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Pashayee-Khamene F, Heidari Z, Asbaghi O, Ashtary-Larky D, Goudarzi K, Forbes SC, Candow DG, Bagheri R, Ghanavati M, Dutheil F. Creatine supplementation protocols with or without training interventions on body composition: a GRADE-assessed systematic review and dose-response meta-analysis. J Int Soc Sports Nutr 2024; 21:2380058. [PMID: 39042054 PMCID: PMC11268231 DOI: 10.1080/15502783.2024.2380058] [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: 02/06/2024] [Accepted: 07/02/2024] [Indexed: 07/24/2024] Open
Abstract
BACKGROUND Despite the robust evidence demonstrating positive effects from creatine supplementation (primarily when associated with resistance training) on measures of body composition, there is a lack of a comprehensive evaluation regarding the influence of creatine protocol parameters (including dose and form) on body mass and estimates of fat-free and fat mass. METHODS Randomized controlled trials (RCTs) evaluating the effect of creatine supplementation on body composition were included. Electronic databases, including PubMed, Web of Science, and Scopus were searched up to July 2023. Heterogeneity tests were performed. Random effect models were assessed based on the heterogeneity tests, and pooled data were examined to determine the weighted mean difference (WMD) with a 95% confidence interval (CI). RESULTS From 4831 initial records, a total of 143 studies met the inclusion criteria. Creatine supplementation increased body mass (WMD: 0.86 kg; 95% CI: 0.76 to 0.96, I2 = 0%) and fat-free mass (WMD: 0.82 kg; 95% CI: 0.57 to 1.06, I2 = 0%) while reducing body fat percentage (WMD: -0.28 %; 95% CI: -0.47 to -0.09; I2 = 0%). Studies that incorporated a maintenance dose of creatine or performed resistance training in conjunction with supplementation had greater effects on body composition. CONCLUSION Creatine supplementation has a small effect on body mass and estimates of fat-free mass and body fat percentage. These findings were more robust when combined with resistance training.
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Affiliation(s)
| | - Zeinab Heidari
- Ahvaz Jundishapur University of Medical Sciences, Student research committee, Ahvaz, Iran
| | - Omid Asbaghi
- Shahid Beheshti University of Medical Sciences, Cancer Research Center, Tehran, Iran
| | - Damoon Ashtary-Larky
- Ahvaz Jundishapur University of Medical Sciences, Nutrition and Metabolic Diseases Research Center, Ahvaz, Iran
| | - Kian Goudarzi
- Shahid Beheshti University of Medical Sciences, Faculty of Medicine, Tehran, Iran
| | - Scott C Forbes
- Brandon University, Department of Physical Education Studies, Brandon, MB, Canada
| | - Darren G. Candow
- University of Regina, Faculty of Kinesiology and Health Studies, Regina, SK, Canada
| | - Reza Bagheri
- University of Isfahan, Department of Exercise Physiology, Isfahan, Iran
| | - Matin Ghanavati
- Shahid Beheshti University of Medical Sciences, National Nutrition and Food Technology Research Institute, (Faculty of Nutrition Science and Food Technology), Tehran, Iran
| | - Fred Dutheil
- University Hospital of Clermont–Ferrand, Université Clermont Auvergne, CNRS, LaPSCo, Physiological and Psychosocial Stress, CHU Clermont–Ferrand, Occupational and Environmental Medicine, Clermont–Ferrand, France
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Nutritional Ergogenic Aids in Combat Sports: A Systematic Review and Meta-Analysis. Nutrients 2022; 14:nu14132588. [PMID: 35807770 PMCID: PMC9268044 DOI: 10.3390/nu14132588] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Revised: 06/16/2022] [Accepted: 06/21/2022] [Indexed: 01/21/2023] Open
Abstract
Nutritional ergogenic aids (NEAs) are substances included within the group of sports supplements. Although they are widely consumed by athletes, evidence-based analysis is required to support training outcomes or competitive performance in specific disciplines. Combat sports have a predominant use of anaerobic metabolism as a source of energy, reaching peak exertion or sustained effort for very short periods of time. In this context, the use of certain NEAs could help athletes to improve their performance in those specific combat skills (i.e., the number of attacks, throws and hits; jump height; and grip strength, among others) as well as in general physical aspects (time to exhaustion [TTE], power, fatigue perception, heart rate, use of anaerobic metabolism, etc.). Medline/PubMed, Scopus and EBSCO were searched from their inception to May 2022 for randomised controlled trials (RCTs). Out of 677 articles found, 55 met the predefined inclusion criteria. Among all the studied NEAs, caffeine (5–10 mg/kg) showed strong evidence for its use in combat sports to enhance the use of glycolytic pathways for energy production during high-intensity actions due to a greater production of and tolerance to blood lactate levels. In this regard, abilities including the number of attacks, reaction time, handgrip strength, power and TTE, among others, were improved. Buffering supplements such as sodium bicarbonate, sodium citrate and beta-alanine may have a promising role in high and intermittent exertion during combat, but more studies are needed in grappling combat sports to confirm their efficacy during sustained isometric exertion. Other NEAs, including creatine, beetroot juice or glycerol, need further investigation to strengthen the evidence for performance enhancement in combat sports. Caffeine is the only NEA that has shown strong evidence for performance enhancement in combat sports.
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Wax B, Kerksick CM, Jagim AR, Mayo JJ, Lyons BC, Kreider RB. Creatine for Exercise and Sports Performance, with Recovery Considerations for Healthy Populations. Nutrients 2021; 13:1915. [PMID: 34199588 PMCID: PMC8228369 DOI: 10.3390/nu13061915] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 05/27/2021] [Accepted: 05/30/2021] [Indexed: 02/06/2023] Open
Abstract
Creatine is one of the most studied and popular ergogenic aids for athletes and recreational weightlifters seeking to improve sport and exercise performance, augment exercise training adaptations, and mitigate recovery time. Studies consistently reveal that creatine supplementation exerts positive ergogenic effects on single and multiple bouts of short-duration, high-intensity exercise activities, in addition to potentiating exercise training adaptations. In this respect, supplementation consistently demonstrates the ability to enlarge the pool of intracellular creatine, leading to an amplification of the cell's ability to resynthesize adenosine triphosphate. This intracellular expansion is associated with several performance outcomes, including increases in maximal strength (low-speed strength), maximal work output, power production (high-speed strength), sprint performance, and fat-free mass. Additionally, creatine supplementation may speed up recovery time between bouts of intense exercise by mitigating muscle damage and promoting the faster recovery of lost force-production potential. Conversely, contradictory findings exist in the literature regarding the potential ergogenic benefits of creatine during intermittent and continuous endurance-type exercise, as well as in those athletic tasks where an increase in body mass may hinder enhanced performance. The purpose of this review was to summarize the existing literature surrounding the efficacy of creatine supplementation on exercise and sports performance, along with recovery factors in healthy populations.
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Affiliation(s)
- Benjamin Wax
- Applied Physiology Laboratory, Department of Kinesiology, Mississippi State University, Mississippi State, MS 39759, USA
| | - Chad M. Kerksick
- Exercise & Performance Nutrition Laboratory, College of Science, Technology, and Health, Lindenwood University, St. Charles, MO 63301, USA
| | - Andrew R. Jagim
- Sports Medicine, Mayo Clinic Health System, La Crosse, WI 54601, USA;
| | - Jerry J. Mayo
- Department of Nutrition and Family Sciences, University of Central Arkansas, Conway, AR 72035, USA;
| | - Brian C. Lyons
- Health, Kinesiology, and Sport Management Department, University of Wisconsin—Parkside, Kenosha, WI 53141, USA;
| | - Richard B. Kreider
- Exercise & Sport Nutrition Lab, Human Clinical Research Facility, Department of Health & Kinesiology, Texas A&M University, College Station, TX 77843, USA;
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Bonilla DA, Kreider RB, Stout JR, Forero DA, Kerksick CM, Roberts MD, Rawson ES. Metabolic Basis of Creatine in Health and Disease: A Bioinformatics-Assisted Review. Nutrients 2021; 13:nu13041238. [PMID: 33918657 PMCID: PMC8070484 DOI: 10.3390/nu13041238] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 04/01/2021] [Accepted: 04/07/2021] [Indexed: 02/06/2023] Open
Abstract
Creatine (Cr) is a ubiquitous molecule that is synthesized mainly in the liver, kidneys, and pancreas. Most of the Cr pool is found in tissues with high-energy demands. Cr enters target cells through a specific symporter called Na+/Cl−-dependent Cr transporter (CRT). Once within cells, creatine kinase (CK) catalyzes the reversible transphosphorylation reaction between [Mg2+:ATP4−]2− and Cr to produce phosphocreatine (PCr) and [Mg2+:ADP3−]−. We aimed to perform a comprehensive and bioinformatics-assisted review of the most recent research findings regarding Cr metabolism. Specifically, several public databases, repositories, and bioinformatics tools were utilized for this endeavor. Topics of biological complexity ranging from structural biology to cellular dynamics were addressed herein. In this sense, we sought to address certain pre-specified questions including: (i) What happens when creatine is transported into cells? (ii) How is the CK/PCr system involved in cellular bioenergetics? (iii) How is the CK/PCr system compartmentalized throughout the cell? (iv) What is the role of creatine amongst different tissues? and (v) What is the basis of creatine transport? Under the cellular allostasis paradigm, the CK/PCr system is physiologically essential for life (cell survival, growth, proliferation, differentiation, and migration/motility) by providing an evolutionary advantage for rapid, local, and temporal support of energy- and mechanical-dependent processes. Thus, we suggest the CK/PCr system acts as a dynamic biosensor based on chemo-mechanical energy transduction, which might explain why dysregulation in Cr metabolism contributes to a wide range of diseases besides the mitigating effect that Cr supplementation may have in some of these disease states.
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Affiliation(s)
- Diego A. Bonilla
- Research Division, Dynamical Business & Science Society–DBSS International SAS, Bogotá 110861, Colombia
- Research Group in Biochemistry and Molecular Biology, Universidad Distrital Francisco José de Caldas, Bogotá 110311, Colombia
- Research Group in Physical Activity, Sports and Health Sciences (GICAFS), Universidad de Córdoba, Montería 230002, Colombia
- kDNA Genomics, Joxe Mari Korta Research Center, University of the Basque Country UPV/EHU, 20018 Donostia-San Sebastián, Spain
- Correspondence: ; Tel.: +57-320-335-2050
| | - Richard B. Kreider
- Exercise & Sport Nutrition Laboratory, Human Clinical Research Facility, Texas A&M University, College Station, TX 77843, USA;
| | - Jeffrey R. Stout
- Physiology of Work and Exercise Response (POWER) Laboratory, Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL 32816, USA;
| | - Diego A. Forero
- Professional Program in Sport Training, School of Health and Sport Sciences, Fundación Universitaria del Área Andina, Bogotá 111221, Colombia;
| | - Chad M. Kerksick
- Exercise and Performance Nutrition Laboratory, School of Health Sciences, Lindenwood University, Saint Charles, MO 63301, USA;
| | - Michael D. Roberts
- School of Kinesiology, Auburn University, Auburn, AL 36849, USA;
- Edward via College of Osteopathic Medicine, Auburn, AL 36849, USA
| | - Eric S. Rawson
- Department of Health, Nutrition and Exercise Science, Messiah University, Mechanicsburg, PA 17055, USA;
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Domingues WJR, Ritti-Dias RM, Cucato GG, Wolosker N, Zerati AE, Puech-Leão P, Coelho DB, Nunhes PM, Moliterno AA, Avelar A. Effect of Creatine Supplementation on Functional Capacity and Muscle Oxygen Saturation in Patients with Symptomatic Peripheral Arterial Disease: A Pilot Study of a Randomized, Double-Blind Placebo-Controlled Clinical Trial. Nutrients 2021; 13:E149. [PMID: 33466233 PMCID: PMC7824795 DOI: 10.3390/nu13010149] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 11/24/2020] [Accepted: 12/08/2020] [Indexed: 12/17/2022] Open
Abstract
The aim of the study was to verify the effects of creatine (Cr) supplementation on functional capacity (walking capacity; primary outcome) and calf muscle oxygen saturation (StO2) (secondary outcome) in symptomatic peripheral arterial disease (PAD) patients. Twenty-nine patients, of both sexes, were randomized (1:1) in a double-blind manner for administration of placebo (PLA, n = 15) or creatine monohydrate (Cr, n = 14). The supplementation protocol consisted of 20 g/day for 1 week divided into four equal doses (loading phase), followed by single daily doses of 5 g in the subsequent 7 weeks (maintenance phase). Functional capacity (total walking distance) was assessed by the 6 min walk test, and calf muscle StO2 was assessed through near infrared spectroscopy. The measurements were collected before and after loading and after the maintenance phase. The level of significance was p < 0.05. No significant differences were found for function capacity (total walking distance (PLA: pre 389 ± 123 m vs. post loading 413 ± 131 m vs. post maintenance 382 ± 99 m; Cr: pre 373 ± 149 m vs. post loading 390 ± 115 m vs. post maintenance 369 ± 115 m, p = 0.170) and the calf muscle StO2 parameters (p > 0.05). Short- and long-term Cr supplementation does not influence functional capacity and calf muscle StO2 parameters in patients with symptomatic PAD.
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Affiliation(s)
| | - Raphael Mendes Ritti-Dias
- Postgraduate Program in Rehabilitation Sciences, Nove de Julho University, Sao Paulo 03155-000, Brazil;
| | - Gabriel Grizzo Cucato
- Department of Sport, Exercise and Rehabilitation, Northumbria University, Newcastle upon Tyne NE1 8PP, UK;
| | - Nelson Wolosker
- Hospital Israelita Albert Einstein, Sao Paulo 05652-900, Brazil;
| | | | - Pedro Puech-Leão
- Faculty of Medicine Sao Paulo University, Sao Paulo 04021-001, Brazil;
| | - Daniel Boari Coelho
- Center for Engineering, Modeling and Applied Social Sciences (CECS), Federal University of ABC, São Bernardo do Campo 09606-070, Brazil;
| | - Pollyana Mayara Nunhes
- Department of Physical Education, State University of Maringa, Maringa 87020-900, Brazil; (P.M.N.); (A.A.M.); (A.A.)
| | - André Alberto Moliterno
- Department of Physical Education, State University of Maringa, Maringa 87020-900, Brazil; (P.M.N.); (A.A.M.); (A.A.)
| | - Ademar Avelar
- Department of Physical Education, State University of Maringa, Maringa 87020-900, Brazil; (P.M.N.); (A.A.M.); (A.A.)
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Nutritional Ergogenic Aids in Racquet Sports: A Systematic Review. Nutrients 2020; 12:nu12092842. [PMID: 32957505 PMCID: PMC7551004 DOI: 10.3390/nu12092842] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 09/11/2020] [Accepted: 09/15/2020] [Indexed: 12/26/2022] Open
Abstract
A nutritional ergogenic aid (NEA) can help athletes optimize performance, but an evidence-based analysis is required in order to support training outcomes or competition performance in specific events. Racquet sports players are regularly exposed to a high-intensity workload throughout the tournament season. The activity during a match is characterized by variable durations (2–4 h) of repeated high-intensity bouts interspersed with standardized rest periods. Medline/PubMed, Scopus, and EBSCO were searched from their inception until February 2020 for randomized controlled trials (RCTs). Two independent reviewers extracted data, after which they assessed the risk of bias and the quality of trials. Out of 439 articles found, 21 met the predefined criteria: tennis (15 trials), badminton (three trials), paddle (one trial), and squash (two trials). Among all the studied NEAs, acute dosages of caffeine (3–6 mg/kg) 30–60 min before a match have been proven to improve specific skills and accuracy but may not contribute to improve perceived exertion. Currently, creatine, sodium bicarbonate, sodium citrate, beetroot juice, citrulline, and glycerol need more studies to strengthen the evidence regarding improved performance in racquet sports.
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7
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Domingues WJR, Ritti-Dias RM, Cucato GG, Wolosker N, Zerati AE, Puech-Leão P, Nunhes PM, Moliterno AA, Avelar A. Does Creatine Supplementation Affect Renal Function in Patients with Peripheral Artery Disease? A Randomized, Double Blind, Placebo-controlled, Clinical Trial. Ann Vasc Surg 2019; 63:45-52. [PMID: 31563660 DOI: 10.1016/j.avsg.2019.07.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 06/12/2019] [Accepted: 07/11/2019] [Indexed: 01/15/2023]
Abstract
BACKGROUND Case studies and reviews have shown that creatine supplementation can affect kidney function. The objective of this study is to verify the effects of 8 weeks of creatine supplementation on renal function (creatinine clearance: primary outcome) in patients with symptomatic peripheral arterial disease. METHODS Twenty-nine patients, of both genders, were randomized (1:1) in a double-blind manner for administration of Placebo (PLA; n = 15) or creatine monohydrate (Cr; n = 14). The supplementation protocol consisted of 20 g/day for 1 week divided into 4 equal doses (loading phase), followed by single daily doses of 5 g in the subsequent 7 weeks (maintenance phase). Before and after the supplementation period, markers of renal function, serum creatinine, creatinine excretion rate, and creatinine clearance were evaluated. The Generalized Estimation Equation Model was used for comparison between groups. The level of significance was P < 0.05. RESULTS No significant differences were found between groups before and after the intervention for serum creatinine (Cr: pre 1.00 ± 0.15 mL/dL vs. post 1.07 ± 0.16 mL/dL; PLA: pre 1.30 ± 0.53 mL/dL vs. post 1.36 ± 0.47 mL/dL, P = 0.590), creatinine excretion rate (Cr: pre 81.73 ± 43.80 mg/dL vs. post 102.92 ± 59.57 mg/dL; PLA: pre 74.37 ± 38.90 mg/dL vs. post 86.22 ± 39.94 mg/dL, P = 0.560), or creatinine clearance (Cr; pre 108 ± 59 mL/min/1.73 m2 vs. post 117 ± 52 mL/min/1.73 m2; PLA: pre 88 ± 49 mL/min/1.73 m2 vs. post 82 ± 47 mL/min/1.73 m2, P = 0.366). CONCLUSIONS Eight weeks of creatine supplementation is safe and does not compromise the renal function of patients with peripheral arterial disease.
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Silveira R, Andrade-Souza VA, Arcoverde L, Tomazini F, Sansonio A, Bishop DJ, Bertuzzi R, Lima-Silva AE. Caffeine Increases Work Done above Critical Power, but Not Anaerobic Work. Med Sci Sports Exerc 2018; 50:131-140. [PMID: 28832393 DOI: 10.1249/mss.0000000000001408] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE The assumption that the curvature constant (W') of the power-duration relationship represents anaerobic work capacity is a controversial, unresolved question. We investigated if caffeine ingestion could increase total work done above critical power (CP), and if this would be accompanied by greater anaerobic energy expenditure and by an enhanced maintenance of maximal oxidative metabolic rate. METHODS Nine men (26.6 ± 5.3 yr, V˙O2max 40.6 ± 5.8 mL·kg·min) cycled until exhaustion at different exercise intensities on different days to determine the CP and W'. On separated days, participants cycled until exhaustion in the severe-intensity domain (136% ± 7% of CP) after ingesting either caffeine (5 mg·kg body mass) or a placebo. RESULTS Time to exhaustion was 34% longer with caffeine compared with placebo, and this was accompanied by a greater work done above CP (23.7 ± 5.7 vs 17.5 ± 3.6 kJ; 130% ± 30% vs 95% ± 14% of W', P < 0.01). Caffeine increased the aerobic energy expenditure (296.4 ± 91.0 vs 210.2 ± 71.9 kJ, P < 0.01), but not anaerobic lactic, anaerobic alactic, and total anaerobic (lactic + alactic) energy expenditure. The end values of heart rate and ventilation were higher with caffeine, but the V˙O2 end was similar between conditions and was not different from V˙O2max. Caffeine did not change time to reach V˙O2max but increased time maintained at V˙O2max (199.3 ± 105.9 vs 111.9 ± 87.1 s, P < 0.05). CONCLUSIONS Caffeine increased total work done above CP, but this was not associated with greater anaerobic work. Rather, this was associated with a higher tolerance to maintain exercise at maximal oxidative metabolic rate.
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Affiliation(s)
- Rodrigo Silveira
- 1Sport Science Research Group, Department of Physical Education and Sports Science, Academic Center of Vitoria, Federal University of Pernambuco, Vitoria de Santo Antao, Pernambuco, BRAZIL; 2Institute of Sport, Exercise and Active Living, College of Sport and Exercise Science, Victoria University, Melbourne, Victoria, AUSTRALIA; 3School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, AUSTRALIA; 4Endurance Performance Research Group (GEDAE-USP), School of Physical Education and Sport, University of São Paulo, Sao Paulo, BRAZIL; and 5Human Performance Research Group, Academic Department of Physical Education, Technological Federal University of Parana, Curitiba, Parana, BRAZIL
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Christensen PM, Shirai Y, Ritz C, Nordsborg NB. Caffeine and Bicarbonate for Speed. A Meta-Analysis of Legal Supplements Potential for Improving Intense Endurance Exercise Performance. Front Physiol 2017; 8:240. [PMID: 28536531 PMCID: PMC5422435 DOI: 10.3389/fphys.2017.00240] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 04/05/2017] [Indexed: 12/13/2022] Open
Abstract
A 1% change in average speed is enough to affect medal rankings in intense Olympic endurance events lasting ~45 s to 8 min which for example includes 100 m swimming and 400 m running (~1 min), 1,500 m running and 4000 m track cycling (~4 min) and 2,000 m rowing (~6-8 min). To maximize the likelihood of winning, athletes utilizes legal supplements with or without scientifically documented beneficial effects on performance. Therefore, a continued systematic evidence based evaluation of the possible ergogenic effects is of high importance. A meta-analysis was conducted with a strict focus on closed-end performance tests in humans in the time domain from 45 s to 8 min. These test include time-trials or total work done in a given time. This selection criterion results in a high relevance for athletic performance. Only peer-reviewed placebo controlled studies were included. The often applied and potentially ergogenic supplements beta-alanine, bicarbonate, caffeine and nitrate were selected for analysis. Following a systematic search in Pubmed and SportsDiscuss combined with evaluation of cross references a total of 7 (beta-alanine), 25 (bicarbonate), 9 (caffeine), and 5 (nitrate) studies was included in the meta-analysis. For each study, performance was converted to an average speed (km/h) from which an effect size (ES; Cohens d with 95% confidence intervals) was calculated. A small effect and significant performance improvement relative to placebo was observed for caffeine (ES: 0.41 [0.15–0.68], P = 0.002) and bicarbonate (ES: 0.40 [0.27–0.54], P < 0.001). Trivial and non-significant effects on performance was observed for nitrate (ES: 0.19 [−0.03–0.40], P = 0.09) and beta-alanine (ES: 0.17 [−0.12–0.46], P = 0.24). Thus, caffeine's and bicarbonate's ergogenic effect is clearly documented for intense endurance performance. Importantly, for all supplements an individualized approach may improve the ergogenic effect on performance.
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Affiliation(s)
- Peter M Christensen
- Section of Integrated Physiology, Department of Nutrition, Exercise and Sports, University of CopenhagenCopenhagen, Denmark.,Team DanmarkCopenhagen, Denmark
| | - Yusuke Shirai
- Section of Integrated Physiology, Department of Nutrition, Exercise and Sports, University of CopenhagenCopenhagen, Denmark
| | - Christian Ritz
- Section of Integrated Physiology, Department of Nutrition, Exercise and Sports, University of CopenhagenCopenhagen, Denmark
| | - Nikolai B Nordsborg
- Section of Integrated Physiology, Department of Nutrition, Exercise and Sports, University of CopenhagenCopenhagen, Denmark
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10
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Effects of caffeine ingestion on endurance performance in mentally fatigued individuals. Eur J Appl Physiol 2016; 116:2293-2303. [PMID: 27695980 DOI: 10.1007/s00421-016-3483-y] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 09/25/2016] [Indexed: 11/27/2022]
Abstract
PURPOSE To examine the effects of caffeine ingestion on physiological and perceptual responses in mentally fatigued individuals. METHODS Eight male physically active subjects completed four cycling constant-workload tests in four experimental conditions at 80 % of maximal power output: control (C), mental fatigue (MF), mental fatigue plus caffeine ingestion (5 mg/kg) (MF-CAF), and mental fatigue plus placebo (MF-PLA). The mental fatigue was induced by a continuous performance task A-X version (AX-CPT). Before and after the AX-CPT, the profile of mood state (POMS) and blood samples for lactate measurement were collected. Oxygen consumption ([Formula: see text]), rating of perceived exertion (RPE), and electromyography (EMG) activity were measured during the cycling test. RESULTS The time to exhaustion in C, MF, MF-PLA, and MF-CAF were 251 ± 30, 222 ± 23, 248 ± 28, and 285 ± 42 s, respectively. Delta values (corrected by C condition) were higher in MF-CAF than MF (P = 0.031). MF-CAF reported higher Vigor scores when compared with C (P = 0.046) and MF (P = 0.020). RPE at the first minute was significantly higher in MF-PLA than in C (P = 0.050); at the second minute, RPE was higher in MF-PLA than in C (P = 0.049) and MF-CAF (P = 0.048). EMG activity was not different between the conditions. CONCLUSIONS Caffeine ingestion increased approximately 14 % endurance performance after the induction of mental fatigue. This effect was accompanied by a tendency to improvement in mood state (i.e., vigor). Therefore, caffeine ingestion can promote a beneficial effect on endurance performance in mentally fatigued individuals.
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Christensen PM, Jacobs RA, Bonne T, Flück D, Bangsbo J, Lundby C. A short period of high-intensity interval training improves skeletal muscle mitochondrial function and pulmonary oxygen uptake kinetics. J Appl Physiol (1985) 2016; 120:1319-27. [PMID: 26846547 DOI: 10.1152/japplphysiol.00115.2015] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 02/02/2016] [Indexed: 11/22/2022] Open
Abstract
The aim of the present study was to examine whether improvements in pulmonary oxygen uptake (V̇o2) kinetics following a short period of high-intensity training (HIT) would be associated with improved skeletal muscle mitochondrial function. Ten untrained male volunteers (age 26 ± 2 yr; mean ± SD) performed six HIT sessions (8-12 × 60 s at incremental test peak power; 271 ± 52 W) over a 2-wk period. Before and after the HIT period, V̇o2 kinetics was modeled during moderate-intensity cycling (110 ± 19 W). Mitochondrial function was assessed with high-resolution respirometry (HRR), and maximal activities of oxidative enzymes citrate synthase (CS) and cytochrome c oxidase (COX) were accordingly determined. In response to HIT, V̇o2 kinetics became faster (τ: 20.4 ± 4.4 vs. 28.9 ± 6.1 s; P < 0.01) and fatty acid oxidation (ETFP) and leak respiration (LN) both became elevated (P < 0.05). Activity of CS and COX did not increase in response to training. Both before and after the HIT period, fast V̇o2 kinetics (low τ values) was associated with large values for ETFP, electron transport system capacity (ETS), and electron flow specific to complex II (CIIP) (P < 0.05). Collectively, these findings support that selected measures of mitochondrial function obtained with HRR are important for fast V̇o2 kinetics and better markers than maximal oxidative enzyme activity in describing the speed of the V̇o2 response during moderate-intensity exercise.
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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
| | - Robert A Jacobs
- Health and Physical Education, School of Teaching and Learning, Western Carolina University, Cullowhee, North Carolina; Department of Physical Therapy, Western Carolina University, Cullowhee, North Carolina; and
| | - Thomas Bonne
- Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Daniela Flück
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
| | - Jens Bangsbo
- Department of Nutrition, Exercise and Sports, Section of Integrated Physiology, University of Copenhagen, Copenhagen, Denmark
| | - Carsten Lundby
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
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