101
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Regulation of Muscle Glycogen Metabolism during Exercise: Implications for Endurance Performance and Training Adaptations. Nutrients 2018; 10:nu10030298. [PMID: 29498691 PMCID: PMC5872716 DOI: 10.3390/nu10030298] [Citation(s) in RCA: 121] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 02/23/2018] [Accepted: 02/27/2018] [Indexed: 11/16/2022] Open
Abstract
Since the introduction of the muscle biopsy technique in the late 1960s, our understanding of the regulation of muscle glycogen storage and metabolism has advanced considerably. Muscle glycogenolysis and rates of carbohydrate (CHO) oxidation are affected by factors such as exercise intensity, duration, training status and substrate availability. Such changes to the global exercise stimulus exert regulatory effects on key enzymes and transport proteins via both hormonal control and local allosteric regulation. Given the well-documented effects of high CHO availability on promoting exercise performance, elite endurance athletes are typically advised to ensure high CHO availability before, during and after high-intensity training sessions or competition. Nonetheless, in recognition that the glycogen granule is more than a simple fuel store, it is now also accepted that glycogen is a potent regulator of the molecular cell signaling pathways that regulate the oxidative phenotype. Accordingly, the concept of deliberately training with low CHO availability has now gained increased popularity amongst athletic circles. In this review, we present an overview of the regulatory control of CHO metabolism during exercise (with a specific emphasis on muscle glycogen utilization) in order to discuss the effects of both high and low CHO availability on modulating exercise performance and training adaptations, respectively.
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102
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Post-Exercise Carbohydrate-Energy Replacement Attenuates Insulin Sensitivity and Glucose Tolerance the Following Morning in Healthy Adults. Nutrients 2018; 10:nu10020123. [PMID: 29370143 PMCID: PMC5852699 DOI: 10.3390/nu10020123] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Revised: 01/22/2018] [Accepted: 01/24/2018] [Indexed: 12/29/2022] Open
Abstract
The carbohydrate deficit induced by exercise is thought to play a key role in increased post-exercise insulin action. However, the effects of replacing carbohydrate utilized during exercise on postprandial glycaemia and insulin sensitivity are yet to be determined. This study therefore isolated the extent to which the insulin-sensitizing effects of exercise are dependent on the carbohydrate deficit induced by exercise, relative to other exercise-mediated mechanisms. Fourteen healthy adults performed a 90-min run at 70% V˙O2max starting at 1600–1700 h before ingesting either a non-caloric artificially-sweetened placebo solution (CHO-DEFICIT) or a 15% carbohydrate solution (CHO-REPLACE; 221.4 ± 59.3 g maltodextrin) to precisely replace the measured quantity of carbohydrate oxidized during exercise. The alternate treatment was then applied one week later in a randomized, placebo-controlled, and double-blinded crossover design. A standardized low-carbohydrate evening meal was consumed in both trials before overnight recovery ahead of a two-hour oral glucose tolerance test (OGTT) the following morning to assess glycemic and insulinemic responses to feeding. Compared to the CHO-DEFICIT condition, CHO-REPLACE increased the incremental area under the plasma glucose curve by a mean difference of 68 mmol·L−1 (95% CI: 4 to 132 mmol·L−1; p = 0.040) and decreased the Matsuda insulin sensitivity index by a mean difference of −2 au (95% CI: −1 to −3 au; p = 0.001). This is the first study to demonstrate that post-exercise feeding to replaceme the carbohydrate expended during exercise can attenuate glucose tolerance and insulin sensitivity the following morning. The mechanism through which exercise improves insulin sensitivity is therefore (at least in part) dependent on carbohydrate availability and so the day-to-day metabolic health benefits of exercise might be best attained by maintaining a carbohydrate deficit overnight.
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103
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Shamlan G, Bech P, Robertson MD, Collins AL. Acute effects of exercise intensity on subsequent substrate utilisation, appetite, and energy balance in men and women. Appl Physiol Nutr Metab 2017; 42:1247-1253. [DOI: 10.1139/apnm-2017-0280] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Exercise is capable of influencing the regulation of energy balance by acutely modulating appetite and energy intake coupled to effects on substrate utilization. Yet, few studies have examined acute effects of exercise intensity on aspects of both energy intake and energy metabolism, independently of energy cost of exercise. Furthermore, little is known as to the gender differences of these effects. One hour after a standardised breakfast, 40 (19 female), healthy participants (BMI 23.6 ± 3.6 kg·m−2, V̇O2peak 34.4 ± 6.8 mL·kg−1·min−1) undertook either high-intensity intermittent cycling (HIIC) consisting of 8 repeated 60 s bouts of cycling at 95% V̇O2peak or low-intensity continuous cycling (LICC), equivalent to 50% V̇O2peak, matched for energy cost (∼950 kJ) followed by 90 mins of rest, in a randomised crossover design. Throughout each study visit, satiety was assessed subjectively using visual analogue scales alongside blood metabolites and GLP-1. Energy expenditure and substrate utilization were measured over 75 min postexercise via indirect calorimetry. Energy intake was assessed for 48 h postintervention. No differences in appetite, GLP-1, or energy intakes were observed between HIIC and LICC, with or without stratifying for gender. Significant differences in postexercise nonesterified fatty acid concentrations were observed between intensities in both genders, coupled to a significantly lower respiratory exchange ratio following HIIC (P = 0.0028), with a trend towards greater reductions in respiratory exchange ratioin males (P = 0.079). In conclusion, high-intensity exercise, if energy matched, does not lead to greater appetite or energy intake, but may exert additional beneficial metabolic effects that may be more pronounced in males.
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Affiliation(s)
- Ghalia Shamlan
- Nutritional Sciences, Faculty of Health & Medical Sciences, University of Surrey, Guildford, Surrey, GU2 7XH, United Kingdom
| | - Paul Bech
- Department of Diabetes, Endocrinology and Metabolism, Imperial College London, Hammersmith Hospital, London W12 0NN, United Kingdom
| | - M. Denise Robertson
- Nutritional Sciences, Faculty of Health & Medical Sciences, University of Surrey, Guildford, Surrey, GU2 7XH, United Kingdom
| | - Adam L. Collins
- Nutritional Sciences, Faculty of Health & Medical Sciences, University of Surrey, Guildford, Surrey, GU2 7XH, United Kingdom
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104
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Smith HA, Gonzalez JT, Thompson D, Betts JA. Dietary carbohydrates, components of energy balance, and associated health outcomes. Nutr Rev 2017; 75:783-797. [DOI: 10.1093/nutrit/nux045] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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105
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Association of the Composite Inflammatory Biomarker GlycA, with Exercise-Induced Changes in Body Habitus in Men and Women with Prediabetes. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2017. [PMID: 28642810 PMCID: PMC5470023 DOI: 10.1155/2017/5608287] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
GlycA is a new composite measure of systemic inflammation and a predictor of many inflammatory diseases. GlycA is the nuclear magnetic resonance spectroscopy-derived signal arising from glucosamine residues on acute-phase proteins. This study aimed to evaluate how exercise-based lifestyle interventions modulate GlycA in persons at risk for type 2 diabetes. GlycA, fitness, and body habitus were measured in 169 sedentary adults (45–75 years) with prediabetes randomly assigned to one of four six-month exercise-based lifestyle interventions. Interventions included exercise prescription based on the amount (energy expenditure (kcal/kg weight/week (KKW)) and intensity (%VO2peak). The groups were (1) low-amount/moderate-intensity (10KKW/50%) exercise; (2) high-amount/moderate-intensity (16KKW/50%) exercise; (3) high-amount/vigorous-intensity (16KKW/75%) exercise; and (4) a Clinical Lifestyle (combined diet plus low-amount/moderate-intensity exercise) intervention. Six months of exercise training and/or diet-reduced GlycA (mean Δ: −6.8 ± 29.2 μmol/L; p = 0.006) and increased VO2peak (mean Δ: 1.98 ± 2.6 mL/kg/min; p < 0.001). Further, visceral (mean Δ: −21.1 ± 36.6 cm2) and subcutaneous fat (mean Δ: −24.3 ± 41.0 cm2) were reduced, while liver density (mean Δ: +2.3 ± 6.5HU) increased, all p < 0.001. When including individuals in all four interventions, GlycA reductions were associated with reductions in visceral adiposity (p < 0.03). Exercise-based lifestyle interventions reduced GlycA concentrations through mechanisms related to exercise-induced modulations of visceral adiposity. This trial is registered with Clinical Trial Registration Number NCT00962962.
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106
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Vandoorne T, De Smet S, Ramaekers M, Van Thienen R, De Bock K, Clarke K, Hespel P. Intake of a Ketone Ester Drink during Recovery from Exercise Promotes mTORC1 Signaling but Not Glycogen Resynthesis in Human Muscle. Front Physiol 2017; 8:310. [PMID: 28588499 PMCID: PMC5440563 DOI: 10.3389/fphys.2017.00310] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 04/28/2017] [Indexed: 01/07/2023] Open
Abstract
Purpose: Ketone bodies are energy substrates produced by the liver during prolonged fasting or low-carbohydrate diet. The ingestion of a ketone ester (KE) rapidly increases blood ketone levels independent of nutritional status. KE has recently been shown to improve exercise performance, but whether it can also promote post-exercise muscle protein or glycogen synthesis is unknown. Methods: Eight healthy trained males participated in a randomized double-blind placebo-controlled crossover study. In each session, subjects undertook a bout of intense one-leg glycogen-depleting exercise followed by a 5-h recovery period during which they ingested a protein/carbohydrate mixture. Additionally, subjects ingested a ketone ester (KE) or an isocaloric placebo (PL). Results: KE intake did not affect muscle glycogen resynthesis, but more rapidly lowered post-exercise AMPK phosphorylation and resulted in higher mTORC1 activation, as evidenced by the higher phosphorylation of its main downstream targets S6K1 and 4E-BP1. As enhanced mTORC1 activation following KE suggests higher protein synthesis rates, we used myogenic C2C12 cells to further confirm that ketone bodies increase both leucine-mediated mTORC1 activation and protein synthesis in muscle cells. Conclusion: Our results indicate that adding KE to a standard post-exercise recovery beverage enhances the post-exercise activation of mTORC1 but does not affect muscle glycogen resynthesis in young healthy volunteers. In vitro, we confirmed that ketone bodies potentiate the increase in mTORC1 activation and protein synthesis in leucine-stimulated myotubes. Whether, chronic oral KE intake during recovery from exercise can facilitate training-induced muscular adaptation and remodeling need to be further investigated.
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Affiliation(s)
- Tijs Vandoorne
- Exercise Physiology Research Group, Department of Kinesiology, KU LeuvenLeuven, Belgium
| | - Stefan De Smet
- Exercise Physiology Research Group, Department of Kinesiology, KU LeuvenLeuven, Belgium
| | - Monique Ramaekers
- Exercise Physiology Research Group, Department of Kinesiology, KU LeuvenLeuven, Belgium
| | - Ruud Van Thienen
- Exercise Physiology Research Group, Department of Kinesiology, KU LeuvenLeuven, Belgium
| | - Katrien De Bock
- Exercise Physiology Research Group, Department of Kinesiology, KU LeuvenLeuven, Belgium.,Laboratory of Exercise and Health, Department of Health Sciences and Technology, ETH ZurichZurich, Switzerland
| | - Kieran Clarke
- Department of Physiology, Anatomy and Genetics, University of OxfordOxford, United Kingdom
| | - Peter Hespel
- Exercise Physiology Research Group, Department of Kinesiology, KU LeuvenLeuven, Belgium
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107
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Burke LM, van Loon LJC, Hawley JA. Postexercise muscle glycogen resynthesis in humans. J Appl Physiol (1985) 2017; 122:1055-1067. [DOI: 10.1152/japplphysiol.00860.2016] [Citation(s) in RCA: 110] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 10/12/2016] [Accepted: 10/23/2016] [Indexed: 11/22/2022] Open
Abstract
Since the pioneering studies conducted in the 1960s in which glycogen status was investigated using the muscle biopsy technique, sports scientists have developed a sophisticated appreciation of the role of glycogen in cellular adaptation and exercise performance, as well as sites of storage of this important metabolic fuel. While sports nutrition guidelines have evolved during the past decade to incorporate sport-specific and periodized manipulation of carbohydrate (CHO) availability, athletes attempt to maximize muscle glycogen synthesis between important workouts or competitive events so that fuel stores closely match the demands of the prescribed exercise. Therefore, it is important to understand the factors that enhance or impair this biphasic process. In the early postexercise period (0–4 h), glycogen depletion provides a strong drive for its own resynthesis, with the provision of CHO (~1 g/kg body mass) optimizing this process. During the later phase of recovery (4–24 h), CHO intake should meet the anticipated fuel needs of the training/competition, with the type, form, and pattern of intake being less important than total intake. Dietary strategies that can enhance glycogen synthesis from suboptimal amounts of CHO or energy intake are of practical interest to many athletes; in this scenario, the coingestion of protein with CHO can assist glycogen storage. Future research should identify other factors that enhance the rate of synthesis of glycogen storage in a limited time frame, improve glycogen storage from a limited CHO intake, or increase muscle glycogen supercompensation.
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Affiliation(s)
- Louise M. Burke
- Centre for Exercise and Nutrition, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Victoria, Australia
- Department of Sport Nutrition, Australian Institute of Sport, Belconnen, Australia
| | - Luc J. C. van Loon
- Centre for Exercise and Nutrition, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Victoria, Australia
- NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre, Maastricht, The Netherlands; and
| | - John A. Hawley
- Centre for Exercise and Nutrition, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Victoria, Australia
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
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108
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Rosset R, Egli L, Lecoultre V. Glucose-fructose ingestion and exercise performance: The gastrointestinal tract and beyond. Eur J Sport Sci 2017; 17:874-884. [PMID: 28441908 DOI: 10.1080/17461391.2017.1317035] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Carbohydrate ingestion can improve endurance exercise performance. In the past two decades, research has repeatedly reported the performance benefits of formulations comprising both glucose and fructose (GLUFRU) over those based on glucose (GLU). This has been usually related to additive effects of these two monosaccharides on the gastrointestinal tract whereby intestinal carbohydrate absorption is enhanced and discomfort limited. This is only a partial explanation, since glucose and fructose are also metabolized through different pathways after being absorbed from the gut. In contrast to glucose that is readily used by every body cell type, fructose is specifically targeted to the liver where it is mainly converted into glucose and lactate. The ingestion of GLUFRU may thereby profoundly alter hepatic function ultimately raising both glucose and lactate fluxes. During exercise, this particular profile of circulating carbohydrate may induce a spectrum of effects on muscle metabolism possibly resulting in an improved performance. Compared to GLU alone, GLUFRU ingestion could also induce several non-metabolic effects which are so far largely unexplored. Through its metabolite lactate, fructose may act on central fatigue and/or alter metabolic regulation. Future research could further define the effects of GLUFRU over other exercise modalities and different athletic populations, using several of the hypotheses discussed in this review.
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Affiliation(s)
- Robin Rosset
- a Department of Physiology , University of Lausanne , Lausanne , Switzerland
| | - Léonie Egli
- b Nestle Research Center Singapore , Singapore , Singapore
| | - Virgile Lecoultre
- c Centre for Metabolic Disease , Broye Intercantonal Hospital , Estavayer-le-Lac , Switzerland
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109
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Gonzalez JT, Fuchs CJ, Betts JA, van Loon LJC. Glucose Plus Fructose Ingestion for Post-Exercise Recovery-Greater than the Sum of Its Parts? Nutrients 2017; 9:E344. [PMID: 28358334 PMCID: PMC5409683 DOI: 10.3390/nu9040344] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 03/27/2017] [Indexed: 01/24/2023] Open
Abstract
Carbohydrate availability in the form of muscle and liver glycogen is an important determinant of performance during prolonged bouts of moderate- to high-intensity exercise. Therefore, when effective endurance performance is an objective on multiple occasions within a 24-h period, the restoration of endogenous glycogen stores is the principal factor determining recovery. This review considers the role of glucose-fructose co-ingestion on liver and muscle glycogen repletion following prolonged exercise. Glucose and fructose are primarily absorbed by different intestinal transport proteins; by combining the ingestion of glucose with fructose, both transport pathways are utilised, which increases the total capacity for carbohydrate absorption. Moreover, the addition of glucose to fructose ingestion facilitates intestinal fructose absorption via a currently unidentified mechanism. The co-ingestion of glucose and fructose therefore provides faster rates of carbohydrate absorption than the sum of glucose and fructose absorption rates alone. Similar metabolic effects can be achieved via the ingestion of sucrose (a disaccharide of glucose and fructose) because intestinal absorption is unlikely to be limited by sucrose hydrolysis. Carbohydrate ingestion at a rate of ≥1.2 g carbohydrate per kg body mass per hour appears to maximise post-exercise muscle glycogen repletion rates. Providing these carbohydrates in the form of glucose-fructose (sucrose) mixtures does not further enhance muscle glycogen repletion rates over glucose (polymer) ingestion alone. In contrast, liver glycogen repletion rates are approximately doubled with ingestion of glucose-fructose (sucrose) mixtures over isocaloric ingestion of glucose (polymers) alone. Furthermore, glucose plus fructose (sucrose) ingestion alleviates gastrointestinal distress when the ingestion rate approaches or exceeds the capacity for intestinal glucose absorption (~1.2 g/min). Accordingly, when rapid recovery of endogenous glycogen stores is a priority, ingesting glucose-fructose mixtures (or sucrose) at a rate of ≥1.2 g·kg body mass-1·h-1 can enhance glycogen repletion rates whilst also minimising gastrointestinal distress.
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Affiliation(s)
| | - Cas J Fuchs
- Department of Human Biology and Movement Sciences, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+ (MUMC+), P.O. Box 616, 6200 MD Maastricht, The Netherlands.
| | - James A Betts
- Department for Health, University of Bath, Bath BA2 7AY, UK.
| | - Luc J C van Loon
- Department of Human Biology and Movement Sciences, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+ (MUMC+), P.O. Box 616, 6200 MD Maastricht, The Netherlands.
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110
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Pillon Barcelos R, Freire Royes LF, Gonzalez-Gallego J, Bresciani G. Oxidative stress and inflammation: liver responses and adaptations to acute and regular exercise. Free Radic Res 2017; 51:222-236. [PMID: 28166653 DOI: 10.1080/10715762.2017.1291942] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The liver is remarkably important during exercise outcomes due to its contribution to detoxification, synthesis, and release of biomolecules, and energy supply to the exercising muscles. Recently, liver has been also shown to play an important role in redox status and inflammatory modulation during exercise. However, while several studies have described the adaptations of skeletal muscles to acute and chronic exercise, hepatic changes are still scarcely investigated. Indeed, acute intense exercise challenges the liver with increased reactive oxygen species (ROS) and inflammation onset, whereas regular training induces hepatic antioxidant and anti-inflammatory improvements. Acute and regular exercise protocols in combination with antioxidant and anti-inflammatory supplementation have been also tested to verify hepatic adaptations to exercise. Although positive results have been reported in some acute models, several studies have shown an increased exercise-related stress upon liver. A similar trend has been observed during training: while synergistic effects of training and antioxidant/anti-inflammatory supplementations have been occasionally found, others reported a blunting of relevant adaptations to exercise, following the patterns described in skeletal muscles. This review discusses current data regarding liver responses and adaptation to acute and regular exercise protocols alone or combined with antioxidant and anti-inflammatory supplementation. The understanding of the mechanisms behind these modulations is of interest for both exercise-related health and performance outcomes.
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Affiliation(s)
- Rômulo Pillon Barcelos
- a Instituto de Ciências Biológicas , Universidade de Passo Fundo , Passo Fundo , Brazil.,b Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica (PPGBTOx) , Universidade Federal de Santa Maria (UFSM) , Santa Maria , Brazil
| | - Luiz Fernando Freire Royes
- b Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica (PPGBTOx) , Universidade Federal de Santa Maria (UFSM) , Santa Maria , Brazil.,c Laboratório de Bioquímica do Exercício, Centro de Educação Física e Desportos , Universidade Federal de Santa Maria (UFSM) , Santa Maria , Brazil
| | - Javier Gonzalez-Gallego
- d Institute of Biomedicine (IBIOMED) and Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) , University of León , León , Spain
| | - Guilherme Bresciani
- e Grupo de Investigación en Rendimiento Físico y Salud (IRyS), Escuela de Educación Física , Pontificia Universidad Católica de Valparaiso , Valparaiso , Chile
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