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Aisyah R, Ohshima N, Watanabe D, Nakagawa Y, Sakuma T, Nitschke F, Nakamura M, Sato K, Nakahata K, Yokoyama C, Marchioni CR, Kumrungsee T, Shimizu T, Sotomaru Y, Takeo T, Nakagata N, Izumi T, Miura S, Minassian BA, Yamamoto T, Wada M, Yanaka N. GDE5/Gpcpd1 activity determines phosphatidylcholine composition in skeletal muscle and regulates contractile force in mice. Commun Biol 2024; 7:604. [PMID: 38769369 PMCID: PMC11106330 DOI: 10.1038/s42003-024-06298-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 05/07/2024] [Indexed: 05/22/2024] Open
Abstract
Glycerophosphocholine (GPC) is an important precursor for intracellular choline supply in phosphatidylcholine (PC) metabolism. GDE5/Gpcpd1 hydrolyzes GPC into choline and glycerol 3-phosphate; this study aimed to elucidate its physiological function in vivo. Heterozygous whole-body GDE5-deficient mice reveal a significant GPC accumulation across tissues, while homozygous whole-body knockout results in embryonic lethality. Skeletal muscle-specific GDE5 deletion (Gde5 skKO) exhibits reduced passive force and improved fatigue resistance in electrically stimulated gastrocnemius muscles in vivo. GDE5 deficiency also results in higher glycolytic metabolites and glycogen levels, and glycerophospholipids alteration, including reduced levels of phospholipids that bind polyunsaturated fatty acids (PUFAs), such as DHA. Interestingly, this PC fatty acid compositional change is similar to that observed in skeletal muscles of denervated and Duchenne muscular dystrophy mouse models. These are accompanied by decrease of GDE5 expression, suggesting a regulatory role of GDE5 activity for glycerophospholipid profiles. Furthermore, a DHA-rich diet enhances contractile force and lowers fatigue resistance, suggesting a functional relationship between PC fatty acid composition and muscle function. Finally, skinned fiber experiments show that GDE5 loss increases the probability of the ryanodine receptor opening and lowers the maximum Ca2+-activated force. Collectively, GDE5 activity plays roles in PC and glucose/glycogen metabolism in skeletal muscle.
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Affiliation(s)
- Rahmawati Aisyah
- Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | | | - Daiki Watanabe
- Graduate School of Humanities and Social Sciences, Hiroshima University, Hiroshima, Japan
- Graduate School of Sport and Health Sciences, Osaka University of Health and Sport Sciences, Osaka, Japan
| | - Yoshiko Nakagawa
- Center for Animal Resources and Development (CARD), Kumamoto University, Kumamoto, Japan
| | - Tetsushi Sakuma
- Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Felix Nitschke
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Minako Nakamura
- Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Koji Sato
- Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Kaori Nakahata
- Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Chihiro Yokoyama
- Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Charlotte R Marchioni
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | | | - Takahiko Shimizu
- Aging Stress Response Research Project Team, National Center for Geriatrics and Gerontology, Aichi, Japan
| | - Yusuke Sotomaru
- Natural Science Center for Basic Research and Development, Hiroshima University, Hiroshima, Japan
| | - Toru Takeo
- Center for Animal Resources and Development (CARD), Kumamoto University, Kumamoto, Japan
| | - Naomi Nakagata
- Center for Animal Resources and Development (CARD), Kumamoto University, Kumamoto, Japan
| | - Takashi Izumi
- Graduate School of Medicine, Gunma University, Gunma, Japan
- Faculty of Health Care, Teikyo Heisei University, Tokyo, Japan
| | - Shinji Miura
- Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, Shizuoka, Japan
| | - Berge A Minassian
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Takashi Yamamoto
- Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Masanobu Wada
- Graduate School of Humanities and Social Sciences, Hiroshima University, Hiroshima, Japan
| | - Noriyuki Yanaka
- Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan.
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Pignanelli C, Robertson AA, Hirsch SM, Power GA, Burr JF. The addition of blood flow restriction during resistance exercise does not increase prolonged low-frequency force depression. Exp Physiol 2024; 109:738-753. [PMID: 38562023 PMCID: PMC11061635 DOI: 10.1113/ep091753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 03/15/2024] [Indexed: 04/04/2024]
Abstract
At a given exercise intensity, blood flow restriction (BFR) reduces the volume of exercise required to impair post-exercise neuromuscular function. Compared to traditional exercise, the time course of recovery is less clear. After strenuous exercise, force output assessed with electrical muscle stimulation is impaired to a greater extent at low versus high stimulation frequencies, a condition known as prolonged low-frequency force depression (PLFFD). It is unclear if BFR increases PLFFD after exercise. This study tested if BFR during exercise increases PLFFD and slows recovery of neuromuscular function compared to regular exercise. Fifteen physically active participants performed six low-load sets of knee-extensions across four conditions: resistance exercise to task failure (RETF), resistance exercise to task failure with BFR applied continuously (BFRCONT) or intermittently (BFRINT), and resistance exercise matched to the lowest exercise volume condition (REVM). Maximal voluntary contraction (MVC) force output, voluntary activation and a force-frequency (1-100 Hz) curve were measured before and 0, 1, 2, 3, 4 and 24 h after exercise. Exercise to task failure caused similar reductions at 0 h for voluntary activation (RETF = 81.0 ± 14.2%, BFRINT = 80.9 ± 12.4% and BFRCONT = 78.6 ± 10.7%) and MVC force output (RETF = 482 ± 168 N, BFRINT = 432 ± 174 N, and BFRCONT = 443 ± 196 N), which recovered to baseline values between 4 and 24 h. PLFFD occurred only after RETF at 1 h supported by a higher frequency to evoke 50% of the force production at 100 Hz (1 h: 17.5 ± 4.4 vs. baseline: 15 ± 4.1 Hz, P = 0.0023), BFRINT (15.5 ± 4.0 Hz; P = 0.03), and REVM (14.9 ± 3.1 Hz; P = 0.002), with a trend versus BFRCONT (15.7 ± 3.5 Hz; P = 0.063). These findings indicate that, in physically active individuals, using BFR during exercise does not impair the recovery of neuromuscular function by 24 h post-exercise.
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Affiliation(s)
- Christopher Pignanelli
- Department of Human Health & Nutritional SciencesUniversity of GuelphGuelphOntarioCanada
| | - Alexa A. Robertson
- Department of Human Health & Nutritional SciencesUniversity of GuelphGuelphOntarioCanada
| | - Steven M. Hirsch
- Faculty of Kinesiology and Physical EducationUniversity of TorontoTorontoOntarioCanada
| | - Geoffrey A. Power
- Department of Human Health & Nutritional SciencesUniversity of GuelphGuelphOntarioCanada
| | - Jamie F. Burr
- Department of Human Health & Nutritional SciencesUniversity of GuelphGuelphOntarioCanada
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Nielsen J, Jensen R, Ørtenblad N. Assessments of individual fiber glycogen and mitochondrial volume percentages reveal a graded reduction in muscle oxidative power during prolonged exhaustive exercise. Scand J Med Sci Sports 2024; 34:e14571. [PMID: 38389143 DOI: 10.1111/sms.14571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 12/21/2023] [Accepted: 01/17/2024] [Indexed: 02/24/2024]
Abstract
During submaximal exercise, there is a heterogeneous recruitment of skeletal muscle fibers, with an ensuing heterogeneous depletion of muscle glycogen both within and between fiber types. Here, we show that the mean (95% CI) mitochondrial volume as a percentage of fiber volume of non-glycogen-depleted fibers was 2 (-10:6), 5 (-21:11), and 12 (-21:-2)% lower than all the sampled fibers after continuing exercise for 1, 2 h, and until task failure, respectively. Therefore, a glycogen-dependent fatigue of individual fibers during submaximal exercise may reduce the muscular oxidative power. These findings suggest a relationship between glycogen and mitochondrial content in individual muscle fibers, which is important for understanding fatigue during prolonged exercise.
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Affiliation(s)
- Joachim Nielsen
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Rasmus Jensen
- Research Center for Applied Health Science, University College South Denmark, Odense, Denmark
| | - Niels Ørtenblad
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
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Vigh-Larsen JF, Ørtenblad N, Nielsen J, Emil Andersen O, Overgaard K, Mohr M. The Role of Muscle Glycogen Content and Localization in High-Intensity Exercise Performance: A Placebo-Controlled Trial. Med Sci Sports Exerc 2022; 54:2073-2086. [PMID: 35868015 DOI: 10.1249/mss.0000000000003002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE We investigated the coupling between muscle glycogen content and localization and high-intensity exercise performance using a randomized, placebo-controlled, parallel-group design with emphasis on single-fiber subcellular glycogen concentrations and sarcoplasmic reticulum Ca 2+ kinetics. METHODS Eighteen well-trained participants performed high-intensity intermittent glycogen-depleting exercise, followed by randomization to a high- (CHO; ~1 g CHO·kg -1 ·h -1 ; n = 9) or low-carbohydrate placebo diet (PLA, <0.1 g CHO·kg -1 ·h -1 ; n = 9) for a 5-h recovery period. At baseline, after exercise, and after the carbohydrate manipulation assessments of repeated sprint ability (5 × 6-s maximal cycling sprints with 24 s of rest), neuromuscular function and ratings of perceived exertion during standardized high-intensity cycling (~90% Wmax ) were performed, while muscle and blood samples were collected. RESULTS The exercise and carbohydrate manipulations led to distinct muscle glycogen concentrations in CHO and PLA at the whole-muscle (291 ± 78 vs 175 ± 100 mmol·kg -1 dry weight (dw), P = 0.020) and subcellular level in each of three local regions ( P = 0.001-0.046). This was coupled with near-depleted glycogen concentrations in single fibers of both main fiber types in PLA, especially in the intramyofibrillar region (within the myofibrils). Furthermore, increased ratings of perceived exertion and impaired repeated sprint ability (~8% loss, P < 0.001) were present in PLA, with the latter correlating moderately to very strongly ( r = 0.47-0.71, P = 0.001-0.049) with whole-muscle glycogen and subcellular glycogen fractions. Finally, sarcoplasmic reticulum Ca 2+ uptake, but not release, was superior in CHO, whereas neuromuscular function, including prolonged low-frequency force depression, was unaffected by dietary manipulation. CONCLUSIONS Together, these results support an important role of muscle glycogen availability for high-intensity exercise performance, which may be mediated by reductions in single-fiber levels, particularly in distinct subcellular regions, despite only moderately lowered whole-muscle glycogen concentrations.
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Affiliation(s)
| | - Niels Ørtenblad
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, DENMARK
| | - Joachim Nielsen
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, DENMARK
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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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Brownstein CG, Metra M, Sabater Pastor F, Faricier R, Millet GY. Disparate Mechanisms of Fatigability in Response to Prolonged Running versus Cycling of Matched Intensity and Duration. Med Sci Sports Exerc 2022; 54:872-882. [PMID: 35072662 DOI: 10.1249/mss.0000000000002863] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
INTRODUCTION Running and cycling represent two of the most common forms of endurance exercise. However, a direct comparison of the neuromuscular consequences of these two modalities after prolonged exercise has never been made. The aim of this study was to compare the alterations in neuromuscular function induced by matched-intensity and duration cycling and running exercise. METHODS During separate visits, 17 endurance-trained male participants performed 3 h of cycling and running at 105% of the gas exchange threshold. Neuromuscular assessments were taken are preexercise, midexercise, and postexercise, including knee extensor maximal voluntary contractions (MVC), voluntary activation (VA), high- and low-frequency doublets (Db100 and Db10, respectively), potentiated twitches (Qtw,pot), motor evoked potentials (MEP), and thoracic motor evoked potentials (TMEP). RESULTS After exercise, MVC was similarly reduced by ~25% after both running and cycling. However, reductions in VA were greater after running (-16% ± 10%) than cycling (-10% ± 5%; P < 0.05). Similarly, reductions in TMEP were greater after running (-78% ± 24%) than cycling (-15% ± 60%; P = 0.01). In contrast, reductions in Db100 (running vs cycling, -6% ± 21% vs -13% ± 6%) and Db10:100 (running vs cycling, -6% ± 16% vs -19% ± 13%) were greater for cycling than running (P ≤ 0.04). CONCLUSIONS Despite similar decrements in the knee extensor MVC after running and cycling, the mechanisms responsible for force loss differed. Running-based endurance exercise is associated with greater impairments in nervous system function, particularly at the spinal level, whereas cycling-based exercise elicits greater impairments in contractile function. Differences in the mechanical and metabolic demands imposed on the quadriceps could explain the disparate mechanisms of neuromuscular impairment after these two exercise modalities.
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Affiliation(s)
- Callum G Brownstein
- Univ Lyon, UJM-Saint-Etienne, Inter-university Laboratory of Human Movement Biology, EA 7424, F-42023, Saint-Etienne, FRANCE
| | - Mélanie Metra
- Univ Lyon, UJM-Saint-Etienne, Inter-university Laboratory of Human Movement Biology, EA 7424, F-42023, Saint-Etienne, FRANCE
| | - Frederic Sabater Pastor
- Univ Lyon, UJM-Saint-Etienne, Inter-university Laboratory of Human Movement Biology, EA 7424, F-42023, Saint-Etienne, FRANCE
| | - Robin Faricier
- Univ Lyon, UJM-Saint-Etienne, Inter-university Laboratory of Human Movement Biology, EA 7424, F-42023, Saint-Etienne, FRANCE
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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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Henselmans M, Bjørnsen T, Hedderman R, Vårvik FT. The Effect of Carbohydrate Intake on Strength and Resistance Training Performance: A Systematic Review. Nutrients 2022; 14:nu14040856. [PMID: 35215506 PMCID: PMC8878406 DOI: 10.3390/nu14040856] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 02/11/2022] [Accepted: 02/16/2022] [Indexed: 12/04/2022] Open
Abstract
High carbohydrate intakes are commonly recommended for athletes of various sports, including strength trainees, to optimize performance. However, the effect of carbohydrate intake on strength training performance has not been systematically analyzed. A systematic literature search was conducted for trials that manipulated carbohydrate intake, including supplements, and measured strength, resistance training or power either acutely or after a diet and strength training program. Studies were categorized as either (1) acute supplementation, (2) exercise-induced glycogen depletion with subsequent carbohydrate manipulation, (3) short-term (2–7 days) carbohydrate manipulation or (4) changes in performance after longer-term diet manipulation and strength training. Forty-nine studies were included: 19 acute, six glycogen depletion, seven short-term and 17 long-term studies. Participants were strength trainees or athletes (39 studies), recreationally active (six studies) or untrained (four studies). Acutely, higher carbohydrate intake did not improve performance in 13 studies and enhanced performance in six studies, primarily in those with fasted control groups and workouts with over 10 sets per muscle group. One study found that a carbohydrate meal improved performance compared to water but not in comparison to a sensory-matched placebo breakfast. There was no evidence of a dose-response effect. After glycogen depletion, carbohydrate supplementation improved performance in three studies compared to placebo, in particular during bi-daily workouts, but not in research with isocaloric controls. None of the seven short-term studies found beneficial effects of carbohydrate manipulation. Longer-term changes in performance were not influenced by carbohydrate intake in 15 studies; one study favored the higher- and one the lower-carbohydrate condition. Carbohydrate intake per se is unlikely to strength training performance in a fed state in workouts consisting of up to 10 sets per muscle group. Performance during higher volumes may benefit from carbohydrates, but more studies with isocaloric control groups, sensory-matched placebos and locally measured glycogen depletion are needed.
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Affiliation(s)
- Menno Henselmans
- The International Scientific Research Foundation for Fitness and Nutrition, David Blesstraat 28HS, 1073 LC Amsterdam, The Netherlands; (R.H.); (F.T.V.)
- Correspondence: ; Tel.: +31-61-809-5999
| | - Thomas Bjørnsen
- Department of Sport Science and Physical Education, Faculty of Health and Sport Sciences, University of Agder, 4630 Kristiansand, Norway;
| | - Richie Hedderman
- The International Scientific Research Foundation for Fitness and Nutrition, David Blesstraat 28HS, 1073 LC Amsterdam, The Netherlands; (R.H.); (F.T.V.)
| | - Fredrik Tonstad Vårvik
- The International Scientific Research Foundation for Fitness and Nutrition, David Blesstraat 28HS, 1073 LC Amsterdam, The Netherlands; (R.H.); (F.T.V.)
- Department of Sport Science and Physical Education, Faculty of Health and Sport Sciences, University of Agder, 4630 Kristiansand, Norway;
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Starving Your Performance? Reduced Preexercise Hunger Increases Resistance Exercise Performance. Int J Sports Physiol Perform 2021; 17:458-464. [PMID: 34872065 DOI: 10.1123/ijspp.2021-0166] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 07/01/2021] [Accepted: 07/21/2021] [Indexed: 11/18/2022]
Abstract
BACKGROUND Preexercise food intake enhances exercise performance due, in part, to the provision of exogenous carbohydrate. Food intake also suppresses hunger, but the specific influence of hunger on exercise performance has not been investigated. This study aimed to manipulate hunger by altering preexercise meal viscosity to examine whether hunger influences performance. METHODS Sixteen resistance-trained males completed 2 experimental trials ingesting either high viscosity semisolid (SEM) and low viscosity liquid (LIQ) carbohydrate-containing meals 2 hours before performing 4 sets of back squat (85 [22] kg) and bench press (68 [13] kg) to failure at 90% 10-repetition maximum. Subjective hunger/fullness as well as plasma concentrations of glucose, insulin, ghrelin, and peptide tyrosine-tyrosine were measured before and periodically after the meal. Repetitions completed in sets were used to determine exercise performance. RESULTS Hunger was lower, and fullness was greater during SEM compared with LIQ immediately before and during exercise (P < .05). Total repetitions completed for back squat were approximately 10% greater in SEM (SEM 57 [9]; LIQ 51 [7] repetitions; P = .001) with no difference in bench press repetitions (SEM 48 [11]; LIQ 48 [10] repetitions; P = .621). Postprandial glucose concentrations were greater during LIQ (12% increase in peak glucose) but were similar throughout exercise. CONCLUSION This study demonstrates that exercise performance in back squat was increased in the SEM trial concomitant to a reduction in hunger. Therefore, this study provides novel data that suggest that exercise performance might be influenced by hunger, at least for resistance exercise.
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10
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Bennett S, Tiollier E, Brocherie F, Owens DJ, Morton JP, Louis J. Three weeks of a home-based "sleep low-train low" intervention improves functional threshold power in trained cyclists: A feasibility study. PLoS One 2021; 16:e0260959. [PMID: 34855913 PMCID: PMC8639084 DOI: 10.1371/journal.pone.0260959] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 11/21/2021] [Indexed: 11/24/2022] Open
Abstract
Background “Sleep Low-Train Low” is a training-nutrition strategy intended to purposefully reduce muscle glycogen availability around specific exercise sessions, potentially amplifying the training stimulus via augmented cell signalling. The aim of this study was to assess the feasibility of a 3-week home-based “sleep low-train low” programme and its effects on cycling performance in trained athletes. Methods Fifty-five trained athletes (Functional Threshold Power [FTP]: 258 ± 52W) completed a home-based cycling training program consisting of evening high-intensity training (6 × 5 min at 105% FTP), followed by low-intensity training (1 hr at 75% FTP) the next morning, three times weekly for three consecutive weeks. Participant’s daily carbohydrate (CHO) intake (6 g·kg-1·d-1) was matched but timed differently to manipulate CHO availability around exercise: no CHO consumption post- HIT until post-LIT sessions [Sleep Low (SL), n = 28] or CHO consumption evenly distributed throughout the day [Control (CON), n = 27]. Sessions were monitored remotely via power data uploaded to an online training platform, with performance tests conducted pre-, post-intervention. Results LIT exercise intensity reduced by 3% across week 1, 3 and 2% in week 2 (P < 0.01) with elevated RPE in SL vs. CON (P < 0.01). SL enhanced FTP by +5.5% vs. +1.2% in CON (P < 0.01). Comparable increases in 5-min peak power output (PPO) were observed between groups (P < 0.01) with +2.3% and +2.7% in SL and CON, respectively (P = 0.77). SL 1-min PPO was unchanged (+0.8%) whilst CON improved by +3.9% (P = 0.0144). Conclusion Despite reduced relative training intensity, our data demonstrate short-term “sleep low-train low” intervention improves FTP compared with typically “normal” CHO availability during exercise. Importantly, training was completed unsupervised at home (during the COVID-19 pandemic), thus demonstrating the feasibility of completing a “sleep low-train low” protocol under non-laboratory conditions.
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Affiliation(s)
- Samuel Bennett
- Research Institute for Sport and Exercise Science (RISES), Liverpool John Moores University, Liverpool, United Kingdom
- Laboratory Sport, Expertise and Performance (EA 7370), French Institute of Sport, Paris, France
| | - Eve Tiollier
- Laboratory Sport, Expertise and Performance (EA 7370), French Institute of Sport, Paris, France
| | - Franck Brocherie
- Laboratory Sport, Expertise and Performance (EA 7370), French Institute of Sport, Paris, France
| | - Daniel J. Owens
- Research Institute for Sport and Exercise Science (RISES), Liverpool John Moores University, Liverpool, United Kingdom
| | - James P. Morton
- Research Institute for Sport and Exercise Science (RISES), Liverpool John Moores University, Liverpool, United Kingdom
| | - Julien Louis
- Research Institute for Sport and Exercise Science (RISES), Liverpool John Moores University, Liverpool, United Kingdom
- * E-mail:
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Oldfield C, Moffatt TL, Dolinsky VW, Duhamel TA. Sirtuin 3 overexpression preserves maximal sarco(endo)plasmic reticulum calcium ATPase activity in the skeletal muscle of mice subjected to high fat-high sucrose-feeding. Can J Physiol Pharmacol 2021; 100:361-370. [PMID: 34695364 DOI: 10.1139/cjpp-2021-0587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Sarco(endo)plasmic reticulum calcium (Ca2+) ATPase (SERCA) transports Ca2+ in muscle. Impaired SERCA activity contributes to diabetic myopathy. Sirtuin (SIRT) 3 regulates muscle metabolism and function. However, it is unknown if SIRT3 regulates muscle SERCA activity. We determined if SIRT3 overexpression enhances SERCA activity in mouse gastrocnemius muscle and if SIRT3 overexpression preserves gastrocnemius SERCA activity in a model of type 2 diabetes, induced by high fat-high sucrose (HFHS)-feeding. We also determined if the acetylation status of SERCA proteins in mouse gastrocnemius is altered by SIRT3 overexpression or HFHS-feeding. Wild-type (WT) mice and SIRT3 transgenic (SIRT3TG) mice, overexpressing SIRT3 in skeletal muscle, were fed a standard- or HFHS-diet for 4-months. SIRT3TG and WT mice developed obesity and glucose intolerance after 4-months of HFHS-feeding. SERCA Vmax was higher in gastrocnemius of SIRT3TG mice, compared to WT mice. HFHS-fed mice had lower SERCA1a protein levels and lower SERCA Vmax in their gastrocnemius than control-fed mice. The decrease in SERCA Vmax in gastrocnemius muscle due to HFHS-feeding was attenuated by SIRT3 overexpression in HFHS-fed SIRT3TG mice. SERCA1a and SERCA2a acetylation in mouse gastrocnemius was not altered by genotype or diet. These findings suggest SIRT3 overexpression improves SERCA function in diabetic mouse skeletal muscle.
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Affiliation(s)
- Christopher Oldfield
- University of Manitoba Faculty of Kinesiology and Recreation Management, 175106, Winnipeg, Canada.,St. Boniface Hospital Albrechtsen Research Centre, Institute of Cardiovascular Sciences, Manitoba, Canada;
| | - Teri L Moffatt
- St Boniface General Hospital Research Centre, 120927, Winnipeg, Manitoba, Canada;
| | - Vernon W Dolinsky
- University of Manitoba, Pharmacology and Therapeutics, 601 J. Buhler Research Centre, 715 McDermot Avenue, Winnipeg, Manitoba, Canada, R3E 3P4;
| | - Todd A Duhamel
- St. Boniface General Hospital Research Center, 351 Tach� Avenue, Winnipeg, Manitoba, Canada, R2H 2A6;
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12
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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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13
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Gejl KD, Andersson EP, Nielsen J, Holmberg HC, Ørtenblad N. Effects of Acute Exercise and Training on the Sarcoplasmic Reticulum Ca 2+ Release and Uptake Rates in Highly Trained Endurance Athletes. Front Physiol 2020; 11:810. [PMID: 32733285 PMCID: PMC7359889 DOI: 10.3389/fphys.2020.00810] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 06/18/2020] [Indexed: 11/16/2022] Open
Abstract
Little is presently known about the effects of acute high-intensity exercise or training on release and uptake of Ca2+ by the sarcoplasmic reticulum (SR). The aims here were to characterize this regulation in highly trained athletes following (1) repeated bouts of high-intensity exercise and (2) a period of endurance training including high-intensity sessions. Eleven cross-country skiers (25 ± 4 years, 65 ± 4 mL O2⋅kg−1⋅min–1) performed four self-paced sprint time-trials (STT 1-4) lasting ≈ 4 min each (STT 1–4) and separated by 45 min of recovery; while 19 triathletes and road cyclists (25 ± 4 years, 65 ± 5 mL O2⋅kg−1⋅min–1) completed 4 weeks of endurance training in combination with three sessions of high-intensity interval cycling per week. Release (μmol⋅g–1 prot⋅min–1) and uptake [tau (s)] of Ca2+ by SR vesicles isolated from m. triceps brachii and m. vastus lateralis were determined before and after STT 1 and 4 in the skiers and in m. vastus lateralis before and after the 4 weeks of training in the endurance athletes. The Ca2+ release rate was reduced by 17–18% in both limbs already after STT 1 (arms: 2.52 ± 0.74 to 2.08 ± 0.60; legs: 2.41 ± 0.45 to 1.98 ± 0.51, P < 0.0001) and attenuated further following STT 4 (arms: 2.24 ± 0.67 to 1.95 ± 0.45; legs: 2.13 ± 0.51 to 1.83 ± 0.36, P < 0.0001). Also, there was a tendency toward an impairment in the SR Ca2+ uptake from pre STT1 to post STT4 in both arms and legs (arms: from 22.0 ± 3.7 s to 25.3 ± 6.0 s; legs: from 22.5 ± 4.7 s to 25.5 ± 7.7 s, P = 0.05). Endurance training combined with high-intensity exercise increased the Ca2+ release rate by 9% (1.76 ± 0.38 to 1.91 ± 0.44, P = 0.009), without altering the Ca2+ uptake (29.6 ± 7.0 to 29.1 ± 8.7 s; P = 0.98). In conclusion, the Ca2+ release and uptake rates by SR in exercising limbs of highly trained athletes declines gradually by repetitive bouts of high-intensity exercise. We also demonstrate, for the first time, that the SR Ca2+ release rate can be enhanced by a specific program of training in highly trained athletes, which may have important implications for performance parameters.
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Affiliation(s)
- Kasper Degn Gejl
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Erik P Andersson
- Swedish Winter Sports Research Centre, Department of Health Sciences, Mid Sweden University, Östersund, Sweden
| | - Joachim Nielsen
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Hans-Christer Holmberg
- Swedish Winter Sports Research Centre, Department of Health Sciences, Mid Sweden University, Östersund, Sweden.,Department of Physiology and Pharmacology, Biomedicum C5, Karolinska Institute, Stockholm, Sweden
| | - Niels Ørtenblad
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
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14
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Olsson K, Cheng AJ, Al‐Ameri M, Wyckelsma VL, Rullman E, Westerblad H, Lanner JT, Gustafsson T, Bruton JD. Impaired sarcoplasmic reticulum Ca2+release is the major cause of fatigue‐induced force loss in intact single fibres from human intercostal muscle. J Physiol 2019; 598:773-787. [DOI: 10.1113/jp279090] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Accepted: 11/22/2019] [Indexed: 12/15/2022] Open
Affiliation(s)
- Karl Olsson
- Department of Laboratory MedicineSection of Clinical PhysiologyKarolinska Institutet Alfred Nobels Allé 8 141 52 Huddinge Sweden
| | - Arthur J. Cheng
- Department of Physiology and PharmacologyBiomedicum C5Karolinska Institutet Tomtebodavägen 16 Solna 171 65 Sweden
- School of Kinesiology and Health ScienceFaculty of HealthYork University 4700 Keele Street Toronto Canada M3J 1P3
| | - Mamdoh Al‐Ameri
- Department of Molecular Medicine and SurgeryKarolinska InstitutetKarolinska University Hospital Solna 171 76 Stockholm Sweden
| | - Victoria L. Wyckelsma
- Department of Physiology and PharmacologyBiomedicum C5Karolinska Institutet Tomtebodavägen 16 Solna 171 65 Sweden
| | - Eric Rullman
- Department of Laboratory MedicineSection of Clinical PhysiologyKarolinska Institutet Alfred Nobels Allé 8 141 52 Huddinge Sweden
| | - Håkan Westerblad
- Department of Physiology and PharmacologyBiomedicum C5Karolinska Institutet Tomtebodavägen 16 Solna 171 65 Sweden
| | - Johanna T. Lanner
- Department of Physiology and PharmacologyBiomedicum C5Karolinska Institutet Tomtebodavägen 16 Solna 171 65 Sweden
| | - Thomas Gustafsson
- Department of Laboratory MedicineSection of Clinical PhysiologyKarolinska Institutet Alfred Nobels Allé 8 141 52 Huddinge Sweden
| | - Joseph D. Bruton
- Department of Physiology and PharmacologyBiomedicum C5Karolinska Institutet Tomtebodavägen 16 Solna 171 65 Sweden
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15
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Cheng AJ, Hwee DT, Kim LH, Durham N, Yang HT, Hinken AC, Kennedy AR, Terjung RL, Jasper JR, Malik FI, Westerblad H. Fast skeletal muscle troponin activator CK-2066260 increases fatigue resistance by reducing the energetic cost of muscle contraction. J Physiol 2019; 597:4615-4625. [PMID: 31246276 PMCID: PMC6851859 DOI: 10.1113/jp278235] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 06/26/2019] [Indexed: 01/26/2023] Open
Abstract
Key points Skeletal muscle fatigue limits performance in various physical activities, with exercise intolerance being a key symptom in a broad spectrum of diseases. We investigated whether a small molecule fast skeletal troponin activator (FSTA), CK‐2066260, can mitigate muscle fatigue by reducing the cytosolic free [Ca2+] required to produce a given submaximal force and hence decreasing the energy requirement. Isolated intact single mouse muscle fibres and rat muscles in‐situ treated with CK‐2066260 showed improved muscle endurance., which was accompanied by decreased ATP demand and reduced glycogen usage. CK‐2066260 treatment improved in‐vivo exercise capacity in healthy rats and in a rat model of peripheral artery insufficiency. In conclusion, we show that the FSTA CK‐2066260 effectively counteracts muscle fatigue in rodent skeletal muscle in vitro, in situ, and in vivo. This may translate to humans and provide a promising pharmacological treatment to patients suffering from severe muscle weakness and exercise intolerance.
Abstract Skeletal muscle fatigue limits performance during physical exercise and exacerbated muscle fatigue is a prominent symptom among a broad spectrum of diseases. The present study investigated whether skeletal muscle fatigue is affected by the fast skeletal muscle troponin activator (FSTA) CK‐2066260, which increases myofibrillar Ca2+ sensitivity and amplifies the submaximal force response. Because more force is produced for a given Ca2+, we hypothesized that CK‐2066260 could mitigate muscle fatigue by reducing the energetic cost of muscle activation. Isolated single mouse muscle fibres were fatigued by 100 repeated 350 ms contractions while measuring force and the cytosolic free [Ca2+] or [Mg2+] ([Mg2+]i). When starting fatiguing stimulation at matching forces (i.e. lower stimulation frequency with CK‐2066260): force was decreased by ∼50% with and by ∼75% without CK‐2066260; [Mg2+]i was increased by ∼10% with and ∼32% without CK‐2066260, reflecting a larger decrease in [ATP] in the latter. The glycogen content in in situ stimulated rat muscles fatigued by repeated contractions at matching forces was about two times higher with than without CK‐2066260. Voluntary exercise capacity, assessed by rats performing rotarod exercise and treadmill running, was improved in the presence of CK‐2066260. CK‐2066260 treatment also increased skeletal muscle fatigue resistance and exercise performance in a rat model of peripheral artery insufficiency. In conclusion, we demonstrate that the FSTA CK‐2066260 mitigates skeletal muscle fatigue by reducing the metabolic cost of force generation. Skeletal muscle fatigue limits performance in various physical activities, with exercise intolerance being a key symptom in a broad spectrum of diseases. We investigated whether a small molecule fast skeletal troponin activator (FSTA), CK‐2066260, can mitigate muscle fatigue by reducing the cytosolic free [Ca2+] required to produce a given submaximal force and hence decreasing the energy requirement. Isolated intact single mouse muscle fibres and rat muscles in‐situ treated with CK‐2066260 showed improved muscle endurance., which was accompanied by decreased ATP demand and reduced glycogen usage. CK‐2066260 treatment improved in‐vivo exercise capacity in healthy rats and in a rat model of peripheral artery insufficiency. In conclusion, we show that the FSTA CK‐2066260 effectively counteracts muscle fatigue in rodent skeletal muscle in vitro, in situ, and in vivo. This may translate to humans and provide a promising pharmacological treatment to patients suffering from severe muscle weakness and exercise intolerance.
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Affiliation(s)
- Arthur J Cheng
- Department of Physiology and Pharmacology, Karolinska Institutet, 171 77, Stockholm, Sweden
| | - Darren T Hwee
- Research and Early Development, Cytokinetics, Inc., South San Francisco, CA, 94080, USA
| | - Leo H Kim
- Research and Early Development, Cytokinetics, Inc., South San Francisco, CA, 94080, USA
| | - Nickie Durham
- Research and Early Development, Cytokinetics, Inc., South San Francisco, CA, 94080, USA
| | - Hsiao T Yang
- Department of Biomedical Sciences, University of Missouri, Columbia, MO, 65211, USA
| | - Aaron C Hinken
- Research and Early Development, Cytokinetics, Inc., South San Francisco, CA, 94080, USA
| | - Adam R Kennedy
- Research and Early Development, Cytokinetics, Inc., South San Francisco, CA, 94080, USA
| | - Ronald L Terjung
- Department of Biomedical Sciences, University of Missouri, Columbia, MO, 65211, USA
| | - Jeffrey R Jasper
- Research and Early Development, Cytokinetics, Inc., South San Francisco, CA, 94080, USA
| | - Fady I Malik
- Research and Early Development, Cytokinetics, Inc., South San Francisco, CA, 94080, USA
| | - Håkan Westerblad
- Department of Physiology and Pharmacology, Karolinska Institutet, 171 77, Stockholm, Sweden
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16
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Effects of reduced muscle glycogen on excitation-contraction coupling in rat fast-twitch muscle: a glycogen removal study. J Muscle Res Cell Motil 2019; 40:353-364. [PMID: 31236763 DOI: 10.1007/s10974-019-09524-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Accepted: 06/11/2019] [Indexed: 02/08/2023]
Abstract
The aim of this study was to investigate the effects of an enzymatic removal of glycogen on excitation-contraction coupling in mechanically skinned fibres of rat fast-twitch muscles, with a focus on the changes in the function of Na+-K+-pump and ryanodine receptor (RyR). Glycogen present in the skinned fibres and binding to microsomes was removed using glucoamylase (GA). Exposure of whole muscle to 20 U mL-1 GA for 6 min resulted in a 72% decrease in the glycogen content. Six minutes of GA treatment led to an 18 and a 22% reduction in depolarization- and action potential-induced forces in the skinned fibres, respectively. There was a minor but statistically significant increase in the repriming period, most likely because of an impairment of the Na+-K+-pump function. GA treatment exerted no effect on the maximum Ca2+ release rate from the RyR in the microsomes and the myofibrillar Ca2+ sensitivity in the skinned fibres. These results indicate that reduced glycogen per se can decrease muscle performance due to the impairment of SR Ca2+ release and suggest that although Na+-K+-pump function is adversely affected by reduced glycogen, the extent of the impairment is not sufficient to reduce Ca2+ release from the sarcoplasmic reticulum. This study provides direct evidence that glycogen above a certain amount is required for the preservation of the functional events preceding Ca2+ release from the sarcoplasmic reticulum.
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17
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Impey SG, Hearris MA, Hammond KM, Bartlett JD, Louis J, Close GL, Morton JP. Fuel for the Work Required: A Theoretical Framework for Carbohydrate Periodization and the Glycogen Threshold Hypothesis. Sports Med 2018; 48:1031-1048. [PMID: 29453741 PMCID: PMC5889771 DOI: 10.1007/s40279-018-0867-7] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
Deliberately training with reduced carbohydrate (CHO) availability to enhance endurance-training-induced metabolic adaptations of skeletal muscle (i.e. the 'train low, compete high' paradigm) is a hot topic within sport nutrition. Train-low studies involve periodically training (e.g., 30-50% of training sessions) with reduced CHO availability, where train-low models include twice per day training, fasted training, post-exercise CHO restriction and 'sleep low, train low'. When compared with high CHO availability, data suggest that augmented cell signalling (73% of 11 studies), gene expression (75% of 12 studies) and training-induced increases in oxidative enzyme activity/protein content (78% of 9 studies) associated with 'train low' are especially apparent when training sessions are commenced within a specific range of muscle glycogen concentrations. Nonetheless, such muscle adaptations do not always translate to improved exercise performance (e.g. 37 and 63% of 11 studies show improvements or no change, respectively). Herein, we present our rationale for the glycogen threshold hypothesis, a window of muscle glycogen concentrations that simultaneously permits completion of required training workloads and activation of the molecular machinery regulating training adaptations. We also present the 'fuel for the work required' paradigm (representative of an amalgamation of train-low models) whereby CHO availability is adjusted in accordance with the demands of the upcoming training session(s). In order to strategically implement train-low sessions, our challenge now is to quantify the glycogen cost of habitual training sessions (so as to inform the attainment of any potential threshold) and ensure absolute training intensity is not compromised, while also creating a metabolic milieu conducive to facilitating the endurance phenotype.
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Affiliation(s)
- Samuel G Impey
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Tom Reilly Building, Byrom St Campus, Liverpool, L3 3AF, UK
| | - Mark A Hearris
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Tom Reilly Building, Byrom St Campus, Liverpool, L3 3AF, UK
| | - Kelly M Hammond
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Tom Reilly Building, Byrom St Campus, Liverpool, L3 3AF, UK
| | - Jonathan D Bartlett
- Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Footscray Park, Ballarat Road, Melbourne, VIC, 8001, Australia
| | - Julien Louis
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Tom Reilly Building, Byrom St Campus, Liverpool, L3 3AF, UK
| | - Graeme L Close
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Tom Reilly Building, Byrom St Campus, Liverpool, L3 3AF, UK
| | - James P Morton
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Tom Reilly Building, Byrom St Campus, Liverpool, L3 3AF, UK.
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18
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Santana JO, de Freitas MC, Dos Santos DM, Rossi FE, Lira FS, Rosa-Neto JC, Caperuto EC. Beta-Alanine Supplementation Improved 10-km Running Time Trial in Physically Active Adults. Front Physiol 2018; 9:1105. [PMID: 30135662 PMCID: PMC6092497 DOI: 10.3389/fphys.2018.01105] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 07/23/2018] [Indexed: 11/13/2022] Open
Abstract
The purpose of this study was to investigate the effects of β-alanine supplementation on a 10 km running time trial and lactate concentration in physically active adults. Sixteen healthy subjects were divided randomly into two groups: β-alanine (n = 8) and placebo group (n = 8). The experimental group ingested 5 g/day of β-alanine plus 1 g of resistant starch, and control group ingested 6 g of resistant starch, both for 23 days. Time to complete a 10-km running time trial and lactate concentration following the test were assessed at baseline and post 23 days. The running training program was performed three times per week on non-consecutive days (day 1: running 7 km; day 2: six sprints of 500 m at maximum speed with 2 min of recovery; day 3: running 12 km). The time to complete a 10-km running time trial decreased significantly only for the β-alanine group (Pre = 3441 ± 326.7, Post = 3209 ± 270.5 s, p < 0.05). When analyzing the delta (Time post minus Time at baseline value) there was a statistically significant difference between the β-alanine vs placebo group (-168.8 ± 156.6 vs. -53.60 ± 78.81 s, p = 0.007), respectively. In addition, the β-alanine group presented lower blood lactate concentration after the 10-km test (β-alanine: Pre = 8.45 ± 1.94 vs. Post = 6.95 ± 2.44 mmol/L; Placebo: Pre = 8.7 ± 3.0 vs. Post = 10.8 ± 2.5 mmol/L, p = 0.03). In conclusion, β-alanine supplementation improved the 10-km running time trial and reduced lactate concentration in physically active adults.
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Affiliation(s)
- Jeferson O Santana
- Department of Physical Education, University São Judas Tadeu, São Paulo, Brazil
| | - Marcelo C de Freitas
- Skeletal Muscle Assessment Laboratory, Department of Physical Education, School of Technology and Sciences, São Paulo State University, Presidente Prudente, Brazil
| | - Diana M Dos Santos
- Department of Physical Education, University São Judas Tadeu, São Paulo, Brazil
| | - Fabrício E Rossi
- Immunometabolism of Skeletal Muscle and Exercise Research Group, Department of Physical Education, Federal University of Piauí, Teresina, Brazil
| | - Fabio S Lira
- Exercise and Immunometabolism Research Group, Department of Physical Education, São Paulo State University, Presidente Prudente, Brazil
| | - José C Rosa-Neto
- Biomedical Sciences Institute, São Paulo University, São Paulo, Brazil
| | - Erico C Caperuto
- Department of Physical Education, University São Judas Tadeu, São Paulo, Brazil
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19
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Hanya E, Katz A. Increased temperature accelerates glycogen synthesis and delays fatigue in isolated mouse muscle during repeated contractions. Acta Physiol (Oxf) 2018; 223:e13027. [PMID: 29297989 DOI: 10.1111/apha.13027] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 12/27/2017] [Accepted: 12/28/2017] [Indexed: 01/05/2023]
Abstract
AIM Elevated glycogen content in muscle delays fatigue during exercise. We examined if increasing muscle temperature during recovery from exercise affects glycogen synthesis and muscle performance during a subsequent bout of exercise. METHODS Isolated mouse extensor digitorum longus muscles were stimulated electrically to perform repeated tetanic contractions until force decreased to 40% of initial at 25°C. Thereafter, muscles recovered for 120 minutes at 25°C (control), 120 minutes at 35°C or 60 minutes at 35°C followed by 60 minutes at 25°C. After recovery, muscles were again stimulated to fatigue at 25°C. RESULTS In the control group, the number of contractions in the second run was slightly less than during the first run (92 ± 5%). Following recovery for 120 minutes at 35°C, the number of contractions was similar to the first run (98 ± 6%). Allowing recovery for 120 minutes at 35°C in the presence of the antioxidant N-acetylcysteine also did not alter the number of contractions in the second run (98 ± 3%). However, recovery for 60 minutes at 35°C followed by 60 minutes at 25°C resulted in an increase in the number of contractions during the second run (110 ± 2%, P < .001). Incorporation of [14 C]glucose into glycogen (glycogen synthesis) during recovery was 1.7-fold higher at 35°C vs 25°C (1.44 ± 0.08 μmol (30 min)-1 (g wet muscle)-1 vs 0.84 ± 0.04; P < .001). CONCLUSION These data demonstrate that, under the conditions studied, elevating muscle temperature for 60 minutes following a bout of repeated contractions delays muscle fatigue during a subsequent bout of repeated contractions and this is associated with enhanced glycogen synthesis in isolated muscle.
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Affiliation(s)
- E. Hanya
- Department of Physical Therapy; School of Health Sciences; Ariel University; Ariel Israel
| | - A. Katz
- Department of Physical Therapy; School of Health Sciences; Ariel University; Ariel Israel
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20
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Cheng AJ, Willis SJ, Zinner C, Chaillou T, Ivarsson N, Ørtenblad N, Lanner JT, Holmberg HC, Westerblad H. Post-exercise recovery of contractile function and endurance in humans and mice is accelerated by heating and slowed by cooling skeletal muscle. J Physiol 2017; 595:7413-7426. [PMID: 28980321 DOI: 10.1113/jp274870] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Accepted: 09/20/2017] [Indexed: 12/22/2022] Open
Abstract
KEY POINTS We investigated whether intramuscular temperature affects the acute recovery of exercise performance following fatigue-induced by endurance exercise. Mean power output was better preserved during an all-out arm-cycling exercise following a 2 h recovery period in which the upper arms were warmed to an intramuscular temperature of ̴ 38°C than when they were cooled to as low as 15°C, which suggested that recovery of exercise performance in humans is dependent on muscle temperature. Mechanisms underlying the temperature-dependent effect on recovery were studied in intact single mouse muscle fibres where we found that recovery of submaximal force and restoration of fatigue resistance was worsened by cooling (16-26°C) and improved by heating (36°C). Isolated whole mouse muscle experiments confirmed that cooling impaired muscle glycogen resynthesis. We conclude that skeletal muscle recovery from fatigue-induced by endurance exercise is impaired by cooling and improved by heating, due to changes in glycogen resynthesis rate. ABSTRACT Manipulation of muscle temperature is believed to improve post-exercise recovery, with cooling being especially popular among athletes. However, it is unclear whether such temperature manipulations actually have positive effects. Accordingly, we studied the effect of muscle temperature on the acute recovery of force and fatigue resistance after endurance exercise. One hour of moderate-intensity arm cycling exercise in humans was followed by 2 h recovery in which the upper arms were either heated to 38°C, not treated (33°C), or cooled to ∼15°C. Fatigue resistance after the recovery period was assessed by performing 3 × 5 min sessions of all-out arm cycling at physiological temperature for all conditions (i.e. not heated or cooled). Power output during the all-out exercise was better maintained when muscles were heated during recovery, whereas cooling had the opposite effect. Mechanisms underlying the temperature-dependent effect on recovery were tested in mouse intact single muscle fibres, which were exposed to ∼12 min of glycogen-depleting fatiguing stimulation (350 ms tetani given at 10 s interval until force decreased to 30% of the starting force). Fibres were subsequently exposed to the same fatiguing stimulation protocol after 1-2 h of recovery at 16-36°C. Recovery of submaximal force (30 Hz), the tetanic myoplasmic free [Ca2+ ] (measured with the fluorescent indicator indo-1), and fatigue resistance were all impaired by cooling (16-26°C) and improved by heating (36°C). In addition, glycogen resynthesis was faster at 36°C than 26°C in whole flexor digitorum brevis muscles. We conclude that recovery from exhaustive endurance exercise is accelerated by raising and slowed by lowering muscle temperature.
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Affiliation(s)
| | - Sarah J Willis
- Swedish Winter Sports Research Centre, Mid Sweden University, Östersund, Sweden
| | - Christoph Zinner
- Swedish Winter Sports Research Centre, Mid Sweden University, Östersund, Sweden
| | - Thomas Chaillou
- Karolinska Institutet, Stockholm, Sweden.,Örebro Universitet, Örebro, Sweden
| | | | | | | | - Hans-Christer Holmberg
- Karolinska Institutet, Stockholm, Sweden.,Swedish Winter Sports Research Centre, Mid Sweden University, Östersund, Sweden
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21
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Kent JA, Ørtenblad N, Hogan MC, Poole DC, Musch TI. No Muscle Is an Island: Integrative Perspectives on Muscle Fatigue. Med Sci Sports Exerc 2017; 48:2281-2293. [PMID: 27434080 DOI: 10.1249/mss.0000000000001052] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Muscle fatigue has been studied with a variety approaches, tools and technologies. The foci of these studies have ranged tremendously, from molecules to the entire organism. Single cell and animal models have been used to gain mechanistic insight into the fatigue process. The theme of this review is the concept that the mechanisms of muscle fatigue do not occur in isolation in vivo: muscular work is supported by many complex physiological systems, any of which could fail during exercise and thus contribute to fatigue. To advance our overall understanding of fatigue, a combination of models and approaches is necessary. In this review, we examine the roles that neuromuscular properties, intracellular glycogen, oxygen metabolism, and blood flow play in the fatigue process during exercise and pathological conditions.
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Affiliation(s)
- Jane A Kent
- 1Department of Kinesiology, University of Massachusetts, Amherst MA; 2Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, DENMARK; 3Department of Health Sciences, Mid Sweden University, Östersund, SWEDEN; 4Department of Medicine, University of California, San Diego, CA; and 5Department of Kinesiology, Kansas State University, Manhattan, KS
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Central activation, metabolites, and calcium handling during fatigue with repeated maximal isometric contractions in human muscle. Eur J Appl Physiol 2017; 117:1557-1571. [PMID: 28527013 DOI: 10.1007/s00421-017-3640-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 05/08/2017] [Indexed: 12/19/2022]
Abstract
PURPOSE To determine the roles of calcium (Ca2+) handling by sarcoplasmic reticulum (SR) and central activation impairment (i.e., central fatigue) during fatigue with repeated maximal voluntary isometric contractions (MVC) in human muscles. METHODS Contractile performance was assessed during 3 min of repeated MVCs (7-s contraction, 3-s rest, n = 17). In ten participants, in vitro SR Ca2+-handling, metabolites, and fibre-type composition were quantified in biopsy samples from quadriceps muscle, along with plasma venous [K+]. In 11 participants, central fatigue was compared using tetanic stimulation superimposed on MVC in quadriceps and adductor pollicis muscles. RESULTS The decline of peak MVC force with fatigue was similar for both muscles. Fatigue resistance correlated directly with % type I fibre area in quadriceps (r = 0.77, P = 0.009). The maximal rate of ryanodine-induced Ca2+-release and Ca2+-uptake fell by 31 ± 26 and 28 ± 13%, respectively. The tetanic force depression was correlated with the combined reduction of ATP and PCr, and increase of lactate (r = 0.77, P = 0.009). Plasma venous [K+] increased from 4.0 ± 0.3 to 5.4 ± 0.8 mM over 1-3-min exercise. Central fatigue occurred during the early contractions in the quadriceps in 7 out of 17 participants (central activation ratio fell from 0.98 ± 0.05 to 0.86 ± 0.11 at 1 min), but dwindled at exercise cessation. Central fatigue was seldom apparent in adductor pollicis. CONCLUSIONS Fatigue with repeated MVC in human limb muscles mainly involves peripheral aspects which include impaired SR Ca2+-handling and we speculate that anaerobic metabolite changes are involved. A faster early force loss in quadriceps muscle with some participants is attributed to central fatigue.
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23
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Gejl KD, Ørtenblad N, Andersson E, Plomgaard P, Holmberg H, Nielsen J. Local depletion of glycogen with supramaximal exercise in human skeletal muscle fibres. J Physiol 2017; 595:2809-2821. [PMID: 27689320 PMCID: PMC5407966 DOI: 10.1113/jp273109] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 09/26/2016] [Indexed: 01/29/2023] Open
Abstract
KEY POINTS Glycogen is stored in local spatially distinct compartments within skeletal muscle fibres and is the main energy source during supramaximal exercise. Using quantitative electron microscopy, we show that supramaximal exercise induces a differential depletion of glycogen from these compartments and also demonstrate how this varies with fibre types. Repeated exercise alters this compartmentalized glycogen depletion. The results obtained in the present study help us understand the muscle metabolic dynamics of whole body repeated supramaximal exercise, and suggest that the muscle has a compartmentalized local adaptation to repeated exercise, which affects glycogen depletion. ABSTRACT Skeletal muscle glycogen is heterogeneously distributed in three separated compartments (intramyofibrillar, intermyofibrillar and subsarcolemmal). Although only constituting 3-13% of the total glycogen volume, the availability of intramyofibrillar glycogen is of particular importance to muscle function. The present study aimed to investigate the depletion of these three subcellular glycogen compartments during repeated supramaximal exercise in elite athletes. Ten elite cross-country skiers (aged 25 ± 4 years, V̇O2 max : 65 ± 4 ml kg-1 min-1 ; mean ± SD) performed four ∼4 min supramaximal sprint time trials (STT 1-4) with 45 min of recovery. The subcellular glycogen volumes in musculus triceps brachii were quantified from electron microscopy images before and after both STT 1 and 4. During STT 1, the depletion of intramyofibrillar glycogen was higher in type 1 fibres [-52%; (-89:-15%)] than type 2 fibres [-15% (-52:22%)] (P = 0.02), whereas the depletion of intermyofibrillar glycogen [main effect: -19% (-33:0%), P = 0.006] and subsarcolemmal glycogen [main effect: -35% (-66:0%), P = 0.03] was similar between fibre types. By contrast, only intermyofibrillar glycogen volume was significantly reduced during STT 4, in both fibre types [main effect: -31% (-50:-11%), P = 0.002]. Furthermore, for each of the subcellular compartments, the depletion of glycogen during STT 1 was associated with the volumes of glycogen before STT 1. In conclusion, the depletion of spatially distinct glycogen compartments differs during supramaximal exercise. Furthermore, the depletion changes with repeated exercise and is fibre type-dependent.
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Affiliation(s)
- Kasper D. Gejl
- Department of Sports Science and Clinical BiomechanicsSDU Muscle Research ClusterUniversity of Southern DenmarkOdenseDenmark
| | - Niels Ørtenblad
- Department of Sports Science and Clinical BiomechanicsSDU Muscle Research ClusterUniversity of Southern DenmarkOdenseDenmark
- Swedish Winter Sports Research CentreDepartment of Health SciencesMid Sweden UniversityÖstersundSweden
| | - Erik Andersson
- Swedish Winter Sports Research CentreDepartment of Health SciencesMid Sweden UniversityÖstersundSweden
| | - Peter Plomgaard
- The Centre of Inflammation and MetabolismDepartment of Infectious Diseases and CMRCRigshospitaletCopenhagenDenmark
- Department of Clinical BiochemistryRigshospitaletCopenhagenDenmark
| | - Hans‐Christer Holmberg
- Swedish Winter Sports Research CentreDepartment of Health SciencesMid Sweden UniversityÖstersundSweden
- Swedish Olympic CommitteeStockholmSweden
| | - Joachim Nielsen
- Department of Sports Science and Clinical BiomechanicsSDU Muscle Research ClusterUniversity of Southern DenmarkOdenseDenmark
- Department of PathologySDU Muscle Research ClusterOdense University HospitalOdense
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Black MI, Jones AM, Blackwell JR, Bailey SJ, Wylie LJ, McDonagh STJ, Thompson C, Kelly J, Sumners P, Mileva KN, Bowtell JL, Vanhatalo A. Muscle metabolic and neuromuscular determinants of fatigue during cycling in different exercise intensity domains. J Appl Physiol (1985) 2016; 122:446-459. [PMID: 28008101 PMCID: PMC5429469 DOI: 10.1152/japplphysiol.00942.2016] [Citation(s) in RCA: 158] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 12/12/2016] [Accepted: 12/16/2016] [Indexed: 01/15/2023] Open
Abstract
The gas exchange threshold and the critical power demarcate discrete exercise intensity domains. For the first time, we show that the limit of tolerance during whole body exercise within these domains is characterized by distinct metabolic and neuromuscular responses. Fatigue development during exercise greater than critical power is associated with the attainment of consistent “limiting” values of muscle metabolites, whereas substrate availability and limitations to muscle activation may constrain performance at lower intensities. Lactate or gas exchange threshold (GET) and critical power (CP) are closely associated with human exercise performance. We tested the hypothesis that the limit of tolerance (Tlim) during cycle exercise performed within the exercise intensity domains demarcated by GET and CP is linked to discrete muscle metabolic and neuromuscular responses. Eleven men performed a ramp incremental exercise test, 4–5 severe-intensity (SEV; >CP) constant-work-rate (CWR) tests until Tlim, a heavy-intensity (HVY; <CP but >GET) CWR test until Tlim, and a moderate-intensity (MOD; <GET) CWR test until Tlim. Muscle biopsies revealed that a similar (P > 0.05) muscle metabolic milieu (i.e., low pH and [PCr] and high [lactate]) was attained at Tlim (approximately 2–14 min) for all SEV exercise bouts. The muscle metabolic perturbation was greater at Tlim following SEV compared with HVY, and also following SEV and HVY compared with MOD (all P < 0.05). The normalized M-wave amplitude for the vastus lateralis (VL) muscle decreased to a similar extent following SEV (−38 ± 15%), HVY (−68 ± 24%), and MOD (−53 ± 29%), (P > 0.05). Neural drive to the VL increased during SEV (4 ± 4%; P < 0.05) but did not change during HVY or MOD (P > 0.05). During SEV and HVY, but not MOD, the rates of change in M-wave amplitude and neural drive were correlated with changes in muscle metabolic ([PCr], [lactate]) and blood ionic/acid-base status ([lactate], [K+]) (P < 0.05). The results of this study indicate that the metabolic and neuromuscular determinants of fatigue development differ according to the intensity domain in which the exercise is performed. NEW & NOTEWORTHY The gas exchange threshold and the critical power demarcate discrete exercise intensity domains. For the first time, we show that the limit of tolerance during whole-body exercise within these domains is characterized by distinct metabolic and neuromuscular responses. Fatigue development during exercise greater than critical power is associated with the attainment of consistent “limiting” values of muscle metabolites, whereas substrate availability and limitations to muscle activation may constrain performance at lower intensities.
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Affiliation(s)
- Matthew I Black
- College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom.,School of Sport, Exercise and Health Sciences, Loughborough University, United Kingdom; and
| | - Andrew M Jones
- College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom
| | - Jamie R Blackwell
- College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom
| | - Stephen J Bailey
- College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom.,School of Sport, Exercise and Health Sciences, Loughborough University, United Kingdom; and
| | - Lee J Wylie
- College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom
| | - Sinead T J McDonagh
- College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom
| | - Christopher Thompson
- College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom
| | - James Kelly
- College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom
| | - Paul Sumners
- Sport and Exercise Science Research Centre, School of Applied Sciences, London South Bank University, London, United Kingdom
| | - Katya N Mileva
- Sport and Exercise Science Research Centre, School of Applied Sciences, London South Bank University, London, United Kingdom
| | - Joanna L Bowtell
- College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom
| | - Anni Vanhatalo
- College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom;
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Knuiman P, Hopman MTE, Mensink M. Glycogen availability and skeletal muscle adaptations with endurance and resistance exercise. Nutr Metab (Lond) 2015; 12:59. [PMID: 26697098 PMCID: PMC4687103 DOI: 10.1186/s12986-015-0055-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 12/11/2015] [Indexed: 11/22/2022] Open
Abstract
It is well established that glycogen depletion affects endurance exercise performance negatively. Moreover, numerous studies have demonstrated that post-exercise carbohydrate ingestion improves exercise recovery by increasing glycogen resynthesis. However, recent research into the effects of glycogen availability sheds new light on the role of the widely accepted energy source for adenosine triphosphate (ATP) resynthesis during endurance exercise. Indeed, several studies showed that endurance training with low glycogen availability leads to similar and sometimes even better adaptations and performance compared to performing endurance training sessions with replenished glycogen stores. In the case of resistance exercise, a few studies have been performed on the role of glycogen availability on the early post-exercise anabolic response. However, the effects of low glycogen availability on phenotypic adaptations and performance following prolonged resistance exercise remains unclear to date. This review summarizes the current knowledge about the effects of glycogen availability on skeletal muscle adaptations for both endurance and resistance exercise. Furthermore, it describes the role of glycogen availability when both exercise modes are performed concurrently.
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Affiliation(s)
- Pim Knuiman
- Division of Human Nutrition, Wageningen University, Bomenweg 4, 6703 HD Wageningen, The Netherlands
| | - Maria T E Hopman
- Division of Human Nutrition, Wageningen University, Bomenweg 4, 6703 HD Wageningen, The Netherlands ; Radboud University, Radboud Institute for Health Sciences, Department of Physiology, Geert Grooteplein-West 32, 6525 GA Nijmegen, The Netherlands
| | - Marco Mensink
- Division of Human Nutrition, Wageningen University, Bomenweg 4, 6703 HD Wageningen, The Netherlands
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26
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Ørtenblad N, Nielsen J. Muscle glycogen and cell function - Location, location, location. Scand J Med Sci Sports 2015; 25 Suppl 4:34-40. [DOI: 10.1111/sms.12599] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/01/2015] [Indexed: 11/28/2022]
Affiliation(s)
- N. Ørtenblad
- Department of Sports Science and Clinical Biomechanics; SDU Muscle Research Cluster; University of Southern Denmark; Odense Denmark
- Swedish Winter Sports Research Centre; Department of Health Sciences; Mid Sweden University; Sweden
| | - J. Nielsen
- Department of Sports Science and Clinical Biomechanics; SDU Muscle Research Cluster; University of Southern Denmark; Odense Denmark
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27
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Santalla A, Nogales-Gadea G, Ørtenblad N, Brull A, de Luna N, Pinós T, Lucia A. McArdle disease: a unique study model in sports medicine. Sports Med 2015; 44:1531-44. [PMID: 25028051 DOI: 10.1007/s40279-014-0223-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
McArdle disease is arguably the paradigm of exercise intolerance in humans. This disorder is caused by inherited deficiency of myophosphorylase, the enzyme isoform that initiates glycogen breakdown in skeletal muscles. Because patients are unable to obtain energy from their muscle glycogen stores, this disease provides an interesting model of study for exercise physiologists, allowing insight to be gained into the understanding of glycogen-dependent muscle functions. Of special interest in the field of muscle physiology and sports medicine are also some specific (if not unique) characteristics of this disorder, such as the so-called 'second wind' phenomenon, the frequent exercise-induced rhabdomyolysis and myoglobinuria episodes suffered by patients (with muscle damage also occurring under basal conditions), or the early appearance of fatigue and contractures, among others. In this article we review the main pathophysiological features of this disorder leading to exercise intolerance as well as the currently available therapeutic possibilities. Patients have been traditionally advised by clinicians to refrain from exercise, yet sports medicine and careful exercise prescription are their best allies at present because no effective enzyme replacement therapy is expected to be available in the near future. As of today, although unable to restore myophosphorylase deficiency, the 'simple' use of exercise as therapy seems probably more promising and practical for patients than more 'complex' medical approaches.
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28
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Hostrup M, Kalsen A, Ortenblad N, Juel C, Mørch K, Rzeppa S, Karlsson S, Backer V, Bangsbo J. β2-adrenergic stimulation enhances Ca2+ release and contractile properties of skeletal muscles, and counteracts exercise-induced reductions in Na+-K+-ATPase Vmax in trained men. J Physiol 2014; 592:5445-59. [PMID: 25344552 DOI: 10.1113/jphysiol.2014.277095] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The aim of the present study was to examine the effect of β2-adrenergic stimulation on skeletal muscle contractile properties, sarcoplasmic reticulum (SR) rates of Ca(2+) release and uptake, and Na(+)-K(+)-ATPase activity before and after fatiguing exercise in trained men. The study consisted of two experiments (EXP1, n = 10 males, EXP2, n = 20 males), where β2-adrenoceptor agonist (terbutaline) or placebo was randomly administered in double-blinded crossover designs. In EXP1, maximal voluntary isometric contraction (MVC) of m. quadriceps was measured, followed by exercise to fatigue at 120% of maximal oxygen uptake (V̇O2, max ). A muscle biopsy was taken after MVC (non-fatigue) and at time of fatigue. In EXP2, contractile properties of m. quadriceps were measured with electrical stimulations before (non-fatigue) and after two fatiguing 45 s sprints. Non-fatigued MVCs were 6 ± 3 and 6 ± 2% higher (P < 0.05) with terbutaline than placebo in EXP1 and EXP2, respectively. Furthermore, peak twitch force was 11 ± 7% higher (P < 0.01) with terbutaline than placebo at non-fatigue. After sprints, MVC declined (P < 0.05) to the same levels with terbutaline as placebo, whereas peak twitch force was lower (P < 0.05) and half-relaxation time was prolonged (P < 0.05) with terbutaline. Rates of SR Ca(2+) release and uptake at 400 nm [Ca(2+)] were 15 ± 5 and 14 ± 5% (P < 0.05) higher, respectively, with terbutaline than placebo at non-fatigue, but declined (P < 0.05) to similar levels at time of fatigue. Na(+)-K(+)-ATPase activity was unaffected by terbutaline compared with placebo at non-fatigue, but terbutaline counteracted exercise-induced reductions in maximum rate of activity (Vmax) at time of fatigue. In conclusion, increased contractile force induced by β2-adrenergic stimulation is associated with enhanced rate of Ca(2+) release in humans. While β2-adrenergic stimulation elicits positive inotropic and lusitropic effects on non-fatigued m. quadriceps, these effects are blunted when muscles fatigue.
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Affiliation(s)
- M Hostrup
- Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Denmark Department of Respiratory Research, Bispebjerg University Hospital, Denmark
| | - A Kalsen
- Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Denmark Department of Respiratory Research, Bispebjerg University Hospital, Denmark
| | - N Ortenblad
- Department of Sports Science and Biomechanics, University of Southern Denmark, Denmark Swedish Winter Sports Research Centre, Mid Sweden University, Sweden
| | - C Juel
- Department of Biology, University of Copenhagen, Denmark
| | - K Mørch
- Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Denmark
| | - S Rzeppa
- Norwegian Doping Control Laboratory, Oslo University Hospital, Norway
| | - S Karlsson
- Department of Respiratory Research, Bispebjerg University Hospital, Denmark
| | - V Backer
- Department of Respiratory Research, Bispebjerg University Hospital, Denmark
| | - J Bangsbo
- Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Denmark
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29
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Gejl KD, Hvid LG, Frandsen U, Jensen K, Sahlin K, Ørtenblad N. Muscle glycogen content modifies SR Ca2+ release rate in elite endurance athletes. Med Sci Sports Exerc 2014; 46:496-505. [PMID: 24091991 DOI: 10.1249/mss.0000000000000132] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE The aim of the present study was to investigate the influence of muscle glycogen content on sarcoplasmic reticulum (SR) function and peak power output (Wpeak) in elite endurance athletes. METHODS Fourteen highly trained male triathletes (VO2max = 66.5 ± 1.3 mL O2·kg·min), performed 4 h of glycogen-depleting cycling exercise (HRmean = 73% ± 1% of maximum). During the first 4 h of recovery, athletes received either water (H2O) or carbohydrate (CHO), separating alterations in muscle glycogen content from acute changes affecting SR function and performance. Thereafter, all subjects received CHO-enriched food for the remaining 20-h recovery period. RESULTS Immediately after exercise, muscle glycogen content and SR Ca release rate was reduced to 32% ± 4% (225 ± 28 mmol·kg dw) and 86% ± 2% of initial levels, respectively (P < 0.01). Glycogen markedly recovered after 4 h of recovery with CHO (61% ± 2% of preexercise) and SR Ca release rate returned to preexercise level. However, in the absence of CHO during the first 4 h of recovery, glycogen and SR Ca release rate remained depressed, with the normalization of both parameters at the end of the 24 h of recovery after receiving a CHO-enriched diet. Linear regression demonstrated a significant correlation between SR Ca release rate and muscle glycogen content (P < 0.01, r = 0.30). The 4 h of cycling exercise reduced Wpeak by 5.5%-8.9% at different cadences (P < 0.05), and Wpeak was normalized after 4 h of recovery with CHO, whereas Wpeak remained depressed (P < 0.05) after water provision. Wpeak was fully recovered after 24 h in both the H2O and the CHO group. CONCLUSION In conclusion, the present results suggest that low muscle glycogen depresses muscle SR Ca release rate, which may contribute to fatigue and delayed recovery of Wpeak 4 h postexercise.
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Affiliation(s)
- Kasper Degn Gejl
- 1Institute of Sports Science and Clinical Biomechanics, SDU Muscle Research Cluster (SMRC), University of Southern Denmark, Odense, DENMARK; 2Swedish Winter Sports Research Centre, Department of Health Sciences, Mid Sweden University, Östersund, SWEDEN; and 3The Åstrand Laboratory, Swedish School of Sport and Health Sciences, Stockholm, SWEDEN
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30
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Souglis AG, Chryssanthopoulos CI, Travlos AK, Zorzou AE, Gissis IT, Papadopoulos CN, Sotiropoulos AA. The effect of high vs. low carbohydrate diets on distances covered in soccer. J Strength Cond Res 2014; 27:2235-47. [PMID: 23168373 DOI: 10.1519/jsc.0b013e3182792147] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The purpose of this study was to compare the distances covered during a 11-a-side soccer match after players had consumed either a high carbohydrate (CHO) or a low CHO diet. Twenty-two male professional soccer players formed 2 teams (A and B), of similar age, body characteristics, and training experience. The 2 teams played against each other twice with a week interval between. For 3.5 days before the first match, the players of team A followed a high CHO diet that provided 8 g CHO per kg body mass (BM) (HC), whereas team B players followed a low CHO diet that provided 3 g CHO per kg BM (LC) for the same time period. Before the second match the dietary treatment was reversed and followed for the same time period. Training during the study was controlled, and distances covered were measured using global positioning system technology. Every player covered a greater total distance in HC compared with the distance covered in LC (HC: 9,380 ± 98 m vs. LC: 8,077 ± 109 m; p < 0.01). All distances covered from easy jogging (7.15 km·h-1) to sprinting (24.15 km·h-1) were also higher in HC compared with LC (p < 0.01). When players followed the HC treatment, they won the match (team A vs. team B: 3-1 for the first game and 1-2 for the second game). The HC diet probably helped players to cover a greater distance compared with LC. Soccer players should avoid eating a low (3 g CHO per kg BM) CHO diet 3-4 days before an important soccer match and have a high CHO intake that provides at least 8 g CHO per kg BM.
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Affiliation(s)
- Athanasios G Souglis
- Department of Physical Education and Sports Science, University of Athens, Athens, Greece.
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31
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Nielsen J, Cheng AJ, Ørtenblad N, Westerblad H. Subcellular distribution of glycogen and decreased tetanic Ca2+ in fatigued single intact mouse muscle fibres. J Physiol 2014; 592:2003-12. [PMID: 24591577 DOI: 10.1113/jphysiol.2014.271528] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
In skeletal muscle fibres, glycogen has been shown to be stored at different subcellular locations: (i) between the myofibrils (intermyofibrillar); (ii) within the myofibrils (intramyofibrillar); and (iii) subsarcolemmal. Of these, intramyofibrillar glycogen has been implied as a critical regulator of sarcoplasmic reticulum Ca(2+) release. The aim of the present study was to test directly how the decrease in cytoplasmic free Ca(2+) ([Ca(2+)]i) during repeated tetanic contractions relates to the subcellular glycogen distribution. Single fibres of mouse flexor digitorum brevis muscles were fatigued with 70 Hz, 350 ms tetani given at 2 s (high-intensity fatigue, HIF) or 10 s (low-intensity fatigue, LIF) intervals, while force and [Ca(2+)]i were measured. Stimulation continued until force decreased to 30% of its initial value. Fibres were then prepared for analyses of subcellular glycogen distribution by transmission electron microscopy. At fatigue, tetanic [Ca(2+)]i was reduced to 70 ± 4% and 54 ± 4% of the initial in HIF (P < 0.01, n = 9) and LIF (P < 0.01, n = 5) fibres, respectively. At fatigue, the mean inter- and intramyofibrillar glycogen content was 60-75% lower than in rested control fibres (P < 0.05), whereas subsarcolemmal glycogen was similar to control. Individual fibres showed a good correlation between the fatigue-induced decrease in tetanic [Ca(2+)]i and the reduction in intermyofibrillar (P = 0.051) and intramyofibrillar (P = 0.0008) glycogen. In conclusion, the fatigue-induced decrease in tetanic [Ca(2+)]i, and hence force, is accompanied by major reductions in inter- and intramyofibrillar glycogen. The stronger correlation between decreased tetanic [Ca(2+)]i and reduced intramyofibrillar glycogen implies that sarcoplasmic reticulum Ca(2+) release critically depends on energy supply from the intramyofibrillar glycogen pool.
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32
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Takahashi Y, Matsunaga Y, Tamura Y, Urushibata E, Terada S, Hatta H. Post-exercise taurine administration enhances glycogen repletion in tibialis anterior muscle. JOURNAL OF PHYSICAL FITNESS AND SPORTS MEDICINE 2014. [DOI: 10.7600/jpfsm.3.531] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Abstract
Studies performed at the beginning of the last century revealed the importance of carbohydrate as a fuel during exercise, and the importance of muscle glycogen on performance has subsequently been confirmed in numerous studies. However, the link between glycogen depletion and impaired muscle function during fatigue is not well understood and a direct cause-and-effect relationship between glycogen and muscle function remains to be established. The use of electron microscopy has revealed that glycogen is not homogeneously distributed in skeletal muscle fibres, but rather localized in distinct pools. Furthermore, each glycogen granule has its own metabolic machinery with glycolytic enzymes and regulating proteins. One pool of such glycogenolytic complexes is localized within the myofibrils in close contact with key proteins involved in the excitation-contraction coupling and Ca2+ release from the sarcoplasmic reticulum (SR). We and others have provided experimental evidence in favour of a direct role of decreased glycogen, localized within the myofibrils, for the reduction in SR Ca2+ release during fatigue. This is consistent with compartmentalized energy turnover and distinctly localized glycogen pools being of key importance for SR Ca2+ release and thereby affecting muscle contractility and fatigability.
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Affiliation(s)
- Niels Ørtenblad
- N. Ørtenblad: Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, DK-5230 Odense M, Denmark.
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Abstract
Purpose:The aim of this systematic literature review was to outline the various preexperimental maximal cycle-test protocols, terminology, and performance indicators currently used to classify subject groups in sportscience research and to construct a classification system for cycling-related research.Methods:A database of 130 subject-group descriptions contains information on preexperimental maximal cycle-protocol designs, terminology of the subject groups, biometrical and physiological data, cycling experience, and parameters. Kolmogorov-Smirnov test, 1-way ANOVA, post hoc Bonferroni (P < .05), and trend lines were calculated on height, body mass, relative and absolute maximal oxygen consumption (VO2max), and peak power output (PPO).Results:During preexperimental testing, an initial workload of 100 W and a workload increase of 25 W are most frequently used. Three-minute stages provide the most reliable and valid measures of endurance performance. After obtaining data on a subject group, researchers apply various terms to define the group. To solve this complexity, the authors introduced the neutral term performance levels 1 to 5, representing untrained, recreationally trained, trained, well-trained, and professional subject groups, respectively. The most cited parameter in literature to define subject groups is relative VO2max, and therefore no overlap between different performance levels may occur for this principal parameter. Another significant cycling parameter is the absolute PPO. The description of additional physiological information and current and past cycling data is advised.Conclusion:This review clearly shows the need to standardize the procedure for classifying subject groups. Recommendations are formulated concerning preexperimental testing, terminology, and performance indicators.
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35
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Nielsen J, Ørtenblad N. Physiological aspects of the subcellular localization of glycogen in skeletal muscle. Appl Physiol Nutr Metab 2013; 38:91-9. [DOI: 10.1139/apnm-2012-0184] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Glucose is stored in skeletal muscle fibers as glycogen, a branched-chain polymer observed in electron microscopy images as roughly spherical particles (known as β-particles of 10–45 nm in diameter), which are distributed in distinct localizations within the myofibers and are physically associated with metabolic and scaffolding proteins. Although the subcellular localization of glycogen has been recognized for more than 40 years, the physiological role of the distinct localizations has received sparse attention. Recently, however, studies involving stereological, unbiased, quantitative methods have investigated the role and regulation of these distinct deposits of glycogen. In this report, we review the available literature regarding the subcellular localization of glycogen in skeletal muscle as investigated by electron microscopy studies and put this into perspective in terms of the architectural, topological, and dynamic organization of skeletal muscle fibers. In summary, the distribution of glycogen within skeletal muscle fibers has been shown to depend on the fiber phenotype, individual training status, short-term immobilization, and exercise and to influence both muscle contractility and fatigability. Based on all these data, the available literature strongly indicates that the subcellular localization of glycogen has to be taken into consideration to fully understand and appreciate the role and regulation of glycogen metabolism and signaling in skeletal muscle. A full understanding of these phenomena may prove vital in elucidating the mechanisms that integrate basic cellular events with changing glycogen content.
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Affiliation(s)
- Joachim Nielsen
- SDU Muscle Research Cluster (SMRC), Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark, Campusvej 55, DK-5230 Odense, Denmark; Swedish Winter Sports Research Centre, Department of Health Sciences, Mid Sweden University, 83125 Östersund, Sweden
| | - Niels Ørtenblad
- SDU Muscle Research Cluster (SMRC), Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark, Campusvej 55, DK-5230 Odense, Denmark; Swedish Winter Sports Research Centre, Department of Health Sciences, Mid Sweden University, 83125 Östersund, Sweden
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Wada M, Kuratani M, Kanzaki K. Calcium kinetics of sarcoplasmic reticulum and muscle fatigue. JOURNAL OF PHYSICAL FITNESS AND SPORTS MEDICINE 2013. [DOI: 10.7600/jpfsm.2.169] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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37
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Maximal voluntary contraction force, SR function and glycogen resynthesis during the first 72 h after a high-level competitive soccer game. Eur J Appl Physiol 2011; 111:2987-95. [PMID: 21448723 DOI: 10.1007/s00421-011-1919-y] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 03/08/2011] [Indexed: 10/18/2022]
Abstract
The aim of this study was to examine maximal voluntary knee-extensor contraction force (MVC force), sarcoplasmic reticulum (SR) function and muscle glycogen levels in the days after a high-level soccer game when players ingested an optimised diet. Seven high-level male soccer players had a vastus lateralis muscle biopsy and a blood sample collected in a control situation and at 0, 24, 48 and 72 h after a competitive soccer game. MVC force, SR function, muscle glycogen, muscle soreness and plasma myoglobin were measured. MVC force sustained over 1 s was 11 and 10% lower (P < 0.05) after 0 and 24 h, respectively, compared with control. The rate of SR Ca(2+) uptake at 800 nM [Ca(2+)](free) was lower (P < 0.05) after 0 h (2.5 μmol Ca(2+) g prot(-1) min(-1)) than for all other time points (24 h: 5.1 μmol Ca(2+) g prot(-1) min(-1)). However, SR Ca(2+) release rate was not affected. Plasma myoglobin was sixfold higher (P < 0.05) immediately after the game, but normalised 24 h after the game. Quadriceps muscle soreness (0-10 VAS-scale) was higher (P < 0.05) after 0 h (3.6), 24 h (1.8), 48 h (1.1) and 72 h (1.4) compared with control (0.1). Muscle glycogen was 57 and 27% lower (P < 0.001) 0 and 24 h after the game compared with control (193 and 328 vs. 449 mmol kg d w(-1)). In conclusion, maximal voluntary contraction force and SR Ca(2+) uptake were impaired and muscle soreness was elevated after a high-level soccer game, with faster recovery of SR function in comparison with MVC force, soreness and muscle glycogen.
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38
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Ørtenblad N, Nielsen J, Saltin B, Holmberg HC. Role of glycogen availability in sarcoplasmic reticulum Ca2+ kinetics in human skeletal muscle. J Physiol 2010; 589:711-25. [PMID: 21135051 DOI: 10.1113/jphysiol.2010.195982] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Glucose is stored as glycogen in skeletal muscle. The importance of glycogen as a fuel during exercise has been recognized since the 1960s; however, little is known about the precise mechanism that relates skeletal muscle glycogen to muscle fatigue. We show that low muscle glycogen is associated with an impairment of muscle ability to release Ca(2+), which is an important signal in the muscle activation. Thus, depletion of glycogen during prolonged, exhausting exercise may contribute to muscle fatigue by causing decreased Ca(2+) release inside the muscle. These data provide indications of a signal that links energy utilization, i.e. muscle contraction, with the energy content in the muscle, thereby inhibiting a detrimental depletion of the muscle energy store.
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Affiliation(s)
- Niels Ørtenblad
- Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense M, Denmark.
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39
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Muscle metabolic, enzymatic and transporter responses to a session of prolonged cycling. Eur J Appl Physiol 2010; 111:827-37. [DOI: 10.1007/s00421-010-1709-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/20/2010] [Indexed: 12/19/2022]
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40
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Green HJ, Burnett M, Duhamel TA, D'Arsigny C, O'Donnell DE, Webb KA, Ouyang J. Abnormal sarcoplasmic reticulum Ca2+-sequestering properties in skeletal muscle in chronic obstructive pulmonary disease. Am J Physiol Cell Physiol 2008; 295:C350-7. [DOI: 10.1152/ajpcell.00224.2008] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The objective of this study was to investigate the hypothesis that alterations in sarcoplasmic reticulum (SR) Ca2+-cycling properties would occur in skeletal muscle in patients with moderate to severe chronic obstructive pulmonary disease (COPD). To investigate this hypothesis, tissue samples were obtained from the vastus lateralis of 8 patients with COPD [age 65.6 ± 3.2 yr; forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) = 44 ± 2%; mean ± SE] and 10 healthy age-matched controls (CON, age 67.5 ± 2.5 yr; FEV1/FVC = 77 ± 2%), and homogenates were analyzed for a wide range of SR properties. Compared with CON, COPD displayed (in μmol·g protein−1·min−1) a 16% lower maximal Ca2+-ATPase activity [maximal velocity ( Vmax), 158 ± 10 vs. 133 ± 7, P < 0.05] and a 17% lower Ca2+uptake (4.65 ± 0.039 vs. 3.85 ± 0.26, P < 0.05) that occurred in the absence of differences in Ca2+release. The lower Vmaxin COPD was also accompanied by an 11% lower ( P < 0.05) Ca2+sensitivity, as measured by the Hill coefficient (defined as the relationship between Ca2+-ATPase activity and free cytosolic Ca2+concentration for 10–90% Vmax). For the sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) isoforms, SERCA1a was 16% higher ( P < 0.05) and SERCA2a was 14% lower ( P < 0.05) in COPD. It is concluded that moderate to severe COPD results in abnormalities in SR Ca2+-ATPase properties that cannot be explained by changes in the SERCA isoform phenotypes. The reduced catalytic properties of SERCA in COPD suggest a disturbance in Ca2+cycling, possibly resulting in impairment in Ca2+-mediated mechanical function and/or second messenger regulated processes.
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41
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Burnley M, Jones AM. Viewpoint: Fatigue mechanisms determining exercise performance: integrative physiology is systems physiology. J Appl Physiol (1985) 2008; 104:1545. [PMID: 18504821 DOI: 10.1152/japplphysiol.90427.2008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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42
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STEWART RILEYD, DUHAMEL TODDA, RICH SHARON, TUPLING ARUSSELL, GREEN HOWARDJ. Effects of Consecutive Days of Exercise and Recovery on Muscle Mechanical Function. Med Sci Sports Exerc 2008; 40:316-25. [DOI: 10.1249/mss.0b013e31815adf02] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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43
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Matsunaga S, Mishima T, Yamada T, Inashima S, Wada M. Alterations in in vitro function and protein oxidation of rat sarcoplasmic reticulum Ca2+-ATPase during recovery from high-intensity exercise. Exp Physiol 2007; 93:426-33. [PMID: 18156168 DOI: 10.1113/expphysiol.2007.040477] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The hypothesis tested in this study was that the extent to which sarcoplasmic reticulum (SR) Ca(2+)-ATPase is oxidized would correlate with a decline in its activity. For this purpose, changes in the SR Ca(2+)-sequestering ability and the contents of carbonyl and sulfhydryl groups during recovery after exercise were examined in the superficial portions of vastus lateralis muscles from rats subjected to 5 min running at an intensity corresponding to maximal oxygen uptake (50 m min(-1), 10% gradient). A single bout of exercise elicited a 22.4% reduction (P < 0.05) in SR Ca(2+)-ATPase activity. The decreased activity progressively reverted to normal levels during recovery after exercise, reaching normal levels after 60 min of recovery. This change was paralleled by a depressed SR Ca(2+)-uptake rate, and the proportional alteration in these two variables resulted in no change in the ratio of Ca(2+)-uptake rate to Ca(2+)-ATPase activity. The contents of SR Ca(2+)-ATPase protein and sulfhydryl groups in microsomes were unchanged after exercise and during recovery periods. In contrast, the content of carbonyl groups in SR Ca(2+)-ATPase behaved in an opposite manner to that of SR Ca(2+)-ATPase activity. An approximately 80% augmentation (P < 0.05) in the carbonyl group content occurred immediately after exercise. The elevated carbonyl content decreased towards normal levels during 60 min of recovery. These results are strongly suggestive that oxidation of SR Ca(2+)-ATPase is responsible, at least in part, for a decay in the SR Ca(2+)-pumping function produced by high-intensity exercise and imply that oxidized proteins may be repaired during recovery from exercise.
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Affiliation(s)
- Satoshi Matsunaga
- Research Center for Urban Health and Sports, Osaka City University, Sugimoto, Sumiyoshi, Osaka, Japan.
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Duhamel TA, Green HJ, Stewart RD, Foley KP, Smith IC, Ouyang J. Muscle metabolic, SR Ca2+-cycling responses to prolonged cycling, with and without glucose supplementation. J Appl Physiol (1985) 2007; 103:1986-98. [DOI: 10.1152/japplphysiol.01440.2006] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study investigated the effects of prolonged exercise, with and without glucose supplementation, on metabolism and sarcoplasmic reticulum (SR) Ca2+-handling properties in working vastus lateralis muscle. Fifteen untrained volunteers [peak O2consumption (V̇o2peak) = 3.45 ± 0.17 l/min; mean ± SE] cycled at ∼60% V̇o2peakon two occasions, during which they were provided with either an artificially sweetened placebo beverage (NG) or a 6% glucose (G) beverage (∼1.00 g carbohydrate/kg body mass). Beverage supplementation started at 30 min of exercise and continued every 15 min thereafter. SR Ca2+handling, metabolic, and substrate responses were assessed in tissue extracted from the vastus lateralis at rest, after 30 min and 90 min of exercise, and at fatigue in both conditions. Plasma glucose during G was 15–23% higher ( P < 0.05) than those observed during NG following 60 min of exercise until fatigue. Cycle time to fatigue was increased ( P < 0.05) by ∼19% during G (137 ± 7 min) compared with NG (115 ± 6 min). Prolonged exercise reduced ( P < 0.05) maximal Ca2+-ATPase activity (−18.4%), SR Ca2+uptake (−27%), and both Phase 1 (−22.2%) and Phase 2 (−34.2%) Ca2+-release rates during NG. The exercise-induced reductions in SR Ca2+-cycling properties were not altered during G. The metabolic responses to exercise were all unaltered by glucose supplementation, since no differences in respiratory exchange ratios, carbohydrate and lipid oxidation rates, and muscle metabolite and glycogen contents were observed between NG and G. These results indicate that the maintenance of blood glucose homeostasis by glucose supplementation is without effect in modifying the muscle metabolic, endogenous glycogen, or SR Ca2+-handling responses.
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45
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Duhamel TA, Stewart RD, Tupling AR, Ouyang J, Green HJ. Muscle sarcoplasmic reticulum calcium regulation in humans during consecutive days of exercise and recovery. J Appl Physiol (1985) 2007; 103:1212-20. [PMID: 17656626 DOI: 10.1152/japplphysiol.00437.2007] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The study investigated the hypothesis that three consecutive days of prolonged cycle exercise would result in a sustained reduction in the Ca(2+)-cycling properties of the vastus lateralis in the absence of changes in the sarcoplasmic (endoplasmic) reticulum Ca(2+)-ATPase (SERCA) protein. Tissue samples were obtained at preexercise (Pre) and postexercise (Post) on day 1 (E1) and day 3 (E3) and during recovery day 1 (R1), day 2 (R2), and day 3 (R3) in 12 active but untrained volunteers (age 19.2 +/- 0.27 yr; mean +/- SE) and analyzed for changes (nmol.mg protein(-1).min(-1)) in maximal Ca(2+)-ATPase activity (V(max)), Ca(2+) uptake and Ca(2+) release (phase 1 and phase 2), and SERCA isoform expression (SERCA1a and SERCA2a). At E1, reductions (P < 0.05) from Pre to Post in V(max) (150 +/- 7 vs. 121 +/- 7), Ca(2+) uptake (7.79 +/- 0.28 vs. 5.71 +/- 0.33), and both phases of Ca(2+) release (phase 1, 20.3 +/- 1.3 vs. 15.2 +/- 1.1; phase 2, 7.70 +/- 0.60 vs. 4.99 +/- 0.48) were found. In contrast to V(max), which recovered at Pre E3 and then remained stable at Post E3 and throughout recovery, Ca(2+) uptake remained depressed (P < 0.05) at E3 Pre and Post and at R1 as did phase 2 of Ca(2+) release. Exercise resulted in an increase (P < 0.05) in SERCA1a (14% at R2) but not SERCA2a. It is concluded that rapidly adapting mechanisms protect V(max) following the onset of regular exercise but not Ca(2+) uptake and Ca(2+) release.
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Affiliation(s)
- T A Duhamel
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
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