C Poole
- Department of Anatomy and Physiology, Kansas State University, Manhattan, KS 66506, USA; Department of Kinesiology, Kansas State University, Manhattan, KS 66506, USA.
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Phillips SM, Thompson R, Oliver JL. Overestimation of required recovery time during repeated sprint exercise with self-regulated recovery. J Strength Cond Res 2014; 28:3385-92. [PMID: 25028995 DOI: 10.1519/jsc.0000000000000529] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This study investigated the reliability and accuracy of self-regulated recovery time and performance during repeated sprinting. On 4 occasions, 14 men (24.5 ± 5.0 years) completed 10 × 6 seconds cycle sprints against 7.5% body mass, self-regulating (SR) recovery time to maintain performance. Subjects then repeated the test, but with a reduced recovery (RR) of 10% less recovery time. Across the first 4 trials, there were no between-trial differences in peak power output (PPO) or mean power output (MPO), recovery time, or fatigue index (p > 0.05). Random variation in recovery time was reduced across trials 3-4 (coefficient of variation [CV] = 7.5%, 95% confidence limits [CL] = 5.4-12.4%) compared with trials 1-2 (CV = 16.0, 95% CL = 11.4-27.0%) and 2-3 (CV = 10.1%, 95% CL = 7.2-16.7%) but was consistent across trials for PPO and MPO (between-trials CV, ≤3.3%). There were no trial effects for any performance, physiological, or perceptual measures when comparing SR with RR (p > 0.05), although heart rate and perceptual measures increased with subsequent sprint efforts (p ≤ 0.05). After 2 familiarization trials, subjects can reliably self-regulate recovery time to maintain performance during repeated sprints. However, subjects overestimate the amount of recovery time required, as reducing this time by 10% had no effect on performance, perceptual, or physiological parameters. Self-regulated sprinting is potentially a reliable training tool, particularly for sprint training where maintenance of work is desired. However, overestimation of required recovery time means that performance improvements may not be achieved if the goal of training is improvement of repeated sprint performance with incomplete recovery.
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Affiliation(s)
- Shaun M Phillips
- 1Division of Sport and Exercise Sciences, Abertay University, Dundee, United Kingdom; 2Physical Education and Sport Sciences Department, University of Limerick, Limerick, United Kingdom; and 3Cardiff School of Sport, Cardiff Metropolitan University, Cardiff, United Kingdom
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Scribbans TD, Edgett BA, Vorobej K, Mitchell AS, Joanisse SD, Matusiak JBL, Parise G, Quadrilatero J, Gurd BJ. Fibre-specific responses to endurance and low volume high intensity interval training: striking similarities in acute and chronic adaptation. PLoS One 2014; 9:e98119. [PMID: 24901767 PMCID: PMC4047011 DOI: 10.1371/journal.pone.0098119] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 04/28/2014] [Indexed: 11/18/2022] Open
Abstract
The current study involved the completion of two distinct experiments. Experiment 1 compared fibre specific and whole muscle responses to acute bouts of either low-volume high-intensity interval training (LV-HIT) or moderate-intensity continuous endurance exercise (END) in a randomized crossover design. Experiment 2 examined the impact of a six-week training intervention (END or LV-HIT; 4 days/week), on whole body and skeletal muscle fibre specific markers of aerobic and anaerobic capacity. Six recreationally active men (Age: 20.7±3.8 yrs; VO2peak: 51.9±5.1 mL/kg/min) reported to the lab on two separate occasions for experiment 1. Following a muscle biopsy taken in a fasted state, participants completed an acute bout of each exercise protocol (LV-HIT: 8, 20-second intervals at ∼170% of VO2peak separated by 10 seconds of rest; END: 30 minutes at ∼65% of VO2peak), immediately followed by a muscle biopsy. Glycogen content of type I and IIA fibres was significantly (p<0.05) reduced, while p-ACC was significantly increased (p<0.05) following both protocols. Nineteen recreationally active males (n = 16) and females (n = 3) were VO2peak-matched and assigned to either the LV-HIT (n = 10; 21±2 yrs) or END (n = 9; 20.7±3.8 yrs) group for experiment 2. After 6 weeks, both training protocols induced comparable increases in aerobic capacity (END: Pre: 48.3±6.0, Mid: 51.8±6.0, Post: 55.0±6.3 mL/kg/min LV-HIT: Pre: 47.9±8.1, Mid: 50.4±7.4, Post: 54.7±7.6 mL/kg/min), fibre-type specific oxidative and glycolytic capacity, glycogen and IMTG stores, and whole-muscle capillary density. Interestingly, only LV-HIT induced greater improvements in anaerobic performance and estimated whole-muscle glycolytic capacity. These results suggest that 30 minutes of END exercise at ∼65% VO2peak or 4 minutes of LV-HIT at ∼170% VO2peak induce comparable changes in the intra-myocellular environment (glycogen content and signaling activation); correspondingly, training-induced adaptations resulting for these protocols, and other HIT and END protocols are strikingly similar.
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Affiliation(s)
- Trisha D. Scribbans
- School of Kinesiology and Health Studies, Queen’s University, Kingston, Ontario, Canada
| | - Brittany A. Edgett
- School of Kinesiology and Health Studies, Queen’s University, Kingston, Ontario, Canada
| | - Kira Vorobej
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Andrew S. Mitchell
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Sophie D. Joanisse
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | | | - Gianni Parise
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Joe Quadrilatero
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Brendon J. Gurd
- School of Kinesiology and Health Studies, Queen’s University, Kingston, Ontario, Canada
- * E-mail:
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Hatef B, Bahrpeyma F, Mohajeri Tehrani MR. The comparison of muscle strength and short-term endurance in the different periods of type 2 diabetes. J Diabetes Metab Disord 2014; 13:22. [PMID: 24476108 PMCID: PMC3929159 DOI: 10.1186/2251-6581-13-22] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Accepted: 12/19/2013] [Indexed: 12/25/2022]
Abstract
Background Patients with type 2 diabetes (T2DM) are subjected to reduction in the quality and oxidative capacity of muscles. The effect of duration of diabetes on the muscle endurance response is not clear and strength as well. Objective The aim of this study was the assessment of strength and endurance of knee extensor and flexor in the patients with T2DM < 10 and T2DM > 10 years in comparison with age, sex, BMI, ABI and PAI-matched health control subjects. Methods Isometric maximal peak torque (MPT) of knee extensor and flexor before and after 40 isokinetic repetitions with velocity of 150 degree/s were recorded in 18 patients with T2DM < 10 Y , 12 patients with T2DM > 10 Y and 20 matched health control (HC) groups. Results Both diabetic patient groups had significant lower isometric and isotonic knee extensor and flexor strength than HC. The endurance indices indicated that whereas the isometric MPT of flexor movement was reduced after isokinetic protocol in the both patient groups in comparison with HC, the less decline was seen in the isotonic torque and work during isokinetic protocol in the T2DM > 10 Y group in comparison with two other groups. The HbA1c and FPG were significantly correlated with strength not with endurance indices. Conclusions It seems the progression of diabetes accompanied with vascular, neural and muscular deficits activate, some adaptive and compensatory processes which can maintain muscle performance.
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Affiliation(s)
| | - Farid Bahrpeyma
- Department of physical therapy, Faculty of Medical Science, Tarbiat Modares University, Tehran, Iran.
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Cairns SP. Holistic approaches to understanding mechanisms of fatigue in high-intensity sport. FATIGUE-BIOMEDICINE HEALTH AND BEHAVIOR 2013. [DOI: 10.1080/21641846.2013.765086] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Dietary nitrate supplementation improves team sport-specific intense intermittent exercise performance. Eur J Appl Physiol 2013; 113:1673-84. [PMID: 23370859 DOI: 10.1007/s00421-013-2589-8] [Citation(s) in RCA: 144] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 01/08/2013] [Indexed: 10/27/2022]
Abstract
Recent studies have suggested that dietary inorganic nitrate (NO₃(-)) supplementation may improve muscle efficiency and endurance exercise tolerance but possible effects during team sport-specific intense intermittent exercise have not been examined. We hypothesized that NO₃(-) supplementation would enhance high-intensity intermittent exercise performance. Fourteen male recreational team-sport players were assigned in a double-blind, randomized, crossover design to consume 490 mL of concentrated, nitrate-rich beetroot juice (BR) and nitrate-depleted placebo juice (PL) over ~30 h preceding the completion of a Yo-Yo intermittent recovery level 1 test (Yo-Yo IR1). Resting plasma nitrite concentration ([NO₂(-)]) was ~400% greater in BR compared to PL. Plasma [NO₂(-)] declined by 20% in PL (P < 0.05) and by 54 % in BR (P < 0.05) from pre-exercise to end-exercise. Performance in the Yo-Yo IR1 was 4.2% greater (P < 0.05) with BR (1,704 ± 304 m) compared to PL (1,636 ± 288 m). Blood [lactate] was not different between BR and PL, but the mean blood [glucose] was lower (3.8 ± 0.8 vs. 4.2 ± 1.1 mM, P < 0.05) and the rise in plasma [K(+)] tended to be reduced in BR compared to PL (P = 0.08). These findings suggest that NO₃(-) supplementation may promote NO production via the nitrate-nitrite-NO pathway and enhance Yo-Yo IR1 test performance, perhaps by facilitating greater muscle glucose uptake or by better maintaining muscle excitability. Dietary NO₃(-) supplementation improves performance during intense intermittent exercise and may be a useful ergogenic aid for team sports players.
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Bret C, Lacour JR, Bourdin M, Locatelli E, De Angelis M, Faina M, Rahmani A, Messonnier L. Differences in lactate exchange and removal abilities between high-level African and Caucasian 400-m track runners. Eur J Appl Physiol 2012; 113:1489-98. [PMID: 23269493 DOI: 10.1007/s00421-012-2573-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Accepted: 12/07/2012] [Indexed: 11/28/2022]
Abstract
The present study aimed to investigate (1) whether high-level 400-m track runners of different ethnic origin displayed divergent post-run blood lactate concentrations (p400m[La]) and (2) if this discrepancy was based on differences in lactate exchange and removal abilities. Twenty male African (n = 12) and Caucasian (n = 8) runners, paired in terms of personal record, performed (1) an all-out 400-m run to measure p400m[La] at 3, 5 and 7 min into recovery and (2) a 1-min 25.2 km h(-1) running (not maximal but standardized) exercise followed by 90-min passive recovery to determine individual blood lactate recovery curves (IBLRC). IBLRCs were fitted to a bi-exponential time function: [Formula: see text] where γ 1 and γ 2 denote lactate exchange ability between the previously worked muscles and blood, and overall ability for lactate removal, respectively. The quantity of lactate accumulated at the end of the 1-min exercise (Q LaA) was also estimated. Our study showed that after the all-out 400-m run, p400m[La] was lower in African than in Caucasian runners at 3 and 5 min but not at 7 min into recovery. After the standardized exercise, γ 1 and γ 2 were lower (p < 0.01) and Q LaA was higher (p < 0.05) in African than in Caucasian runners. These data suggest that for similar performance levels, ethnicity involves differences in lactate accumulation, exchange and removal.
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Affiliation(s)
- Carine Bret
- Exercise Physiology Laboratory, LPE EA 4338, University of Savoie, 73 376 Le Bourget du Lac Cedex, France.
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45
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Bogdanis GC. Effects of physical activity and inactivity on muscle fatigue. Front Physiol 2012; 3:142. [PMID: 22629249 PMCID: PMC3355468 DOI: 10.3389/fphys.2012.00142] [Citation(s) in RCA: 158] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Accepted: 04/27/2012] [Indexed: 12/22/2022] Open
Abstract
The aim of this review was to examine the mechanisms by which physical activity and inactivity modify muscle fatigue. It is well known that acute or chronic increases in physical activity result in structural, metabolic, hormonal, neural, and molecular adaptations that increase the level of force or power that can be sustained by a muscle. These adaptations depend on the type, intensity, and volume of the exercise stimulus, but recent studies have highlighted the role of high intensity, short-duration exercise as a time-efficient method to achieve both anaerobic and aerobic/endurance type adaptations. The factors that determine the fatigue profile of a muscle during intense exercise include muscle fiber composition, neuromuscular characteristics, high energy metabolite stores, buffering capacity, ionic regulation, capillarization, and mitochondrial density. Muscle fiber-type transformation during exercise training is usually toward the intermediate type IIA at the expense of both type I and IIx myosin heavy-chain isoforms. High-intensity training results in increases of both glycolytic and oxidative enzymes, muscle capillarization, improved phosphocreatine resynthesis and regulation of K+, H+, and lactate ions. Decreases of the habitual activity level due to injury or sedentary lifestyle result in partial or even compete reversal of the adaptations due to previous training, manifested by reductions in fiber cross-sectional area, decreased oxidative capacity, and capillarization. Complete immobilization due to injury results in markedly decreased force output and fatigue resistance. Muscle unloading reduces electromyographic activity and causes muscle atrophy and significant decreases in capillarization and oxidative enzymes activity. The last part of the review discusses the beneficial effects of intermittent high-intensity exercise training in patients with different health conditions to demonstrate the powerful effect of exercise on health and well being.
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Affiliation(s)
- Gregory C Bogdanis
- Department of Physical Education and Sports Science, University of Athens Athens, Greece
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46
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Adijanto J, Philp NJ. The SLC16A family of monocarboxylate transporters (MCTs)--physiology and function in cellular metabolism, pH homeostasis, and fluid transport. CURRENT TOPICS IN MEMBRANES 2012. [PMID: 23177990 DOI: 10.1016/b978-0-12-394316-3.00009-0] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The SLC16A family of monocarboxylate transporters (MCTs) is composed of 14 members. MCT1 through MCT4 (MCTs 1-4) are H(+)-coupled monocarboxylate transporters, MCT8 and MCT10 transport thyroid hormone and aromatic amino acids, while the substrate specificity and function of other MCTs have yet to be determined. The focus of this review is on MCTs 1-4 because their role in lactate transport is intrinsically linked to cellular metabolism in various biological systems, including skeletal muscle, brain, retina, and testis. Although MCTs 1-4 all transport lactate, they differ in their transport kinetics and vary in tissue and subcellular distribution, where they facilitate "lactate-shuttling" between glycolytic and oxidative cells within tissues and across blood-tissue barriers. However, the role of MCTs 1-4 is not confined to cellular metabolism. By interacting with bicarbonate transport proteins and carbonic anhydrases, MCTs participate in the regulation of pH homeostasis and fluid transport in renal proximal tubule and corneal endothelium, respectively. Here, we provide a comprehensive review of MCTs 1-4, linking their cellular distribution to their functions in various parts of the human body, so that we can better understand the physiological roles of MCTs at the systemic level.
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Affiliation(s)
- Jeffrey Adijanto
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA.
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Phillips SM, Sproule J, Turner AP. Carbohydrate ingestion during team games exercise: current knowledge and areas for future investigation. Sports Med 2011; 41:559-85. [PMID: 21688869 DOI: 10.2165/11589150-000000000-00000] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
There is a growing body of research on the influence of ingesting carbohydrate-electrolyte solutions immediately prior to and during prolonged intermittent, high-intensity exercise (team games exercise) designed to replicate field-based team games. This review presents the current body of knowledge in this area, and identifies avenues of further research. Almost all early work supported the ingestion of carbohydrate-electrolyte solutions during prolonged intermittent exercise, but was subject to methodological limitations. A key concern was the use of exercise protocols characterized by prolonged periods at the same exercise intensity, the lack of maximal- or high-intensity work components and long periods of seated recovery, which failed to replicate the activity pattern or physiological demand of team games exercise. The advent of protocols specifically designed to replicate the demands of field-based team games enabled a more externally valid assessment of the influence of carbohydrate ingestion during this form of exercise. Once again, the research overwhelmingly supports carbohydrate ingestion immediately prior to and during team games exercise for improving time to exhaustion during intermittent running. While the external validity of exhaustive exercise at fixed prescribed intensities as an assessment of exercise capacity during team games may appear questionable, these assessments should perhaps not be viewed as exhaustive exercise tests per se, but as indicators of the ability to maintain high-intensity exercise, which is a recognized marker of performance and fatigue during field-based team games. Possible mechanisms of exercise capacity enhancement include sparing of muscle glycogen, glycogen resynthesis during low-intensity exercise periods and attenuated effort perception during exercise. Most research fails to show improvements in sprint performance during team games exercise with carbohydrate ingestion, perhaps due to the lack of influence of carbohydrate on sprint performance when endogenous muscle glycogen concentration remains above a critical threshold of ∼200 mmol/kg dry weight. Despite the increasing number of publications in this area, few studies have attempted to drive the research base forward by investigating potential modulators of carbohydrate efficacy during team games exercise, preventing the formulation of optimal carbohydrate intake guidelines. Potential modulators may be different from those during prolonged steady-state exercise due to the constantly changing exercise intensity and frequency, duration and intensity of rest intervals, potential for team games exercise to slow the rate of gastric emptying and the restricted access to carbohydrate-electrolyte solutions during many team games. This review highlights fluid volume, carbohydrate concentration, carbohydrate composition and solution osmolality; the glycaemic index of pre-exercise meals; fluid and carbohydrate ingestion patterns; fluid temperature; carbohydrate mouthwashes; carbohydrate supplementation in different ambient temperatures; and investigation of all of these areas in different subject populations as important avenues for future research to enable a more comprehensive understanding of carbohydrate ingestion during team games exercise.
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Affiliation(s)
- Shaun M Phillips
- Institute of Sport, Physical Education and Health Studies, University of Edinburgh, Edinburgh, UK.
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Skeletal muscle ATP turnover and single fibre ATP and PCr content during intense exercise at different muscle temperatures in humans. Pflugers Arch 2011; 462:885-93. [PMID: 21947579 DOI: 10.1007/s00424-011-1032-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Revised: 09/08/2011] [Accepted: 09/14/2011] [Indexed: 10/17/2022]
Abstract
The effect of temperature on skeletal muscle ATP turnover, pulmonary oxygen uptake and single fibre ATP and PCr content was studied during intense cycling exercise. Six healthy male subjects performed 6-min intense (Δ50%LT-VO(2peak)) cycling, at 60 rpm, under conditions of normal (N) and elevated muscle temperature (ET). Muscle biopsies obtained from the vastus lateralis at rest, 2 and 6 min were analysed for homogenate ATP, PCr, lactate and glycogen, allowing estimation of anaerobic ATP turnover. Freeze-dried single fibres from biopsies were characterised according to their myosin heavy chain composition (type I, IIA or IIAX) and analysed for ATP and PCr content. Pulmonary gas exchange was measured throughout. There was no difference in pulmonary oxygen uptake between the trials. The elevation of muscle temperature resulted in a lower (P < 0.05) PCr content, higher (P < 0.05) lactate content and greater (P < 0.05) anaerobic ATP turnover after 2 min of exercise. There was no effect of temperature on these measures at 6 min. In single fibres it was observed that in ET, there was a lower (P < 0.05) PCr content in type I fibres after 2 min with no differences between conditions after 6 min. The present study demonstrates that elevation of muscle temperature results in a greater anaerobic ATP turnover and type I fibre PCr degradation during the initial 2 min of intense exercise.
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Fuentes T, Guerra B, Ponce-González JG, Morales-Alamo D, Guadalupe-Grau A, Olmedillas H, Rodríguez-García L, Feijoo D, De Pablos-Velasco P, Fernández-Pérez L, Santana A, Calbet JAL. Skeletal muscle signaling response to sprint exercise in men and women. Eur J Appl Physiol 2011; 112:1917-27. [PMID: 21928060 DOI: 10.1007/s00421-011-2164-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Accepted: 09/02/2011] [Indexed: 11/24/2022]
Abstract
To determine if there is a sex dimorphism in the skeletal muscle signaling response to sprint exercise, 17 men and ten women performed a 30-s Wingate test. Muscle biopsies were taken before, immediately after the exercise and at 30 and 120 min during the recovery period. Thr(172)-AMPKα, Ser(221)-ACCβ, Thy(705)-STAT3, Thr(202)/Thy(204)-ERK1/2 and Thr(180)/Thy(182)-p38MAPK phosphorylation responses to sprint exercise were not statistically different between men and women. AMPKα phosphorylation was enhanced fourfold 30 min after the sprint exercise in males and females (P < 0.01). ACCβ phosphorylation was enhanced by about threefold just after the sprint test exercise and 30 min into the recovery period in males and females (P < 0.01). STAT3 phosphorylation was increased 2 h after the Wingate test compared to the value observed right after the end of the exercise (P < 0.05), and 30 min after the Wingate test there was a 2.5-fold increase in ERK1/2 phosphorylation, compared to both the pre-exercise and to the value observed right after the Wingate test (both, P < 0.05). In conclusion, the skeletal muscle signaling response to a single bout of sprint exercise mediated by AMPK, ACC, STAT3, ERK and p38MAPK is not statistically different between men and women. Marked increases in AMPKα, ACCβ, STAT3 and ERK phosphorylation were observed after a single 30-s all-out sprint (Wingate test) in the vastus lateralis.
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Affiliation(s)
- Teresa Fuentes
- Department of Physical Education, Campus Universitario de Tafira, University of Las Palmas de Gran Canaria, 35017 Las Palmas de Gran Canaria, Spain
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Blood lactate and sEMG at different knee angles during fatiguing leg press exercise. Eur J Appl Physiol 2011; 112:1349-58. [PMID: 21800091 DOI: 10.1007/s00421-011-2090-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Accepted: 07/12/2011] [Indexed: 10/17/2022]
Abstract
The purpose of this study was to examine the changes in peak power output, blood lactate concentrations and surface electromyographic activity (sEMG) of the agonist [vastus lateralis (VL) and vastus medialis (VM)] and the antagonist [biceps femoris (BF)] muscles at two angular positions intervals (90-67° and 23-0° of knee flexion), during a set of 10 repetitions leading to failure of bilateral leg press exercise. Fatiguing exercise resulted in increased blood lactate concentrations, the agonist mean rectified voltage (MRV) at 90-67° of flexion, the antagonist average MRV at 23-0° of flexion and the spectral parameter proposed by Dimitrov (FI(nsm5)) (P < 0.01-0.05). Significant decreases (P < 0.01-0.05) were observed in power output, median frequency (F(med)) of the agonist muscles at both angular position intervals and of the antagonist muscle at 90-67° of flexion. No changes were observed in the antagonist/agonist MRV activation ratio. The present data suggest that the shift of frequency spectrum to lower frequencies and the accumulation of lactate and/or H(+), but not the antagonist/agonist MRV activation ratio, may be relevant independent factors associated with fatigue.
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