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Effects of Creatine Monohydrate on Endurance Performance in a Trained Population: A Systematic Review and Meta-analysis. Sports Med 2023; 53:1017-1027. [PMID: 36877404 DOI: 10.1007/s40279-023-01823-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/08/2023] [Indexed: 03/07/2023]
Abstract
BACKGROUND There is robust evidence that creatine monohydrate supplementation can enhance short-term high-intensity exercise in athletes. However, the effect of creatine monohydrate supplementation on aerobic performance and its role during aerobic activities is still controversial. OBJECTIVE The purpose of this systematic review and meta-analysis was to evaluate the supplementation effects of creatine monohydrate on endurance performance in a trained population. METHODS The search strategy in this systematic review and meta-analysis was designed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and PubMed/MEDLINE, Web of Science, and Scopus databases were explored from inception until 19 May, 2022. Only human experimental trials, controlled with a placebo group, evaluating the effects of creatine monohydrate supplementation on endurance performance in a trained population were analyzed in this systematic review and meta-analysis. The methodological quality of included studies was evaluated using the Physiotherapy Evidence Database (PEDro) scale. RESULTS A total of 13 studies satisfied all the eligibility criteria and were included in this systematic review and meta-analysis. The results for the pooled meta-analysis showed a non-significant change in endurance performance after creatine monohydrate supplementation in a trained population (p = 0.47), with a trivial negative effect (pooled standardized mean difference = - 0.07 [95% confidence interval - 0.32 to 0.18]; I2 = 34.75%). Further, after excluding the studies not evenly distributed around the base of the funnel plot, the results were similar (pooled standardized mean difference = - 0.07 [95% confidence interval - 0.27 to 0.13]; I2 = 0%; p = 0.49). CONCLUSIONS Creatine monohydrate supplementation was shown to be ineffective on endurance performance in a trained population. CLINICAL TRIAL REGISTRATION The study protocol was registered in the Prospective Register of Systematic Review (PROSPERO) with the following registration number: CRD42022327368.
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Gras D, Lanhers C, Bagheri R, Ugbolue UC, Coudeyre E, Pereira B, Zak M, Bouillon-Minois JB, Dutheil F. Creatine supplementation and VO 2max: a systematic review and meta-analysis. Crit Rev Food Sci Nutr 2021:1-12. [PMID: 34859731 DOI: 10.1080/10408398.2021.2008864] [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: 10/19/2022]
Abstract
Although creatine supplementation is well-known to increase exercise performance in acute high-intensity exercises, its role in aerobic performance based on VO2max is more controversial. Thus, we performed a systematic review and meta-analysis on the effects of creatine supplementation on VO2max. PubMed, Cochrane, Embase, and ScienceDirect were searched for randomized controlled trials (RCTs) reporting VO2max in creatine supplementation and placebo groups before and after supplementation. We computed a random-effects meta-analysis on VO2max at baseline, within groups following supplementation, on changes on VO2max between groups, and after supplementation between groups. Sensitivity analyses and meta-regression were conducted. We included 19 RCTs for a total of 424 individuals (mean age 30 years old, 82% men). VO2max did not differ at baseline between groups (creatine and placebo). Participants in both groups were engaged in exercise interventions in most studies (80%). Using changes in VO2max, VO2max increased in both groups but increased less after creatine supplementation than placebo (effect size [ES] = -0.32, 95%CI = -0.51 to -0.12, p = 0.002). Comparisons after creatine supplementation confirmed a lower VO2max in the creatine group compared to the placebo group (ES= -0.20, 95%CI = -0.39 to -0.001, p = 0.049). Meta-analysis after exclusion from meta-funnel resulted in similar outcomes in a subgroup of young and healthy participants. Meta-regressions on characteristics of supplementation, physical training, or sociodemographic were not statistically significant. Creatine supplementation has a negative effect on VO2max, regardless of the characteristics of training, supplementation, or population characteristics.Supplemental data for this article is available online at https://doi.org/10.1080/10408398.2021.2008864 .
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Affiliation(s)
- Damien Gras
- CHU Clermont-Ferrand, Physical and Rehabilitation Medicine, Université Clermont Auvergne, University Hospital of Clermont-Ferrand, Clermont-Ferrand, France
| | - Charlotte Lanhers
- CHU Clermont-Ferrand, Physical and Rehabilitation Medicine, Université Clermont Auvergne, University Hospital of Clermont-Ferrand, Clermont-Ferrand, France
| | - Reza Bagheri
- Department of Exercise Physiology, University of Isfahan, Isfahan, Iran
| | - Ukadike Chris Ugbolue
- University of the West of Scotland, School of Health and Life Sciences, Institute for Clinical Exercise & Health Science, South Lanarkshire, Scotland, UK
| | - Emmanuel Coudeyre
- INRAE, Human Nutrition Unit (UNH), Université Clermont Auvergne, University Hospital of Clermont-Ferrand, CHU Clermont-Ferrand, Physical and Rehabilitation Medicine, Clermont-Ferrand, France
| | - Bruno Pereira
- CHU Clermont-Ferrand, Biostatistics, University Hospital of Clermont-Ferrand, Clermont-Ferrand, France
| | - Marek Zak
- Faculty of Medicine and Health Sciences, Institute of Physiotherapy, The Jan Kochanowski University, Kielce, Poland
| | - Jean-Baptiste Bouillon-Minois
- Université Clermont Auvergne, CNRS, LaPSCo, Physiological and Psychosocial Stress, University Hospital of Clermont-Ferrand, CHU Clermont-Ferrand, Emergency Medicine, Clermont-Ferrand, France
| | - Frédéric Dutheil
- Université Clermont Auvergne, CNRS, LaPSCo, Physiological and Psychosocial Stress, University Hospital of Clermont-Ferrand, CHU Clermont-Ferrand, Occupational and Environmental Medicine, WittyFit, Clermont-Ferrand, France
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Creatine Supplementation in Women's Health: A Lifespan Perspective. Nutrients 2021; 13:nu13030877. [PMID: 33800439 PMCID: PMC7998865 DOI: 10.3390/nu13030877] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 03/01/2021] [Accepted: 03/05/2021] [Indexed: 12/14/2022] Open
Abstract
Despite extensive research on creatine, evidence for use among females is understudied. Creatine characteristics vary between males and females, with females exhibiting 70–80% lower endogenous creatine stores compared to males. Understanding creatine metabolism pre- and post-menopause yields important implications for creatine supplementation for performance and health among females. Due to the hormone-related changes to creatine kinetics and phosphocreatine resynthesis, supplementation may be particularly important during menses, pregnancy, post-partum, during and post-menopause. Creatine supplementation among pre-menopausal females appears to be effective for improving strength and exercise performance. Post-menopausal females may also experience benefits in skeletal muscle size and function when consuming high doses of creatine (0.3 g·kg−1·d−1); and favorable effects on bone when combined with resistance training. Pre-clinical and clinical evidence indicates positive effects from creatine supplementation on mood and cognition, possibly by restoring brain energy levels and homeostasis. Creatine supplementation may be even more effective for females by supporting a pro-energetic environment in the brain. The purpose of this review was to highlight the use of creatine in females across the lifespan with particular emphasis on performance, body composition, mood, and dosing strategies.
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Rothschild JA, Bishop DJ. Effects of Dietary Supplements on Adaptations to Endurance Training. Sports Med 2020; 50:25-53. [PMID: 31531769 DOI: 10.1007/s40279-019-01185-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Endurance training leads to a variety of adaptations at the cellular and systemic levels that serve to minimise disruptions in whole-body homeostasis caused by exercise. These adaptations are differentially affected by training volume, training intensity, and training status, as well as by nutritional choices that can enhance or impair the response to training. A variety of supplements have been studied in the context of acute performance enhancement, but the effects of continued supplementation concurrent to endurance training programs are less well characterised. For example, supplements such as sodium bicarbonate and beta-alanine can improve endurance performance and possibly training adaptations during endurance training by affecting buffering capacity and/or allowing an increased training intensity, while antioxidants such as vitamin C and vitamin E may impair training adaptations by blunting cellular signalling but appear to have little effect on performance outcomes. Additionally, limited data suggest the potential for dietary nitrate (in the form of beetroot juice), creatine, and possibly caffeine, to further enhance endurance training adaptation. Therefore, the objective of this review is to examine the impact of dietary supplements on metabolic and physiological adaptations to endurance training.
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Affiliation(s)
- Jeffrey A Rothschild
- Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand. .,TriFit Performance Center, Santa Monica, CA, USA.
| | - David J Bishop
- Institute for Health and Sport, Victoria University, Melbourne, VIC, Australia.,School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia
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Abstract
Presently, sports and energy drinks are widely spread not only among athletes, but also among ordinary people of different ages. The purpose of these beverages is to effectively compensate for the loss of water, energy and electrolytes in the human body before or after some exhausting activities. A questionnaire survey on energy drinks conducted in all eight federal districts of the Russian Federation shows that the younger groups of the Russian population (aged 12–17 and 18–30) drink tonic beverages more often than the older groups (aged 31–45 and 45–60). Further, a recent rise in unreasonable consumption of sports and energy drinks among teenagers may lead to various diseases: obesity, type 2 diabetes, heart disease and tooth enamel erosion. Finally, the authors analyse the composition of energy beverages and thoroughly describe each of their main components (L-carnitine, creatine, caffeine, taurine, and juice-containing products). These components are used by athletes due to their effects: L-carnitine helps reduce the signs of physical and mental overstrain, and stimulates working capacity; creatine improves endurance and anaerobic activity; caffeine raises aerobic endurance by increasing the oxidation of fats, thereby helping preserve glycogen in the muscles; taurine plays an important role as an antioxidant protector in the regulation of Ca++ transport, and as a regulator of osmotic pressure in the tissues.
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Kerksick CM, Wilborn CD, Roberts MD, Smith-Ryan A, Kleiner SM, Jäger R, Collins R, Cooke M, Davis JN, Galvan E, Greenwood M, Lowery LM, Wildman R, Antonio J, Kreider RB. ISSN exercise & sports nutrition review update: research & recommendations. J Int Soc Sports Nutr 2018; 15:38. [PMID: 30068354 PMCID: PMC6090881 DOI: 10.1186/s12970-018-0242-y] [Citation(s) in RCA: 367] [Impact Index Per Article: 61.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 07/17/2018] [Indexed: 12/18/2022] Open
Abstract
Background Sports nutrition is a constantly evolving field with hundreds of research papers published annually. In the year 2017 alone, 2082 articles were published under the key words ‘sport nutrition’. Consequently, staying current with the relevant literature is often difficult. Methods This paper is an ongoing update of the sports nutrition review article originally published as the lead paper to launch the Journal of the International Society of Sports Nutrition in 2004 and updated in 2010. It presents a well-referenced overview of the current state of the science related to optimization of training and performance enhancement through exercise training and nutrition. Notably, due to the accelerated pace and size at which the literature base in this research area grows, the topics discussed will focus on muscle hypertrophy and performance enhancement. As such, this paper provides an overview of: 1.) How ergogenic aids and dietary supplements are defined in terms of governmental regulation and oversight; 2.) How dietary supplements are legally regulated in the United States; 3.) How to evaluate the scientific merit of nutritional supplements; 4.) General nutritional strategies to optimize performance and enhance recovery; and, 5.) An overview of our current understanding of nutritional approaches to augment skeletal muscle hypertrophy and the potential ergogenic value of various dietary and supplemental approaches. Conclusions This updated review is to provide ISSN members and individuals interested in sports nutrition with information that can be implemented in educational, research or practical settings and serve as a foundational basis for determining the efficacy and safety of many common sport nutrition products and their ingredients.
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Affiliation(s)
- Chad M Kerksick
- Exercise and Performance Nutrition Laboratory, School of Health Sciences, Lindenwood University, St. Charles, MO, USA.
| | - Colin D Wilborn
- Exercise & Sport Science Department, University of Mary-Hardin Baylor, Belton, TX, USA
| | | | - Abbie Smith-Ryan
- Department of Exercise and Sport Science, University of North Carolina, Chapel Hill, NC, USA
| | | | | | - Rick Collins
- Collins Gann McCloskey and Barry PLLC, Mineola, NY, USA
| | - Mathew Cooke
- Department of Health and Medical Sciences, Swinburne University of Technology, Hawthorn, Victoria, Australia
| | - Jaci N Davis
- Exercise & Sport Science Department, University of Mary-Hardin Baylor, Belton, TX, USA
| | - Elfego Galvan
- University of Texas Medical Branch, Galveston, TX, USA
| | - Mike Greenwood
- Exercise & Sports Nutrition Lab, Human Clinical Research Facility, Texas A&M University, College Station, TX, USA
| | - Lonnie M Lowery
- Department of Human Performance & Sport Business, University of Mount Union, Alliance, OH, USA
| | | | - Jose Antonio
- Department of Health and Human Performance, Nova Southeastern University, Davie, FL, USA
| | - Richard B Kreider
- Exercise & Sports Nutrition Lab, Human Clinical Research Facility, Texas A&M University, College Station, TX, USA.
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Changing to a vegetarian diet reduces the body creatine pool in omnivorous women, but appears not to affect carnitine and carnosine homeostasis: a randomised trial. Br J Nutr 2018; 119:759-770. [DOI: 10.1017/s000711451800017x] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
AbstractBalanced vegetarian diets are popular, although they are nearly absent in creatine and carnosine and contain considerably less carnitine than non-vegetarian diets. Few longitudinal intervention studies investigating the effect of a vegetarian diet on the availability of these compounds currently exist. We aimed to investigate the effect of transiently switching omnivores onto a vegetarian diet for 6 months on muscle and plasma creatine, carnitine and carnosine homeostasis. In a 6-month intervention, forty omnivorous women were ascribed to three groups: continued omnivorous diet (control,n10), vegetarian diet without supplementation (Veg+Pla,n15) and vegetarian diet combined with dailyβ-alanine (0·8–0·4 g/d) and creatine supplementation (1 g creatine monohydrate/d) (Veg+Suppl,n15). Before (0 months; 0M), after 3 months (3M) and 6 months (6M), a fasted venous blood sample and 24-h urine was collected, and muscle carnosine content was determined by proton magnetic resonance spectroscopy (1H-MRS). Muscle biopsies were obtained at 0M and 3M. Plasma creatine and muscle total creatine content declined from 0M to 3M in Veg+Pla (P=0·013 andP=0·009, respectively), whereas plasma creatine increased from 0M in Veg+Suppl (P=0·004). None of the carnitine-related compounds in plasma or muscle showed a significant time×group interaction effect.1H-MRS-determined muscle carnosine content was unchanged over 6M in control and Veg+Pla, but increased in Veg+Suppl in soleus (P<0·001) and gastrocnemius (P=0·001) muscle. To conclude, the body creatine pool declined over a 3-month vegetarian diet in omnivorous women, which was ameliorated when accompanied by low-dose dietary creatine supplementation. Carnitine and carnosine homeostasis was unaffected by a 3- or 6-month vegetarian diet, respectively.
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Sanchez-Gonzalez MA, Wieder R, Kim JS, Vicil F, Figueroa A. Creatine supplementation attenuates hemodynamic and arterial stiffness responses following an acute bout of isokinetic exercise. Eur J Appl Physiol 2011; 111:1965-71. [DOI: 10.1007/s00421-011-1832-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Accepted: 01/07/2011] [Indexed: 01/27/2023]
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Kreider RB, Wilborn CD, Taylor L, Campbell B, Almada AL, Collins R, Cooke M, Earnest CP, Greenwood M, Kalman DS, Kerksick CM, Kleiner SM, Leutholtz B, Lopez H, Lowery LM, Mendel R, Smith A, Spano M, Wildman R, Willoughby DS, Ziegenfuss TN, Antonio J. ISSN exercise & sport nutrition review: research & recommendations. J Int Soc Sports Nutr 2010. [PMCID: PMC2853497 DOI: 10.1186/1550-2783-7-7] [Citation(s) in RCA: 161] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Sports nutrition is a constantly evolving field with hundreds of research papers published annually. For this reason, keeping up to date with the literature is often difficult. This paper is a five year update of the sports nutrition review article published as the lead paper to launch the JISSN in 2004 and presents a well-referenced overview of the current state of the science related to how to optimize training and athletic performance through nutrition. More specifically, this paper provides an overview of: 1.) The definitional category of ergogenic aids and dietary supplements; 2.) How dietary supplements are legally regulated; 3.) How to evaluate the scientific merit of nutritional supplements; 4.) General nutritional strategies to optimize performance and enhance recovery; and, 5.) An overview of our current understanding of the ergogenic value of nutrition and dietary supplementation in regards to weight gain, weight loss, and performance enhancement. Our hope is that ISSN members and individuals interested in sports nutrition find this review useful in their daily practice and consultation with their clients.
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Graef JL, Smith AE, Kendall KL, Fukuda DH, Moon JR, Beck TW, Cramer JT, Stout JR. The effects of four weeks of creatine supplementation and high-intensity interval training on cardiorespiratory fitness: a randomized controlled trial. J Int Soc Sports Nutr 2009; 6:18. [PMID: 19909536 PMCID: PMC2780977 DOI: 10.1186/1550-2783-6-18] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2009] [Accepted: 11/12/2009] [Indexed: 01/29/2023] Open
Abstract
Background High-intensity interval training has been shown to be a time-efficient way to induce physiological adaptations similar to those of traditional endurance training. Creatine supplementation may enhance high-intensity interval training, leading to even greater physiological adaptations. The purpose of this study was to determine the effects of high-intensity interval training (HIIT) and creatine supplementation on cardiorespiratory fitness and endurance performance (maximal oxygen consumption (VO2PEAK), time-to-exhaustion (VO2PEAKTTE), ventilatory threshold (VT), and total work done (TWD)) in college-aged men. Methods Forty-three recreationally active men completed a graded exercise test to determine VO2PEAK, VO2PEAKTTE, and VT. In addition, participants completed a time to exhaustion (TTE) ride at 110% of the maximum workload reached during the graded exercise test to determine TWD (TTE (sec) × W = J). Following testing, participants were randomly assigned to one of three groups: creatine (creatine citrate) (Cr; n = 16), placebo (PL; n = 17), or control (n = 10) groups. The Cr and PL groups completed four weeks of HIIT prior to post-testing. Results Significant improvements in VO2PEAK and VO2PEAKTTE occurred in both training groups. Only the Cr group significantly improved VT (16% vs. 10% improvement in PL). No changes occurred in TWD in any group. Conclusion In conclusion, HIIT is an effective and time-efficient way to improve maximal endurance performance. The addition of Cr improved VT, but did not increase TWD. Therefore, 10 g of Cr per day for five days per week for four weeks does not seem to further augment maximal oxygen consumption, greater than HIIT alone; however, Cr supplementation may improve submaximal exercise performance.
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Affiliation(s)
- Jennifer L Graef
- Department of Health and Exercise Science, University of Oklahoma, Huston Huffman Center, 1401 Asp Avenue, Norman, OK 73019, USA
| | - Abbie E Smith
- Department of Health and Exercise Science, University of Oklahoma, Huston Huffman Center, 1401 Asp Avenue, Norman, OK 73019, USA
| | - Kristina L Kendall
- Department of Health and Exercise Science, University of Oklahoma, Huston Huffman Center, 1401 Asp Avenue, Norman, OK 73019, USA
| | - David H Fukuda
- Department of Health and Exercise Science, University of Oklahoma, Huston Huffman Center, 1401 Asp Avenue, Norman, OK 73019, USA
| | - Jordan R Moon
- Department of Health and Exercise Science, University of Oklahoma, Huston Huffman Center, 1401 Asp Avenue, Norman, OK 73019, USA
| | - Travis W Beck
- Department of Health and Exercise Science, University of Oklahoma, Huston Huffman Center, 1401 Asp Avenue, Norman, OK 73019, USA
| | - Joel T Cramer
- Department of Health and Exercise Science, University of Oklahoma, Huston Huffman Center, 1401 Asp Avenue, Norman, OK 73019, USA
| | - Jeffrey R Stout
- Department of Health and Exercise Science, University of Oklahoma, Huston Huffman Center, 1401 Asp Avenue, Norman, OK 73019, USA
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BAZZUCCHI ILENIA, FELICI FRANCESCO, SACCHETTI MASSIMO. Effect of Short-Term Creatine Supplementation on Neuromuscular Function. Med Sci Sports Exerc 2009; 41:1934-41. [DOI: 10.1249/mss.0b013e3181a2c05c] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Smith AE, Walter AA, Herda TJ, Ryan ED, Moon JR, Cramer JT, Stout JR. Effects of creatine loading on electromyographic fatigue threshold during cycle ergometry in college-aged women. J Int Soc Sports Nutr 2007; 4:20. [PMID: 18039377 PMCID: PMC2244642 DOI: 10.1186/1550-2783-4-20] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2007] [Accepted: 11/26/2007] [Indexed: 11/16/2022] Open
Abstract
The purpose of this study was to examine the effects of 5 days of Creatine (Cr) loading on the electromyographic fatigue threshold (EMGFT) in college-aged women. Fifteen healthy college-aged women (mean ± SD = 22.3 ± 1.7 yrs) volunteered to participate in this double-blind, placebo-controlled study and were randomly placed into either placebo (PL – 10 g of flavored dextrose powder; n = 8) or creatine (Cr – 5 g di-creatine citrate plus 10 g of flavored dextrose powder; n = 7; Creatine Edge, FSI Nutrition) loading groups. Each group ingested one packet 4 times per day (total of 20 g/day) for 5 days. Prior to and following supplementation, each subject performed a discontinuous incremental cycle ergometer test to determine their EMGFT value, using bipolar surface electrodes placed on the longitudinal axis of the right vastus lateralis. Subjects completed a total of four, 60 second work bouts (ranging from 100–350 W). The EMG amplitude was averaged over 10 second intervals and plotted over the 60 second work bout. The resulting slopes from each successive work bouts were used to calculate EMGFT. A two-way ANOVA (group [Cr vs. PL] × time [pre vs. post]) resulted in a significant (p = 0.031) interaction. Furthermore, a dependent samples t-test showed a 14.5% ± 3.5% increase in EMGFT from pre- to post-supplementation with Cr (p = 0.009), but no change for the PL treatment (-2.2 ± 5.8%; p = 0.732). In addition, a significant increase (1.0 ± 0.34 kg; p = 0.049) in weight (kg) was observed in the Cr group but no change for PL (-0.2 kg ± 0.2 kg). These findings suggest that 5 days of Cr loading in women may be an effective strategy for delaying the onset of neuromuscular fatigue during cycle ergometry.
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Affiliation(s)
- Abbie E Smith
- Metabolic and Body Composition Laboratory, Department of Health and Exercise Science, University of Oklahoma, Norman, OK 73019, USA.
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Zoeller RF, Stout JR, O'kroy JA, Torok DJ, Mielke M. Effects of 28 days of beta-alanine and creatine monohydrate supplementation on aerobic power, ventilatory and lactate thresholds, and time to exhaustion. Amino Acids 2006; 33:505-10. [PMID: 16953366 DOI: 10.1007/s00726-006-0399-6] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2006] [Accepted: 07/17/2006] [Indexed: 11/30/2022]
Abstract
The effect of beta-alanine (beta-Ala) alone or in combination with creatine monohydrate (Cr) on aerobic exercise performance is unknown. The purpose of this study was to examine the effects of 4 weeks of beta-Ala and Cr supplementation on indices of endurance performance. Fifty-five men (24.5 +/- 5.3 yrs) participated in a double-blind, placebo-controlled study and randomly assigned to one of 4 groups; placebo (PL, n = 13), creatine (Cr, n = 12), beta-alanine (beta-Ala, n = 14), or beta-alanine plus creatine (CrBA, n = 16). Prior to and following supplementation, participants performed a graded exercise test on a cycle ergometer to determine VO(2peak), time to exhaustion (TTE), and power output, VO(2), and percent VO(2peak) associated with VT and LT. No significant group effects were found. However, within groups, a significant time effect was observed for CrBa on 5 of the 8 parameters measured. These data suggest that CrBA may potentially enhance endurance performance.
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Affiliation(s)
- R F Zoeller
- Department of Exercise Science and Health Promotion, Florida Atlantic University, Davie, FL, USA.
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Abstract
Creatine monohydrate (creatine) has become an increasingly popular ingredient in dietary supplements, especially sports nutrition products. A large body of human and animal research suggests that creatine does have a consistent ergogenic effect, particularly with exercises or activities requiring high intensity short bursts of energy. Human data are primarily derived from three types of studies: acute studies, involving high doses (20 g/d) with short duration (< or = 1 week), chronic studies involving lower doses (3-5 g/d) and longer duration (1 year), or a combination of both. Systematic evaluation of the research designs and data do not provide a basis for risk assessment and the usual safe Upper Level of Intake (UL) derived from it unless the newer methods described as the Observed Safe Level (OSL) or Highest Observed Intake (HOI) are utilized. The OSL risk assessment method indicates that the evidence of safety is strong at intakes up to 5 g/d for chronic supplementation, and this level is identified as the OSL. Although much higher levels have been tested under acute conditions without adverse effects and may be safe, the data for intakes above 5 g/d are not sufficient for a confident conclusion of long-term safety.
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Affiliation(s)
- Andrew Shao
- Council for Responsible Nutrition, 1828 L St., NW, Suite 900,Washington, DC 20036-5114, USA.
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Murphy AJ, Watsford ML, Coutts AJ, Richards DAB. Effects of creatine supplementation on aerobic power and cardiovascular structure and function. J Sci Med Sport 2006; 8:305-13. [PMID: 16248471 DOI: 10.1016/s1440-2440(05)80041-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This project aimed to determine 1) whether creatine (Cr) supplementation affects cardiovascular structure and function and 2) to examine its effect on aerobic power. Eighteen males undertook aerobic testing on a cycle ergometer and echocardiographic assessment of the heart. The experimental group (N = 9) ingested 20g x day(-1) of Cr for seven days followed by l0g x day(-1) for a further 21 days. The control group (N = 9) followed an identical protocol ingesting a placebo for the same period. Assessment was performed pre-, mid- (seven days) and post-testing (28 days). A MANOVA with repeated measures was used to test for group differences before and after supplementation. The Cr group demonstrated a significant increase in body mass for the pre-mid (1.0 +/- 0.6 kg) and the pre-post (1.5 +/- 0.7 kg) testing occasions. Submaximal VO2 decreased significantly from the pre-mid and pre-post testing occasions by between 4.8% to 11.4% with Cr supplementation at workloads of 75 W and 150 W. Other oxygen consumption measures and exercise time to exhaustion, for the Cr group, showed decreasing trends that approached significance. Additionally, there was a significant pre-post decrease in maximum heart rate of 3.7%. There were no changes in any of the echocardiographic or blood pressure measures for either group. The present results suggest short term Cr supplementation has no detectable negative effect on cardiac structure or function. Additionally, Cr ingestion improves submaximal cycling efficiency. These results suggest that the increase in efficiency may be related to peripheral factors such an increase in muscle phosphocreatine, rather than central changes.
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Affiliation(s)
- A J Murphy
- Human Performance Laboratory, University of Technology, Sydney, New South Wales.
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Kreider RB, Almada AL, Antonio J, Broeder C, Earnest C, Greenwood M, Incledon T, Kalman DS, Kleiner SM, Leutholtz B, Lowery LM, Mendel R, Stout JR, Willoughby DS, Ziegenfuss TN. ISSN Exercise & Sport Nutrition Review: Research & Recommendations. J Int Soc Sports Nutr 2004. [PMCID: PMC2129137 DOI: 10.1186/1550-2783-1-1-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Sport nutrition is a constantly evolving field with literally thousands of research papers published annually. For this reason, keeping up to date with the literature is often difficult. This paper presents a well-referenced overview of the current state of the science related to how to optimize training through nutrition. More specifically, this article discusses: 1.) how to evaluate the scientific merit of nutritional supplements; 2.) general nutritional strategies to optimize performance and enhance recovery; and, 3.) our current understanding of the available science behind weight gain, weight loss, and performance enhancement supplements. Our hope is that ISSN members find this review useful in their daily practice and consultation with their clients.
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Mesa JLM, Ruiz JR, González-Gross MM, Gutiérrez Sáinz A, Castillo Garzón MJ. Oral creatine supplementation and skeletal muscle metabolism in physical exercise. Sports Med 2003; 32:903-44. [PMID: 12427051 DOI: 10.2165/00007256-200232140-00003] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Creatine is the object of growing interest in the scientific literature. This is because of the widespread use of creatine by athletes, on the one hand, and to some promising results regarding its therapeutic potential in neuromuscular disease on the other. In fact, since the late 1900s, many studies have examined the effects of creatine supplementation on exercise performance. This article reviews the literature on creatine supplementation as an ergogenic aid, including some basic aspects relating to its metabolism, pharmacokinetics and side effects. The use of creatine supplements to increase muscle creatine content above approximately 20 mmol/kg dry muscle mass leads to improvements in high-intensity, intermittent high-intensity and even endurance exercise (mainly in nonweightbearing endurance activities). An effective supplementation scheme is a dosage of 20 g/day for 4-6 days, and 5 g/day thereafter. Based on recent pharmacokinetic data, new regimens of creatine supplementation could be used. Although there are opinion statements suggesting that creatine supplementation may be implicated in carcinogenesis, data to prove this effect are lacking, and indeed, several studies showing anticarcinogenic effects of creatine and its analogues have been published. There is a shortage of scientific evidence concerning the adverse effects following creatine supplementation in healthy individuals even with long-term dosage. Therefore, creatine may be considered as a widespread, effective and safe ergogenic aid.
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Affiliation(s)
- José L M Mesa
- Department of Physiology, School of Medicine, University of Granada, Granada, Spain
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Abstract
While the role of creatine in preventing muscle (peripheral) fatigue for high performance athletes is well understood, its biochemical role in prevention of mental (central) fatigue is not. Creatine is abundant in muscles and the brain and after phosphorylation used as an energy source for adenosine triphosphate synthesis. Using double-blind placebo-controlled paradigm, we demonstrated that dietary supplement of creatine (8 g/day for 5 days) reduces mental fatigue when subjects repeatedly perform a simple mathematical calculation. After taking the creatine supplement, task-evoked increase of cerebral oxygenated hemoglobin in the brains of subjects measured by near infrared spectroscopy was significantly reduced, which is compatible with increased oxygen utilization in the brain.
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Affiliation(s)
- Airi Watanabe
- Department of Neuropsychiatry, Faculty of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo, 113-8655, Tokyo, Japan
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