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Jeppesen JS, Wickham KA, Zeuthen M, Thomassen M, Jessen S, Hellsten Y, Hostrup M, Bangsbo J. Low-Volume Speed Endurance Training with Reduced Volume Improves Short-Term Exercise Performance in Highly Trained Cyclists. Med Sci Sports Exerc 2024; 56:1709-1721. [PMID: 38650113 DOI: 10.1249/mss.0000000000003453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
PURPOSE We investigated the effects of low- and high-volume speed endurance training (SET), with a reduced training volume, on sprint ability, short- and long-term exercise capacity, muscle mitochondrial properties, ion transport proteins, and maximal enzyme activity in highly trained athletes. METHODS Highly trained male cyclists (maximal oxygen consumption (V̇O 2max ): 68.3 ± 5.0 mL·min -1 ·kg -1 , n = 24) completed 6 wk of either low (SET-L; 6 × 30-s intervals, n = 8) or high (SET-H; 12 × 30-s intervals, n = 8) volume SET twice per week with a 30% reduction in training volume. A control group (CON; n = 8) maintained their training. Exercise performance was evaluated by i) 6-s sprinting, ii) a 4-min time trial, and iii) a 60-min preload at 60% V̇O 2max followed by a 20-min time trial. A biopsy of m. vastus lateralis was collected before and after the training intervention. RESULTS In SET-L, 4-min time trial performance was improved ( P < 0.05) by 3.8%, with no change in SET-H and CON. Sprint ability, prolonged endurance exercise capacity, V̇O 2max , muscle mitochondrial respiratory capacity, maximal citrate synthase activity, fiber type-specific mitochondrial proteins (complexes I-V), and phosphofructokinase (PFK) content did not change in any of the groups. In SET-H, maximal activity of muscle PFK and abundance of Na + -K + pump-subunit α 1 , α 2 , β 1 , and phospholemman (FXYD1) were 20%, 50%, 19%, 24%, and 42% higher ( P < 0.05), respectively after compared with before the intervention, with no changes in SET-L or CON. CONCLUSIONS Low SET volume combined with a reduced aerobic low- and moderate-intensity training volume does improve short-duration intense exercise performance and maintain sprinting ability, V̇O 2max , endurance exercise performance, and muscle oxidative capacity, whereas, high volume of SET seems necessary to upregulate muscle ion transporter content and maximal PFK activity in highly trained cyclists.
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Affiliation(s)
- Jan S Jeppesen
- The August Krogh Section for Human Physiology, Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, DENMARK
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Vigh-Larsen JF, Junge N, Cialdella-Kam L, Tomás R, Young L, Krustrup P, Mohr M, Nybo L. Testing in Intermittent Sports-Importance for Training and Performance Optimization in Adult Athletes. Med Sci Sports Exerc 2024; 56:1505-1537. [PMID: 39004796 DOI: 10.1249/mss.0000000000003442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
ABSTRACT Performance in intermittent sports relies on the interplay between multiple physiological systems determining the capacity to perform short explosive efforts as well as repeated intense actions with limited recovery over the course of an entire game. Testing should reflect these demands to allow for sport- and position-specific capacity analyses that eventually may translate into optimized training and improved performance. This may include individual load management and optimized training prescription, intensity targeting for specific positions or individual athletes, as well as benchmarking for monitoring of training progression and enhanced engagement of athletes. This review provides an overview of available tests in different exercise domains identified as relevant (from assessment of single explosive actions to intermittent endurance capacity), forming the basis for recommendations on how to compose a comprehensive yet feasible test battery that may be integrated into the seasonal competition and training plan. The test procedures should cover the performance spectrum of relevance for the individual athlete-also in team sports to account for positional differences. We emphasize the benefits of sport-specific tests, highlight parameters of importance for test standardization, and discuss how the applied test battery may be supplemented with secondary tests directed toward specific energy systems to allow for more in-depth analyses when required (e.g., in terms of an underperforming athlete). The synergy between testing and tracking of match performance (utilizing time-motion or global positioning systems) is highlighted, and although tracking cannot substitute for testing, combining the tools may provide a comprehensive overview of the physiological demands and performance during competition contextualized to the athletes' maximal exercise capacity.
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Affiliation(s)
| | - Nicklas Junge
- Department of Nutrition, Exercise and Sport Sciences, University of Copenhagen, Copenhagen, DENMARK
| | - Lynn Cialdella-Kam
- Warfighter Performance Department, Naval Health Research Center, San Diego, CA
| | - Rita Tomás
- Portugal Football School, Federação Portuguesa de Futebol Avenida das Seleções, Oeiras, PORTUGAL
| | - Laura Young
- American College of Sports Medicine, Indianapolis, IN
| | | | | | - Lars Nybo
- Department of Nutrition, Exercise and Sport Sciences, University of Copenhagen, Copenhagen, DENMARK
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Bangsbo J. 10-20-30 exercise training improves fitness and health. Eur J Sport Sci 2024; 24:1162-1175. [PMID: 39031952 PMCID: PMC11295100 DOI: 10.1002/ejsc.12163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 04/10/2024] [Accepted: 06/23/2024] [Indexed: 07/22/2024]
Abstract
Intense interval exercise training has been shown to improve performance and health of untrained and trained people. However, due to the exercise intensity causing high-perceived exertion, the participants often do not wish to continue the training. The 10-20-30 training concept consists of low intensity for 30 s, 20 s at a moderate pace, and then 10 s with high intensity either running or cycling. A 10-20-30 training session consist of two to four 5-min blocks. The 10-20-30 training improved fitness and performance as well as lowered blood pressure and body fat of both untrained and trained individuals even with a significant reduction in the training volume. Similarly, hypertensive, diabetic, and asthmatic patients lowered body fat, improved fitness, and performance during a 10-20-30-training intervention period. In addition, hypertensive patients reduced systolic and diastolic blood pressure markedly with the 10-20-30 training twice a week for 8 weeks. Diabetic patients lowered long-term blood sugar (HbA1c), which did not occur with moderate-intensity exercise training. Furthermore, asthmatic patients improved their control of asthma and asthma-related quality of life with the 10-20-30 training. The adherence for the patient groups was high (>80%), and no adverse events were reported. Thus, the 10-20-30 training seems to be time efficient and feasible for untrained and trained individuals as well as patients and may be used in the prevention and treatment of noncommunicable diseases.
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Affiliation(s)
- Jens Bangsbo
- The August Krogh Section for Human PhysiologyDepartment of Nutrition, Exercise and SportsUniversity of CopenhagenCopenhagenDenmark
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Lindinger MI, Cairns SP, Sejersted OM. Resting membrane potential and intracellular [Na +] at rest, during fatigue and during recovery in rat soleus muscle fibres in situ. J Physiol 2024; 602:3469-3487. [PMID: 38877870 DOI: 10.1113/jp285870] [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: 11/14/2023] [Accepted: 05/28/2024] [Indexed: 07/17/2024] Open
Abstract
Large trans-sarcolemmal ionic shifts occur with fatiguing exercise or stimulation of isolated muscles. However, it is unknown how resting membrane potential (EM) and intracellular sodium concentration ([Na+]i) change with repeated contractions in living mammals. We investigated (i) whether [Na+]i (peak, kinetics) can reveal changes of Na+-K+ pump activity during brief or fatiguing stimulation and (ii) how resting EM and [Na+]i change during fatigue and recovery of rat soleus muscle in situ. Muscles of anaesthetised rats were stimulated with brief (10 s) or repeated tetani (60 Hz for 200 ms, every 2 s, for 30 s or 300 s) with isometric force measured. Double-barrelled ion-sensitive microelectrodes were used to quantify resting EM and [Na+]i. Post-stimulation data were fitted using polynomials and back-extrapolated to time zero recovery. Mean pre-stimulation resting EM (layer 2-7 fibres) was -71 mV (surface fibres were more depolarised), and [Na+]i was 14 mM. With deeper fibres, 10 s stimulation (2-150 Hz) increased [Na+]i to 38-46 mM whilst simultaneously causing hyperpolarisations (7.3 mV for 2-90 Hz). Fatiguing stimulation for 30 s or 300 s led to end-stimulation resting EM of -61 to -53 mV, which recovered rapidly (T1/2, 8-22 s). Mean end-stimulation [Na+]i increased to 86-101 mM with both fatigue protocols and the [Na+]i recovery time-course (T1/2, 21-35 s) showed no difference between protocols. These combined findings suggest that brief stimulation hyperpolarises the resting EM, likely via maximum Na+-induced stimulation of the Na+-K+ pump. Repeated tetani caused massive depolarisation and elevations of [Na+]i that together lower force, although they likely interact with other factors to cause fatigue. [Na+]i recovery kinetics provided no evidence of impaired Na+-K+ pump activity with fatigue. KEY POINTS: It is uncertain how resting membrane potential, intracellular sodium concentration ([Na+]i), and sodium-potassium (Na+-K+) pump activity change during repeated muscle contractions in living mammals. For rat soleus muscle fibres in situ, brief tetanic stimulation for 10 s led to raised [Na+]i, anticipated to evoke maximal Na+-induced stimulation of the Na+-K+ pump causing an immediate hyperpolarisation of the sarcolemma. More prolonged stimulation with repeated tetanic contractions causes massive elevations of [Na+]i, which together with large depolarisations (via K+ disturbances) likely reduce force production. These effects occurred without impairment of Na+-K+ pump function. Together these findings suggest that rapid activation of the Na+-K+ pump occurs with brief stimulation to maintain excitability, whereas more prolonged stimulation causes rundown of the trans-sarcolemmal K+ gradient (hence depolarisation) and Na+ gradient, which in combination can impair contraction to contribute to fatigue in living mammals.
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Affiliation(s)
- Michael I Lindinger
- Research and Development, The Nutraceutical Alliance Inc., Guelph, Ontario, Canada
| | - Simeon P Cairns
- Sports Performance Research Institute New Zealand, School of Sport and Recreation, Faculty of Health and Environmental Sciences, Auckland University of Technology, Auckland, New Zealand
- Health and Rehabilitation Research Institute, Faculty of Health and Environmental Sciences, Auckland University of Technology, Auckland, New Zealand
| | - Ole M Sejersted
- Institute for Experimental Medical Research, University of Oslo and Oslo University Hospital, Oslo, Norway
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Skattebo Ø, Capelli C, Calbet JAL, Hallén J. Endurance Training Improves Leg Proton Release and Decreases Potassium Release During High-Intensity Exercise in Normoxia and Hypobaric Hypoxia. Scand J Med Sci Sports 2024; 34:e14688. [PMID: 38973702 DOI: 10.1111/sms.14688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 06/03/2024] [Accepted: 06/14/2024] [Indexed: 07/09/2024]
Abstract
AIM To assess the impact of endurance training on skeletal muscle release of H+ and K+. METHODS Nine participants performed one-legged knee extension endurance training at moderate and high intensities (70%-85% of Wpeak), three to four sessions·week-1 for 6 weeks. Post-training, the trained and untrained (control) leg performed two-legged knee extension at low, moderate, and high intensities (40%, 62%, and 83% of Wpeak) in normoxia and hypoxia (~4000 m). The legs were exercised simultaneously to ensure identical arterial inflow concentrations of ions and metabolites, and identical power output was controlled by visual feedback. Leg blood flow was measured (ultrasound Doppler), and acid-base variables, lactate- and K+ concentrations were assessed in arterial and femoral venous blood to study K+ and H+ release. Ion transporter abundances were assessed in muscle biopsies. RESULTS Lactate-dependent H+ release was similar in hypoxia to normoxia (p = 0.168) and was lower in the trained than the control leg at low-moderate intensities (p = 0.060-0.006) but similar during high-intensity exercise. Lactate-independent and total H+ releases were higher in hypoxia (p < 0.05) and increased more with power output in the trained leg (leg-by-power output interactions: p = 0.02). K+ release was similar at low intensity but lower in the trained leg during high-intensity exercise in normoxia (p = 0.024) and hypoxia (p = 0.007). The trained leg had higher abundances of Na+/H+ exchanger 1 (p = 0.047) and Na+/K+ pump subunit α (p = 0.036). CONCLUSION Moderate- to high-intensity endurance training increases lactate-independent H+ release and reduces K+ release during high-intensity exercise, coinciding with increased Na+/H+ exchanger 1 and Na+/K+ pump subunit α muscle abundances.
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Affiliation(s)
- Øyvind Skattebo
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
| | - Carlo Capelli
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Jose A L Calbet
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
- Department of Physical Education, University of las Palmas de Gran Canaria, Las Palmas, Spain
- Research Institute of Biomedical and Health Sciences (IUIBS), Las Palmas de Gran Canaria, Spain
| | - Jostein Hallén
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
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McKenna MJ, Renaud JM, Ørtenblad N, Overgaard K. A century of exercise physiology: effects of muscle contraction and exercise on skeletal muscle Na +,K +-ATPase, Na + and K + ions, and on plasma K + concentration-historical developments. Eur J Appl Physiol 2024; 124:681-751. [PMID: 38206444 PMCID: PMC10879387 DOI: 10.1007/s00421-023-05335-9] [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: 02/02/2023] [Accepted: 09/27/2023] [Indexed: 01/12/2024]
Abstract
This historical review traces key discoveries regarding K+ and Na+ ions in skeletal muscle at rest and with exercise, including contents and concentrations, Na+,K+-ATPase (NKA) and exercise effects on plasma [K+] in humans. Following initial measures in 1896 of muscle contents in various species, including humans, electrical stimulation of animal muscle showed K+ loss and gains in Na+, Cl- and H20, then subsequently bidirectional muscle K+ and Na+ fluxes. After NKA discovery in 1957, methods were developed to quantify muscle NKA activity via rates of ATP hydrolysis, Na+/K+ radioisotope fluxes, [3H]-ouabain binding and phosphatase activity. Since then, it became clear that NKA plays a central role in Na+/K+ homeostasis and that NKA content and activity are regulated by muscle contractions and numerous hormones. During intense exercise in humans, muscle intracellular [K+] falls by 21 mM (range - 13 to - 39 mM), interstitial [K+] increases to 12-13 mM, and plasma [K+] rises to 6-8 mM, whilst post-exercise plasma [K+] falls rapidly, reflecting increased muscle NKA activity. Contractions were shown to increase NKA activity in proportion to activation frequency in animal intact muscle preparations. In human muscle, [3H]-ouabain-binding content fully quantifies NKA content, whilst the method mainly detects α2 isoforms in rats. Acute or chronic exercise affects human muscle K+, NKA content, activity, isoforms and phospholemman (FXYD1). Numerous hormones, pharmacological and dietary interventions, altered acid-base or redox states, exercise training and physical inactivity modulate plasma [K+] during exercise. Finally, historical research approaches largely excluded female participants and typically used very small sample sizes.
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Affiliation(s)
- Michael J McKenna
- Institute for Health and Sport, Victoria University, Melbourne, VIC, 8001, Australia.
- College of Physical Education, Southwest University, Chongqing, China.
- College of Sport Science, Zhuhai College of Science and Technology, Zhuhai, China.
| | - Jean-Marc Renaud
- Department of Cellular and Molecular Medicine, Neuromuscular Research Center, University of Ottawa, Ottawa, ON, Canada
| | - Niels Ørtenblad
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Kristian Overgaard
- Exercise Biology, Department of Public Health, Aarhus University, Aarhus, Denmark
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Christensen PM, Andreasen JJ, Lyngholm J, Søgaard O, Lykkestrup J, Hostrup M, Nybo L, Bangsbo J. Importance of training volume during intensified training in elite cyclists: Maintained vs. reduced volume at moderate intensity. Scand J Med Sci Sports 2024; 34:e14362. [PMID: 37002854 DOI: 10.1111/sms.14362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 03/07/2023] [Accepted: 03/20/2023] [Indexed: 04/04/2023]
Abstract
INTRODUCTION Male elite cyclists (average VO2 -max: 71 mL/min/kg, n = 18) completed 7 weeks of high-intensity interval training (HIT) (3×/week; 4-min and 30-s intervals) during the competitive part of the season. The influence of a maintained or lowered total training volume combined with HIT was evaluated in a two-group design. Weekly moderate-intensity training was lowered by ~33% (~5 h) (LOW, n = 8) or maintained at normal volume (NOR, n = 10). Endurance performance and fatigue resistance were evaluated via 400 kcal time-trials (~20 min) commenced either with or without prior completion of a 120-min preload (including repeated 20-s sprints to simulate physiologic demands during road races). RESULTS Time-trial performance without preload was improved after the intervention (p = 0.006) with a 3% increase in LOW (p = 0.04) and a 2% increase in NOR (p = 0.07). Preloaded time-trial was not significantly improved (p = 0.19). In the preload, average power during repeated sprinting increased by 6% in LOW (p < 0.01) and fatigue resistance in sprinting (start vs end of preload) was improved (p < 0.05) in both groups. Blood lactate during the preload was lowered (p < 0.001) solely in NOR. Measures of oxidative enzyme activity remained unchanged, whereas the glycolytic enzyme PFK increased by 22% for LOW (p = 0.02). CONCLUSION The present study demonstrates that elite cyclists can benefit from intensified training during the competitive season both with maintained and lowered training volume at moderate intensity. In addition to benchmarking the effects of such training in ecological elite settings, the results also indicate how some performance and physiological parameters may interact with training volume.
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Affiliation(s)
- Peter M Christensen
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen O, Denmark
- Team Danmark (Danish elite sport organization), Copenhagen, Denmark
| | - Jesper Juul Andreasen
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen O, Denmark
| | - Jonas Lyngholm
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen O, Denmark
| | - Ole Søgaard
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen O, Denmark
| | - Jakob Lykkestrup
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen O, Denmark
| | - Morten Hostrup
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen O, Denmark
| | - Lars Nybo
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen O, Denmark
| | - Jens Bangsbo
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen O, Denmark
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Renaud JM, Ørtenblad N, McKenna MJ, Overgaard K. Exercise and fatigue: integrating the role of K +, Na + and Cl - in the regulation of sarcolemmal excitability of skeletal muscle. Eur J Appl Physiol 2023; 123:2345-2378. [PMID: 37584745 PMCID: PMC10615939 DOI: 10.1007/s00421-023-05270-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 06/29/2023] [Indexed: 08/17/2023]
Abstract
Perturbations in K+ have long been considered a key factor in skeletal muscle fatigue. However, the exercise-induced changes in K+ intra-to-extracellular gradient is by itself insufficiently large to be a major cause for the force decrease during fatigue unless combined to other ion gradient changes such as for Na+. Whilst several studies described K+-induced force depression at high extracellular [K+] ([K+]e), others reported that small increases in [K+]e induced potentiation during submaximal activation frequencies, a finding that has mostly been ignored. There is evidence for decreased Cl- ClC-1 channel activity at muscle activity onset, which may limit K+-induced force depression, and large increases in ClC-1 channel activity during metabolic stress that may enhance K+ induced force depression. The ATP-sensitive K+ channel (KATP channel) is also activated during metabolic stress to lower sarcolemmal excitability. Taking into account all these findings, we propose a revised concept in which K+ has two physiological roles: (1) K+-induced potentiation and (2) K+-induced force depression. During low-moderate intensity muscle contractions, the K+-induced force depression associated with increased [K+]e is prevented by concomitant decreased ClC-1 channel activity, allowing K+-induced potentiation of sub-maximal tetanic contractions to dominate, thereby optimizing muscle performance. When ATP demand exceeds supply, creating metabolic stress, both KATP and ClC-1 channels are activated. KATP channels contribute to force reductions by lowering sarcolemmal generation of action potentials, whilst ClC-1 channel enhances the force-depressing effects of K+, thereby triggering fatigue. The ultimate function of these changes is to preserve the remaining ATP to prevent damaging ATP depletion.
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Affiliation(s)
- Jean-Marc Renaud
- Faculty of Medicine, Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Rd., Ottawa, ON, K1H 8M5, Canada.
| | - Niels Ørtenblad
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Michael J McKenna
- Institute for Health and Sport, Victoria University, Melbourne, VIC, 8001, Australia
- College of Physical Education, Southwest University, Chongqing, China
- College of Sport Science, Zhuhai College of Science and Technology, Zhuhai, China
| | - Kristian Overgaard
- Exercise Biology, Department of Public Health, Aarhus University, Aarhus, Denmark
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Hostrup M, Lemminger AK, Thomsen LB, Schaufuss A, Alsøe TL, Bergen GK, Bell AB, Bangsbo J, Thomassen M. High-Intensity Training Represses FXYD5 and Glycosylates Na,K-ATPase in Type II Muscle Fibres, Which Are Linked with Improved Muscle K+ Handling and Performance. Int J Mol Sci 2023; 24:ijms24065587. [PMID: 36982661 PMCID: PMC10051537 DOI: 10.3390/ijms24065587] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 03/10/2023] [Accepted: 03/12/2023] [Indexed: 03/17/2023] Open
Abstract
Na+/K+ ATPase (NKA) comprises several subunits to provide isozyme heterogeneity in a tissue-specific manner. An abundance of NKA α, β, and FXYD1 subunits is well-described in human skeletal muscle, but not much is known about FXYD5 (dysadherin), a regulator of NKA and β1 subunit glycosylation, especially with regard to fibre-type specificity and influence of sex and exercise training. Here, we investigated muscle fibre-type specific adaptations in FXYD5 and glycosylated NKAβ1 to high-intensity interval training (HIIT), as well as sex differences in FXYD5 abundance. In nine young males (23.8 ± 2.5 years of age) (mean ± SD), 3 weekly sessions of HIIT for 6 weeks enhanced muscle endurance (220 ± 102 vs. 119 ± 99 s, p < 0.01) and lowered leg K+ release during intense knee-extensor exercise (0.5 ± 0.8 vs. 1.0 ± 0.8 mmol·min–1, p < 0.01) while also increasing cumulated leg K+ reuptake 0–3 min into recovery (2.1 ± 1.5 vs. 0.3 ± 0.9 mmol, p < 0.01). In type IIa muscle fibres, HIIT lowered FXYD5 abundance (p < 0.01) and increased the relative distribution of glycosylated NKAβ1 (p < 0.05). FXYD5 abundance in type IIa muscle fibres correlated inversely with the maximal oxygen consumption (r = –0.53, p < 0.05). NKAα2 and β1 subunit abundances did not change with HIIT. In muscle fibres from 30 trained males and females, we observed no sex (p = 0.87) or fibre type differences (p = 0.44) in FXYD5 abundance. Thus, HIIT downregulates FXYD5 and increases the distribution of glycosylated NKAβ1 in type IIa muscle fibres, which is likely independent of a change in the number of NKA complexes. These adaptations may contribute to counter exercise-related K+ shifts and enhance muscle performance during intense exercise.
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Hostrup M, Bangsbo J. Performance Adaptations to Intensified Training in Top-Level Football. Sports Med 2023; 53:577-594. [PMID: 36380164 PMCID: PMC9667002 DOI: 10.1007/s40279-022-01791-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/25/2022] [Indexed: 11/17/2022]
Abstract
Because physical demands are surging in football (soccer, USA), clubs are more and more seeking players who have a high capacity to perform repeated intense exercise. High-intensity interval training (HIIT), comprising exercise performed at intensities near or exceeding the capacity of aerobic energy systems, effectively enhances the physical conditioning of players. But given that HIIT imposes high loads, it increases the risk of overload-associated match performance decline and injury. This makes some coaches inclined to conduct HIIT in the weeks leading up to the season and during the season. Therefore, the challenge is how to optimize and dose HIIT during these phases, as they can be decisive. Studies have highlighted the utility of conducting periods of intensified training to overcome the risk of overload while at the same time enhancing performance. During intensified training periods of typically a few weeks, intensity is increased by enlarging the amount of HIIT, for example, aerobic high-intensity training or speed endurance training, while volume at low-to-moderate intensity is significantly reduced. The outcome depends on training composition and prescription-most notably, intensity and duration of bouts and recovery. When work intervals are prescribed for a few minutes at intensities > 90% heart rate max (i.e., aerobic high-intensity training), then beneficial adaptations pertaining to aerobic power and capacity are apparent. But when work intervals are conducted at much higher intensities, as all-out efforts or sprinting of typically 10- to 40-s duration with longer recovery periods (i.e., speed endurance training), beneficial adaptations pertaining to anaerobic energy systems, ion handling, and fatigue resilience are commonly observed. In this review, we discuss the utility of conducting intensified training periods to enhance performance in elite football players during the late preparation phase and competitive season.
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Affiliation(s)
- Morten Hostrup
- The August Krogh Section for Human Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, August Krogh Building 2nd Floor, Universitetsparken 13, 2100, Copenhagen, Denmark.
| | - Jens Bangsbo
- The August Krogh Section for Human Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, August Krogh Building 2nd Floor, Universitetsparken 13, 2100, Copenhagen, Denmark
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Lemminger AK, Fiorenza M, Eibye K, Bangsbo J, Hostrup M. High-Intensity Exercise Training Alters the Effect of N-Acetylcysteine on Exercise-Related Muscle Ionic Shifts in Men. Antioxidants (Basel) 2022; 12:antiox12010053. [PMID: 36670915 PMCID: PMC9855150 DOI: 10.3390/antiox12010053] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 12/15/2022] [Accepted: 12/17/2022] [Indexed: 12/28/2022] Open
Abstract
This study investigated whether high-intensity exercise training alters the effect of N-acetylcysteine (a precursor of antioxidant glutathione) on exercise-related muscle ionic shifts. We assigned 20 recreationally-active men to 6 weeks of high-intensity exercise training, comprising three weekly sessions of 4-10 × 20-s all-out bouts interspersed by 2 min recovery (SET, n = 10), or habitual lifestyle maintenance (n = 10). Before and after SET, we measured ionic shifts across the working muscle, using leg arteriovenous balance technique, during one-legged knee-extensor exercise to exhaustion with and without N-acetylcysteine infusion. Furthermore, we sampled vastus lateralis muscle biopsies for analyses of metabolites, mitochondrial respiratory function, and proteins regulating ion transport and antioxidant defense. SET lowered exercise-related H+, K+, lactate-, and Na+ shifts and enhanced exercise performance by ≈45%. While N-acetylcysteine did not affect exercise-related ionic shifts before SET, it lowered H+, HCO3-, and Na+ shifts after SET. SET enhanced muscle mitochondrial respiratory capacity and augmented the abundance of Na+/K+-ATPase subunits (α1 and β1), ATP-sensitive K+ channel subunit (Kir6.2), and monocarboxylate transporter-1, as well as superoxide dismutase-2 and glutathione peroxidase-1. Collectively, these findings demonstrate that high-intensity exercise training not only induces multiple adaptations that enhance the ability to counter exercise-related ionic shifts but also potentiates the effect of N-acetylcysteine on ionic shifts during exercise.
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Cairns SP, Leader JP, Higgins A, Renaud JM. The peak force - resting membrane potential relationships of mouse fast- and slow-twitch muscle. Am J Physiol Cell Physiol 2022; 322:C1151-C1165. [PMID: 35385328 DOI: 10.1152/ajpcell.00401.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We endeavored to understand the factors determining the peak force‑resting membrane potential (EM) relationships of isolated slow-twitch soleus and fast-twitch extensor digitorum longus (EDL) muscles from mice (25oC), especially in relation to fatigue. Inter-relationships between intracellular K+‑activity (aK+i), extracellular K+‑concentration ([K+]o), resting EM, action potentials and force were studied. The large resting EM variation was mainly due to the variability of aK+i. Action potential overshoot‑resting EM relationships determined at 4 and 8-10mM[K+]o following short (<5min) and prolonged (>50min) depolarization periods revealed a constant overshoot from ‑90 to ‑70mV providing a safety margin. Overshoot decline with depolarization beyond ‑70mV was less following short than prolonged depolarization. Inexcitable fibers occurred only with prolonged depolarization. The overshoot decline during action potential trains (2‑s) exceeded that during short depolarizations. Concomitant lower extracellular [Na+] and raised [K+]o depressed the overshoot in an additive manner and peak force in a synergistic manner. Raised [K+]o-induced force loss was exacerbated with transverse wire versus parallel plate stimulation in soleus, implicating action potential propagation failure in the surface membrane. Increasing stimulus pulse parameters restored tetanic force at 9‑10mM[K+]o in soleus, but not EDL, indicative of action potential failure within trains. The peak tetanic force‑resting EM relationships (determined using resting EM from deeper rather than surface fibers) were dynamic and show pronounced force depression over ‑69 to ‑60mV in both muscle-types, implicating that such depolarization contributes to fatigue. The K+-Na+-interaction shifted this relationship towards less depolarized potentials suggesting that the combined ionic effect is physiologically important during fatigue.
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Affiliation(s)
- Simeon P Cairns
- SPRINZ, School of Sport and Recreation, Faculty of Health and Environmental Sciences, Auckland University of Technology, Auckland, New Zealand.,Health and Rehabilitation Research Institute, Faculty of Health and Environmental Sciences, Auckland University of Technology, Auckland, New Zealand.,Department of Physiology, School of Medicine, University of Auckland, Auckland, New Zealand
| | - John P Leader
- Department of Physiology, University of Otago, Dunedin, New Zealand.,Department of Medicine, University of Otago, Dunedin, New Zealand
| | - Amanda Higgins
- Department of Cellular and Molecular Medicine, Neuromuscular Research Center, University of Ottawa, Ottawa, Canada
| | - Jean-Marc Renaud
- Department of Cellular and Molecular Medicine, Neuromuscular Research Center, University of Ottawa, Ottawa, Canada
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13
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Hostrup M, Cairns SP, Bangsbo J. Muscle Ionic Shifts During Exercise: Implications for Fatigue and Exercise Performance. Compr Physiol 2021; 11:1895-1959. [PMID: 34190344 DOI: 10.1002/cphy.c190024] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Exercise causes major shifts in multiple ions (e.g., K+ , Na+ , H+ , lactate- , Ca2+ , and Cl- ) during muscle activity that contributes to development of muscle fatigue. Sarcolemmal processes can be impaired by the trans-sarcolemmal rundown of ion gradients for K+ , Na+ , and Ca2+ during fatiguing exercise, while changes in gradients for Cl- and Cl- conductance may exert either protective or detrimental effects on fatigue. Myocellular H+ accumulation may also contribute to fatigue development by lowering glycolytic rate and has been shown to act synergistically with inorganic phosphate (Pi) to compromise cross-bridge function. In addition, sarcoplasmic reticulum Ca2+ release function is severely affected by fatiguing exercise. Skeletal muscle has a multitude of ion transport systems that counter exercise-related ionic shifts of which the Na+ /K+ -ATPase is of major importance. Metabolic perturbations occurring during exercise can exacerbate trans-sarcolemmal ionic shifts, in particular for K+ and Cl- , respectively via metabolic regulation of the ATP-sensitive K+ channel (KATP ) and the chloride channel isoform 1 (ClC-1). Ion transport systems are highly adaptable to exercise training resulting in an enhanced ability to counter ionic disturbances to delay fatigue and improve exercise performance. In this article, we discuss (i) the ionic shifts occurring during exercise, (ii) the role of ion transport systems in skeletal muscle for ionic regulation, (iii) how ionic disturbances affect sarcolemmal processes and muscle fatigue, (iv) how metabolic perturbations exacerbate ionic shifts during exercise, and (v) how pharmacological manipulation and exercise training regulate ion transport systems to influence exercise performance in humans. © 2021 American Physiological Society. Compr Physiol 11:1895-1959, 2021.
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Affiliation(s)
- Morten Hostrup
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Simeon Peter Cairns
- SPRINZ, School of Sport and Recreation, Auckland University of Technology, Auckland, New Zealand.,Health and Rehabilitation Research Institute, Auckland University of Technology, Auckland, New Zealand
| | - Jens Bangsbo
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
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Gliemann L, Rytter N, Yujia L, Tamariz-Ellemann A, Carter H, Hellsten Y. A High Activity Level Is Required for Augmented Muscle Capillarization in Older Women. Med Sci Sports Exerc 2021; 53:894-903. [PMID: 33844669 DOI: 10.1249/mss.0000000000002566] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE This study aimed to evaluate the influence of lifelong regular physical activity on skeletal muscle capillarization in women. METHODS Postmenopausal women, 61±4 yr old, were divided according to self-reported physical activity level over the past 20 yrs: sedentary (SED; n = 14), moderately active (MOD; n = 12), and very active (VERY; n = 15). Leg blood flow (LBF) was determined by ultrasound Doppler, and blood samples were drawn from the femoral artery and vein for calculation of leg oxygen uptake (LVO2) at rest and during one-legged knee extensor exercise. A skeletal muscle biopsy was obtained from the vastus lateralis and analyzed for capillarization and vascular endothelial growth factor (VEGF) and mitochondrial OXPHOS proteins. Platelets were isolated from venous blood and analyzed for VEGF content and effect on endothelial cell proliferation. RESULTS The exercise-induced rise in LBF and LVO2 was faster (P = 0.008) in VERY compared with SED and MOD. Steady-state LBF and LVO2 were lower (P < 0.04) in MOD and VERY compared with SED. Capillary-fiber ratio and capillary density were greater (P < 0.03) in VERY (1.65 ± 0.48 and 409.3 ± 57.5) compared with MOD (1.30 ± 0.19 and 365.0 ± 40.2) and SED (1.30 ± 0.30 and 356.2 ± 66.3). Skeletal muscle VEGF and OXPHOS complexes I, II, and V were ~1.6-fold and ~1.25-fold (P < 0.01) higher, respectively, in VERY compared with SED. Platelets from all groups induced an approximately nine-fold (P < 0.001) increase in endothelial cell proliferation. CONCLUSION A very active lifestyle is associated with superior skeletal muscle exercise hemodynamics and greater potential for oxygen extraction concurrent with a higher skeletal muscle capillarization and mitochondrial capacity.
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Affiliation(s)
- Lasse Gliemann
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, DENMARK
| | - Nicolai Rytter
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, DENMARK
| | | | | | - Howard Carter
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, DENMARK
| | - Ylva Hellsten
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, DENMARK
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15
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Lindinger MI, Cairns SP. Regulation of muscle potassium: exercise performance, fatigue and health implications. Eur J Appl Physiol 2021; 121:721-748. [PMID: 33392745 DOI: 10.1007/s00421-020-04546-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 10/29/2020] [Indexed: 12/30/2022]
Abstract
This review integrates from the single muscle fibre to exercising human the current understanding of the role of skeletal muscle for whole-body potassium (K+) regulation, and specifically the regulation of skeletal muscle [K+]. We describe the K+ transport proteins in skeletal muscle and how they contribute to, or modulate, K+ disturbances during exercise. Muscle and plasma K+ balance are markedly altered during and after high-intensity dynamic exercise (including sports), static contractions and ischaemia, which have implications for skeletal and cardiac muscle contractile performance. Moderate elevations of plasma and interstitial [K+] during exercise have beneficial effects on multiple physiological systems. Severe reductions of the trans-sarcolemmal K+ gradient likely contributes to muscle and whole-body fatigue, i.e. impaired exercise performance. Chronic or acute changes of arterial plasma [K+] (hyperkalaemia or hypokalaemia) have dangerous health implications for cardiac function. The current mechanisms to explain how raised extracellular [K+] impairs cardiac and skeletal muscle function are discussed, along with the latest cell physiology research explaining how calcium, β-adrenergic agonists, insulin or glucose act as clinical treatments for hyperkalaemia to protect the heart and skeletal muscle in vivo. Finally, whether these agents can also modulate K+-induced muscle fatigue are evaluated.
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Affiliation(s)
- Michael I Lindinger
- Research and Development, The Nutraceutical Alliance, Burlington, ON, L7N 2Z9, Canada
| | - Simeon P Cairns
- SPRINZ, School of Sport and Recreation, Faculty of Health and Environmental Sciences, Auckland University of Technology, Auckland, 1020, New Zealand.
- Health and Rehabilitation Research Institute, Faculty of Health and Environmental Sciences, Auckland University of Technology, Auckland, 1020, New Zealand.
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16
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Karlsen T, Solli GS, Samdal ST, Sandbakk Ø. Intensity Control During Block-Periodized High-Intensity Training: Heart Rate and Lactate Concentration During Three Annual Seasons in World-Class Cross-Country Skiers. Front Sports Act Living 2020; 2:549407. [PMID: 33345112 PMCID: PMC7739818 DOI: 10.3389/fspor.2020.549407] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 09/14/2020] [Indexed: 11/25/2022] Open
Abstract
Purpose: To describe heart rate (HR) and blood lactate (Bla−) responses during high-intensity interval training (HIT) in a long-term block-periodized HIT regimen in world-class cross-country (XC) skiers. Methods: Data were collected in 14 world-class female XC skiers (aged 25 ± 5 years; body mass, 60.4 ± 6.5 kg; and maximal HR, 194 ± 8 beats · min−1) throughout three entire seasons. The HR and Bla− values were determined at the end of 572 intervals performed during 63 sessions and 17 HIT blocks utilizing different exercise modes: running, running with poles, and skiing (on-snow and roller ski) with classic and skating techniques. Results: The mean HR was 91 ± 3% of HRmax with a corresponding Bla− of 7.3 ± 2.1 mmol · L−1. The average HR and Bla− values were relatively similar across the different exercise modes, except for a lower HR (~90 vs. 92% of HRmax) for on-snow and roller ski classical skiing and lower Bla− values (5.9 vs. 7.0–7.8 mmol · L−1) for on-snow classical skiing compared to the other modes, both P < 0.05. An increase in HR and Bla− was observed from interval working periods 1 to 3 (90–92% of HRmax and 6.5–7.7 mmol · L−1) and further from 3 to 5 (92–93% of HRmax and 7.7–9.0 mmol · L−1), all P < 0.05. Conclusions: We describe long-term use of HIT-block periodization among world-class XC skiers who achieved target HR and Bla− levels in all six exercise modes employed. According to athletes and coaches, the key to successful blocks was intensity control to allow for high-quality HIT sessions throughout the entire HIT block.
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Affiliation(s)
- Trine Karlsen
- Faculty of Nursing and Health Sciences, Nord University, Bodø, Norway
| | - Guro Strøm Solli
- Department of Sports Science and Physical Education, Faculty of Education and Arts, Nord University, Bodø, Norway.,Department of Neuromedicine and Movement Science, Centre for Elite Sports Research, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
| | | | - Øyvind Sandbakk
- Department of Neuromedicine and Movement Science, Centre for Elite Sports Research, NTNU, Norwegian University of Science and Technology, Trondheim, Norway
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17
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Gunnarsson TP, Ehlers TS, Fiorenza M, Nyberg M, Bangsbo J. Reply to "Letter to the editor: In response to Gunnarsson et al. on improving the quality of exercise interventions". Am J Physiol Cell Physiol 2020; 319:C908-C909. [PMID: 33152261 DOI: 10.1152/ajpcell.00436.2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Thomas P Gunnarsson
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Thomas S Ehlers
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Matteo Fiorenza
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Michael Nyberg
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Jens Bangsbo
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
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18
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Almquist NW, Ettema G, Hopker J, Sandbakk Ø, Rønnestad BR. The Effect of 30-Second Sprints During Prolonged Exercise on Gross Efficiency, Electromyography, and Pedaling Technique in Elite Cyclists. Int J Sports Physiol Perform 2020; 15:562-570. [PMID: 31693997 DOI: 10.1123/ijspp.2019-0367] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 06/27/2019] [Accepted: 07/23/2019] [Indexed: 11/18/2022]
Abstract
BACKGROUND Cycling competitions are often of long duration and include repeated high-intensity efforts. PURPOSE To investigate the effect of repeated maximal sprints during 4 hours of low-intensity cycling on gross efficiency (GE), electromyography patterns, and pedaling technique compared with work-matched low-intensity cycling in elite cyclists. METHODS Twelve elite, male cyclists performed 4 hours of cycling at 50% of maximal oxygen uptake either with 3 sets of 3 × 30-second maximal sprints (E&S) during the first 3 hours or a work-matched cycling without sprints (E) in a randomized order. Oxygen uptake, electromyography, and pedaling technique were recorded throughout the exercises. RESULTS GE was reduced from start to the end of exercise in both conditions (E&S: 19.0 [0.2] vs 18.1 [0.2], E: 19.1% [0.2%] vs 18.1% [0.2%], both P = .001), with no difference in change between conditions (condition × time interaction, P = .8). Integrated electromyography increased from start to end of exercise in m. vastus lateralis and m. vastus medialis (m. vastus medialis: 9.9 [2.4], m. vastus lateralis: 8.5 [4.0] mV, main effect of time: P < .001 and P = .03, respectively) and E&S increased less than E in m. vastus medialis (mean difference -3.3 [1.5] mV, main effect of condition: P = .03, interaction, P = .06). The mechanical effectiveness only decreased in E&S (E&S: -2.2 [0.7], effect size = 0.24 vs E: -1.3 [0.8] percentage points: P = .04 and P = .8, respectively). The mean power output during each set of 3 × 30-second sprints in E&S did not differ (P = .6). CONCLUSIONS GE decreases as a function of time during 4 hours of low-intensity cycling. However, the inclusion of maximal repeated sprinting does not affect the GE changes, and the ability to sprint is maintained throughout the entire session.
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19
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Hegyi B, Chen-Izu Y, Izu LT, Bányász T. Altered K + current profiles underlie cardiac action potential shortening in hyperkalemia and β-adrenergic stimulation. Can J Physiol Pharmacol 2019; 97:773-780. [PMID: 31091413 DOI: 10.1139/cjpp-2019-0056] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Hyperkalemia is known to develop in various conditions including vigorous physical exercise. In the heart, hyperkalemia is associated with action potential (AP) shortening that was attributed to altered gating of K+ channels. However, it remains unknown how hyperkalemia changes the profiles of each K+ current under a cardiac AP. Therefore, we recorded the major K+ currents (inward rectifier K+ current, IK1; rapid and slow delayed rectifier K+ currents, IKr and IKs, respectively) using AP-clamp in rabbit ventricular myocytes. As K+ may accumulate at rapid heart rates during sympathetic stimulation, we also examined the effect of isoproterenol on these K+ currents. We found that IK1 was significantly increased in hyperkalemia, whereas the reduction of driving force for K+ efflux dominated over the altered channel gating in case of IKr and IKs. Overall, the markedly increased IK1 in hyperkalemia overcame the relative decreases of IKr and IKs during AP, resulting in an increased net repolarizing current during AP phase 3. β-Adrenergic stimulation of IKs also provided further repolarizing power during sympathetic activation, although hyperkalemia limited IKs upregulation. These results indicate that facilitation of IK1 in hyperkalemia and β-adrenergic stimulation of IKs represent important compensatory mechanisms against AP prolongation and arrhythmia susceptibility.
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Affiliation(s)
- Bence Hegyi
- a Department of Pharmacology, University of California, Davis, CA 95616, USA
| | - Ye Chen-Izu
- a Department of Pharmacology, University of California, Davis, CA 95616, USA.,b Department of Biomedical Engineering, University of California, Davis, CA 95616, USA.,c Department of Internal Medicine/Cardiology, University of California, Davis, CA 95616, USA
| | - Leighton T Izu
- a Department of Pharmacology, University of California, Davis, CA 95616, USA
| | - Tamás Bányász
- a Department of Pharmacology, University of California, Davis, CA 95616, USA.,d Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
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20
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Christiansen D, Eibye KH, Rasmussen V, Voldbye HM, Thomassen M, Nyberg M, Gunnarsson TGP, Skovgaard C, Lindskrog MS, Bishop DJ, Hostrup M, Bangsbo J. Cycling with blood flow restriction improves performance and muscle K + regulation and alters the effect of anti-oxidant infusion in humans. J Physiol 2019; 597:2421-2444. [PMID: 30843602 DOI: 10.1113/jp277657] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Accepted: 02/27/2019] [Indexed: 12/14/2022] Open
Abstract
KEY POINTS Training with blood flow restriction (BFR) is a well-recognized strategy for promoting muscle hypertrophy and strength. However, its potential to enhance muscle function during sustained, intense exercise remains largely unexplored. In the present study, we report that interval training with BFR augments improvements in performance and reduces net K+ release from contracting muscles during high-intensity exercise in active men. A better K+ regulation after BFR-training is associated with an elevated blood flow to exercising muscles and altered muscle anti-oxidant function, as indicated by a higher reduced to oxidized glutathione (GSH:GSSG) ratio, compared to control, as well as an increased thigh net K+ release during intense exercise with concomitant anti-oxidant infusion. Training with BFR also invoked fibre type-specific adaptations in the abundance of Na+ ,K+ -ATPase isoforms (α1 , β1 , phospholemman/FXYD1). Thus, BFR-training enhances performance and K+ regulation during intense exercise, which may be a result of adaptations in anti-oxidant function, blood flow and Na+ ,K+ -ATPase-isoform abundance at the fibre-type level. ABSTRACT We examined whether blood flow restriction (BFR) augments training-induced improvements in K+ regulation and performance during intense exercise in men, and also whether these adaptations are associated with an altered muscle anti-oxidant function, blood flow and/or with fibre type-dependent changes in Na+ ,K+ -ATPase-isoform abundance. Ten recreationally-active men (25 ± 4 years, 49.7 ± 5.3 mL kg-1 min-1 ) performed 6 weeks of interval cycling, where one leg trained without BFR (control; CON-leg) and the other trained with BFR (BFR-leg, pressure: ∼180 mmHg). Before and after training, femoral arterial and venous K+ concentrations and artery blood flow were measured during single-leg knee-extensor exercise at 25% (Ex1) and 90% of thigh incremental peak power (Ex2) with i.v. infusion of N-acetylcysteine (NAC) or placebo (saline) and a resting muscle biopsy was collected. After training, performance increased more in BFR-leg (23%) than in CON-leg (12%, P < 0.05), whereas K+ release during Ex2 was attenuated only from BFR-leg (P < 0.05). The muscle GSH:GSSG ratio at rest and blood flow during exercise was higher in BFR-leg than in CON-leg after training (P < 0.05). After training, NAC increased resting muscle GSH concentration and thigh net K+ release during Ex2 only in BFR-leg (P < 0.05), whereas the abundance of Na+ ,K+ -ATPase-isoform α1 in type II (51%), β1 in type I (33%), and FXYD1 in type I (108%) and type II (60%) fibres was higher in BFR-leg than in CON-leg (P < 0.05). Thus, training with BFR elicited greater improvements in performance and reduced thigh K+ release during intense exercise, which were associated with adaptations in muscle anti-oxidant function, blood flow and Na+ ,K+ -ATPase-isoform abundance at the fibre-type level.
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Affiliation(s)
- Danny Christiansen
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark.,Institute for Health and Sport (IHES), Victoria University, Melbourne, VIC, Australia
| | - Kasper H Eibye
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | - Villads Rasmussen
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | - Hans M Voldbye
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | - Martin Thomassen
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | - Michael Nyberg
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | - Thomas G P Gunnarsson
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | - Casper Skovgaard
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | - Mads S Lindskrog
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | - David J Bishop
- Institute for Health and Sport (IHES), Victoria University, Melbourne, VIC, Australia.,School of Medical and Health Sciences, Edith Cowan University, Perth, WA, Australia
| | - Morten Hostrup
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | - Jens Bangsbo
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
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21
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Christiansen D. Molecular stressors underlying exercise training-induced improvements in K + regulation during exercise and Na + ,K + -ATPase adaptation in human skeletal muscle. Acta Physiol (Oxf) 2019; 225:e13196. [PMID: 30288889 DOI: 10.1111/apha.13196] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 09/12/2018] [Accepted: 09/28/2018] [Indexed: 12/28/2022]
Abstract
Despite substantial progress made towards a better understanding of the importance of skeletal muscle K+ regulation for human physical function and its association with several disease states (eg type-II diabetes and hypertension), the molecular basis underpinning adaptations in K+ regulation to various stimuli, including exercise training, remains inadequately explored in humans. In this review, the molecular mechanisms essential for enhancing skeletal muscle K+ regulation and its key determinants, including Na+ ,K+ -ATPase function and expression, by exercise training are examined. Special attention is paid to the following molecular stressors and signaling proteins: oxygenation, redox balance, hypoxia, reactive oxygen species, antioxidant function, Na+ ,K+ , and Ca2+ concentrations, anaerobic ATP turnover, AMPK, lactate, and mRNA expression. On this basis, an update on the effects of different types of exercise training on K+ regulation in humans is provided, focusing on recent discoveries about the muscle fibre-type-dependent regulation of Na+ ,K+ -ATPase-isoform expression. Furthermore, with special emphasis on blood-flow-restricted exercise as an exemplary model to modulate the key molecular mechanisms identified, it is discussed how training interventions may be designed to maximize improvements in K+ regulation in humans. The novel insights gained from this review may help us to better understand how exercise training and other strategies, such as pharmacological interventions, may be best designed to enhance K+ regulation and thus the physical function in humans.
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Affiliation(s)
- Danny Christiansen
- Department of Nutrition, Exercise and Sports (NEXS) University of Copenhagen Copenhagen Denmark
- Institute for Health and Sport (IHES) Victoria University Melbourne Victoria Australia
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22
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Hostrup M, Gunnarsson TP, Fiorenza M, Mørch K, Onslev J, Pedersen KM, Bangsbo J. In-season adaptations to intense intermittent training and sprint interval training in sub-elite football players. Scand J Med Sci Sports 2019; 29:669-677. [PMID: 30676666 DOI: 10.1111/sms.13395] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 01/11/2019] [Accepted: 01/16/2019] [Indexed: 11/28/2022]
Abstract
This study investigated the in-season effect of intensified training comparing the efficacy of duration-matched intense intermittent exercise training with sprint interval training in increasing intermittent running performance, sprint ability, and muscle content of proteins related to ion handling and metabolism in football players. After the first two weeks in the season, 22 sub-elite football players completed either 10 weeks of intense intermittent training using the 10-20-30 training concept (10-20-30, n = 12) or sprint interval training (SIT, n = 10; work/rest ratio: 6-s/54-s) three times weekly, with a ~20% reduction in weekly training time. Before and after the intervention, players performed a Yo-Yo intermittent recovery test level 1 (Yo-Yo IR1) and a 30-m sprint test. Furthermore, players had a muscle biopsy taken from the vastus lateralis. Yo-Yo IR1 performance increased by 330 m (95%CI: 178-482, P ≤ 0.01) in 10-20-30, whereas no change was observed in SIT. Sprint time did not change in 10-20-30 but decreased by 0.04 second (95%CI: 0.00-0.09, P ≤ 0.05) in SIT. Muscle content of HADHA (24%, P ≤ 0.01), PDH-E1α (40%, P ≤ 0.01), complex I-V of the electron transport chain (ETC) (51%, P ≤ 0.01) and Na+ , K+ -ATPase subunits α2 (33%, P ≤ 0.05) and β1 (27%, P ≤ 0.05) increased in 10-20-30, whereas content of DHPR (27%, P ≤ 0.01) and complex I-V of the ETC (31%, P ≤ 0.05) increased in SIT. Intense intermittent training, combining short sprints and a high aerobic load, is superior to regular sprint interval training in increasing intense intermittent running performance during a Yo-Yo IR1 test and muscle content of PDH-E1α and HADHA in sub-elite football players.
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Affiliation(s)
- Morten Hostrup
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Thomas P Gunnarsson
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Matteo Fiorenza
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Kristian Mørch
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Johan Onslev
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Kasper M Pedersen
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Jens Bangsbo
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
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Gunnarsson TP, Brandt N, Fiorenza M, Hostrup M, Pilegaard H, Bangsbo J. Inclusion of sprints in moderate intensity continuous training leads to muscle oxidative adaptations in trained individuals. Physiol Rep 2019; 7:e13976. [PMID: 30793541 PMCID: PMC6384299 DOI: 10.14814/phy2.13976] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 11/16/2018] [Indexed: 12/21/2022] Open
Abstract
This study examined adaptations in muscle oxidative capacity and exercise performance induced by two work- and duration-matched exercise protocols eliciting different muscle metabolic perturbations in trained individuals. Thirteen male subjects ( V ˙ O2 -max 53.5 ± 7.0 mL·kg-1 ·min-1 ) (means ± SD) performed 8 weeks (three sessions/week) of training consisting of 60 min of moderate intensity continuous cycling (157 ± 20 W) either without (C) or with (C+S) inclusion of 30-s sprints (473 ± 79 W) every 10 min. Total work performed during training was matched between groups. Muscle biopsies and arm venous blood were collected before as well as immediately and 2 h after exercise during the first and last training session. Plasma epinephrine and lactate concentrations after the first and last training session were 2-3-fold higher in C+S than in C. After the first and last training session, muscle phosphocreatine and pH were lower (12-25 mmol·kg d.w.-1 and 0.2-0.4 units, respectively) and muscle lactate higher (48-64 mmol·kg d.w.-1 ) in C+S than in C, whereas exercise-induced changes in muscle PGC-1α mRNA levels were similar within- and between-groups. Muscle content of cytochrome c oxidase IV and citrate synthase (CS) increased more in C+S than in C, and content of CS in type II muscle fibers increased in C+S only (9-17%), with no difference between groups. Performance during a 45-min time-trial improved by 4 ± 3 and 9 ± 3% in C+S and C, respectively, whereas peak power output at exhaustion during an incremental test increased by 3 ± 3% in C+S only, with no difference between groups. In conclusion, addition of sprints in moderate intensity continuous exercise causes muscle oxidative adaptations in trained male individuals which appear to be independent of the exercise-induced PGC-1α mRNA response. Interestingly, time-trial performance improved similarly between groups, suggesting that changes in content of mitochondrial proteins are of less importance for endurance performance in trained males.
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Affiliation(s)
- Thomas P. Gunnarsson
- Department of Nutrition, Exercise and SportsUniversity of CopenhagenCopenhagenDenmark
| | - Nina Brandt
- Department of BiologyUniversity of CopenhagenCopenhagenDenmark
| | - Matteo Fiorenza
- Department of Nutrition, Exercise and SportsUniversity of CopenhagenCopenhagenDenmark
| | - Morten Hostrup
- Department of Nutrition, Exercise and SportsUniversity of CopenhagenCopenhagenDenmark
| | | | - Jens Bangsbo
- Department of Nutrition, Exercise and SportsUniversity of CopenhagenCopenhagenDenmark
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Aboodarda SJ, Mira J, Floreani M, Jaswal R, Moon SJ, Amery K, Rupp T, Millet GY. Effects of endurance cycling training on neuromuscular fatigue in healthy active men. Part II: Corticospinal excitability and voluntary activation. Eur J Appl Physiol 2018; 118:2295-2305. [DOI: 10.1007/s00421-018-3951-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 07/23/2018] [Indexed: 10/28/2022]
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25
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Effects of endurance training on neuromuscular fatigue in healthy active men. Part I: Strength loss and muscle fatigue. Eur J Appl Physiol 2018; 118:2281-2293. [PMID: 30121882 DOI: 10.1007/s00421-018-3950-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 07/23/2018] [Indexed: 01/26/2023]
Abstract
PURPOSE The adaptations induced by endurance training on the neuromuscular function remain under investigation and, for methodological reasons, unclear. This study investigates the effects of cycling training on neuromuscular fatigue and its peripheral contribution measured during and immediately after cycling exercise. METHODS Fourteen healthy men performed a fatigue test before a 9-week cycling program (PRE) and two tests after training: at the same absolute power output as PRE (POSTABS) and based on the post-training maximal aerobic power (POSTREL). Throughout the tests and at exhaustion (EXH), maximal voluntary contraction (MVC) and peripheral fatigue were assessed in the quadriceps muscle by electrical nerve stimulation [single twitch (Pt); high-frequency doublet (Db100) and low-to-high-frequency ratio (Db10:100)]. RESULTS Time to EXH was longer in POSTABS than PRE (34 ± 5 vs. 27 ± 4 min, P < 0.001), and POSTREL tended to be longer than PRE (30 ± 6 min, P = 0.053). MVC and peripheral fatigue were overall less depressed in POSTABS than PRE at isotime. At EXH, MVC and Db10:100 were similarly reduced in all sessions (-37 to - 42% and - 30 to - 37%, respectively). Db100 tended to be less depressed in POSTABS than PRE (-40 ± 9 vs. - 48 ± 16%, P = 0.050) and in POSTREL than PRE (-39 ± 9%, P = 0.071). Pt decreased similarly in POSTABS and PRE (-52 ± 16 vs. - 54 ± 16%), but POSTREL tended to be less depressed than PRE (-48 ± 14%, P = 0.075). CONCLUSIONS This study confirms fatigue attenuation at isotime after training. Yet lower or similar fatigue at EXH indicates that, unlike previously suggested, fatigue tolerance may not be upregulated after 9 weeks of cycling training.
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Thomassen M, Hostrup M, Murphy RM, Cromer BA, Skovgaard C, Gunnarsson TP, Christensen PM, Bangsbo J. Abundance of ClC-1 chloride channel in human skeletal muscle: fiber type specific differences and effect of training. J Appl Physiol (1985) 2018; 125:470-478. [DOI: 10.1152/japplphysiol.01042.2017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cl− channel protein 1 (ClC-1) may be important for excitability and contractility in skeletal muscle, but ClC-1 abundance has not been examined in human muscle. The aim of the present study was to examine ClC-1 abundance in human skeletal muscle, including fiber type specific differences and the effect of exercise training. A commercially available antibody was tested with positive and negative control tissue, and it recognized specifically ClC-1 in the range from 100 to 150 kDa. Abundance of ClC-1 was 38% higher ( P < 0.01) in fast twitch Type IIa muscle fibers than in slow twitch Type I. Muscle ClC-1 abundance did not change with 4 wk of training consisting of 30 min cycling at 85% of maximal heart rate (HRmax) and 3 × 30-s all out sprints or during a 7-wk training period with 10–12 × 30 s uphill cycling and 4–5 × ~4 min cycling at 90%–95% of HRmax. ClC-1 abundance correlated negatively ( P < 0.01) with maximal oxygen consumption ( r = –0.552) and incremental exercise performance ( r = –0.546). In addition, trained cyclists had lower ( P < 0.01) ClC-1 abundance than lesser trained individuals. The present observations indicate that a low abundance of muscle ClC-1 may be beneficial for exercise performance, but the role of abundance and regulation of ClC-1 in skeletal muscle of humans with respect to exercise performance and trainability need to be elucidated. NEW & NOTEWORTHY Abundance of the Cl− channel protein 1 (ClC-1) chloride channel may be important for excitability and contractility in human skeletal muscle and may therefore have implications for fatigue development. In this study, we confirmed ClC-1 specificity for a commercially available antibody, and this study is first to our knowledge to determine ClC-1 protein abundance in human muscle by Western blotting. We observed that abundance of ClC-1 was higher in fast compared with slow twitch fibers and lower in trained individuals than in recreationally active.
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Affiliation(s)
- Martin Thomassen
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Morten Hostrup
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Robyn M. Murphy
- Department of Biochemistry & Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
| | - Brett A. Cromer
- Department of Chemistry and Biotechnology, Swinburne University, Melbourne, Victoria, Australia
| | - Casper Skovgaard
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Thomas P. Gunnarsson
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Peter M. Christensen
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Jens Bangsbo
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
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27
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Wyckelsma VL, Levinger I, Murphy RM, Petersen AC, Perry BD, Hedges CP, Anderson MJ, McKenna MJ. Intense interval training in healthy older adults increases skeletal muscle [ 3H]ouabain-binding site content and elevates Na +,K +-ATPase α 2 isoform abundance in Type II fibers. Physiol Rep 2017; 5:5/7/e13219. [PMID: 28373411 PMCID: PMC5392511 DOI: 10.14814/phy2.13219] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Accepted: 02/27/2017] [Indexed: 12/12/2022] Open
Abstract
Young adults typically adapt to intense exercise training with an increased skeletal muscle Na+,K+-ATPase (NKA) content, concomitant with reduced extracellular potassium concentration [K+] during exercise and enhanced exercise performance. Whether these changes with longitudinal training occur in older adults is unknown and was investigated here. Fifteen older adults (69.4 ± 3.5 years, mean ± SD) were randomized to either 12 weeks of intense interval training (4 × 4 min at 90-95% peak heart rate), 3 days/week (IIT, n = 8); or no exercise controls (n = 7). Before and after training, participants completed an incremental cycle ergometer exercise test until a rating of perceived exertion of 17 (very hard) on a 20-point scale was attained, with measures of antecubital venous [K+]v Participants underwent a resting muscle biopsy prior to and at 48-72 h following the final training session. After IIT, the peak exercise work rate (25%), oxygen uptake (16%) and heart rate (6%) were increased (P < 0.05). After IIT, the peak exercise plasma [K+]v tended to rise (P = 0.07), while the rise in plasma [K+]v relative to work performed (nmol.L-1J-1) was unchanged. Muscle NKA content increased by 11% after IIT (P < 0.05). Single fiber measurements, increased in NKA α2 isoform in Type II fibers after IIT (30%, P < 0.05), with no changes to the other isoforms in single fibers or homogenate. Thus, intense exercise training in older adults induced an upregulation of muscle NKA, with a fiber-specific increase in NKA α2 abundance in Type II fibers, coincident with increased muscle NKA content and enhanced exercise performance.
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Affiliation(s)
- Victoria L Wyckelsma
- Clinical Exercise Science Research Program, Institute of Sport, Exercise and Active Living (ISEAL), Victoria, Australia
| | - Itamar Levinger
- Clinical Exercise Science Research Program, Institute of Sport, Exercise and Active Living (ISEAL), Victoria, Australia
| | - Robyn M Murphy
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Victoria, Australia
| | - Aaron C Petersen
- Clinical Exercise Science Research Program, Institute of Sport, Exercise and Active Living (ISEAL), Victoria, Australia
| | - Ben D Perry
- Clinical Exercise Science Research Program, Institute of Sport, Exercise and Active Living (ISEAL), Victoria, Australia.,Renal Division, Department of Medicine, Emory University, Atlanta, Georgia
| | - Christopher P Hedges
- Clinical Exercise Science Research Program, Institute of Sport, Exercise and Active Living (ISEAL), Victoria, Australia
| | - Mitchell J Anderson
- Clinical Exercise Science Research Program, Institute of Sport, Exercise and Active Living (ISEAL), Victoria, Australia.,Baker IDI Heart and Diabetes Institute, Melbourne, Australia
| | - Michael J McKenna
- Clinical Exercise Science Research Program, Institute of Sport, Exercise and Active Living (ISEAL), Victoria, Australia
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28
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Fransson D, Nielsen TS, Olsson K, Christensson T, Bradley PS, Fatouros IG, Krustrup P, Nordsborg NB, Mohr M. Skeletal muscle and performance adaptations to high-intensity training in elite male soccer players: speed endurance runs versus small-sided game training. Eur J Appl Physiol 2017; 118:111-121. [PMID: 29119246 PMCID: PMC5754420 DOI: 10.1007/s00421-017-3751-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2017] [Accepted: 10/24/2017] [Indexed: 11/04/2022]
Abstract
Purpose To examine the skeletal muscle and performance responses across two different exercise training modalities which are highly applied in soccer training. Methods Using an RCT design, 39 well-trained male soccer players were randomized into either a speed endurance training (SET; n = 21) or a small-sided game group (SSG; n = 18). Over 4 weeks, thrice weekly, SET performed 6–10 × 30-s all-out runs with 3-min recovery, while SSG completed 2 × 7–9-min small-sided games with 2-min recovery. Muscle biopsies were obtained from m. vastus lateralis pre and post intervention and were subsequently analysed for metabolic enzyme activity and muscle protein expression. Moreover, the Yo–Yo Intermittent Recovery level 2 test (Yo–Yo IR2) was performed. Results Muscle CS maximal activity increased (P < 0.05) by 18% in SET only, demonstrating larger (P < 0.05) improvement than SSG, while HAD activity increased (P < 0.05) by 24% in both groups. Na+–K+ ATPase α1 subunit protein expression increased (P < 0.05) in SET and SSG (19 and 37%, respectively), while MCT4 protein expression rose (P < 0.05) by 30 and 61% in SET and SSG, respectively. SOD2 protein expression increased (P < 0.05) by 28 and 37% in SET and SSG, respectively, while GLUT-4 protein expression increased (P < 0.05) by 40% in SSG only. Finally, SET displayed 39% greater improvement (P < 0.05) in Yo–Yo IR2 performance than SSG. Conclusion Speed endurance training improved muscle oxidative capacity and exercise performance more pronouncedly than small-sided game training, but comparable responses were in muscle ion transporters and antioxidative capacity in well-trained male soccer players.
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Affiliation(s)
- Dan Fransson
- Department of Food and Nutrition, and Sport Science, Center for Health and Human Performance, University of Gothenburg, Gothenburg, Sweden
| | - Tobias Schmidt Nielsen
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Karl Olsson
- Department of Health and Caring Sciences, Linnaeus University, Kalmar, Sweden
| | - Tobias Christensson
- Department of Food and Nutrition, and Sport Science, Center for Health and Human Performance, University of Gothenburg, Gothenburg, Sweden
| | - Paul S Bradley
- Research Institute of Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - Ioannis G Fatouros
- School of Physical Education and Sport Science, University of Thessaly, Karies, Trikala, Greece
| | - Peter Krustrup
- Department of Sports Science and Clinical Biomechanics, SDU Sport and Health Sciences Cluster (SHSC), University of Southern Denmark, Odense, Denmark.,Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | | | - Magni Mohr
- Department of Food and Nutrition, and Sport Science, Center for Health and Human Performance, University of Gothenburg, Gothenburg, Sweden. .,Department of Sports Science and Clinical Biomechanics, SDU Sport and Health Sciences Cluster (SHSC), University of Southern Denmark, Odense, Denmark. .,Faculty of Health Sciences, Centre of Health Science, University of the Faroe Islands, Jónas Broncks gøta 25. 3rd floor, Tórshavn, Faroe Islands.
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29
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Bellenger CR, Fuller JT, Thomson RL, Davison K, Robertson EY, Buckley JD. Monitoring Athletic Training Status Through Autonomic Heart Rate Regulation: A Systematic Review and Meta-Analysis. Sports Med 2017; 46:1461-86. [PMID: 26888648 DOI: 10.1007/s40279-016-0484-2] [Citation(s) in RCA: 164] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
BACKGROUND Autonomic regulation of heart rate (HR) as an indicator of the body's ability to adapt to an exercise stimulus has been evaluated in many studies through HR variability (HRV) and post-exercise HR recovery (HRR). Recently, HR acceleration has also been investigated. OBJECTIVE The aim of this systematic literature review and meta-analysis was to evaluate the effect of negative adaptations to endurance training (i.e., a period of overreaching leading to attenuated performance) and positive adaptations (i.e., training leading to improved performance) on autonomic HR regulation in endurance-trained athletes. METHODS We searched Ovid MEDLINE, Embase, CINAHL, SPORTDiscus, PubMed, and Academic Search Premier databases from inception until April 2015. Included articles examined the effects of endurance training leading to increased or decreased exercise performance on four measures of autonomic HR regulation: resting and post-exercise HRV [vagal-related indices of the root-mean-square difference of successive normal R-R intervals (RMSSD), high frequency power (HFP) and the standard deviation of instantaneous beat-to-beat R-R interval variability (SD1) only], and post-exercise HRR and HR acceleration. RESULTS Of the 5377 records retrieved, 27 studies were included in the systematic review and 24 studies were included in the meta-analysis. Studies inducing increases in performance showed small increases in resting RMSSD [standardised mean difference (SMD) = 0.58; P < 0.001], HFP (SMD = 0.55; P < 0.001) and SD1 (SMD = 0.23; P = 0.16), and moderate increases in post-exercise RMSSD (SMD = 0.60; P < 0.001), HFP (SMD = 0.90; P < 0.04), SD1 (SMD = 1.20; P = 0.04), and post-exercise HRR (SMD = 0.63; P = 0.002). A large increase in HR acceleration (SMD = 1.34) was found in the single study assessing this parameter. Studies inducing decreases in performance showed a small increase in resting RMSSD (SMD = 0.26; P = 0.01), but trivial changes in resting HFP (SMD = 0.04; P = 0.77) and SD1 (SMD = 0.04; P = 0.82). Post-exercise RMSSD (SMD = 0.64; P = 0.04) and HFP (SMD = 0.49; P = 0.18) were increased, as was HRR (SMD = 0.46; P < 0.001), while HR acceleration was decreased (SMD = -0.48; P < 0.001). CONCLUSIONS Increases in vagal-related indices of resting and post-exercise HRV, post-exercise HRR, and HR acceleration are evident when positive adaptation to training has occurred, allowing for increases in performance. However, increases in post-exercise HRV and HRR also occur in response to overreaching, demonstrating that additional measures of training tolerance may be required to determine whether training-induced changes in these parameters are related to positive or negative adaptations. Resting HRV is largely unaffected by overreaching, although this may be the result of methodological issues that warrant further investigation. HR acceleration appears to decrease in response to overreaching training, and thus may be a potential indicator of training-induced fatigue.
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Affiliation(s)
- Clint R Bellenger
- Alliance for Research in Exercise, Nutrition and Activity (ARENA), Sansom Institute for Health Research, University of South Australia, GPO Box 2471, Adelaide, SA, 5001, Australia.
| | - Joel T Fuller
- Alliance for Research in Exercise, Nutrition and Activity (ARENA), Sansom Institute for Health Research, University of South Australia, GPO Box 2471, Adelaide, SA, 5001, Australia
| | - Rebecca L Thomson
- Alliance for Research in Exercise, Nutrition and Activity (ARENA), Sansom Institute for Health Research, University of South Australia, GPO Box 2471, Adelaide, SA, 5001, Australia
| | - Kade Davison
- Alliance for Research in Exercise, Nutrition and Activity (ARENA), Sansom Institute for Health Research, University of South Australia, GPO Box 2471, Adelaide, SA, 5001, Australia
| | | | - Jonathan D Buckley
- Alliance for Research in Exercise, Nutrition and Activity (ARENA), Sansom Institute for Health Research, University of South Australia, GPO Box 2471, Adelaide, SA, 5001, Australia
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30
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Skovgaard C, Almquist NW, Bangsbo J. The effect of repeated periods of speed endurance training on performance, running economy, and muscle adaptations. Scand J Med Sci Sports 2017; 28:381-390. [DOI: 10.1111/sms.12916] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/12/2017] [Indexed: 12/30/2022]
Affiliation(s)
- C. Skovgaard
- Department of Nutrition; Exercise and Sports; Section of Integrated Physiology; University of Copenhagen; Copenhagen Denmark
- Team Danmark (Danish Elite Sports Organization); Copenhagen Denmark
| | - N. W. Almquist
- Department of Nutrition; Exercise and Sports; Section of Integrated Physiology; University of Copenhagen; Copenhagen Denmark
| | - J. Bangsbo
- Department of Nutrition; Exercise and Sports; Section of Integrated Physiology; University of Copenhagen; Copenhagen Denmark
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31
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McGawley K, Juudas E, Kazior Z, Ström K, Blomstrand E, Hansson O, Holmberg HC. No Additional Benefits of Block- Over Evenly-Distributed High-Intensity Interval Training within a Polarized Microcycle. Front Physiol 2017; 8:413. [PMID: 28659826 PMCID: PMC5468439 DOI: 10.3389/fphys.2017.00413] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 05/30/2017] [Indexed: 12/31/2022] Open
Abstract
Introduction: The current study aimed to investigate the responses to block- versus evenly-distributed high-intensity interval training (HIT) within a polarized microcycle. Methods: Twenty well-trained junior cross-country skiers (10 males, age 17.6 ± 1.5 and 10 females, age 17.3 ± 1.5) completed two, 3-week periods of training (EVEN and BLOCK) in a randomized, crossover-design study. In EVEN, 3 HIT sessions (5 × 4-min of diagonal-stride roller-skiing) were completed at a maximal sustainable intensity each week while low-intensity training (LIT) was distributed evenly around the HIT. In BLOCK, the same 9 HIT sessions were completed in the second week while only LIT was completed in the first and third weeks. Heart rate (HR), session ratings of perceived exertion (sRPE), and perceived recovery (pREC) were recorded for all HIT and LIT sessions, while distance covered was recorded for each HIT interval. The recovery-stress questionnaire for athletes (RESTQ-Sport) was completed weekly. Before and after EVEN and BLOCK, resting saliva and muscle samples were collected and an incremental test and 600-m time-trial (TT) were completed. Results: Pre- to post-testing revealed no significant differences between EVEN and BLOCK for changes in resting salivary cortisol, testosterone, or IgA, or for changes in muscle capillary density, fiber area, fiber composition, enzyme activity (CS, HAD, and PFK) or the protein content of VEGF or PGC-1α. Neither were any differences observed in the changes in skiing economy, V˙O2max or 600-m time-trial performance between interventions. These findings were coupled with no significant differences between EVEN and BLOCK for distance covered during HIT, summated HR zone scores, total sRPE training load, overall pREC or overall recovery-stress state. However, 600-m TT performance improved from pre- to post-training, irrespective of intervention (P = 0.003), and a number of hormonal and muscle biopsy markers were also significantly altered post-training (P < 0.05). Discussion: The current study shows that well-trained junior cross-country skiers are able to complete 9 HIT sessions within 1 week without compromising total work done and without experiencing greater stress or reduced recovery over a 3-week polarized microcycle. However, the findings do not support block-distributed HIT as a superior method to a more even distribution of HIT in terms of enhancing physiological or performance adaptions.
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Affiliation(s)
- Kerry McGawley
- Department of Health Sciences, Swedish Winter Sports Research Centre, Mid Sweden UniversityÖstersund, Sweden
| | - Elisabeth Juudas
- Department of Health Sciences, Swedish Winter Sports Research Centre, Mid Sweden UniversityÖstersund, Sweden
| | - Zuzanna Kazior
- Department of Health Sciences, Swedish Winter Sports Research Centre, Mid Sweden UniversityÖstersund, Sweden.,Åstrand Laboratory, Swedish School of Sport and Health SciencesStockholm, Sweden
| | - Kristoffer Ström
- Department of Health Sciences, Swedish Winter Sports Research Centre, Mid Sweden UniversityÖstersund, Sweden.,Diabetes and Endocrinology, Department of Clinical Sciences, Lund University Diabetes Centre, Lund UniversityMalmö, Sweden
| | - Eva Blomstrand
- Åstrand Laboratory, Swedish School of Sport and Health SciencesStockholm, Sweden
| | - Ola Hansson
- Diabetes and Endocrinology, Department of Clinical Sciences, Lund University Diabetes Centre, Lund UniversityMalmö, Sweden
| | - Hans-Christer Holmberg
- Department of Health Sciences, Swedish Winter Sports Research Centre, Mid Sweden UniversityÖstersund, Sweden
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32
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McGinley C, Bishop DJ. Rest interval duration does not influence adaptations in acid/base transport proteins following 10 wk of sprint-interval training in active women. Am J Physiol Regul Integr Comp Physiol 2017; 312:R702-R717. [DOI: 10.1152/ajpregu.00459.2016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 01/17/2017] [Accepted: 01/30/2017] [Indexed: 12/21/2022]
Abstract
The removal of protons (H+) produced during intense exercise is important for skeletal muscle function, yet it remains unclear how best to structure exercise training to improve muscle pH regulation. We investigated whether 4 wk of work-matched sprint-interval trining (SIT), performed 3 days/wk, with either 1 ( Rest-1; n = 7) or 5 ( Rest-5; n = 7) min of rest between sprints, influenced adaptations in acid/base transport protein content, nonbicarbonate muscle buffer capacity (βmin vitro), and exercise capacity in active women. Following 1 wk of posttesting, comprising a biopsy, a repeated-sprint ability (RSA) test, and a graded-exercise test, maintenance of adaptations was then studied by reducing SIT volume to 1 day/wk for a further 5 wk. After 4 wk of SIT, there was increased protein abundance of monocarboxylate transporter (MCT)-1, sodium/hydrogen exchanger (NHE)-1, and carbonic anhydrase (CA) XIV for both groups, but rest interval duration did not influence the adaptive response. In contrast, greater improvements in total work performed during the RSA test after 4 wk of SIT were evident for Rest-5 compared with Rest-1 (effect size: 0.51; 90% confidence limits ±0.37), whereas both groups had similarly modest improvements in V̇o2peak. When training volume was reduced to 1 day/wk, enhanced acid/base transport protein abundance was maintained, although NHE1 content increased further for Rest-5 only. Finally, our data support intracellular lactate as a signaling molecule for inducing MCT1 expression, but neither lactate nor H+ accumulation appears to be important signaling factors in MCT4 regulation.
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Affiliation(s)
- Cian McGinley
- College of Sport and Exercise Science, Victoria University, Melbourne, Victoria, Australia
- Sportscotland Institute of Sport, Stirling, Scotland
| | - David J. Bishop
- College of Sport and Exercise Science, Victoria University, Melbourne, Victoria, Australia
- Institute of Sport, Exercise, and Active Living, Victoria University, Melbourne, Victoria, Australia; and
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33
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Skovgaard C, Almquist NW, Bangsbo J. Effect of increased and maintained frequency of speed endurance training on performance and muscle adaptations in runners. J Appl Physiol (1985) 2017; 122:48-59. [DOI: 10.1152/japplphysiol.00537.2016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 10/05/2016] [Accepted: 11/07/2016] [Indexed: 01/04/2023] Open
Abstract
The aim of the study was, in runners accustomed to speed endurance training (SET), to examine the effect of increased and maintained frequency of SET on performance and muscular adaptations. After familiarization (FAM) to SET, 18 male ( n = 14) and female ( n = 4) runners (V̇o2max: 57.3 ± 3.4 ml/min; means ± SD) completed 20 sessions of maintained low-frequency (LF; every fourth day; n = 7) or high-frequency (HF; every second day; n = 11) SET. Before FAM as well as before and after an intervention period (INT), subjects completed a series of running tests and a biopsy from m. vastus lateralis was collected. Ten-kilometer performance improved ( P < 0.05) ~3.5% during FAM with no further change during INT. Time to exhaustion at 90% vV̇o2max was 15 and 22% longer ( P < 0.05) during FAM and a further 12 and 16% longer ( P < 0.05) during INT in HF and LF, respectively. During FAM, muscle expression of NHE1 and maximal activity of citrate synthase (CS) and phosphofructokinase (PFK) increased ( P < 0.05), running economy (RE) improved ( P < 0.05), and V̇o2max was unchanged. During INT, both HF and LF increased ( P < 0.05) muscle expression of NKAβ1, whereas maximal activity of CS and PFK, RE, and V̇o2max were unchanged. Furthermore, during INT, muscle expression of FXYD1 and SERCA1, and FXYD1 activity increased ( P < 0.05) in HF, while muscle expression of SERCA2 decreased ( P < 0.05) in LF. Thus increased or maintained frequency of SET leads to further improvements in short-term exercise capacity, but not in 10-km running performance. The better short-term exercise capacity may be associated with elevated expression of muscle proteins related to Na+/K+ transportation and Ca2+ reuptake. NEW & NOTEWORTHY Ten speed endurance training (SET) sessions improved short-term exercise capacity and 10-km performance, which was followed by further improved short-term exercise capacity, but unchanged 10-km performance after 20 SET sessions performed with either high frequency (4 per 8 days) or continued low frequency (2 per 8 days) in trained runners. The further gain in short-term exercise capacity was associated with changes in muscle expression of proteins of importance for the development of fatigue.
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Affiliation(s)
- Casper Skovgaard
- Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Copenhagen, Denmark; and
- Team Danmark (Danish Elite Sports Organization), Copenhagen, Denmark
| | - Nicki Winfield Almquist
- Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Copenhagen, Denmark; and
| | - Jens Bangsbo
- Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Copenhagen, Denmark; and
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Purkhús E, Krustrup P, Mohr M. High-Intensity Training Improves Exercise Performance in Elite Women Volleyball Players During a Competitive Season. J Strength Cond Res 2016; 30:3066-3072. [PMID: 26950353 DOI: 10.1519/jsc.0000000000001408] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Purkhús, E, Krustrup, P, and Mohr, M. High-intensity training improves exercise performance in elite women volleyball players during a competitive season. J Strength Cond Res 30(11): 3066-3072, 2016-Elite women volleyball players (n = 25; mean ± SD: age, 19 ± 5 years; height, 171 ± 7 cm; weight, 63 ± 10 kg) volunteered to participate in the study. They were randomized into a high-intensity training (HIT; n = 13) group and a control (CON; n = 12) group. In addition to the normal team training and games, HIT performed 6-10 × 30-seconds all-out running intervals separated by 3-minute recovery periods 3 times per week during a 4-week in-season period whereas CON only completed the team training sessions and games. Preintervention and postintervention, all players completed the arrowhead agility test (AAT), a repeated sprint test (RST; 5 × 30 meters separated by 25 seconds of recovery), and the Yo-Yo Intermittent Recovery level 2 test (Yo-Yo IR2) followed by a-10 minute rest period and the Yo-Yo IR1 test. Mean running distance during HIT in week 1 was 152 ± 4 m and increased (p ≤ 0.05) by 4.6% (159 ± 3 m) in week 4. The AAT performance improved (p ≤ 0.05) by 2.3% (18.87 ± 0.97-18.44 ± 1.06 seconds) and RST by 4.3% postintervention in the HIT group only. Baseline RST fatigue index was 7.0 ± 2.9 and 6.2 ± 5.0% in HIT and CON, respectively, but was lowered (p ≤ 0.05) to 2.7 ± 3.0% posttraining in HIT and remained unaltered in CON (5.5 ± 5.0%). In HIT, Yo-Yo IR2 and Yo-Yo IR1 performance improved by 12.6 and 18.3% postintervention, respectively, with greater (p ≤ 0.05) Yo-yo IR1 change scores than in CON. In conclusion, additional high-intensity in-season training performed as interval running improved agility, repeated sprint ability, and high-intensity intermittent exercise performance in elite women volleyball players.
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Affiliation(s)
- Elisabeth Purkhús
- 1Department of Nutrition, Exercise and Sports, Section of Human Physiology, Copenhagen Centre for Team Sport and Health, University of Copenhagen, Copenhagen, Denmark; 2Faculty of Natural and Health Sciences, University of the Faroe Islands, Tórshavn, Faroe Islands; 3Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom; and 4Department of Food and Nutrition, and Sport Science, Center of Health and Human Performance, University of Gothenburg, Gothenburg, Sweden
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McGinley C, Bishop DJ. Influence of training intensity on adaptations in acid/base transport proteins, muscle buffer capacity, and repeated-sprint ability in active men. J Appl Physiol (1985) 2016; 121:1290-1305. [DOI: 10.1152/japplphysiol.00630.2016] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 10/03/2016] [Accepted: 10/06/2016] [Indexed: 11/22/2022] Open
Abstract
McGinley C, Bishop DJ. Influence of training intensity on adaptations in acid/base transport proteins, muscle buffer capacity, and repeated-sprint ability in active men. J Appl Physiol 121: 1290–1305, 2016. First published October 14, 2016; doi: 10.1152/japplphysiol.00630.2016 .—This study measured the adaptive response to exercise training for each of the acid-base transport protein families, including providing isoform-specific evidence for the monocarboxylate transporter (MCT)1/4 chaperone protein basigin and for the electrogenic sodium-bicarbonate cotransporter (NBCe)1. We investigated whether 4 wk of work-matched, high-intensity interval training (HIIT), performed either just above the lactate threshold (HIITΔ20; n = 8), or close to peak aerobic power (HIITΔ90; n = 8), influenced adaptations in acid-base transport protein abundance, nonbicarbonate muscle buffer capacity (βmin vitro), and exercise capacity in active men. Training intensity did not discriminate between adaptations for most proteins measured, with abundance of MCT1, sodium/hydrogen exchanger (NHE) 1, NBCe1, carbonic anhydrase (CA) II, and CAXIV increasing after 4 wk, whereas there was little change in CAIII and CAIV abundance. βmin vitro also did not change. However, MCT4 protein content only increased for HIITΔ20 [effect size (ES): 1.06, 90% confidence limits × / ÷ 0.77], whereas basigin protein content only increased for HIITΔ90 (ES: 1.49, × / ÷ 1.42). Repeated-sprint ability (5 × 6-s sprints; 24 s passive rest) improved similarly for both groups. Power at the lactate threshold only improved for HIITΔ20 (ES: 0.49; 90% confidence limits ± 0.38), whereas peak O2 uptake did not change for either group. Detraining was characterized by the loss of adaptations for all of the proteins measured and for repeated-sprint ability 6 wk after removing the stimulus of HIIT. In conclusion, 4 wk of HIIT induced improvements in each of the acid-base transport protein families, but, remarkably, a 40% difference in training intensity did not discriminate between most adaptations.
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Affiliation(s)
- Cian McGinley
- College of Sport and Exercise Science, Victoria University, Melbourne, Victoria, Australia; and
| | - David J. Bishop
- College of Sport and Exercise Science, Victoria University, Melbourne, Victoria, Australia; and
- Institute of Sport, Exercise and Active Living (ISEAL), Victoria University, Melbourne, Victoria, Australia
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McGinley C, Bishop DJ. Distinct protein and mRNA kinetics of skeletal muscle proton transporters following exercise can influence interpretation of adaptations to training. Exp Physiol 2016; 101:1565-1580. [DOI: 10.1113/ep085921] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 09/27/2016] [Indexed: 01/19/2023]
Affiliation(s)
- Cian McGinley
- College of Sport and Exercise Science; Victoria University; Melbourne Victoria Australia
| | - David J. Bishop
- College of Sport and Exercise Science; Victoria University; Melbourne Victoria Australia
- Institute of Sport; Exercise and Active Living (ISEAL); Victoria University; Melbourne Victoria Australia
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Hostrup M, Bangsbo J. Limitations in intense exercise performance of athletes - effect of speed endurance training on ion handling and fatigue development. J Physiol 2016; 595:2897-2913. [PMID: 27673449 DOI: 10.1113/jp273218] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 09/21/2016] [Indexed: 01/10/2023] Open
Abstract
Mechanisms underlying fatigue development and limitations for performance during intense exercise have been intensively studied during the past couple of decades. Fatigue development may involve several interacting factors and depends on type of exercise undertaken and training level of the individual. Intense exercise (½-6 min) causes major ionic perturbations (Ca2+ , Cl- , H+ , K+ , lactate- and Na+ ) that may reduce sarcolemmal excitability, Ca2+ release and force production of skeletal muscle. Maintenance of ion homeostasis is thus essential to sustain force production and power output during intense exercise. Regular speed endurance training (SET), i.e. exercise performed at intensities above that corresponding to maximum oxygen consumption (V̇O2, max ), enhances intense exercise performance. However, most of the studies that have provided mechanistic insight into the beneficial effects of SET have been conducted in untrained and recreationally active individuals, making extrapolation towards athletes' performance difficult. Nevertheless, recent studies indicate that only a few weeks of SET enhances intense exercise performance in highly trained individuals. In these studies, the enhanced performance was not associated with changes in V̇O2, max and muscle oxidative capacity, but rather with adaptations in muscle ion handling, including lowered interstitial concentrations of K+ during and in recovery from intense exercise, improved lactate- -H+ transport and H+ regulation, and enhanced Ca2+ release function. The purpose of this Topical Review is to provide an overview of the effect of SET and to discuss potential mechanisms underlying enhancements in performance induced by SET in already well-trained individuals with special emphasis on ion handling in skeletal muscle.
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Affiliation(s)
- Morten Hostrup
- Section of Integrated Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark.,Department of Respiratory Research, Bispebjerg University Hospital, Denmark
| | - Jens Bangsbo
- Section of Integrated Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark
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Skovgaard C, Brandt N, Pilegaard H, Bangsbo J. Combined speed endurance and endurance exercise amplify the exercise-induced PGC-1α and PDK4 mRNA response in trained human muscle. Physiol Rep 2016; 4:4/14/e12864. [PMID: 27456910 PMCID: PMC4962071 DOI: 10.14814/phy2.12864] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 06/07/2016] [Indexed: 11/24/2022] Open
Abstract
The aim of this study was to investigate the mRNA response related to mitochondrial biogenesis, metabolism, angiogenesis, and myogenesis in trained human skeletal muscle to speed endurance exercise (S), endurance exercise (E), and speed endurance followed by endurance exercise (S + E). Seventeen trained male subjects (maximum oxygen uptake (VO2-max): 57.2 ± 3.7 (mean ± SD) mL·min(-1)·kg(-1)) performed S (6 × 30 sec all-out), E (60 min ~60% VO2-max), and S + E on a cycle ergometer on separate occasions. Muscle biopsies were obtained at rest and 1, 2, and 3 h after the speed endurance exercise (S and S + E) and at rest, 0, 1, and 2 h after exercise in E In S and S + E, muscle peroxisome proliferator-activated receptor-γ coactivator-1 (PGC-1α) and pyruvate dehydrogenase kinase-4 (PDK4) mRNA were higher (P < 0.05) 2 and 3 h after speed endurance exercise than at rest. Muscle PGC-1α and PDK4 mRNA levels were higher (P < 0.05) after exercise in S + E than in S and E, and higher (P < 0.05) in S than in E after exercise. In S and S + E, muscle vascular endothelial growth factor mRNA was higher (P < 0.05) 1 (S only), 2 and 3 h after speed endurance exercise than at rest. In S + E, muscle regulatory factor-4 and muscle heme oxygenase-1 mRNA were higher (P < 0.05) 1, 2, and 3 h after speed endurance exercise than at rest. In S, muscle hexokinase II mRNA was higher (P < 0.05) 2 and 3 h after speed endurance exercise than at rest and higher (P < 0.05) than in E after exercise. These findings suggest that in trained subjects, speed endurance exercise provides a stimulus for muscle mitochondrial biogenesis, substrate regulation, and angiogenesis that is not evident with endurance exercise. These responses are reinforced when speed endurance exercise is followed by endurance exercise.
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Affiliation(s)
- Casper Skovgaard
- Section of Integrated Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark Team Danmark (Danish elite sports institution), Copenhagen, Denmark
| | - Nina Brandt
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | | | - Jens Bangsbo
- Section of Integrated Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
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Effect of speed endurance and strength training on performance, running economy and muscular adaptations in endurance-trained runners. Eur J Appl Physiol 2016; 116:1331-41. [DOI: 10.1007/s00421-016-3356-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 03/10/2016] [Indexed: 10/21/2022]
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Thomassen M, Gunnarsson TP, Christensen PM, Pavlovic D, Shattock MJ, Bangsbo J. Intensive training and reduced volume increases muscle FXYD1 expression and phosphorylation at rest and during exercise in athletes. Am J Physiol Regul Integr Comp Physiol 2016; 310:R659-69. [PMID: 26791827 DOI: 10.1152/ajpregu.00081.2015] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 01/18/2016] [Indexed: 01/10/2023]
Abstract
The present study examined the effect of intensive training in combination with marked reduction in training volume on phospholemman (FXYD1) expression and phosphorylation at rest and during exercise. Eight well-trained cyclists replaced their regular training with speed-endurance training (10-12 × ∼30-s sprints) two or three times per week and aerobic high-intensity training (4-5 × 3-4 min at 90-95% of peak aerobic power output) 1-2 times per week for 7 wk and reduced the training volume by 70%. Muscle biopsies were obtained before and during a repeated high-intensity exercise protocol, and protein expression and phosphorylation were determined by Western blot analysis. Expression of FXYD1 (30%), actin (40%), mammalian target of rapamycin (mTOR) (12%), phospholamban (PLN) (16%), and Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) γ/δ (25%) was higher (P < 0.05) than before the training intervention. In addition, after the intervention, nonspecific FXYD1 phosphorylation was higher (P < 0.05) at rest and during exercise, mainly achieved by an increased FXYD1 Ser-68 phosphorylation, compared with before the intervention. CaMKII, Thr-287, and eukaryotic elongation factor 2 Thr-56 phosphorylation at rest and during exercise, overall PKCα/β, Thr-638/641, and mTOR Ser-2448 phosphorylation during repeated intense exercise as well as resting PLN Thr-17 phosphorylation were also higher (P < 0.05) compared with before the intervention period. Thus, a period of high-intensity training with reduced training volume increases expression and phosphorylation levels of FXYD1, which may affect Na(+)/K(+) pump activity and muscle K(+) homeostasis during intense exercise. Furthermore, higher expression of CaMKII and PLN, as well as increased phosphorylation of CaMKII Thr-287 may have improved intracellular Ca(2+) handling.
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Affiliation(s)
- Martin Thomassen
- Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Copenhagen, Denmark; and
| | - Thomas P Gunnarsson
- Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Copenhagen, Denmark; and
| | - Peter M Christensen
- Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Copenhagen, Denmark; and
| | - Davor Pavlovic
- Cardiovascular Division, King's College London, The Rayne Institute, St. Thomas' Hospital, London, United Kingdom
| | - Michael J Shattock
- Cardiovascular Division, King's College London, The Rayne Institute, St. Thomas' Hospital, London, United Kingdom
| | - Jens Bangsbo
- Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Copenhagen, Denmark; and
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Christensen PM, Gunnarsson TP, Thomassen M, Wilkerson DP, Nielsen JJ, Bangsbo J. Unchanged content of oxidative enzymes in fast-twitch muscle fibers and V˙O2 kinetics after intensified training in trained cyclists. Physiol Rep 2015; 3:3/7/e12428. [PMID: 26152692 PMCID: PMC4552518 DOI: 10.14814/phy2.12428] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
The present study examined if high intensity training (HIT) could increase the expression of oxidative enzymes in fast-twitch muscle fibers causing a faster oxygen uptake () response during intense (INT), but not moderate (MOD), exercise and reduce the slow component and muscle metabolic perturbation during INT. Pulmonary kinetics was determined in eight trained male cyclists (-max: 59 ± 4 (means ± SD) mL min−1 kg−1) during MOD (205 ± 12 W ∼65% -max) and INT (286 ± 17 W ∼85% -max) exercise before and after a 7-week HIT period (30-sec sprints and 4-min intervals) with a 50% reduction in volume. Both before and after HIT the content in fast-twitch fibers of CS (P < 0.05) and COX-4 (P < 0.01) was lower, whereas PFK was higher (P < 0.001) than in slow-twitch fibers. Content of CS, COX-4, and PFK in homogenate and fast-twitch fibers was unchanged with HIT. Maximal activity (μmol g DW−1 min−1) of CS (56 ± 8 post-HIT vs. 59 ± 10 pre-HIT), HAD (27 ± 6 vs. 29 ± 3) and PFK (340 ± 69 vs. 318 ± 105) and the capillary to fiber ratio (2.30 ± 0.16 vs. 2.38 ± 0.20) was unaltered following HIT. kinetics was unchanged with HIT and the speed of the primary response did not differ between MOD and INT. Muscle creatine phosphate was lower (42 ± 15 vs. 66 ± 17 mmol kg DW−1) and muscle lactate was higher (40 ± 18 vs. 14 ± 5 mmol kg DW−1) at 6 min of INT (P < 0.05) after compared to before HIT. A period of intensified training with a volume reduction did not increase the content of oxidative enzymes in fast-twitch fibers, and did not change kinetics.
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Affiliation(s)
- Peter M Christensen
- Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Copenhagen, Denmark Team Danmark (Danish Elite Sport Organization), Copenhagen, Denmark
| | - Thomas P Gunnarsson
- Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Martin Thomassen
- Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Daryl P Wilkerson
- Sport and Health Sciences, St Luke's Campus University of Exeter, Exeter, UK
| | - Jens Jung Nielsen
- Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Jens Bangsbo
- Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Copenhagen, Denmark
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Skovgaard C, Christensen PM, Larsen S, Andersen TR, Thomassen M, Bangsbo J. Concurrent speed endurance and resistance training improves performance, running economy, and muscle NHE1 in moderately trained runners. J Appl Physiol (1985) 2014; 117:1097-109. [PMID: 25190744 DOI: 10.1152/japplphysiol.01226.2013] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The purpose of this study was to examine whether speed endurance training (SET, repeated 30-s sprints) and heavy resistance training (HRT, 80-90% of 1 repetition maximum) performed in succession are compatible and lead to performance improvements in moderately trained endurance runners. For an 8-wk intervention period (INT) 23 male runners [maximum oxygen uptake (V̇O(2max)) 59 ± 1 ml·min(-1)·kg(-1); values are means ± SE] either maintained their training (CON, n = 11) or performed high-intensity concurrent training (HICT, n = 12) consisting of two weekly sessions of SET followed by HRT and two weekly sessions of aerobic training with an average reduction in running distance of 42%. After 4 wk of HICT, performance was improved (P < 0.05) in a 10-km run (42:30 ± 1:07 vs. 44:11 ± 1:08 min:s) with no further improvement during the last 4 wk. Performance in a 1,500-m run (5:10 ± 0:05 vs. 5:27 ± 0:08 min:s) and in the Yo-Yo IR2 test (706 ± 97 vs. 491 ± 65 m) improved (P < 0.001) only following 8 wk of INT. In HICT, running economy (189 ± 4 vs. 195 ± 4 ml·kg(-1)·km(-1)), muscle content of NHE1 (35%) and dynamic muscle strength was augmented (P < 0.01) after compared with before INT, whereas V̇O(2max), muscle morphology, capillarization, content of muscle Na(+)/K(+) pump subunits, and MCT4 were unaltered. No changes were observed in CON. The present study demonstrates that SET and HRT, when performed in succession, lead to improvements in both short- and long-term running performance together with improved running economy as well as increased dynamic muscle strength and capacity for muscular H(+) transport in moderately trained endurance runners.
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Affiliation(s)
- Casper Skovgaard
- Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Copenhagen, Denmark; and Team Danmark (Danish Elite Sport Organization), Copenhagen, Denmark
| | - Peter M Christensen
- Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Copenhagen, Denmark; and Team Danmark (Danish Elite Sport Organization), Copenhagen, Denmark
| | - Sonni Larsen
- Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Copenhagen, Denmark; and
| | - Thomas Rostgaard Andersen
- Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Copenhagen, Denmark; and
| | - Martin Thomassen
- Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Copenhagen, Denmark; and
| | - Jens Bangsbo
- Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Copenhagen, Denmark; and
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Kilen A, Larsson TH, Jørgensen M, Johansen L, Jørgensen S, Nordsborg NB. Effects of 12 weeks high-intensity & reduced-volume training in elite athletes. PLoS One 2014; 9:e95025. [PMID: 24736598 PMCID: PMC3988165 DOI: 10.1371/journal.pone.0095025] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Accepted: 03/22/2014] [Indexed: 11/18/2022] Open
Abstract
It was investigated if high-intensity interval training (HIT) at the expense of total training volume improves performance, maximal oxygen uptake and swimming economy. 41 elite swimmers were randomly allocated to a control (CON) or HIT group. For 12 weeks both groups trained ∼12 h per week. HIT comprised ∼5 h vs. 1 h and total distance was ∼17 km vs. 35 km per week for HIT and CON, respectively. HIT was performed as 6-10×10-30 s maximal effort interspersed by 2–4 minutes of rest. Performance of 100 m all-out freestyle and 200 m freestyle was similar before and after the intervention in both HIT (60.4±4.0 vs. 60.3±4.0 s; n = 13 and 133.2±6.4 vs. 132.6±7.7 s; n = 14) and CON (60.2±3.7 vs. 60.6±3.8 s; n = 15 and 133.5±7.0 vs. 133.3±7.6 s; n = 15). Maximal oxygen uptake during swimming was similar before and after the intervention in both the HIT (4.0±0.9 vs. 3.8±1.0 l O2×min−1; n = 14) and CON (3.8±0.7 vs. 3.8±0.7 l O2×min−1; n = 11) group. Oxygen uptake determined at fixed submaximal speed was not significantly affected in either group by the intervention. Body fat % tended to increase (P = 0.09) in the HIT group (15.4±1.6% vs. 16.3±1.6%; P = 0.09; n = 16) and increased (P<0.05) in the CON group (13.9±1.5% vs. 14.9±1.5%; n = 17). A distance reduction of 50% and a more than doubled HIT amount for 12 weeks did neither improve nor compromise performance or physiological capacity in elite swimmers.
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Affiliation(s)
- Anders Kilen
- Department of Nutrition, Exercise and Sport, University of Copenhagen, Copenhagen, Denmark
| | | | - Majke Jørgensen
- Department of Nutrition, Exercise and Sport, University of Copenhagen, Copenhagen, Denmark
| | | | | | - Nikolai B Nordsborg
- Department of Nutrition, Exercise and Sport, University of Copenhagen, Copenhagen, Denmark
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