|
1
|
Caswell AM, Tripp TR, Kontro H, Edgett BA, Wiley JP, Lun V, MacInnis MJ. The influence of sex, hemoglobin mass, and skeletal muscle characteristics on cycling critical power. J Appl Physiol (1985) 2024; 137:10-22. [PMID: 38779761 DOI: 10.1152/japplphysiol.00120.2024] [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: 02/15/2024] [Revised: 04/29/2024] [Accepted: 05/15/2024] [Indexed: 05/25/2024] Open
Abstract
Critical power (CP) represents an important threshold for exercise performance and fatiguability. We sought to determine the extent to which sex, hemoglobin mass (Hbmass), and skeletal muscle characteristics influence CP. Before CP determination (i.e., 3-5 constant work rate trials to task failure), Hbmass and skeletal muscle oxidative capacity (τ) were measured and vastus lateralis (VL) muscle biopsy samples were collected from 12 females and 12 males matched for aerobic fitness relative to fat-free mass (FFM) [means (SD); V̇o2max: 59.2 (7.7) vs. 59.5 (7.1) mL·kg·FFM-1·min-1, respectively]. Males had a significantly greater CP than females in absolute units [225 (28) vs. 170 (43) W; P = 0.001] but not relative to body mass [3.0 (0.6) vs. 2.7 (0.6) W·kg·BM-1; P = 0.267] or FFM [3.6 (0.7) vs. 3.7 (0.8) W·kg·FFM-1; P = 0.622]. Males had significantly greater W' (P ≤ 0.030) and greater Hbmass (P ≤ 0.016) than females, regardless of the normalization approach; however, there were no differences in mitochondrial protein content (P = 0.375), τ (P = 0.603), or MHC I proportionality (P = 0.574) between males and females. Whether it was expressed in absolute or relative units, CP was positively correlated with Hbmass (0.444 ≤ r ≤ 0.695; P < 0.05), mitochondrial protein content (0.413 ≤ r ≤ 0.708; P < 0.05), and MHC I proportionality (0.506 ≤ r ≤ 0.585; P < 0.05), and negatively correlated with τ when expressed in relative units only (-0.588 ≤ r ≤ -0.527; P < 0.05). Overall, CP was independent of sex, but variability in CP was related to Hbmass and skeletal muscle characteristics. The extent to which manipulations in these physiological parameters influence CP warrants further investigation to better understand the factors underpinning CP.NEW & NOTEWORTHY In males and females matched for aerobic fitness [maximal oxygen uptake normalized to fat-free mass (FFM)], absolute critical power (CP) was greater in males, but relative CP (per kilogram body mass or FFM) was similar between sexes. CP correlated with hemoglobin mass, mitochondrial protein content, myosin heavy chain type I proportion, and skeletal muscle oxidative capacity. These findings demonstrate the importance of matching sexes for aerobic fitness, but further experiments are needed to determine causality.
Collapse
Affiliation(s)
- Allison M Caswell
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Thomas R Tripp
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Hilkka Kontro
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Brittany A Edgett
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - J Preston Wiley
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
- Sport Medicine Centre, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Victor Lun
- Sport Medicine Centre, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Martin J MacInnis
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| |
Collapse
|
|
2
|
Nicholson M, Poulus D, Robergs R, Kelly V, McNulty C. How Much Energy Do E'Athletes Use during Gameplay? Quantifying Energy Expenditure and Heart Rate Variability Within E'Athletes. SPORTS MEDICINE - OPEN 2024; 10:44. [PMID: 38630170 PMCID: PMC11024080 DOI: 10.1186/s40798-024-00708-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 03/26/2024] [Indexed: 04/20/2024]
Abstract
BACKGROUND Research into esports suggests that e'athletes experience physiological stressors and demands during competition and training. The physiological demands of esports are poorly understood and need to be investigated further to inform future training guidelines, optimise performance outcomes, and manage e'athlete wellbeing. This research aimed to quantify the metabolic rate of esports gameplay and compare this outcome with heart rate variability within expert e'athletes. RESULTS Thirteen healthy male participants ranked within the top 10% of their respective esports title participated in the study (age = 20.7 ± 2.69 years; BMI = 24.6 ± 5.89 kg·m- 2). Expired gas analysis indirect calorimetry measured gas exchange during rest and gaming. Compared to resting conditions, competitive esports gameplay significantly increased median energy expenditure (1.28 (IQR 1.16-1.49) kcal·min- 1 vs. 1.45 (IQR 1.20-1.77) kcal·min- 1, p = .02), oxygen consumption (0.27 (IQR 0.24-0.30) L·min- 1 vs. 0.29 (IQR 0.24-0.35) L·min- 1, p = .02) and carbon dioxide production (0.20 (IQR 0.19-0.27) L·min- 1vs. 0.27 (IQR 0.24-0.33) L·min- 1, p = .01). Competitive gameplay also resulted in a significant increase in heart rate (84.5 (IQR 74.1-96.1) bpm vs. 87.1 (IQR 80.3-104) bpm, p = .01) and decrease in R-R interval's (710 (IQR 624-810) ms vs. 689 (IQR 579-747) ms, p = .02) when compared to rest. However, there were no significant differences in time or frequency measures of heart rate variability. CONCLUSIONS The data reveal increased physiological responses to metabolic rate, energy expenditure and cardiovascular function to esports game play within expert e'athletes. Further physiological research into the physical demands on e'athletes, the influence of different training programs to esport performance, and the added multivariate determinants to elite level esport performance are warranted.
Collapse
Affiliation(s)
- Mitchell Nicholson
- School of Exercise and Nutrition Sciences, Faculty of Health, Queensland University of Technology (QUT), Victoria Park Road, Kelvin Grove, Brisbane, QLD, 4059, Australia.
| | - Dylan Poulus
- Physical Activity, Sport and Exercise Research Theme, Faculty of Health, Southern Cross University, Gold Coast, QLD, Australia
- Manna Institute, Southern Cross University, Gold Coast, Australia
| | - Rob Robergs
- School of Exercise and Nutrition Sciences, Faculty of Health, Queensland University of Technology (QUT), Victoria Park Road, Kelvin Grove, Brisbane, QLD, 4059, Australia
| | - Vincent Kelly
- School of Exercise and Nutrition Sciences, Faculty of Health, Queensland University of Technology (QUT), Victoria Park Road, Kelvin Grove, Brisbane, QLD, 4059, Australia
| | - Craig McNulty
- School of Exercise and Nutrition Sciences, Faculty of Health, Queensland University of Technology (QUT), Victoria Park Road, Kelvin Grove, Brisbane, QLD, 4059, Australia
| |
Collapse
|
|
3
|
Ashcroft SP, Stocks B, Egan B, Zierath JR. Exercise induces tissue-specific adaptations to enhance cardiometabolic health. Cell Metab 2024; 36:278-300. [PMID: 38183980 DOI: 10.1016/j.cmet.2023.12.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 10/06/2023] [Accepted: 12/05/2023] [Indexed: 01/08/2024]
Abstract
The risk associated with multiple cancers, cardiovascular disease, diabetes, and all-cause mortality is decreased in individuals who meet the current recommendations for physical activity. Therefore, regular exercise remains a cornerstone in the prevention and treatment of non-communicable diseases. An acute bout of exercise results in the coordinated interaction between multiple tissues to meet the increased energy demand of exercise. Over time, the associated metabolic stress of each individual exercise bout provides the basis for long-term adaptations across tissues, including the cardiovascular system, skeletal muscle, adipose tissue, liver, pancreas, gut, and brain. Therefore, regular exercise is associated with a plethora of benefits throughout the whole body, including improved cardiorespiratory fitness, physical function, and glycemic control. Overall, we summarize the exercise-induced adaptations that occur within multiple tissues and how they converge to ultimately improve cardiometabolic health.
Collapse
Affiliation(s)
- Stephen P Ashcroft
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ben Stocks
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Brendan Egan
- School of Health and Human Performance, Dublin City University, Dublin, Ireland
| | - Juleen R Zierath
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Integrative Physiology, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; Integrative Physiology, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.
| |
Collapse
|
|
4
|
Kourek C, Karatzanos E, Nanas S, Karabinis A, Dimopoulos S. Exercise training in heart transplantation. World J Transplant 2021; 11:466-479. [PMID: 34868897 PMCID: PMC8603635 DOI: 10.5500/wjt.v11.i11.466] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 08/12/2021] [Accepted: 10/27/2021] [Indexed: 02/06/2023] Open
Abstract
Heart transplantation remains the gold standard in the treatment of end-stage heart failure (HF). Heart transplantation patients present lower exercise capacity due to cardiovascular and musculoskeletal alterations leading thus to poor quality of life and reduction in the ability of daily self-service. Impaired vascular function and diastolic dysfunction cause lower cardiac output while decreased skeletal muscle oxidative fibers, enzymes and capillarity cause arteriovenous oxygen difference, leading thus to decreased peak oxygen uptake in heart transplant recipients. Exercise training improves exercise capacity, cardiac and vascular endothelial function in heart transplant recipients. Pre-rehabilitation regular aerobic or combined exercise is beneficial for patients with end-stage HF awaiting heart transplantation in order to maintain a higher fitness level and reduce complications afterwards like intensive care unit acquired weakness or cardiac cachexia. All hospitalized patients after heart transplantation should be referred to early mobilization of skeletal muscles through kinesiotherapy of the upper and lower limbs and respiratory physiotherapy in order to prevent infections of the respiratory system prior to hospital discharge. Moreover, all heart transplant recipients after hospital discharge who have not already participated in an early cardiac rehabilitation program should be referred to a rehabilitation center by their health care provider. Although high intensity interval training seems to have more benefits than moderate intensity continuous training, especially in stable transplant patients, individualized training based on the abilities and needs of each patient still remains the most appropriate approach. Cardiac rehabilitation appears to be safe in heart transplant patients. However, long-term follow-up data is incomplete and, therefore, further high quality and adequately-powered studies are needed to demonstrate the long-term benefits of exercise training in this population.
Collapse
Affiliation(s)
- Christos Kourek
- Clinical Ergospirometry, Exercise & Rehabilitation Laboratory, Evaggelismos Hospital, Athens 10676, Attica, Greece
| | - Eleftherios Karatzanos
- Clinical Ergospirometry, Exercise & Rehabilitation Laboratory, Evaggelismos Hospital, Athens 10676, Attica, Greece
| | - Serafim Nanas
- Clinical Ergospirometry, Exercise & Rehabilitation Laboratory, Evaggelismos Hospital, Athens 10676, Attica, Greece
| | - Andreas Karabinis
- Cardiac Surgery Intensive Care Unit, Onassis Cardiac Surgery Center, Athens 17674, Greece
| | - Stavros Dimopoulos
- Clinical Ergospirometry, Exercise & Rehabilitation Laboratory, Evaggelismos Hospital, Athens 10676, Attica, Greece
- Cardiac Surgery Intensive Care Unit, Onassis Cardiac Surgery Center, Athens 17674, Greece
| |
Collapse
|
|
5
|
Castro A, Duft RG, de Oliveira-Nunes SG, de Andrade ALL, Cavaglieri CR, Chacon-Mikahil MPT. Association Between Changes in Serum and Skeletal Muscle Metabolomics Profile With Maximum Power Output Gains in Response to Different Aerobic Training Programs: The Times Study. Front Physiol 2021; 12:756618. [PMID: 34744794 PMCID: PMC8563999 DOI: 10.3389/fphys.2021.756618] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 09/23/2021] [Indexed: 01/13/2023] Open
Abstract
Purpose: High heterogeneity of the response of cardiorespiratory fitness (CRF) to standardized exercise doses has been reported in different training programs, but the associated mechanisms are not widely known. This study investigated whether changes in the metabolic profile and pathways in blood serum and the skeletal muscle are associated with the inter-individual variability of CRF responses to 8-wk of continuous endurance training (ET) or high-intensity interval training (HIIT). Methods: Eighty men, young and sedentary, were randomized into three groups, of which 70 completed 8 wk of intervention (> 90% of sessions): ET, HIIT, or control. Blood and vastus lateralis muscle tissue samples, as well as the measurement of CRF [maximal power output (MPO)] were obtained before and after the intervention. Blood serum and skeletal muscle samples were analyzed by 600 MHz 1H-NMR spectroscopy (metabolomics). Associations between the pretraining to post-training changes in the metabolic profile and MPO gains were explored via three analytical approaches: (1) correlation between pretraining to post-training changes in metabolites' concentration levels and MPO gains; (2) significant differences between low and high MPO responders; and (3) metabolite contribution to significantly altered pathways related to MPO gains. After, metabolites within these three levels of evidence were analyzed by multiple stepwise linear regression. The significance level was set at 1%. Results: The metabolomics profile panel yielded 43 serum and 70 muscle metabolites. From the metabolites within the three levels of evidence (15 serum and 4 muscle metabolites for ET; 5 serum and 1 muscle metabolites for HIIT), the variance in MPO gains was explained: 77.4% by the intervention effects, 6.9, 2.3, 3.2, and 2.2% by changes in skeletal muscle pyruvate and valine, serum glutamine and creatine phosphate, respectively, in ET; and 80.9% by the intervention effects; 7.2, 2.2, and 1.2% by changes in skeletal muscle glycolate, serum creatine and creatine phosphate, respectively, in HIIT. The most changed and impacted pathways by these metabolites were: arginine and proline metabolism, glycine, serine and threonine metabolism, and glyoxylate and dicarboxylate metabolism for both ET and HIIT programs; and additional alanine, aspartate and glutamate metabolism, arginine biosynthesis, glycolysis/gluconeogenesis, and pyruvate metabolism for ET. Conclusion: These results suggest that regulating the metabolism of amino acids and carbohydrates may be a potential mechanism for understanding the inter-individual variability of CRF in responses to ET and HIIT programs.
Collapse
Affiliation(s)
- Alex Castro
- Laboratory of Exercise Physiology, School of Physical Education, University of Campinas (UNICAMP), São Paulo, Brazil.,Nuclear Magnetic Resonance Laboratory, Department of Chemistry, Federal University of São Carlos (UFSCar), São Paulo, Brazil
| | - Renata G Duft
- Laboratory of Exercise Physiology, School of Physical Education, University of Campinas (UNICAMP), São Paulo, Brazil
| | | | | | - Claudia R Cavaglieri
- Laboratory of Exercise Physiology, School of Physical Education, University of Campinas (UNICAMP), São Paulo, Brazil
| | | |
Collapse
|
|
6
|
Regulation of Energy Substrate Metabolism in Endurance Exercise. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18094963. [PMID: 34066984 PMCID: PMC8124511 DOI: 10.3390/ijerph18094963] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 04/24/2021] [Accepted: 04/26/2021] [Indexed: 12/25/2022]
Abstract
The human body requires energy to function. Adenosine triphosphate (ATP) is the cellular currency for energy-requiring processes including mechanical work (i.e., exercise). ATP used by the cells is ultimately derived from the catabolism of energy substrate molecules—carbohydrates, fat, and protein. In prolonged moderate to high-intensity exercise, there is a delicate interplay between carbohydrate and fat metabolism, and this bioenergetic process is tightly regulated by numerous physiological, nutritional, and environmental factors such as exercise intensity and duration, body mass and feeding state. Carbohydrate metabolism is of critical importance during prolonged endurance-type exercise, reflecting the physiological need to regulate glucose homeostasis, assuring optimal glycogen storage, proper muscle fuelling, and delaying the onset of fatigue. Fat metabolism represents a sustainable source of energy to meet energy demands and preserve the ‘limited’ carbohydrate stores. Coordinated neural, hormonal and circulatory events occur during prolonged endurance-type exercise, facilitating the delivery of fatty acids from adipose tissue to the working muscle for oxidation. However, with increasing exercise intensity, fat oxidation declines and is unable to supply ATP at the rate of the exercise demand. Protein is considered a subsidiary source of energy supporting carbohydrates and fat metabolism, contributing to approximately 10% of total ATP turnover during prolonged endurance-type exercise. In this review we present an overview of substrate metabolism during prolonged endurance-type exercise and the regulatory mechanisms involved in ATP turnover to meet the energetic demands of exercise.
Collapse
|
|
7
|
Hargreaves M, Spriet LL. Skeletal muscle energy metabolism during exercise. Nat Metab 2020; 2:817-828. [PMID: 32747792 DOI: 10.1038/s42255-020-0251-4] [Citation(s) in RCA: 585] [Impact Index Per Article: 117.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 06/25/2020] [Indexed: 12/12/2022]
Abstract
The continual supply of ATP to the fundamental cellular processes that underpin skeletal muscle contraction during exercise is essential for sports performance in events lasting seconds to several hours. Because the muscle stores of ATP are small, metabolic pathways must be activated to maintain the required rates of ATP resynthesis. These pathways include phosphocreatine and muscle glycogen breakdown, thus enabling substrate-level phosphorylation ('anaerobic') and oxidative phosphorylation by using reducing equivalents from carbohydrate and fat metabolism ('aerobic'). The relative contribution of these metabolic pathways is primarily determined by the intensity and duration of exercise. For most events at the Olympics, carbohydrate is the primary fuel for anaerobic and aerobic metabolism. Here, we provide an overview of exercise metabolism and the key regulatory mechanisms ensuring that ATP resynthesis is closely matched to the ATP demand of exercise. We also summarize various interventions that target muscle metabolism for ergogenic benefit in athletic events.
Collapse
Affiliation(s)
- Mark Hargreaves
- Department of Physiology, University of Melbourne, Melbourne, Victoria, Australia.
| | - Lawrence L Spriet
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada.
| |
Collapse
|
|
8
|
Rocha LC, Pimentel Neto J, de Sant'Ana JS, Jacob CDS, Barbosa GK, Krause Neto W, Watanabe IS, Ciena AP. Repercussions on sarcomeres of the myotendinous junction and the myofibrillar type adaptations in response to different trainings on vertical ladder. Microsc Res Tech 2020; 83:1190-1197. [PMID: 32500573 DOI: 10.1002/jemt.23510] [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: 02/21/2020] [Revised: 04/14/2020] [Accepted: 04/16/2020] [Indexed: 12/25/2022]
Abstract
The myofibrillary types establish to the skeletal muscle functional and adaptive properties that influence the sarcomeric arrangement during muscle contraction and may have repercussions on an important related force transmission region of the locomotor apparatus, the myotendinous junction (MTJ). This study aimed to describe changes in myofibrillary type and sarcomeric lengths in the belly muscle and MTJ of the soleus and plantaris muscles associated with training protocols in vertical ladder. Thirty adults male Wistar rats were divided into three groups (n = 10): Control (CTR), No-load Training (NLT), and Load Training (LT). Morphoquantitative analysis of different fibers types and sarcomere lengths were performed in distinct regions of plantaris and soleus muscles. In the plantaris muscle with both trainings, there was an increase in the cross-sectional area (CSA) in Type I and II fibers (p < .0001) while sarcomeric lengths revealed greater lengths in the proximal and distal sarcomeres of NLT, although in the LT we found greater lengths in the belly and MTJ sarcomeres. The soleus muscle showed an increase in CSA muscle fiber only in the NLT (p < .0001) and revealed alterations in belly and MTJ sarcomere lengths with training. We concluded that plantaris muscle has an adaptive effect directly associated with training load, with hypertrophy in both trainings and sarcomere length inverse from belly and MTJ, in LT associated with increased force generation and transmission at the MTJ, although soleus muscle has a lower adaptive response to training stimuli with variation in the belly and distal sarcomere of the MTJ.
Collapse
Affiliation(s)
- Lara Caetano Rocha
- Laboratory of Morphology and Physical Activity (LAMAF), Institute of Biosciences, São Paulo State University (UNESP), Rio Claro, Brazil
| | - Jurandyr Pimentel Neto
- Laboratory of Morphology and Physical Activity (LAMAF), Institute of Biosciences, São Paulo State University (UNESP), Rio Claro, Brazil
| | - Jossei Soares de Sant'Ana
- Laboratory of Morphology and Physical Activity (LAMAF), Institute of Biosciences, São Paulo State University (UNESP), Rio Claro, Brazil
| | - Carolina Dos Santos Jacob
- Laboratory of Morphology and Physical Activity (LAMAF), Institute of Biosciences, São Paulo State University (UNESP), Rio Claro, Brazil
| | - Gabriela Klein Barbosa
- Laboratory of Morphology and Physical Activity (LAMAF), Institute of Biosciences, São Paulo State University (UNESP), Rio Claro, Brazil
| | - Walter Krause Neto
- Department of Physical Education, Laboratory of Morphoquantitative Studies and Immunohistochemistry, São Judas Tadeu University, São Paulo, Brazil
| | - Ii-Sei Watanabe
- Department of Anatomy, Institute of Biomedical Sciences-III, University of São Paulo (USP), São Paulo, Brazil
| | - Adriano Polican Ciena
- Laboratory of Morphology and Physical Activity (LAMAF), Institute of Biosciences, São Paulo State University (UNESP), Rio Claro, Brazil
| |
Collapse
|
|
9
|
Chrøis KM, Dohlmann TL, Søgaard D, Hansen CV, Dela F, Helge JW, Larsen S. Mitochondrial adaptations to high intensity interval training in older females and males. Eur J Sport Sci 2019; 20:135-145. [DOI: 10.1080/17461391.2019.1615556] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Karoline Maise Chrøis
- Xlab, Center for Healthy Aging, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Tine Lovsø Dohlmann
- Xlab, Center for Healthy Aging, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ditte Søgaard
- Xlab, Center for Healthy Aging, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Camilla Vestergaard Hansen
- Xlab, Center for Healthy Aging, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Flemming Dela
- Xlab, Center for Healthy Aging, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Geriatrics, Bispebjerg University Hospital, Copenhagen, Denmark
| | - Jørn Wulff Helge
- Xlab, Center for Healthy Aging, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Steen Larsen
- Xlab, Center for Healthy Aging, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- Clinical Research Centre, Medical University of Bialystok, Bialystok, Poland
| |
Collapse
|
|
10
|
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: 139] [Impact Index Per Article: 19.9] [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.
Collapse
|
|
11
|
Gudiksen A, Bertholdt L, Stankiewicz T, Tybirk J, Plomgaard P, Bangsbo J, Pilegaard H. Effects of training status on PDH regulation in human skeletal muscle during exercise. Pflugers Arch 2017; 469:1615-1630. [PMID: 28801776 DOI: 10.1007/s00424-017-2019-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 06/13/2017] [Accepted: 06/14/2017] [Indexed: 12/23/2022]
Abstract
Pyruvate dehydrogenase (PDH) is the gateway enzyme for carbohydrate-derived pyruvate feeding into the TCA cycle. PDH may play a central role in regulating substrate shifts during exercise, but the influence of training state on PDH regulation during exercise is not fully elucidated. The purpose of this study was to investigate the impact of training state on post-translational regulation of PDHa activity during submaximal and exhaustive exercise. Eight untrained and nine endurance exercise-trained healthy male subjects performed incremental exercise on a cycle ergometer: 40 min at 50% incremental peak power output (IPPO), 10 min at 65% (IPPO), followed by 80% (IPPO) until exhaustion. Trained subjects had higher (P < 0.05) PDH-E1α, PDK1, PDK2, PDK4, and PDP1 protein content as well as PDH phosphorylation and PDH acetylation. Exercising at the same relative intensity led to similar muscle PDH activation in untrained and trained subjects, whereas PDHa activity at exhaustion was higher (P < 0.05) in trained than untrained. Furthermore, exercise induced similar PDH dephosphorylation in untrained and trained subjects, while PDH acetylation was increased (P < 0.05) only in trained subjects. In conclusion, PDHa activity and PDH dephosphorylation were well adjusted to the relative exercise intensity during submaximal exercise. In addition, higher PDHa activity in trained than untrained at exhaustion seemed related to differences in glycogen utilization rather than differences in PDH phosphorylation and acetylation state, although site-specific contributions cannot be ruled out.
Collapse
Affiliation(s)
- Anders Gudiksen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, August Krogh Building, Universitetsparken 13, 2100, Copenhagen, Denmark
| | - Lærke Bertholdt
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, August Krogh Building, Universitetsparken 13, 2100, Copenhagen, Denmark
| | - Tomasz Stankiewicz
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, August Krogh Building, Universitetsparken 13, 2100, Copenhagen, Denmark
| | - Jonas Tybirk
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Peter Plomgaard
- Department of Clinical Biochemistry, Rigshospitalet, Copenhagen, Denmark.,Centre of Inflammation and Metabolism and the Centre for Physical Activity Research, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Jens Bangsbo
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Henriette Pilegaard
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, August Krogh Building, Universitetsparken 13, 2100, Copenhagen, Denmark.
| |
Collapse
|
|
12
|
Ydfors M, Hughes MC, Laham R, Schlattner U, Norrbom J, Perry CGR. Modelling in vivo creatine/phosphocreatine in vitro reveals divergent adaptations in human muscle mitochondrial respiratory control by ADP after acute and chronic exercise. J Physiol 2016; 594:3127-40. [PMID: 26631938 DOI: 10.1113/jp271259] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 11/19/2015] [Indexed: 01/14/2023] Open
Abstract
KEY POINTS Mitochondrial respiratory sensitivity to ADP is thought to influence muscle fitness and is partly regulated by cytosolic-mitochondrial diffusion of ADP or phosphate shuttling via creatine/phosphocreatine (Cr/PCr) through mitochondrial creatine kinase (mtCK). Previous measurements of respiration in vitro with Cr (saturate mtCK) or without (ADP/ATP diffusion) show mixed responses of ADP sensitivity following acute exercise vs. less sensitivity after chronic exercise. In human muscle, modelling in vivo 'exercising' [Cr:PCr] during in vitro assessments revealed novel responses to exercise that differ from detections with or without Cr (±Cr). Acute exercise increased ADP sensitivity when measured without Cr but had no effect ±Cr or with +Cr:PCr, whereas chronic exercise increased sensitivity ±Cr but lowered sensitivity with +Cr:PCr despite increased markers of mitochondrial oxidative capacity. Controlling in vivo conditions during in vitro respiratory assessments reveals responses to exercise that differ from typical ±Cr comparisons and challenges our understanding of how exercise improves metabolic control in human muscle. ABSTRACT Mitochondrial respiratory control by ADP (Kmapp ) is viewed as a critical regulator of muscle energy homeostasis. However, acute exercise increases, decreases or has no effect on Kmapp in human muscle, whereas chronic exercise surprisingly decreases sensitivity despite greater mitochondrial content. We hypothesized that modelling in vivo mitochondrial creatine kinase (mtCK)-dependent phosphate-shuttling conditions in vitro would reveal increased sensitivity (lower Kmapp ) after acute and chronic exercise. The Kmapp was determined in vitro with 20 mm Cr (+Cr), 0 mm Cr (-Cr) or 'in vivo exercising' 20 mm Cr/2.4 mm PCr (Cr:PCr) on vastus lateralis biopsies sampled from 11 men before, immediately after and 3 h after exercise on the first, fifth and ninth sessions over 3 weeks. Dynamic responses to acute exercise occurred throughout training, whereby the first session did not change Kmapp with in vivo Cr:PCr despite increases in -Cr. The fifth session decreased sensitivity with Cr:PCr or +Cr despite no change in -Cr. Chronic exercise increased sensitivity ±Cr in association with increased electron transport chain content (+33-62% complexes I-V), supporting classic proposals that link increased sensitivity to oxidative capacity. However, in vivo Cr:PCr reveals a perplexing decreased sensitivity, contrasting the increases seen ±Cr. Functional responses occurred without changes in fibre type or proteins regulating mitochondrial-cytosolic energy exchange (mtCK, VDAC and ANT). Despite the dynamic responses seen with ±Cr, modelling in vivo phosphate-shuttling conditions in vitro reveals that ADP sensitivity is unchanged after high-intensity exercise and is decreased after training. These findings challenge our understanding of how exercise regulates skeletal muscle energy homeostasis.
Collapse
Affiliation(s)
- Mia Ydfors
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Meghan C Hughes
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada.,Muscle Health Research Centre, York University, Toronto, ON, Canada
| | - Robert Laham
- Muscle Health Research Centre, York University, Toronto, ON, Canada
| | - Uwe Schlattner
- Laboratory of Fundamental and Applied Bioenergetics (LBFA) and SFR Environmental and Systems Biology (BEeSy), University Grenoble Alpes, Grenoble, France
| | - Jessica Norrbom
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Christopher G R Perry
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada.,Muscle Health Research Centre, York University, Toronto, ON, Canada
| |
Collapse
|
|
13
|
Ferraro E, Giammarioli AM, Chiandotto S, Spoletini I, Rosano G. Exercise-induced skeletal muscle remodeling and metabolic adaptation: redox signaling and role of autophagy. Antioxid Redox Signal 2014; 21:154-76. [PMID: 24450966 PMCID: PMC4048572 DOI: 10.1089/ars.2013.5773] [Citation(s) in RCA: 151] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
SIGNIFICANCE Skeletal muscle is a highly plastic tissue. Exercise evokes signaling pathways that strongly modify myofiber metabolism and physiological and contractile properties of skeletal muscle. Regular physical activity is beneficial for health and is highly recommended for the prevention of several chronic conditions. In this review, we have focused our attention on the pathways that are known to mediate physical training-induced plasticity. RECENT ADVANCES An important role for redox signaling has recently been proposed in exercise-mediated muscle remodeling and peroxisome proliferator-activated receptor γ (PPARγ) coactivator-1α (PGC-1α) activation. Still more currently, autophagy has also been found to be involved in metabolic adaptation to exercise. CRITICAL ISSUES Both redox signaling and autophagy are processes with ambivalent effects; they can be detrimental and beneficial, depending on their delicate balance. As such, understanding their role in the chain of events induced by exercise and leading to skeletal muscle remodeling is a very complicated matter. Moreover, the study of the signaling induced by exercise is made even more difficult by the fact that exercise can be performed with several different modalities, with this having different repercussions on adaptation. FUTURE DIRECTIONS Unraveling the complexity of the molecular signaling triggered by exercise on skeletal muscle is crucial in order to define the therapeutic potentiality of physical training and to identify new pharmacological compounds that are able to reproduce some beneficial effects of exercise. In evaluating the effect of new "exercise mimetics," it will also be necessary to take into account the involvement of reactive oxygen species, reactive nitrogen species, and autophagy and their controversial effects.
Collapse
Affiliation(s)
- Elisabetta Ferraro
- 1 Pathophysiology and Treatment of Muscle Wasting Disorders Unit, IRCCS San Raffaele Pisana , Rome, Italy
| | | | | | | | | |
Collapse
|
|
14
|
Bartlett JD, Close GL, Drust B, Morton JP. The Emerging Role of p53 in Exercise Metabolism. Sports Med 2013; 44:303-9. [DOI: 10.1007/s40279-013-0127-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
|
|
15
|
Campos-Ferraz PL, Bozza T, Nicastro H, Lancha AH. Distinct effects of leucine or a mixture of the branched-chain amino acids (leucine, isoleucine, and valine) supplementation on resistance to fatigue, and muscle and liver-glycogen degradation, in trained rats. Nutrition 2013; 29:1388-94. [DOI: 10.1016/j.nut.2013.05.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Revised: 04/08/2013] [Accepted: 05/07/2013] [Indexed: 11/28/2022]
|
|
16
|
Wall BT, Stephens FB, van Loon LJ, Constantin-Teodosiu D, Macdonald IA, Greenhaff PL. Reduced fat oxidation during high intensity, submaximal exercise: is the availability of carnitine important? Eur J Sport Sci 2013. [DOI: 10.1080/17461391.2011.630103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
|
|
17
|
Abstract
Preservation of aerobic fitness and skeletal muscle strength through exercise training can ameliorate metabolic dysfunction and prevent chronic disease. These benefits are mediated in part by extensive metabolic and molecular remodeling of skeletal muscle by exercise. Aerobic and resistance exercise represent extremes on the exercise continuum and elicit markedly different training responses that are mediated by a complex interplay between a myriad of signaling pathways coupled to downstream regulators of transcription and translation. Here, we review the metabolic responses and molecular mechanisms that underpin the adaptatation of skeletal muscle to acute exercise and exercise training.
Collapse
Affiliation(s)
- Brendan Egan
- Institute for Sport and Health, School of Public Health, Physiotherapy and Population Science, University College Dublin, Belfield, Dublin 4, Ireland
| | | |
Collapse
|
|
18
|
Perry CGR, Kane DA, Herbst EAF, Mukai K, Lark DS, Wright DC, Heigenhauser GJF, Neufer PD, Spriet LL, Holloway GP. Mitochondrial creatine kinase activity and phosphate shuttling are acutely regulated by exercise in human skeletal muscle. J Physiol 2012; 590:5475-86. [PMID: 22907058 DOI: 10.1113/jphysiol.2012.234682] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Energy transfer between mitochondrial and cytosolic compartments is predominantly achieved by creatine-dependent phosphate shuttling (PCr/Cr) involving mitochondrial creatine kinase (miCK). However, ADP/ATP diffusion through adenine nucleotide translocase (ANT) and voltage-dependent anion carriers (VDACs) is also involved in this process. To determine if exercise alters the regulation of this system, ADP-stimulated mitochondrial respiratory kinetics were assessed in permeabilized muscle fibre bundles (PmFBs) taken from biopsies before and after 2 h of cycling exercise (60% ) in nine lean males. Concentrations of creatine (Cr) and phosphocreatine (PCr) as well as the contractile state of PmFBs were manipulated in situ. In the absence of contractile signals (relaxed PmFBs) and miCK activity (no Cr), post-exercise respiratory sensitivity to ADP was reduced in situ (up to 126% higher apparent K(m) to ADP) suggesting inhibition of ADP/ATP diffusion between matrix and cytosolic compartments (possibly ANT and VDACs). However this effect was masked in the presence of saturating Cr (no effect of exercise on ADP sensitivity). Given that the role of ANT is thought to be independent of Cr, these findings suggest ADP/ATP, but not PCr/Cr, cycling through the outer mitochondrial membrane (VDACs) may be attenuated in resting muscle after exercise. In contrast, in contracted PmFBs, post-exercise respiratory sensitivity to ADP increased with miCK activation (saturating Cr; 33% lower apparent K(m) to ADP), suggesting prior exercise increases miCK sensitivity in situ. These observations demonstrate that exercise increases miCK-dependent respiratory sensitivity to ADP, promoting mitochondrial-cytosolic energy exchange via PCr/Cr cycling, possibly through VDACs. This effect may mask an underlying inhibition of Cr-independent ADP/ATP diffusion. This enhanced regulation of miCK-dependent phosphate shuttling may improve energy homeostasis through more efficient coupling of oxidative phosphorylation to perturbations in cellular energy charge during subsequent bouts of contraction.
Collapse
Affiliation(s)
- Christopher G R Perry
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
|
19
|
Kiilerich K, Ringholm S, Biensø RS, Fisher JP, Iversen N, van Hall G, Wojtaszewski JFP, Saltin B, Lundby C, Calbet JAL, Pilegaard H. Exercise-induced pyruvate dehydrogenase activation is not affected by 7 days of bed rest. J Appl Physiol (1985) 2011; 111:751-7. [DOI: 10.1152/japplphysiol.00063.2011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
To test the hypothesis that physical inactivity impairs the exercise-induced modulation of pyruvate dehydrogenase (PDH), six healthy normally physically active male subjects completed 7 days of bed rest. Before and immediately after the bed rest, the subjects completed an oral glucose tolerance test (OGTT) and a one-legged knee extensor exercise bout [45 min at 60% maximal load (Wmax)] with muscle biopsies obtained from vastus lateralis before, immediately after exercise, and at 3 h of recovery. Blood samples were taken from the femoral vein and artery before and after 40 min of exercise. Glucose intake elicited a larger ( P ≤ 0.05) insulin response after bed rest than before, indicating glucose intolerance. There were no differences in lactate release/uptake across the exercising muscle before and after bed rest, but glucose uptake after 40 min of exercise was larger ( P ≤ 0.05) before bed rest than after. Muscle glycogen content tended to be higher (0.05< P ≤ 0.10) after bed rest than before, but muscle glycogen breakdown in response to exercise was similar before and after bed rest. PDH-E1α protein content did not change in response to bed rest or in response to the exercise intervention. Exercise increased ( P ≤ 0.05) the activity of PDH in the active form (PDHa) and induced ( P ≤ 0.05) dephosphorylation of PDH-E1α on Ser293, Ser295 and Ser300, with no difference before and after bed rest. In conclusion, although 7 days of bed rest induced whole body glucose intolerance, exercise-induced PDH regulation in skeletal muscle was not changed. This suggests that exercise-induced PDH regulation in skeletal muscle is maintained in glucose-intolerant (e.g., insulin resistant) individuals.
Collapse
Affiliation(s)
- Kristian Kiilerich
- Centre of Inflammation and Metabolism,
- Copenhagen Muscle Research Centre, and
- Department of Biology, August Krogh Building, University of Copenhagen, Copenhagen, Denmark
| | - Stine Ringholm
- Centre of Inflammation and Metabolism,
- Copenhagen Muscle Research Centre, and
- Department of Biology, August Krogh Building, University of Copenhagen, Copenhagen, Denmark
| | - Rasmus S. Biensø
- Centre of Inflammation and Metabolism,
- Copenhagen Muscle Research Centre, and
- Department of Biology, August Krogh Building, University of Copenhagen, Copenhagen, Denmark
| | - James P. Fisher
- School of Sport and Exercise Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Ninna Iversen
- Centre of Inflammation and Metabolism,
- Copenhagen Muscle Research Centre, and
- Department of Biology, August Krogh Building, University of Copenhagen, Copenhagen, Denmark
| | - Gerrit van Hall
- Metabolic Mass-Spectrometry Facility, Rigshospitalet and Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Copenhagen
| | - Jørgen F. P. Wojtaszewski
- Copenhagen Muscle Research Centre, and
- Section of Human Physiology, Department of Exercise and Sport Sciences, University of Copenhagen, Copenhagen
| | - Bengt Saltin
- Copenhagen Muscle Research Centre, and
- Rigshospitalet, Section 7652, Copenhagen, Denmark; and
| | - Carsten Lundby
- Copenhagen Muscle Research Centre, and
- Rigshospitalet, Section 7652, Copenhagen, Denmark; and
| | - Jose A. L. Calbet
- Department of Physical Education, University of Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Canary Islands
| | - Henriette Pilegaard
- Centre of Inflammation and Metabolism,
- Copenhagen Muscle Research Centre, and
- Department of Biology, August Krogh Building, University of Copenhagen, Copenhagen, Denmark
| |
Collapse
|
|
20
|
Love LK, LeBlanc PJ, Inglis JG, Bradley NS, Choptiany J, Heigenhauser GJF, Peters SJ. The relationship between human skeletal muscle pyruvate dehydrogenase phosphatase activity and muscle aerobic capacity. J Appl Physiol (1985) 2011; 111:427-34. [DOI: 10.1152/japplphysiol.00672.2010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Pyruvate dehydrogenase (PDH) is a mitochondrial enzyme responsible for regulating the conversion of pyruvate to acetyl-CoA for use in the tricarboxylic acid cycle. PDH is regulated through phosphorylation and inactivation by PDH kinase (PDK) and dephosphorylation and activation by PDH phosphatase (PDP). The effect of endurance training on PDK in humans has been investigated; however, to date no study has examined the effect of endurance training on PDP in humans. Therefore, the purpose of this study was to examine differences in PDP activity and PDP1 protein content in human skeletal muscle across a range of muscle aerobic capacities. This association is important as higher PDP activity and protein content will allow for increased activation of PDH, and carbohydrate oxidation. The main findings of this study were that 1) PDP activity ( r2 = 0.399, P = 0.001) and PDP1 protein expression ( r2 = 0.153, P = 0.039) were positively correlated with citrate synthase (CS) activity as a marker for muscle aerobic capacity; 2) E1α ( r2 = 0.310, P = 0.002) and PDK2 protein ( r2 = 0.229, P =0.012) are positively correlated with muscle CS activity; and 3) although it is the most abundant isoform, PDP1 protein content only explained ∼18% of the variance in PDP activity ( r2 = 0.184, P = 0.033). In addition, PDP1 in combination with E1α explained ∼38% of the variance in PDP activity ( r2 = 0.383, P = 0.005), suggesting that there may be alternative regulatory mechanisms of this enzyme other than protein content. These data suggest that with higher muscle aerobic capacity (CS activity) there is a greater capacity for carbohydrate oxidation (E1α), in concert with higher potential for PDH activation (PDP activity).
Collapse
Affiliation(s)
- Lorenzo K. Love
- Department of Kinesiology,
- Centre for Muscle Metabolism and Biophysics, Faculty of Applied Health Sciences, Brock University, St. Catharines, Ontario
| | - Paul J. LeBlanc
- Centre for Muscle Metabolism and Biophysics, Faculty of Applied Health Sciences, Brock University, St. Catharines, Ontario
| | - J. Greig Inglis
- Centre for Muscle Metabolism and Biophysics, Faculty of Applied Health Sciences, Brock University, St. Catharines, Ontario
| | - Nicolette S. Bradley
- Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Jon Choptiany
- Department of Kinesiology,
- Centre for Muscle Metabolism and Biophysics, Faculty of Applied Health Sciences, Brock University, St. Catharines, Ontario
| | | | - Sandra J. Peters
- Department of Kinesiology,
- Centre for Muscle Metabolism and Biophysics, Faculty of Applied Health Sciences, Brock University, St. Catharines, Ontario
| |
Collapse
|
|
21
|
Stephens FB, Norton L, Jewell K, Chokkalingam K, Parr T, Tsintzas K. Basal and insulin-stimulated pyruvate dehydrogenase complex activation, glycogen synthesis and metabolic gene expression in human skeletal muscle the day after a single bout of exercise. Exp Physiol 2010; 95:808-18. [DOI: 10.1113/expphysiol.2009.051367] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
|
|
22
|
Effets de différentes méthodes d’entraînement sur les paramètres lactiques. Sci Sports 2010. [DOI: 10.1016/j.scispo.2009.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
|
23
|
McKay BR, Paterson DH, Kowalchuk JM. Effect of short-term high-intensity interval training vs. continuous training on O2 uptake kinetics, muscle deoxygenation, and exercise performance. J Appl Physiol (1985) 2009; 107:128-38. [PMID: 19443744 DOI: 10.1152/japplphysiol.90828.2008] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The early time course of adaptation of pulmonary O(2) uptake (Vo(2)(p)) (reflecting muscle O(2) consumption) and muscle deoxygenation kinetics (reflecting the rate of O(2) extraction) were examined during high-intensity interval (HIT) and lower-intensity continuous endurance (END) training. Twelve male volunteers underwent eight sessions of either HIT (8-12 x 1-min intervals at 120% maximal O(2) uptake separated by 1 min of rest) or END (90-120 min at 65% maximal O(2) uptake). Subjects completed step transitions to a moderate-intensity work rate ( approximately 90% estimated lactate threshold) on five occasions throughout training, and ramp incremental and constant-load performance tests were conducted at pre-, mid-, and posttraining periods. Vo(2)(p) was measured breath-by-breath by mass spectrometry and volume turbine. Deoxygenation (change in deoxygenated hemoglobin concentration; Delta[HHb]) of the vastus lateralis muscle was monitored by near-infrared spectroscopy. The fundamental phase II time constants for Vo(2)(p) (tauVo(2)) and deoxygenation kinetics {effective time constant, tau' = (time delay + tau), Delta[HHb]} during moderate-intensity exercise were estimated using nonlinear least-squares regression techniques. The tauVo(2) was reduced by approximately 20% (P < 0.05) after only two training sessions and by approximately 40% (P < 0.05) after eight training sessions (i.e., posttraining), with no differences between HIT and END. The tau'Delta[HHb] ( approximately 20 s) did not change over the course of eight training sessions. These data suggest that faster activation of muscle O(2) utilization is an early adaptive response to both HIT and lower-intensity END training. That Delta[HHb] kinetics (a measure of fractional O(2) extraction) did not change despite faster Vo(2)(p) kinetics suggests that faster kinetics of muscle O(2) utilization were accompanied by adaptations in local muscle (microvascular) blood flow and O(2) delivery, resulting in a similar "matching" of blood flow to O(2) utilization. Thus faster kinetics of Vo(2)(p) during the transition to moderate-intensity exercise occurs after only 2 days HIT and END training and without changes to muscle deoxygenation kinetics, suggesting concurrent adaptations to microvascular perfusion.
Collapse
Affiliation(s)
- Bryon R McKay
- Canadian Centre for Activity and Aging, School of Kinesiology, Faculty of Health Sciences, HSB 411C, The Univ. of Western Ontario, London, Ontario, Canada N6A 5B9
| | | | | |
Collapse
|
|
24
|
Perry CGR, Heigenhauser GJF, Bonen A, Spriet LL. High-intensity aerobic interval training increases fat and carbohydrate metabolic capacities in human skeletal muscle. Appl Physiol Nutr Metab 2009; 33:1112-23. [PMID: 19088769 DOI: 10.1139/h08-097] [Citation(s) in RCA: 180] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
High-intensity aerobic interval training (HIIT) is a compromise between time-consuming moderate-intensity training and sprint-interval training requiring all-out efforts. However, there are few data regarding the ability of HIIT to increase the capacities of fat and carbohydrate oxidation in skeletal muscle. Using untrained recreationally active individuals, we investigated skeletal muscle and whole-body metabolic adaptations that occurred following 6 weeks of HIIT (~1 h of 10 x 4 min intervals at ~90% of peak oxygen consumption (VO2 peak), separated by 2 min rest, 3 d.week-1). A VO2 peak test, a test to exhaustion (TE) at 90% of pre-training VO2 peak, and a 1 h cycle at 60% of pre-training VO2 peak were performed pre- and post-HIIT. Muscle biopsies were sampled during the TE at rest, after 5 min, and at exhaustion. Training power output increased by 21%, and VO2 peak increased by 9% following HIIT. Muscle adaptations at rest included the following: (i) increased cytochrome c oxidase IV content (18%) and maximal activities of the mitochondrial enzymes citrate synthase (26%), beta-hydroxyacyl-CoA dehydrogenase (29%), aspartate-amino transferase (26%), and pyruvate dehydrogenase (PDH; 21%); (ii) increased FAT/CD36, FABPpm, GLUT 4, and MCT 1 and 4 transport proteins (14%-30%); and (iii) increased glycogen content (59%). Major adaptations during exercise included the following: (i) reduced glycogenolysis, lactate accumulation, and substrate phosphorylation (0-5 min of TE); (ii) unchanged PDH activation (carbohydrate oxidation; 0-5 min of TE); (iii) ~2-fold greater time during the TE; and (iv) increased fat oxidation at 60% of pre-training VO2 peak. This study demonstrated that 18 h of repeated high-intensity exercise sessions over 6 weeks (3 d.week-1) is a powerful method to increase whole-body and skeletal muscle capacities to oxidize fat and carbohydrate in previously untrained individuals.
Collapse
Affiliation(s)
- Christopher G R Perry
- Department of Human Health and Nutritional Sciences, University of Guelph, ON N1G 2W1, Canada.
| | | | | | | |
Collapse
|
|
25
|
Devries MC, Tarnopolsky MA. Muscle Physiology in Healthy Men and Women and Those with Metabolic Myopathies. Phys Med Rehabil Clin N Am 2009; 20:101-31, viii-ix. [DOI: 10.1016/j.pmr.2008.10.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
|
26
|
LeBlanc PJ, Mulligan M, Antolić A, MacPherson L, Inglis JG, Martin D, Roy BD, Peters SJ. Skeletal muscle type comparison of pyruvate dehydrogenase phosphatase activity and isoform expression: effects of obesity and endurance training. Am J Physiol Regul Integr Comp Physiol 2008; 295:R1224-30. [DOI: 10.1152/ajpregu.90320.2008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Pyruvate dehydrogenase (PDH) plays an important role in regulating carbohydrate metabolism in skeletal muscle. PDH is activated by PDH phosphatase (PDP) and deactivated by PDH kinase (PDK). Obesity has a large negative impact on skeletal muscle carbohydrate metabolism, whereas endurance training has been shown to improve regulatory control of skeletal muscle carbohydrate metabolism, more so when coupled with obesity. A majority of this literature has focused on PDK, with little information available on PDP. To determine the relative role of PDP in regulating skeletal muscle PDH activity with obesity and endurance training, obese and lean Zucker rats remained sedentary or were endurance trained (1 h/day, 5 days/wk) for a period of 8 wk. Soleus, red gastrocnemius, (RG), and white gastrocnemius (WG) muscles were sampled after the training period. The main findings were 1) obesity resulted in a 46% decrease in PDP activity expressed per milligram extracted mitochondrial protein only in RG, while PDP isoform content was unchanged; 2) 8 wk of endurance training led to a significant 1.4–2.2-fold increase in PDP activity of all muscle examined from obese rats, and the concomitant increase in PDP1 protein was only seen in soleus and RG; 3) 8 wk of endurance training led to a trending 1.4–2.2-fold increase in PDP activity of all muscle examined from obese rats, and the concomitant increase in PDP1 protein was only seen in soleus and RG; and 4) PDP2 protein content was not affected by obesity or training. These results suggest that decreased PDP activity in oxidative skeletal muscles may play a role in the impairment of carbohydrate metabolism in obese rats, which is reversible with endurance training.
Collapse
|
|
27
|
Li Y, Dash RK, Kim J, Saidel GM, Cabrera ME. Role of NADH/NAD+ transport activity and glycogen store on skeletal muscle energy metabolism during exercise: in silico studies. Am J Physiol Cell Physiol 2008; 296:C25-46. [PMID: 18829894 DOI: 10.1152/ajpcell.00094.2008] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Skeletal muscle can maintain ATP concentration constant during the transition from rest to exercise, whereas metabolic reaction rates may increase substantially. Among the key regulatory factors of skeletal muscle energy metabolism during exercise, the dynamics of cytosolic and mitochondrial NADH and NAD+ have not been characterized. To quantify these regulatory factors, we have developed a physiologically based computational model of skeletal muscle energy metabolism. This model integrates transport and reaction fluxes in distinct capillary, cytosolic, and mitochondrial domains and investigates the roles of mitochondrial NADH/NAD+ transport (shuttling) activity and muscle glycogen concentration (stores) during moderate intensity exercise (60% maximal O2 consumption). The underlying hypothesis is that the cytosolic redox state (NADH/NAD+) is much more sensitive to a metabolic disturbance in contracting skeletal muscle than the mitochondrial redox state. This hypothesis was tested by simulating the dynamic metabolic responses of skeletal muscle to exercise while altering the transport rate of reducing equivalents (NADH and NAD+) between cytosol and mitochondria and muscle glycogen stores. Simulations with optimal parameter estimates showed good agreement with the available experimental data from muscle biopsies in human subjects. Compared with these simulations, a 20% increase (or approximately 20% decrease) in mitochondrial NADH/NAD+ shuttling activity led to an approximately 70% decrease (or approximately 3-fold increase) in cytosolic redox state and an approximately 35% decrease (or approximately 25% increase) in muscle lactate level. Doubling (or halving) muscle glycogen concentration resulted in an approximately 50% increase (or approximately 35% decrease) in cytosolic redox state and an approximately 30% increase (or approximately 25% decrease) in muscle lactate concentration. In both cases, changes in mitochondrial redox state were minimal. In conclusion, the model simulations of exercise response are consistent with the hypothesis that mitochondrial NADH/NAD+ shuttling activity and muscle glycogen stores affect primarily the cytosolic redox state. Furthermore, muscle lactate production is regulated primarily by the cytosolic redox state.
Collapse
Affiliation(s)
- Yanjun Li
- Center for Modeling Integrated Metabolic Systems, Case Western Reserve University, 11100 Euclid Ave., Cleveland, OH 44106-6011, USA
| | | | | | | | | |
Collapse
|
|
28
|
Mourtzakis M, Graham TE, González-Alonso J, Saltin B. Glutamate availability is important in intramuscular amino acid metabolism and TCA cycle intermediates but does not affect peak oxidative metabolism. J Appl Physiol (1985) 2008; 105:547-54. [DOI: 10.1152/japplphysiol.90394.2008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Muscle glutamate is central to reactions producing 2-oxoglutarate, a tricarboxylic acid (TCA) cycle intermediate that essentially expands the TCA cycle intermediate pool during exercise. Paradoxically, muscle glutamate drops ∼40–80% with the onset of exercise and 2-oxoglutarate declines in early exercise. To investigate the physiological relationship between glutamate, oxidative metabolism, and TCA cycle intermediates (i.e., fumarate, malate, 2-oxoglutarate), healthy subjects trained (T) the quadriceps of one thigh on the single-legged knee extensor ergometer (1 h/day at 70% maximum workload for 5 days/wk), while their contralateral quadriceps remained untrained (UT). After 5 wk of training, peak oxygen consumption (V̇o2peak) in the T thigh was greater than that in the UT thigh ( P < 0.05); V̇o2peak was not different between the T and UT thighs with glutamate infusion. Peak exercise under control conditions revealed a greater glutamate uptake in the T thigh compared with rest (7.3 ± 3.7 vs. 1.0 ± 0.1 μmol·min−1·kg wet wt−1, P < 0.05) without increase in TCA cycle intermediates. In the UT thigh, peak exercise (vs. rest) induced an increase in fumarate (0.33 ± 0.07 vs. 0.02 ± 0.01 mmol/kg dry wt (dw), P < 0.05) and malate (2.2 ± 0.4 vs. 0.5 ± 0.03 mmol/kg dw, P < 0.05) and a decrease in 2-oxoglutarate (12.2 ± 1.6 vs. 32.4 ± 6.8 μmol/kg dw, P < 0.05). Overall, glutamate infusion increased arterial glutamate ( P < 0.05) and maintained this increase. Glutamate infusion coincided with elevated fumarate and malate ( P < 0.05) and decreased 2-oxoglutarate ( P < 0.05) at peak exercise relative to rest in the T thigh; there were no further changes in the UT thigh. Although glutamate may have a role in the expansion of the TCA cycle, glutamate and TCA cycle intermediates do not directly affect V̇o2peak in either trained or untrained muscle.
Collapse
|
|
29
|
Boon H, Jonkers RAM, Koopman R, Blaak EE, Saris WHM, Wagenmakers AJM, VAN Loon LJC. Substrate source use in older, trained males after decades of endurance training. Med Sci Sports Exerc 2008; 39:2160-70. [PMID: 18046187 DOI: 10.1249/mss.0b013e3181572ace] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
PURPOSE The purpose of this study was to compare substrate source use in older, long-term exercising, endurance-trained males with sedentary controls. METHODS [U-C]palmitate and [6,6-H2]glucose tracers were applied to assess plasma free fatty acid (FFA) and glucose oxidation rates, and to estimate muscle- and/or lipoprotein-derived triacylglycerol (TG) and muscle glycogen use. Subjects were 10 long-term exercising, endurance-trained males and 10 sedentary controls (age 57 +/- 1 and 60 +/- 2 yr, respectively). Muscle biopsy samples were collected before and after exercise to assess muscle fiber type-specific intramyocellular lipid and glycogen content. RESULTS During exercise, plasma palmitate Ra, Rd, and Rox were significantly greater in the trained subjects compared with the controls (Ra: 0.36 +/- 0.02 and 0.25 +/- 0.02; Rd: 0.36 +/- 0.03 and 0.24 +/- 0.02; Rox: 0.31 +/- 0.02 and 0.20 +/- 0.02 mmol.min, respectively, P < 0.01). This resulted in greater plasma FFA and total fat oxidation rates in the trained versus sedentary subjects (P < 0.001). Muscle- and/or lipoprotein-derived TG use contributed 10 +/- 2 and 11 +/- 3% in the trained and control groups, respectively (NS). No significant net changes in muscle fiber lipid content were observed. CONCLUSIONS Older, endurance-trained males oxidize more fat during moderate-intensity exercise than do sedentary controls. This greater total fat oxidation rate is attributed to a higher plasma FFA release, uptake, and oxidation rate. In contrast, intramyocellular triacylglycerol does not seem to represent a major substrate source during 1 h of moderate-intensity exercise in older trained or sedentary men.
Collapse
Affiliation(s)
- Hanneke Boon
- Department of Human Biology, Nutrition and Toxicology Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands.
| | | | | | | | | | | | | |
Collapse
|
|
30
|
Muscle Physiology in Healthy Men and Women and Those with Metabolic Myopathies. Neurol Clin 2008; 26:115-48; ix. [DOI: 10.1016/j.ncl.2007.11.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
|
31
|
Helge JW, Bentley D, Schjerling P, Willer M, Gibala MJ, Franch J, Tapia-Laliena MA, Daugaard JR, Andersen JL. Four weeks one-leg training and high fat diet does not alter PPARalpha protein or mRNA expression in human skeletal muscle. Eur J Appl Physiol 2007; 101:105-14. [PMID: 17530276 DOI: 10.1007/s00421-007-0479-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/14/2006] [Indexed: 12/01/2022]
Abstract
UNLABELLED Fatty acid metabolism is influenced by training and diet with exercise training mediating this through activation of nuclear hormone receptor peroxisome proliferator-activated receptor alpha (PPARalpha) in skeletal muscle. This study investigated the effect of training and high fat or normal diet on PPARalpha expression in human skeletal muscle. Thirteen men trained one leg (T) four weeks (31.5 h in total), while the other leg (UT) served as control. During the 4 weeks six subjects consumed high fat (FAT) diet and seven subjects maintained a normal (CHO) diet. Biopsies were obtained from vastus lateralis muscle in both legs before and after training. After the biopsy, one-leg extension exercise was performed in random order with both legs 30 min at 95% of workload max. A training effect was evident as citrate synthase activity increased (P < 0.05) by 15% in the trained, but not the control leg in both groups. During exercise respiratory exchange ratio was lower in FAT (0.86 +/- 0.01, 0.83 +/- 0.01, mean +/- SEM) than CHO (0.96 +/- 0.02, 0.94 +/- 0.03) and in UT than T legs, respectively. The PPARalpha protein (144 +/- 44, 104 +/- 28, 79 +/- 15, 79 +/- 14, % of pre level) and PPARalpha mRNA (69 +/- [2, 2], 78 +/- [7, 6], 92 +/- [22, 18], 106 +/- [21, 18], % of pre level, geometric mean +/- SEM) expression remained unchanged by diet and training in FAT (UT, T) and CHO (UT, T), respectively. After the training and diet CS, HAD, PPARalpha, UCP2, UCP3 and mFABP mRNA content remained unchanged, whereas GLUT4 mRNA was lower in both groups and LDHA mRNA was lower (P < 0.05) only in FAT. IN CONCLUSION 4 weeks one leg knee extensor training did not affect PPARalpha protein or mRNA expression. Furthermore, higher fat oxidation during exercise after fat rich diet was not accompanied by an increased PPARalpha protein or mRNA expression after 4 weeks.
Collapse
Affiliation(s)
- J W Helge
- Copenhagen Muscle Research Centre, Department Medical Physiology, Panum Institute building 12, University of Copenhagen, Blegdamsvej 3, 2200 N, Copenhagen, Denmark.
| | | | | | | | | | | | | | | | | |
Collapse
|
|
32
|
Marwood S, Bowtell JL. Effects of glutamine and hyperoxia on pulmonary oxygen uptake and muscle deoxygenation kinetics. Eur J Appl Physiol 2006; 99:149-61. [PMID: 17115180 DOI: 10.1007/s00421-006-0324-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/04/2006] [Indexed: 11/29/2022]
Abstract
The aim of the present study was to determine whether glutamine ingestion, which has been shown to enhance the exercise-induced increase in the tricarboxylic acid intermediate (TCAi) pool size, resulted in augmentation of the rate of increase in oxidative metabolism at the onset of exercise. In addition, the potential interaction with oxygen availability was investigated by completing exercise in both normoxic and hyperoxic conditions. Eight male cyclists cycled for 6 min at 70% VO2max following consumption of a drink (5 ml kg body mass(-1)) containing a placebo or 0.125 g kg body mass(-1) of glutamine in normoxic (CON and GLN respectively) and hyperoxic (HYP and HPG respectively) conditions. Breath-by-breath pulmonary oxygen uptake and continuous, non-invasive muscle deoxygenation (via near infrared spectroscopy: NIRS) data were collected throughout exercise. The time constant of the phase II component of pulmonary oxygen uptake kinetics was unchanged between trials (CON: 21.5 +/- 3.0 vs. GLN: 18.2 +/- 1.3 vs. HYP: 18.9 +/- 2.0 vs. HPG: 18.6 +/- 1.2 s). There was also no alteration of the kinetics of relative muscle deoxygenation as measured via NIRS (CON: 5.9 +/- 0.7 vs. GLN: 7.3 +/- 0.8 vs. HYP: 6.5 +/- 0.9 vs. HPG: 5.2 +/- 0.4 s). Conversely, the mean response time of pulmonary oxygen uptake kinetics was faster (CON: 33.4 +/- 1.2 vs. GLN: 29.8 +/- 2.3 vs. HYP: 33.2 +/- 2.6 vs. HPG: 31.6 +/- 2.6 s) and the time at which muscle deoxygenation increased above pre-exercise values was earlier (CON: 9.6 +/- 0.9 vs. GLN: 8.7 +/- 1.1 vs. HYP: 8.5 +/- 0.8 vs. HPG: 8.4 +/- 0.7 s) following glutamine ingestion. In normoxic conditions, plasma lactate concentration was lower following glutamine ingestion compared to placebo. Whilst the results of the present study provide some support for the present hypothesis, the lack of any alteration in the time constant of pulmonary oxygen uptake and muscle deoxygenation kinetics suggest that the normal exercise induced expansion of the TCAi pool size is not limiting to oxidative metabolism at the onset of cycle exercise at 70% VO2max.
Collapse
Affiliation(s)
- Simon Marwood
- Academy of Sport, Physical Activity and Well-being, London South Bank University, 103 Borough Road, London, SE1 0AA, UK.
| | | |
Collapse
|
|
33
|
Burgomaster KA, Heigenhauser GJF, Gibala MJ. Effect of short-term sprint interval training on human skeletal muscle carbohydrate metabolism during exercise and time-trial performance. J Appl Physiol (1985) 2006; 100:2041-7. [PMID: 16469933 DOI: 10.1152/japplphysiol.01220.2005] [Citation(s) in RCA: 252] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Our laboratory recently showed that six sessions of sprint interval training (SIT) over 2 wk increased muscle oxidative potential and cycle endurance capacity (Burgomaster KA, Hughes SC, Heigenhauser GJF, Bradwell SN, and Gibala MJ. J Appl Physiol 98: 1895–1900, 2005). The present study tested the hypothesis that short-term SIT would reduce skeletal muscle glycogenolysis and lactate accumulation during exercise and increase the capacity for pyruvate oxidation via pyruvate dehydrogenase (PDH). Eight men [peak oxygen uptake (V̇o2 peak) = 3.8 ± 0.2 l/min] performed six sessions of SIT (4–7 × 30-s “all-out” cycling with 4 min of recovery) over 2 wk. Before and after SIT, biopsies (vastus lateralis) were obtained at rest and after each stage of a two-stage cycling test that consisted of 10 min at ∼60% followed by 10 min at ∼90% of V̇o2 peak. Subjects also performed a 250-kJ time trial (TT) before and after SIT to assess changes in cycling performance. SIT increased muscle glycogen content by ∼50% (main effect, P = 0.04) and the maximal activity of citrate synthase (posttraining: 7.8 ± 0.4 vs. pretraining: 7.0 ± 0.4 mol·kg protein −1·h−1; P = 0.04), but the maximal activity of 3-hydroxyacyl-CoA dehydrogenase was unchanged (posttraining: 5.1 ± 0.7 vs. pretraining: 4.9 ± 0.6 mol·kg protein −1·h−1; P = 0.76). The active form of PDH was higher after training (main effect, P = 0.04), and net muscle glycogenolysis (posttraining: 100 ± 16 vs. pretraining: 139 ± 11 mmol/kg dry wt; P = 0.03) and lactate accumulation (posttraining: 55 ± 2 vs. pretraining: 63 ± 1 mmol/kg dry wt; P = 0.03) during exercise were reduced. TT performance improved by 9.6% after training (posttraining: 15.5 ± 0.5 vs. pretraining: 17.2 ± 1.0 min; P = 0.006), and a control group ( n = 8, V̇o2 peak = 3.9 ± 0.2 l/min) showed no change in performance when tested 2 wk apart without SIT (posttraining: 18.8 ± 1.2 vs. pretraining: 18.9 ± 1.2 min; P = 0.74). We conclude that short-term SIT improved cycling TT performance and resulted in a closer matching of glycogenolytic flux and pyruvate oxidation during submaximal exercise.
Collapse
Affiliation(s)
- Kirsten A Burgomaster
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada L8S 4K1
| | | | | |
Collapse
|