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Furtado ETF, Oliveira JPLDE, Pereira ISB, Veiga EP, Silva SFDA, Abreu WCDE. Short term creatine loading improves strength endurance even without changing maximal strength, RPE, fatigue index, blood lactate, and mode state. AN ACAD BRAS CIENC 2024; 96:e20230559. [PMID: 38747788 DOI: 10.1590/0001-3765202420230559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 01/16/2024] [Indexed: 06/15/2024] Open
Abstract
Creatine is consumed by athletes to increase strength and gain muscle. The aim of this study was to evaluate the effects of creatine supplementation on maximal strength and strength endurance. Twelve strength-trained men (25.2 ± 3.4 years) supplemented with 20 g Creatina + 10g maltodextrin or placebo (20g starch + 10g maltodextrin) for five days in randomized order. Maximal strength and strength endurance (4 sets 70% 1RM until concentric failure) were determined in the bench press. In addition, blood lactate, rate of perceived effort, fatigue index, and mood state were evaluated. All measurements were performed before and after the supplementation period. There were no significant changing in maximal strength, blood lactate, RPE, fatigue index, and mood state in either treatment. However, the creatine group performed more repetitions after the supplementation (Cr: Δ = +3.4 reps, p = 0.036, g = 0.53; PLA: Δ = +0.3reps, p = 0.414, g = 0.06), and higher total work (Cr: Δ = +199.5au, p = 0.038, g = 0.52; PLA: Δ = +26.7au, p = 0.402, g = 0.07). Creatine loading for five days allowed the subjects to perform more repetitions, resulting in greater total work, but failed to change the maximum strength.
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Affiliation(s)
- Edilson Tadeu F Furtado
- Universidade Federal de Lavras, Departamento de Nutrição, Faculdade de Ciências da Saúde, Trevo Rotatório Professor Edmir Sá Santos, s/n, 37203-202 Lavras, MG, Brazil
| | - João Paulo L DE Oliveira
- Universidade Federal de Lavras, Departamento de Nutrição, Faculdade de Ciências da Saúde, Trevo Rotatório Professor Edmir Sá Santos, s/n, 37203-202 Lavras, MG, Brazil
| | - Isabela S B Pereira
- Universidade Federal de Lavras, Departamento de Nutrição, Faculdade de Ciências da Saúde, Trevo Rotatório Professor Edmir Sá Santos, s/n, 37203-202 Lavras, MG, Brazil
| | - Elayne P Veiga
- Faculdade Presbiteriana Gammon, Educação Física, Praça Dr. Augusto Silva, 616, 37200-000 Lavras, MG, Brazil
| | - Sandro F DA Silva
- Universidade Federal de Lavras, Faculdade de Ciências da Saúde, Departamento de Educação Física, Trevo Rotatório Professor Edmir Sá Santos, s/n, 37203-202 Lavras, MG, Brazil
| | - Wilson César DE Abreu
- Universidade Federal de Lavras, Departamento de Nutrição, Faculdade de Ciências da Saúde, Trevo Rotatório Professor Edmir Sá Santos, s/n, 37203-202 Lavras, MG, Brazil
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Maicas-Pérez L, Hernández-Lougedo J, Heredia-Elvar JR, Pedauyé-Rueda B, Cañuelo-Márquez AM, Barba-Ruiz M, Lozano-Estevan MDC, García-Fernández P, Maté-Muñoz JL. Effects of Creatine Supplementation after 20 Minutes of Recovery in a Bench Press Exercise Protocol in Moderately Physically Trained Men. Nutrients 2023; 15:nu15030657. [PMID: 36771365 PMCID: PMC9919782 DOI: 10.3390/nu15030657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 01/19/2023] [Accepted: 01/20/2023] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND The aims of this study were to analyse the effect of creatine supplementation on the performance improvement in a bench pressing (BP) strength test of muscle failure and to evaluate muscle fatigue and metabolic stress 20 min after the exercise. METHODS Fifty young and healthy individuals were randomly assigned to a creatine group (n = 25) or a placebo group (n = 25). Three exercise sessions were carried out, with one week of rest between them. In the first week, a progressive load BP test was performed until the individuals reached the one repetition maximum (1RM) in order to for us obtain the load-to-velocity ratio of each participant. In the second week, the participants conducted a three-set BP exercise protocol against 70% 1RM, where they performed the maximum number of repetitions (MNR) until muscle failure occurred, with two minutes of rest between the sets. After one week, and following a supplementation period of 7 days, where half of the participants consumed 0.3 g·kg-1·day-1 of creatine monohydrate (CR) and the other half consumed 0.3 g·kg-1·day-1 of placebo (PLA, maltodextrin), the protocol from the second week was repeated. After each set, and up to 20 min after finishing the exercise, the blood lactate concentrations and mean propulsive velocity (MPV) at 1 m·s-1 were measured. RESULTS The CR group performed a significantly higher number of repetitions in Set 1 (CR = 14.8 repetitions, PLA = 13.6 repetitions, p = 0.006) and Set 2 (CR = 8 repetitions, PLA = 6.7 repetitions, p = 0.006) after supplementation, whereas no significant differences were seen in Set 3 (CR = 5.3 repetitions, PLA = 4.7 repetitions, p = 0.176). However, there was a significant increase in blood lactate at minute 10 (p = 0.003), minute 15 (p = 0.020), and minute 20 (p = 0.015) after the exercise in the post-supplementation period. Similarly, a significant increase was observed in the MPV at 1 m·s-1 in the CR group with respect to the PLA group at 10, 15, and 20 min after the exercise. CONCLUSIONS Although the creatine supplementation improved the performance in the strength test of muscle failure, the metabolic stress and muscle fatigue values were greater during the 20 min of recovery.
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Affiliation(s)
- Luis Maicas-Pérez
- Department of Physical Activity and Sports Science, Alfonso X El Sabio University, 28691 Madrid, Spain
| | - Juan Hernández-Lougedo
- Department of Physiotherapy, Faculty of Health Sciences, Camilo José Cela University, 28692 Madrid, Spain
| | - Juan Ramón Heredia-Elvar
- Department of Physical Activity and Sports Science, Alfonso X El Sabio University, 28691 Madrid, Spain
| | - Blanca Pedauyé-Rueda
- Department of Physical Activity and Sports Science, Alfonso X El Sabio University, 28691 Madrid, Spain
| | - Ana María Cañuelo-Márquez
- Department of Physical Activity and Sports Science, Alfonso X El Sabio University, 28691 Madrid, Spain
| | - Manuel Barba-Ruiz
- Department of Physical Activity and Sports Science, Alfonso X El Sabio University, 28691 Madrid, Spain
| | | | - Pablo García-Fernández
- Department of Radiology, Rehabilitation and Physiotherapy, Complutense University of Madrid, 28040 Madrid, Spain
- IdISSC, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, 28040 Madrid, Spain
- Correspondence:
| | - José Luis Maté-Muñoz
- Department of Radiology, Rehabilitation and Physiotherapy, Complutense University of Madrid, 28040 Madrid, Spain
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Short-Term Creatine Supplementation and Repeated Sprint Ability-A Systematic Review and Meta-Analysis. Int J Sport Nutr Exerc Metab 2022; 32:491-500. [PMID: 36041731 DOI: 10.1123/ijsnem.2022-0072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 07/16/2022] [Accepted: 07/18/2022] [Indexed: 11/18/2022]
Abstract
The aim of this study was to conduct a systematic review and meta-analysis of the effects of short-term creatine supplementation on repeated sprint ability. Fourteen studies met the inclusion criteria of adopting double-blind randomized placebo-controlled designs in which participants (age: 18-60 years) completed a repeated sprint test (number of sprints: 4 < n ≤ 20; sprint duration: ≤10 s; recovery duration: ≤90 s) before and after supplementing with creatine or placebo for 3-7 days in a dose of ∼20 g/day. No exclusion restrictions were placed on the mode of exercise. Meta-analyses were completed using random-effects models, with effects on measures of peak power output, mean power output, and fatigue (performance decline) during each repeated sprint test presented as standardized mean difference (δ), and with effects on body mass and posttest blood lactate concentration presented as raw mean difference (D). Relative to placebo, creatine resulted in a significant increase in body mass (D = 0.79 kg; p < .00001) and mean power output (δ = 0.61; p = .002). However, there was no effect of creatine on measures of peak power (δ = 0.41; p = .10), fatigue (δ = 0.08; p = .61), or posttest blood lactate concentration (D = 0.22 L/min; p = .60). In conclusion, creatine supplementation may increase mean power output during repeated sprint tests, although the absence of corresponding effects on peak power and fatigue means that more research, with measurements of intramuscular creatine content, is necessary to confirm.
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Politis-Barber V, Petrick HL, Raajendiran A, DesOrmeaux GJ, Brunetta HS, dos Reis LM, Mori MA, Wright DC, Watt MJ, Holloway GP. Ckmt1 is Dispensable for Mitochondrial Bioenergetics Within White/Beige Adipose Tissue. FUNCTION 2022; 3:zqac037. [PMID: 37954502 PMCID: PMC10633789 DOI: 10.1093/function/zqac037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 07/05/2022] [Accepted: 07/07/2022] [Indexed: 11/14/2023] Open
Abstract
Within brown adipose tissue (BAT), the brain isoform of creatine kinase (CKB) has been proposed to regulate the regeneration of ADP and phosphocreatine in a futile creatine cycle (FCC) that stimulates energy expenditure. However, the presence of FCC, and the specific creatine kinase isoforms regulating this theoretical model within white adipose tissue (WAT), remains to be fully elucidated. In the present study, creatine did not stimulate respiration in cultured adipocytes, isolated mitochondria or mouse permeabilized WAT. Additionally, while creatine kinase ubiquitous-type, mitochondrial (CKMT1) mRNA and protein were detected in human WAT, shRNA-mediated reductions in Ckmt1 did not decrease submaximal respiration in cultured adipocytes, and ablation of CKMT1 in mice did not alter energy expenditure, mitochondrial responses to pharmacological β3-adrenergic activation (CL 316, 243) or exacerbate the detrimental metabolic effects of consuming a high-fat diet. Taken together, these findings solidify CKMT1 as dispensable in the regulation of energy expenditure, and unlike in BAT, they do not support the presence of FCC within WAT.
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Affiliation(s)
- Valerie Politis-Barber
- Department of Human Health and Nutritional Sciences, University of Guelph, 50 Stone Rd E, Guelph, ON N1G 2W1, Canada
| | - Heather L Petrick
- Department of Human Health and Nutritional Sciences, University of Guelph, 50 Stone Rd E, Guelph, ON N1G 2W1, Canada
| | - Arthe Raajendiran
- Department of Anatomy and Physiology, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Genevieve J DesOrmeaux
- Department of Human Health and Nutritional Sciences, University of Guelph, 50 Stone Rd E, Guelph, ON N1G 2W1, Canada
| | - Henver S Brunetta
- Department of Human Health and Nutritional Sciences, University of Guelph, 50 Stone Rd E, Guelph, ON N1G 2W1, Canada
- Department of Biochemistry and Tissue Biology, University of Campinas, Campinas - SP 13083-970, Brazil
| | - Larissa M dos Reis
- Department of Genetics, Evolution, Microbiology and Immunology, University of Campinas, Campinas - SP 13083-970, Brazil
| | - Marcelo A Mori
- Department of Biochemistry and Tissue Biology, University of Campinas, Campinas - SP 13083-970, Brazil
| | - David C Wright
- Department of Human Health and Nutritional Sciences, University of Guelph, 50 Stone Rd E, Guelph, ON N1G 2W1, Canada
| | - Matthew J Watt
- Department of Anatomy and Physiology, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Graham P Holloway
- Department of Human Health and Nutritional Sciences, University of Guelph, 50 Stone Rd E, Guelph, ON N1G 2W1, Canada
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Bogdanis GC, Nevill ME, Aphamis G, Stavrinou PS, Jenkins DG, Giannaki CD, Lakomy HKA, Williams C. Effects of Oral Creatine Supplementation on Power Output during Repeated Treadmill Sprinting. Nutrients 2022; 14:nu14061140. [PMID: 35334797 PMCID: PMC8950892 DOI: 10.3390/nu14061140] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 03/03/2022] [Accepted: 03/05/2022] [Indexed: 11/16/2022] Open
Abstract
The aim of the present study was to examine the effects of creatine (Cr) supplementation on power output during repeated sprints on a non-motorized treadmill. Sixteen recreationally active males volunteered for this study (age 25.5 ± 4.8 y, height 179 ± 5 cm, body mass 74.8 ± 6.8 kg). All participants received placebo supplementation (75 mg of glucose·kg-1·day-1) for 5 days and then performed a baseline repeated sprints test (6 × 10 s sprints on a non-motorised treadmill). Thereafter, they were randomly assigned into a Cr (75 mg of Cr monohydrate·kg-1·day-1) or placebo supplementation, as above, and the repeated sprints test was repeated. After Cr supplementation, body mass was increased by 0.99 ± 0.83 kg (p = 0.007), peak power output and peak running speed remained unchanged throughout the test in both groups, while the mean power output and mean running speed during the last 5 s of the sprints increased by 4.5% (p = 0.005) and 4.2% to 7.0%, respectively, during the last three sprints (p = 0.005 to 0.001). The reduction in speed within each sprint was also blunted by 16.2% (p = 0.003) following Cr supplementation. Plasma ammonia decreased by 20.1% (p = 0.037) after Cr supplementation, despite the increase in performance. VO2 and blood lactate during the repeated sprints test remained unchanged after supplementation, suggesting no alteration of aerobic or glycolytic contribution to adenosine triphosphate production. In conclusion, Cr supplementation improved the mean power and speed in the second half of a repeated sprint running protocol, despite the increased body mass. This improvement was due to the higher power output and running speed in the last 5 s of each 10 s sprint.
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Affiliation(s)
- Gregory C. Bogdanis
- School of P.E. and Sport Science, National and Kapodistrian University of Athens, 17237 Athens, Greece
- Correspondence: ; Tel.: +30-2107276115
| | - Mary E. Nevill
- Sport, Health and Performance Enhancement (SHAPE) Research Centre, Department of Sport Science, Nottingham Trent University, Nottingham NG11 8NS, UK;
| | - George Aphamis
- Department of Life and Health Sciences, University of Nicosia, Nicosia 2417, Cyprus; (G.A.); (P.S.S.); (C.D.G.)
| | - Pinelopi S. Stavrinou
- Department of Life and Health Sciences, University of Nicosia, Nicosia 2417, Cyprus; (G.A.); (P.S.S.); (C.D.G.)
| | - David G. Jenkins
- School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, QLD 4072, Australia;
- School of Health and Behavioural Sciences, University of the Sunshine Coast, Sippy Downs, QLD 4556, Australia
| | - Christoforos D. Giannaki
- Department of Life and Health Sciences, University of Nicosia, Nicosia 2417, Cyprus; (G.A.); (P.S.S.); (C.D.G.)
| | - Henryk K. A. Lakomy
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, Leics LE11 3TU, UK; (H.K.A.L.); (C.W.)
| | - Clyde Williams
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, Leics LE11 3TU, UK; (H.K.A.L.); (C.W.)
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Anders JPV, Neltner TJ, Smith RW, Keller JL, Housh TJ, Daugherty FJ, Tempesta MS, Dash AK, Munt DJ, Schmidt RJ, Johnson GO. The effects of phosphocreatine disodium salts plus blueberry extract supplementation on muscular strength, power, and endurance. J Int Soc Sports Nutr 2021; 18:60. [PMID: 34503541 PMCID: PMC8427883 DOI: 10.1186/s12970-021-00456-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 07/01/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Numerous studies have demonstrated the efficacy of creatine supplementation for improvements in exercise performance. Few studies, however, have examined the effects of phosphocreatine supplementation on exercise performance. Furthermore, while polyphenols have antioxidant and anti-inflammatory properties, little is known regarding the influence of polyphenol supplementation on muscular strength, power, and endurance. Thus, the purpose of the present study was to compare the effects of 28 days of supplementation with phosphocreatine disodium salts plus blueberry extract (PCDSB), creatine monohydrate (CM), and placebo on measures of muscular strength, power, and endurance. METHODS Thirty-three men were randomly assigned to consume either PCDSB, CM, or placebo for 28 days. Peak torque (PT), average power (AP), and percent decline for peak torque (PT%) and average power (AP%) were assessed from a fatigue test consisting of 50 maximal, unilateral, isokinetic leg extensions at 180°·s- 1 before and after the 28 days of supplementation. Individual responses were assessed to examine the proportion of subjects that exceeded a minimal important difference (MID). RESULTS The results demonstrated significant (p < 0.05) improvements in PT for the PCDSB and CM groups from pre- (99.90 ± 22.47 N·m and 99.95 ± 22.50 N·m, respectively) to post-supplementation (119.22 ± 29.87 N·m and 111.97 ± 24.50 N·m, respectively), but no significant (p = 0.112) change for the placebo group. The PCDSB and CM groups also exhibited significant improvements in AP from pre- (140.18 ± 32.08 W and 143.42 ± 33.84 W, respectively) to post-supplementation (170.12 ± 42.68 W and 159.78 ± 31.20 W, respectively), but no significant (p = 0.279) change for the placebo group. A significantly (p < 0.05) greater proportion of subjects in the PCDSB group exceeded the MID for PT compared to the placebo group, but there were no significant (p > 0.05) differences in the proportion of subjects exceeding the MID between the CM and placebo groups or between the CM and PCDSB groups. CONCLUSIONS These findings indicated that for the group mean responses, 28 days of supplementation with both PCDSB and CM resulted in increases in PT and AP. The PCDSB, however, may have an advantage over CM when compared to the placebo group for the proportion of individuals that respond favorably to supplementation with meaningful increases in muscular strength.
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Affiliation(s)
- John Paul V Anders
- Department of Nutrition and Human Sciences, University of Nebraska-Lincoln, Lincoln, NE, 68510, USA.
| | - Tyler J Neltner
- Department of Nutrition and Human Sciences, University of Nebraska-Lincoln, Lincoln, NE, 68510, USA
| | - Robert W Smith
- Department of Nutrition and Human Sciences, University of Nebraska-Lincoln, Lincoln, NE, 68510, USA
| | - Joshua L Keller
- Department of Health, Kinesiology and Sport, University of South Alabama, Mobile, AL, 36688, USA
| | - Terry J Housh
- Department of Nutrition and Human Sciences, University of Nebraska-Lincoln, Lincoln, NE, 68510, USA
| | | | | | - Alekha K Dash
- Department of Pharmacy Sciences, School of Pharmacy and Health Professions, Omaha, NE, 68178, USA
| | - Daniel J Munt
- Department of Pharmacy Sciences, School of Pharmacy and Health Professions, Omaha, NE, 68178, USA
| | - Richard J Schmidt
- Department of Nutrition and Human Sciences, University of Nebraska-Lincoln, Lincoln, NE, 68510, USA
| | - Glen O Johnson
- Department of Nutrition and Human Sciences, University of Nebraska-Lincoln, Lincoln, NE, 68510, USA
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Tran NT, Muccini AM, Snow RJ, Nitsos I, Hale N, Walker DW, Ellery SJ. The physiological effects of creatine supplementation in fetal sheep before, during and after umbilical cord occlusion and global hypoxia. J Appl Physiol (1985) 2021; 131:1088-1099. [PMID: 34382841 DOI: 10.1152/japplphysiol.00092.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The aim of this study was to investigate the effects of direct creatine infusion on fetal systemic metabolic and cardiovascular responses to mild acute in utero hypoxia. Pregnant ewes (n=28) were surgically instrumented at 118 days gestation (dGa). A constant intravenous infusion of creatine (6 mg.kg-1.h-1) or isovolumetric saline (1.5 ml.h-1) began at 121 dGa. After 10 days, fetuses were subjected to 10-minute umbilical cord occlusion (UCO) to induce mild global hypoxia (saline-UCO, n=8; creatine-UCO, n=7) or sham UCO (saline-control, n=6; creatine-control, n=7). Cardiovascular, arterial blood gases and metabolites, and plasma creatine were monitored prior to, during, and then for 72 hours following the UCO. Total creatine content in discrete fetal brain regions was also measured. Fetal creatine infusion increased plasma concentrations 5-fold but had no significant effects on any measurement pre-UCO. Creatine did not alter fetal physiology during the UCO or in the early recovery stage, up to 24 hours after UCO. During the late recovery stage, 24-72 hours after UCO, there was a significant reduction in the arterial oxygen pressure and saturation in creatine fetuses (PUCO x TREATMENT = 0.02 and0.04, respectively). At 72 hours after UCO, significant creatine loading was detected in cortical grey matter, hippocampus, thalamus and striatum (PTREATMENT = 0.01-0.001). In the striatum, the UCO itself increased total creatine content (PUCO = 0.019). Overall, fetal creatine supplementation may alter oxygen flux following an acute hypoxic insult. Increasing total creatine content in the striatum may also be a fetal adaptation to acute oxygen deprivation.
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Affiliation(s)
- Nhi Thao Tran
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia.,Faculty of Health Science, RMIT University, Melbourne, Victoria, Australia
| | - Anna M Muccini
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia.,Department of Obstetrics and Gynaecology, Monash University, Clayton, Melbourne, Victoria, Australia
| | - Rod J Snow
- Institute for Physical Activity and Nutrition, Deakin University, Burwood, Melbourne, Victoria, Australia
| | - Ilias Nitsos
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia.,Department of Obstetrics and Gynaecology, Monash University, Clayton, Melbourne, Victoria, Australia
| | - Nadia Hale
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia.,Department of Obstetrics and Gynaecology, Monash University, Clayton, Melbourne, Victoria, Australia
| | - David W Walker
- Faculty of Health Science, RMIT University, Melbourne, Victoria, Australia
| | - Stacey J Ellery
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia.,Department of Obstetrics and Gynaecology, Monash University, Clayton, Melbourne, Victoria, Australia
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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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Effects of Creatine in Trained Athletes: A Meta-analysis of 21 Randomized Placebo-Controlled Trials. Am J Ther 2020; 27:e519-e523. [PMID: 32769386 DOI: 10.1097/mjt.0000000000000974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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11
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Zhang L, Li JL, Wang XF, Zhu XD, Gao F, Zhou GH. Attenuating effects of guanidinoacetic acid on preslaughter transport-induced muscle energy expenditure and rapid glycolysis of broilers. Poult Sci 2019; 98:3223-3232. [PMID: 30789221 DOI: 10.3382/ps/pez052] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 01/25/2019] [Indexed: 01/12/2023] Open
Abstract
This study evaluated the effects of dietary guanidinoacetic acid (GAA) supplementation on growth performance, plasma variables, muscle energy status, glycolytic potential, and meat quality of broilers experiencing transport stress during the summer. A total of 320 28-day-old male Arbor Acres broilers were randomly allotted to 3 dietary treatments, including a GAA-free basal control diet (160 birds) and basal diet supplementation with 600 (80 birds) or 1,200 mg/kg (80 birds) GAA for 14 D. On the morning of day 42, after an 8-h fast, the birds fed basal diets were divided into 2 equal groups, and all birds in the 4 groups of 80 birds were transported according to the following protocols: 1) a 0.5-h transport of birds on basal diets (as a lower-stress control group), 2) a 3-h transport of birds on basal diets, and a 3-h transport of birds on basal diets supplemented with either 3) 600 or 4) 1,200 mg/kg GAA. The results revealed that dietary supplementation with GAA at 600 and 1,200 mg/kg for 14 D prior to slaughter did not affect growth performance, carcass traits, and most textural characteristics and chemical composition of the pectoralis major (PM) muscle (P > 0.05). In the GAA-free group, a 3-h transport increased the broiler live weight loss, elevated the plasma corticosterone concentration, decreased the plasma glucose concentration, muscle concentrations of ATP, creatine and energy charge value, increased the muscle AMP concentration and AMP/ATP ratio, and accelerated glycolysis metabolism, which resulted in inferior meat quality (lower pH and higher drip loss, P < 0.05). However, dietary addition of GAA at 1,200 mg/kg increased the mRNA expression of S-adenosyl-l-methionine: N-guanidino-acetate methyltransferase in the liver and creatine transporter in both the liver and PM muscle. It also elevated muscle concentrations of creatine and phosphocreatine (P < 0.05), which helps improve meat quality by ameliorating the 3-h transport-induced muscle energy expenditure and delaying anaerobic glycolysis of broilers.
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Affiliation(s)
- L Zhang
- College of Animal Science and Technology, Jiangsu Provincial Key Laboratory of Animal Origin Food Production and Safety Guarantee, Jiangsu Provincial Key Laboratory of Gastrointestinal Nutrition and Animal Health, Jiangsu Provincial Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - J L Li
- College of Animal Science and Technology, Jiangsu Provincial Key Laboratory of Animal Origin Food Production and Safety Guarantee, Jiangsu Provincial Key Laboratory of Gastrointestinal Nutrition and Animal Health, Jiangsu Provincial Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - X F Wang
- College of Science, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - X D Zhu
- College of Science, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - F Gao
- College of Animal Science and Technology, Jiangsu Provincial Key Laboratory of Animal Origin Food Production and Safety Guarantee, Jiangsu Provincial Key Laboratory of Gastrointestinal Nutrition and Animal Health, Jiangsu Provincial Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - G H Zhou
- College of Animal Science and Technology, Jiangsu Provincial Key Laboratory of Animal Origin Food Production and Safety Guarantee, Jiangsu Provincial Key Laboratory of Gastrointestinal Nutrition and Animal Health, Jiangsu Provincial Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
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12
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Detecting creatine excreted in the urine of swimming athletes by means of Raman spectroscopy. Lasers Med Sci 2019; 35:455-464. [DOI: 10.1007/s10103-019-02843-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 07/08/2019] [Indexed: 01/09/2023]
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13
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Effects of Low-Dose Creatine Monohydrate on Muscle Strength and Endurance. Asian J Sports Med 2018. [DOI: 10.5812/asjsm.62739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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14
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Yáñez-Silva A, Buzzachera CF, Piçarro IDC, Januario RSB, Ferreira LHB, McAnulty SR, Utter AC, Souza-Junior TP. Effect of low dose, short-term creatine supplementation on muscle power output in elite youth soccer players. J Int Soc Sports Nutr 2017; 14:5. [PMID: 28190980 PMCID: PMC5296953 DOI: 10.1186/s12970-017-0162-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 02/01/2017] [Indexed: 12/25/2022] Open
Abstract
Background To determine the effects of a low dose, short-term Creatine monohydrate (Cr) supplementation (0.03 g.kg.d−1 during 14 d) on muscle power output in elite youth soccer players. Methods Using a two-group matched, double blind, placebo-controlled design, nineteen male soccer players (mean age = 17.0 ± 0.5 years) were randomly assigned to either Cr (N = 9) or placebo (N = 10) group. Before and after supplementation, participants performed a 30s Wingate Anaerobic Test (WAnT) to assess peak power output (PPO), mean power output (MPO), fatigue index (FI), and total work. Results There were significant increases in both PPO and MPO after the Cr supplementation period (P ≤ 0.05) but not the placebo period. There were also significant increases in total work, but not FI, after the Cr supplementation and placebo periods (P ≤ 0.05). Notably, there were differences in total work between the Cr and placebo groups after (P ≤ 0.05) but not before the 14 d supplementation period. Conclusion There is substantial evidence to indicate that a low-dose, short-term oral Cr supplementation beneficially affected muscle power output in elite youth soccer players.
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Affiliation(s)
- Aquiles Yáñez-Silva
- Dirección de Investigación, Universidad Mayor Santiago de Chile; Universidad Santo Tomás, Talca. Chile. Carrera de Educación Física, Santiago de Chile, Chile
| | - Cosme F Buzzachera
- Department of Physical Education, North University of Parana, Londrina, Brazil
| | - Ivan Da C Piçarro
- School of Physical Education, Max Planck Faculty, Indaiatuba, Brazil
| | - Renata S B Januario
- Department of Physical Education, North University of Parana, Londrina, Brazil
| | - Luis H B Ferreira
- Department of Physical Education, Research Group on Metabolism, Nutrition and Strength Training, Curitiba, Brazil
| | - Steven R McAnulty
- Department of Health and Exercise Science, Appalachian State University, Boone, USA
| | - Alan C Utter
- Department of Health and Exercise Science, Appalachian State University, Boone, USA
| | - Tacito P Souza-Junior
- Department of Physical Education, Research Group on Metabolism, Nutrition and Strength Training, Curitiba, Brazil.,Department of Health and Exercise Science, Appalachian State University, Boone, USA
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15
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Short-term creatine supplementation has no impact on upper-body anaerobic power in trained wrestlers. J Int Soc Sports Nutr 2015; 12:45. [PMID: 26664350 PMCID: PMC4673838 DOI: 10.1186/s12970-015-0107-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 12/04/2015] [Indexed: 11/25/2022] Open
Abstract
Background Creatine (CR) is considered an effective nutritional supplement having ergogenic effects, which appears more pronounced in upper-body compared to lower-body exercise. Nevertheless, results regarding the impact of CR loading on repeated high-intensity arm-cranking exercise are scarce and in some cases conflicting. Interestingly, few of the conducted studies have structured their research designs to mimic real world sporting events. Therefore, our purpose was to address the hypothesis that CR ingestion would increase anaerobic power output in consecutive upper-body intermittent sprint performance (UBISP) tests designed to simulate wrestling matches on a competition-day. Methods In a double-blind, placebo-controlled, parallel-group study, 20 trained wrestlers were assigned to either placebo or CR supplemented group (0.3 g ∙ kg−1 of body mass per day). Four 6-min UBISP tests interspersed with 30-min recovery periods were performed before (trial 1) and after 5 days (trial 2) of supplementation. Each test consisted of six 15-s periods of arm-cranking at maximal executable cadence against resistance of 0.04 kg ∙ kg−1 body mass interspersed with 40-s unloaded easy cranking periods and 5-s acceleration intervals (T1–T4). Mean power (MP), peak power (PP), fatigue index and heart rate parameters were measured during UBISP tests. Also, body weight and hydration status were assessed. Principle measures were statistical analysed with mixed-model ANOVAs. Results Mean individual CR consumption in the CR group was 24.8 ± 2.5 g ∙ d−1. No significant (P > 0.05) differences occurred in body mass or hydration status indices between the groups or across trials. MP, PP and fatigue index responses were unaffected by supplementation; although, a significant reduction in MP and PP did occurred from T1 to T4 in both trial 1 and 2 (P < 0.001). Overall heart rate responses in the tests tended to be higher in the CR than PLC group (P < 0.05); but, trends in responses in trials and tests were comparable (P > 0.05). Conclusion These results suggest that 5-day CR supplementation has no impact on upper-body muscle anaerobic power output in consecutive UBISP anaerobic tests mimicking wrestling matches on a competition day.
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Sahlin K. Muscle energetics during explosive activities and potential effects of nutrition and training. Sports Med 2015; 44 Suppl 2:S167-73. [PMID: 25355190 PMCID: PMC4213384 DOI: 10.1007/s40279-014-0256-9] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The high-energy demand during high-intensity exercise (HIE) necessitates that anaerobic processes cover an extensive part of the adenosine triphosphate (ATP) requirement. Anaerobic energy release results in depletion of phosphocreatine (PCr) and accumulation of lactic acid, which set an upper limit of anaerobic ATP production and thus HIE performance. This report focuses on the effects of training and ergogenic supplements on muscle energetics and HIE performance. Anaerobic capacity (i.e. the amount of ATP that can be produced) is determined by the muscle content of PCr, the buffer capacity and the volume of the contracting muscle mass. HIE training can increase buffer capacity and the contracting muscle mass but has no effect on the concentration of PCr. Dietary supplementation with creatine (Cr), bicarbonate, or beta-alanine has a documented ergogenic effect. Dietary supplementation with Cr increases muscle Cr and PCr and enhances performance, especially during repeated short periods of HIE. The ergogenic effect of Cr is related to an increase in temporal and spatial buffering of ATP and to increased muscle buffer capacity. Bicarbonate loading increases extracellular buffering and can improve performance during HIE by facilitating lactic acid removal from the contracting muscle. Supplementation with beta-alanine increases the content of muscle carnosine, which is an endogenous intracellular buffer. It is clear that performance during HIE can be improved by interventions that increase the capacity of anaerobic ATP production, suggesting that energetic constraints set a limit for performance during HIE.
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Affiliation(s)
- Kent Sahlin
- Åstrand Laboratory of Work Physiology, GIH, The Swedish School of Sport and Health Sciences, Lidingövägen 1, Box 5626, 11486, Stockholm, Sweden,
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Claudino JG, Mezêncio B, Amaral S, Zanetti V, Benatti F, Roschel H, Gualano B, Amadio AC, Serrão JC. Creatine monohydrate supplementation on lower-limb muscle power in Brazilian elite soccer players. J Int Soc Sports Nutr 2014; 11:32. [PMID: 24991195 PMCID: PMC4077550 DOI: 10.1186/1550-2783-11-32] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 06/06/2014] [Indexed: 12/04/2022] Open
Abstract
Background Studies involving chronic creatine supplementation in elite soccer players are scarce. Therefore, the aim of this study was to examine the effects of creatine monohydrate supplementation on lower-limb muscle power in Brazilian elite soccer players (n = 14 males) during pre-season training. Findings This was a randomized, double-blind, placebo-controlled parallel-group study. Brazilian professional elite soccer players participated in this study. During the pre-season (7 weeks), all the subjects underwent a standardized physical and specific soccer training. Prior to and after either creatine monohydrate or placebo supplementation, the lower-limb muscle power was measured by countermovement jump performance. The Jumping performance was compared between groups at baseline (p = 0.99). After the intervention, jumping performance was lower in the placebo group (percent change = - 0.7%; ES = - 0.3) than in the creatine group (percent change = + 2.4%; ES = + 0.1), but it did not reach statistical significance (p = 0.23 for time x group interaction). Fisher’s exact test revealed that the proportion of subjects that experienced a reduction in jumping performance was significantly greater in the placebo group than in the creatine group (5 and 1, respectively; p = 0.05) after the training. The magnitude-based inferences demonstrated that placebo resulted in a possible negative effect (50%) in jumping performance, whereas creatine supplementation led to a very likely trivial effect (96%) in jumping performance in the creatine group. Conclusions Creatine monohydrate supplementation prevented the decrement in lower-limb muscle power in elite soccer players during a pre-season progressive training.
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Affiliation(s)
- João G Claudino
- School of Physical Education and Sport - Laboratory of Biomechanics, University of Sao Paulo, Av Mello de Moraes, 65, Sao Paulo, SP 05508-030, Brazil
| | - Bruno Mezêncio
- School of Physical Education and Sport - Laboratory of Biomechanics, University of Sao Paulo, Av Mello de Moraes, 65, Sao Paulo, SP 05508-030, Brazil
| | - Sérgio Amaral
- Department of Health and Performance, Red Bull Brazil Football, João Lúcio do Prado street, Km 10, Jarinu, SP 13240-000, Brazil
| | - Vinícius Zanetti
- Department of Health and Performance, Red Bull Brazil Football, João Lúcio do Prado street, Km 10, Jarinu, SP 13240-000, Brazil
| | - Fabiana Benatti
- School of Physical Education and Sport - Laboratory of Applied Nutrition and Metabolism, University of Sao Paulo, Av Mello de Moraes, 65, Sao Paulo, SP 05508-030, Brazil
| | - Hamilton Roschel
- School of Physical Education and Sport - Laboratory of Applied Nutrition and Metabolism, University of Sao Paulo, Av Mello de Moraes, 65, Sao Paulo, SP 05508-030, Brazil ; School of Physical Education and Sport - Laboratory of Neuromuscular Adaptations to Strength Training, University of Sao Paulo, Av Mello de Moraes, 65, Sao Paulo, SP 05508-030, Brazil ; School of Medicine - Division of Rheumatology, University of Sao Paulo, Av Mello de Moraes, 65, Sao Paulo, SP 05508-030, Brazil
| | - Bruno Gualano
- School of Physical Education and Sport - Laboratory of Applied Nutrition and Metabolism, University of Sao Paulo, Av Mello de Moraes, 65, Sao Paulo, SP 05508-030, Brazil ; School of Medicine - Division of Rheumatology, University of Sao Paulo, Av Mello de Moraes, 65, Sao Paulo, SP 05508-030, Brazil
| | - Alberto C Amadio
- School of Physical Education and Sport - Laboratory of Biomechanics, University of Sao Paulo, Av Mello de Moraes, 65, Sao Paulo, SP 05508-030, Brazil
| | - Julio C Serrão
- School of Physical Education and Sport - Laboratory of Biomechanics, University of Sao Paulo, Av Mello de Moraes, 65, Sao Paulo, SP 05508-030, Brazil
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Knapik JJ, Steelman RA, Hoedebecke SS, Farina EK, Austin KG, Lieberman HR. A systematic review and meta-analysis on the prevalence of dietary supplement use by military personnel. Altern Ther Health Med 2014; 14:143. [PMID: 24884570 PMCID: PMC4023532 DOI: 10.1186/1472-6882-14-143] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 04/25/2014] [Indexed: 12/14/2022]
Abstract
Background Although a number of studies have been conducted on the prevalence of dietary supplement (DS) use in military personnel, these investigations have not been previously summarized. This article provides a systematic literature review of this topic. Methods Literature databases, reference lists, and other sources were searched to find studies that quantitatively examined the prevalence of DS use in uniformed military groups. Prevalence data were summarized by gender and military service. Where there were at least two investigations, meta-analysis was performed using a random model and homogeneity of the prevalence values was assessed. Results The prevalence of any DS use for Army, Navy, Air Force, and Marine Corps men was 55%, 60%, 60%, and 61%, respectively; for women corresponding values were 65%, 71%, 76%, and 71%, respectively. Prevalence of multivitamin and/or multimineral (MVM) use for Army, Navy, Air Force, and Marine Corps men was 32%, 46%, 47%, and 41%, respectively; for women corresponding values were 40%, 55%, 63%, and 53%, respectively. Use prevalence of any individual vitamin or mineral supplement for Army, Navy, Air Force, and Marine Corps men was 18%, 27%, 25%, and 24%, respectively; for women corresponding values were 29%, 36%, 40%, and 33%, respectively. Men in elite military groups (Navy Special Operations, Army Rangers, and Army Special Forces) had a use prevalence of 76% for any DS and 37% for MVM, although individual studies were not homogenous. Among Army men, Army women, and elite military men, use prevalence of Vitamin C was 15% for all three groups; for Vitamin E, use prevalence was 8%, 7%, and 9%, respectively; for sport drinks, use prevalence was 22%, 25% and 39%, respectively. Use prevalence of herbal supplements was generally low compared to vitamins, minerals, and sport drinks, ≤5% in most investigations. Conclusions Compared to men, military women had a higher use prevalence of any DS and MVM. Army men and women tended to use DSs and MVM less than other service members. Elite military men appeared to use DSs and sport drinks more than other service members.
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Barber JJ, McDermott AY, McGaughey KJ, Olmstead JD, Hagobian TA. Effects of combined creatine and sodium bicarbonate supplementation on repeated sprint performance in trained men. J Strength Cond Res 2013; 27:252-8. [PMID: 23254493 DOI: 10.1519/jsc.0b013e318252f6b7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Creatine and sodium bicarbonate supplementation independently increase exercise performance, but it remains unclear whether combining these 2 supplements is more beneficial on exercise performance. The purpose of this study was to evaluate the impact of combining creatine monohydrate and sodium bicarbonate supplementation on exercise performance. Thirteen healthy, trained men (21.1 ± 0.6 years, 23.5 ± 0.5 kg·m(-2), 66.7 ± 5.7 ml·(kg·m)(-1) completed 3 conditions in a double-blinded, crossover fashion: (a) Placebo (Pl; 20 g maltodextrin + 0.5 g·kg(-1) maltodextrin), (b) Creatine (Cr; 20 g + 0.5 g·kg(-1) maltodextrin), and (c) Creatine plus sodium bicarbonate (Cr + Sb; 20 g + 0.5 g·kg(-1) sodium bicarbonate). Each condition consisted of supplementation for 2 days followed by a 3-week washout. Peak power, mean power, relative peak power, and bicarbonate concentrations were assessed during six 10-second repeated Wingate sprint tests on a cycle ergometer with a 60-second rest period between each sprint. Compared with Pl, relative peak power was significantly higher in Cr (4%) and Cr + Sb (7%). Relative peak power was significantly lower in sprints 4-6, compared with that in sprint 1, in both Pl and Cr. However, in Cr + Sb, sprint 6 was the only sprint significantly lower compared with sprint 1. Pre-Wingate bicarbonate concentrations were significantly higher in Cr + Sb (10%), compared with in Pl and Cr, and mean concentrations remained higher after sprint 6, although not significantly. Combining creatine and sodium bicarbonate supplementation increased peak and mean power and had the greatest attenuation of decline in relative peak power over the 6 repeated sprints. These data suggest that combining these 2 supplements may be advantageous for athletes participating in high-intensity, intermittent exercise.
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Affiliation(s)
- James J Barber
- Human Performance Laboratory, Department of Kinesiology, California Polytechnic State University San Luis Obispo, San Luis Obispo, CA, USA
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21
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Tang FC, Chan CC, Kuo PL. Contribution of creatine to protein homeostasis in athletes after endurance and sprint running. Eur J Nutr 2013; 53:61-71. [PMID: 23392621 DOI: 10.1007/s00394-013-0498-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2012] [Accepted: 01/17/2013] [Indexed: 11/29/2022]
Abstract
PURPOSE Few studies have focused on the metabolic changes induced by creatine supplementation. This study investigated the effects of creatine supplementation on plasma and urinary metabolite changes of athletes after endurance and sprint running. METHODS Twelve male athletes (20.3 ± 1.4 y) performed two identical (65-70 % maximum heart rate reserved) 60 min running exercises (endurance trial) before and after creatine supplementation (12 g creatine monohydrate/day for 15 days), followed by a 5-day washout period. Subsequently, they performed two identical 100 m sprint running exercises (power trial) before and after 15 days of creatine supplementation in accordance with the supplementary protocol of the endurance trial. Body composition measurements were performed during the entire study. Plasma samples were examined for the concentrations of glucose, lactate, branched-chain amino acids (BCAAs), free-tryptophan (f-TRP), glutamine, alanine, hypoxanthine, and uric acid. Urinary samples were examined for the concentrations of hydroxyproline, 3-methylhistidine, urea nitrogen, and creatinine. RESULTS Creatine supplementation significantly increased body weights of the athletes of endurance trial. Plasma lactate concentration and ratio of f-TRP/BCAAs after recovery from endurance running were significantly decreased with creatine supplementation. Plasma purine metabolites (the sum of hypoxanthine and uric acid), glutamine, urinary 3-methylhistidine, and urea nitrogen concentrations tended to decrease before running in trials with creatine supplements. After running, urinary hydroxyproline concentration significantly increased in the power trial with creatine supplements. CONCLUSIONS The findings suggest that creatine supplementation tended to decrease muscle glycogen and protein degradation, especially after endurance exercise. However, creatine supplementation might induce collagen proteolysis in athletes after sprint running.
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Affiliation(s)
- Fu-Chun Tang
- Graduate Institute of Nutritional Sciences and Education, #162, Hoping E. Rd. 1st Sec, Taipei, 10600, Taiwan, ROC,
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Head SI, Greenaway B, Chan S. Incubating isolated mouse EDL muscles with creatine improves force production and twitch kinetics in fatigue due to reduction in ionic strength. PLoS One 2011; 6:e22742. [PMID: 21850234 PMCID: PMC3151260 DOI: 10.1371/journal.pone.0022742] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Accepted: 07/03/2011] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Creatine supplementation can improve performance during high intensity exercise in humans and improve muscle strength in certain myopathies. In this present study, we investigated the direct effects of acute creatine incubation on isolated mouse fast-twitch EDL muscles, and examined how these effects change with fatigue. METHODS AND RESULTS The extensor digitorum longus muscle from mice aged 12-14 weeks was isolated and stimulated with field electrodes to measure force characteristics in 3 different states: (i) before fatigue; (ii) immediately after a fatigue protocol; and (iii) after recovery. These served as the control measurements for the muscle. The muscle was then incubated in a creatine solution and washed. The measurement of force characteristics in the 3 different states was then repeated. In un-fatigued muscle, creatine incubation increased the maximal tetanic force. In fatigued muscle, creatine treatment increased the force produced at all frequencies of stimulation. Incubation also increased the rate of twitch relaxation and twitch contraction in fatigued muscle. During repetitive fatiguing stimulation, creatine-treated muscles took 55.1±9.5% longer than control muscles to lose half of their original force. Measurement of weight changes showed that creatine incubation increased EDL muscle mass by 7%. CONCLUSION Acute creatine application improves force production in isolated fast-twitch EDL muscle, and these improvements are particularly apparent when the muscle is fatigued. One likely mechanism for this improvement is an increase in Ca(2+) sensitivity of contractile proteins as a result of ionic strength decreases following creatine incubation.
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Affiliation(s)
- Stewart I Head
- School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia.
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Abstract
A well designed diet is the foundation upon which optimal training and performance can be developed. However, as long as competitive sports have existed, athletes have attempted to improve their performance by ingesting a variety of substances. This practice has given rise to a multi-billion-dollar industry that aggressively markets its products as performance enhancing, often without objective, scientific evidence to support such claims. While a number of excellent reviews have evaluated the performance-enhancing effects of most dietary supplements, less attention has been paid to the performance-enhancing claims of dietary supplements in the context of team-sport performance. Dietary supplements that enhance some types of athletic performance may not necessarily enhance team-sport performance (and vice versa). Thus, the first aim of this review is to critically evaluate the ergogenic value of the most common dietary supplements used by team-sport athletes. The term dietary supplements will be used in this review and is defined as any product taken by the mouth, in addition to common foods, that has been proposed to have a performance-enhancing effect; this review will only discuss substances that are not currently banned by the World Anti-Doping Agency. Evidence is emerging to support the performance-enhancing claims of some, but not all, dietary supplements that have been proposed to improve team-sport-related performance. For example, there is good evidence that caffeine can improve single-sprint performance, while caffeine, creatine and sodium bicarbonate ingestion have all been demonstrated to improve multiple-sprint performance. The evidence is not so strong for the performance-enhancing benefits of β-alanine or colostrum. Current evidence does not support the ingestion of ribose, branched-chain amino acids or β-hydroxy-β-methylbutyrate, especially in well trained athletes. More research on the performance-enhancing effects of the dietary supplements highlighted in this review needs to be conducted using team-sport athletes and using team-sport-relevant testing (e.g. single- and multiple-sprint performance). It should also be considered that there is no guarantee that dietary supplements that improve isolated performance (i.e. single-sprint or jump performance) will remain effective in the context of a team-sport match. Thus, more research is also required to investigate the effects of dietary supplements on simulated or actual team-sport performance. A second aim of this review was to investigate any health issues associated with the ingestion of the more commonly promoted dietary supplements. While most of the supplements described in the review appear safe when using the recommended dose, the effects of higher doses (as often taken by athletes) on indices of health remain unknown, and further research is warranted. Finally, anecdotal reports suggest that team-sport athletes often ingest more than one dietary supplement and very little is known about the potential adverse effects of ingesting multiple supplements. Supplements that have been demonstrated to be safe and efficacious when ingested on their own may have adverse effects when combined with other supplements. More research is required to investigate the effects of ingesting multiple supplements (both on performance and health).
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Affiliation(s)
- David Bishop
- Institute of Sport, Exercise and Active Living (ISEAL) and School of Sport and Exercise Science, Victoria University, Melbourne, Victoria, Australia.
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Hickner RC, Dyck DJ, Sklar J, Hatley H, Byrd P. Effect of 28 days of creatine ingestion on muscle metabolism and performance of a simulated cycling road race. J Int Soc Sports Nutr 2010; 7:26. [PMID: 20609257 PMCID: PMC2909923 DOI: 10.1186/1550-2783-7-26] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2010] [Accepted: 07/07/2010] [Indexed: 12/02/2022] Open
Abstract
Purpose The effects of creatine supplementation on muscle metabolism and exercise performance during a simulated endurance road race was investigated. Methods Twelve adult male (27.3 ± 1.0 yr, 178.6 ± 1.4 cm, 78.0 ± 2.5 kg, 8.9 ± 1.1 %fat) endurance-trained (53.3 ± 2.0 ml* kg-1* min-1, cycling ~160 km/wk) cyclists completed a simulated road race on a cycle ergometer (Lode), consisting of a two-hour cycling bout at 60% of peak aerobic capacity (VO2peak) with three 10-second sprints performed at 110% VO2 peak every 15 minutes. Cyclists completed the 2-hr cycling bout before and after dietary creatine monohydrate or placebo supplementation (3 g/day for 28 days). Muscle biopsies were taken at rest and five minutes before the end of the two-hour ride. Results There was a 24.5 ± 10.0% increase in resting muscle total creatine and 38.4 ± 23.9% increase in muscle creatine phosphate in the creatine group (P < 0.05). Plasma glucose, blood lactate, and respiratory exchange ratio during the 2-hour ride, as well as VO2 peak, were not affected by creatine supplementation. Submaximal oxygen consumption near the end of the two-hour ride was decreased by approximately 10% by creatine supplementation (P < 0.05). Changes in plasma volume from pre- to post-supplementation were significantly greater in the creatine group (+14.0 ± 6.3%) than the placebo group (-10.4 ± 4.4%; P < 0.05) at 90 minutes of exercise. The time of the final sprint to exhaustion at the end of the 2-hour cycling bout was not affected by creatine supplementation (creatine pre, 64.4 ± 13.5s; creatine post, 88.8 ± 24.6s; placebo pre, 69.0 ± 24.8s; placebo post 92.8 ± 31.2s: creatine vs. placebo not significant). Power output for the final sprint was increased by ~33% in both groups (creatine vs. placebo not significant). Conclusions It can be concluded that although creatine supplementation may increase resting muscle total creatine, muscle creatine phosphate, and plasma volume, and may lead to a reduction in oxygen consumption during submaximal exercise, creatine supplementation does not improve sprint performance at the end of endurance cycling exercise.
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Affiliation(s)
- Robert C Hickner
- Department of Exercise and Sport Science, Human Performance Laboratory, East Carolina University, Greenville, USA.
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Kuczmarski K. Do Supplements Benefit Exercise? Am J Lifestyle Med 2008. [DOI: 10.1177/1559827608317769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
It is a known fact that exercise will have beneficial effects on one's health. Nutritional supplementation is on the rise, resulting in a billion-dollar industry. However, because these medications are not regulated by the Food and Drug Administration, it is difficult for the public to determine what is safe and effective. Health care providers have to be aware of this lack of knowledge and educate their patients on which supplements are beneficial and which may be harmful to their health.
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Jäger R, Metzger J, Lautmann K, Shushakov V, Purpura M, Geiss KR, Maassen N. The effects of creatine pyruvate and creatine citrate on performance during high intensity exercise. J Int Soc Sports Nutr 2008; 5:4. [PMID: 18269769 PMCID: PMC2276184 DOI: 10.1186/1550-2783-5-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2007] [Accepted: 02/13/2008] [Indexed: 11/28/2022] Open
Abstract
Background A double-blind, placebo-controlled, randomized study was performed to evaluate the effect of oral creatine pyruvate (Cr-Pyr) and creatine citrate (Cr-Cit) supplementation on exercise performance in healthy young athletes. Methods Performance during intermittent handgrip exercise of maximal intensity was evaluated before (pretest) and after (posttest) 28 days of Cr-Pyr (5 g/d, n = 16), Cr-Cit (5 g/d, n = 16) or placebo (pla, 5 g/d, n = 17) intake. Subjects performed ten 15-sec exercise intervals, each followed by 45 sec rest periods. Results Cr-Pyr (p < 0.001) and Cr-Cit (p < 0.01) significantly increased mean power over all intervals. Cr-Cit increased force during the first and second interval (p < 0.01) compared to placebo. The effect of Cr-Cit on force decreased over time and the improvement was not significant at the sixth and ninth interval, whereas Cr-Pyr significantly increased force during all intervals (p < 0.001). Cr-Pyr (p < 0.001) and Cr-Cit (p < 0.01) resulted in an increase in contraction velocity, whereas only Cr-Pyr intake significantly (p < 0.01) increased relaxation velocity. Oxygen consumption measured during rest periods significantly increased with Cr-Pyr (p < 0.05), whereas Cr-Cit and placebo intake did not result in significant improvements. Conclusion It is concluded that four weeks of Cr-Pyr and Cr-Cit intake significantly improves performance during intermittent handgrip exercise of maximal intensity and that Cr-Pyr might benefit endurance, due to enhanced activity of the aerobic metabolism.
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Affiliation(s)
- Ralf Jäger
- Increnovo LLC, 2138 E Lafayette Pl, Milwaukee, WI 53202, USA.
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Faager G, Söderlund K, Sköld CM, Rundgren S, Tollbäck A, Jakobsson P. Creatine supplementation and physical training in patients with COPD: a double blind, placebo-controlled study. Int J Chron Obstruct Pulmon Dis 2008; 1:445-53. [PMID: 18044100 PMCID: PMC2707812 DOI: 10.2147/copd.2006.1.4.445] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Study objectives Patients with chronic obstructive pulmonary disease (COPD) have low exercise capacity and low content of high energetic phosphates in their skeletal muscles. The aim of the present study was to investigate whether creatine supplementation together with exercise training may increase physical performance compared with exercise training in patients with COPD. Design In a randomized, double-blind, placebo-controlled study, 23 patients with COPD (forced expiratory volume in one second [FEV1] < 70% of predicted) were randomized to oral creatine (n = 13) or placebo (n = 10) supplementation during an 8-week rehabilitation programme including exercise training. Physical performance was assessed by Endurance Shuttle Walking Test (ESWT), dyspnea and leg fatigue with Borg CR-10, quality of life with St George’s Respiratory Questionnaire (SGRQ). In addition, lung function test, artery blood gases, grip strength test, muscle strength and fatigue in knee extensors were measured. Results COPD patients receiving creatine supplementation increased their average walking time by 61% (ESWT) (p < 0.05) after the training period compared with 48% (p = 0.07) in the placebo group. Rated dyspnea directly after the ESWT decreased significantly from 7 to 5 (p < 0.05) in the creatine group. However, the difference between the groups was not statistically significant neither in walking time nor in rated dyspnea. Creatine supplementation did not increase the health related quality of life, lung function, artery blood gases, grip strength and knee extensor strength/fatigue. Conclusions Oral creatine supplementation in combination with exercise training showed no significant improvement in physical performance, measured as ESWT, in patients with COPD compared with exercise training alone.
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Affiliation(s)
- Gun Faager
- Department of Neurobiology, Care Sciences and Society, Division of Physiotherapy, Karolinska Institutet, Department of Physiotherapy, Karolinska University Hospital, Solna, Sweden.
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Abstract
AbstractThe use of nutritional supplements in sport is widespread and few serious athletes do not, at some stage in their career, succumb to the temptation to experiment with one or more nutritional supplements. Nutritional ergogenic aids are aimed primarily at enhancing performance (either by affecting energy metabolism or by an effect on the central nervous system), at increasing lean body mass or muscle mass by stimulation of protein synthesis and at reducing body fat content. Although not strictly ergogenic (i.e. capable of enhancing work performance), supplements aimed at increasing resistance to infection and improving general health are seen by athletes as important in reducing the interruptions to training that minor illness and infection can cause. Creatine is perhaps the most widely used supplement in sport at the moment. Supplementation can increase muscle creatine phosphate levels and, although not all published studies show positive results, there is much evidence that performance of short-term high-intensity exercise can be improved by supplementation. Ingestion of large doses of bicarbonate can enhance performance of exercise where metabolic acidosis may be a limiting factor, but there is a significant risk of adverse gastrointestinal side effects. Caffeine can also improve performance, in part by a stimulation of fatty acid mobilization and sparing of the body's limited carbohydrate stores, but also via direct effects on muscle and possibly by central nervous system effects on the perception of effort and fatigue. Carnitine plays an essential role in fatty acid oxidation in muscle but, although supplements are used by athletes, there is no good evidence of a beneficial effect of supplementation. None of these products contravenes the International Olympic Committee regulations on doping in sports, although caffeine is not permitted above a urine concentration of 12 mg/l. Supplementation is particularly prevalent among strength and power athletes, where an increase in muscle mass can benefit performance. Protein supplements have not been shown to be effective except in those rare cases where the dietary protein intake is otherwise inadequate. Individual amino acids, especially ornithine, arginine and glutamine, are also commonly used, but their benefit is not supported by documented evidence. Cr and hydroxymethylbutyrate are also used by strength athletes, but again there are no well-controlled studies to provide evidence of a beneficial effect. Athletes use a wide variety of supplements aimed at improving or maintaining general health and vitamin and mineral supplementation is widespread. There is a theoretical basis, and limited evidence, to support the use of antioxidant vitamins and glutamine during periods of intensive training, but further evidence is required before the use of these supplements can be recommended.
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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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Gotshalk LA, Kraemer WJ, Mendonca MAG, Vingren JL, Kenny AM, Spiering BA, Hatfield DL, Fragala MS, Volek JS. Creatine supplementation improves muscular performance in older women. Eur J Appl Physiol 2007; 102:223-31. [DOI: 10.1007/s00421-007-0580-y] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/20/2007] [Indexed: 01/06/2023]
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Souza Júnior TPD, Dubas JP, Pereira B, Oliveira PRD. Suplementação de creatina e treinamento de força: alterações na resultante de força máxima dinâmica e variáveis antropométricas em universitários submetidos a oito semanas de treinamento de força (hipertrofia). REV BRAS MED ESPORTE 2007. [DOI: 10.1590/s1517-86922007000500005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
OBJETIVO: Verificar as alterações promovidas pela suplementação de creatina nas variáveis antropométricas e da resultante de força máxima dinâmica (RFMD) em universitários submetidos a oito semanas de treinamento de força. METODOLOGIA: Participaram deste estudo, 18 universitários do sexo masculino, com idade entre 19 e 25 anos. Antes do treinamento foram determinadas a estatura (cm), a massa corporal (kg) e testes de ação muscular voluntária máxima dinâmica (1AMVMD), os sujeitos foram assinalados a um dos dois grupos, A (creatina) e B (placebo), foi adotado o protocolo duplo-cego. Após oito semanas de treinamento de força, repetiu-se a bateria de testes do pré-treinamento. RESULTADOS: Após oito semanas, verificou-se que tanto no grupo A como no B houve alterações estatisticamente significantes (ES) na RFMD em todos os exercícios (p = 0,007 a 0,008). A análise da melhora percentual e do delta da RFMD, nos exercícios de agachamento, desenvolvimento e supino fechado, mostrou que o grupo A teve alterações positivas ES superiores ao grupo B (p = 0,008 a 0,038). A massa magra aumentou ES somente no grupo A (p = 0,038). Contudo, o percentual de gordura corporal não mostrou alterações em nenhum dos grupos. A relação entre a melhora percentual (MP) das circunferências (C) do braço e antebraço e a MP na RFMD do exercício de desenvolvimento foi ES (r = 0,481 e 0,546, respectivamente), bem como entre a MP na C da coxa e na MP da RFMD do exercício de agachamento (r = 0,619). CONCLUSÃO: Independente do suplemento ingerido o treinamento de força foi capaz de induzir ajustes positivos na RFMD; contudo, a suplementação de creatina mostrou-se mais eficiente que o placebo, induzindo a maior aumento percentual e de delta na força.
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Spencer M, Bishop D, Dawson B, Goodman C. Physiological and metabolic responses of repeated-sprint activities:specific to field-based team sports. Sports Med 2006; 35:1025-44. [PMID: 16336007 DOI: 10.2165/00007256-200535120-00003] [Citation(s) in RCA: 393] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Field-based team sports, such as soccer, rugby and hockey are popular worldwide. There have been many studies that have investigated the physiology of these sports, especially soccer. However, some fitness components of these field-based team sports are poorly understood. In particular, repeated-sprint ability (RSA) is one area that has received relatively little research attention until recent times. Historically, it has been difficult to investigate the nature of RSA, because of the unpredictability of player movements performed during field-based team sports. However, with improvements in technology, time-motion analysis has allowed researchers to document the detailed movement patterns of team-sport athletes. Studies that have published time-motion analysis during competition, in general, have reported the mean distance and duration of sprints during field-based team sports to be between 10-20 m and 2-3 seconds, respectively. Unfortunately, the vast majority of these studies have not reported the specific movement patterns of RSA, which is proposed as an important fitness component of team sports. Furthermore, there have been few studies that have investigated the physiological requirements of one-off, short-duration sprinting and repeated sprints (<10 seconds duration) that is specific to field-based team sports. This review examines the limited data concerning the metabolic changes occurring during this type of exercise, such as energy system contribution, adenosine triphosphate depletion and resynthesis, phosphocreatine degradation and resynthesis, glycolysis and glycogenolysis, and purine nucleotide loss. Assessment of RSA, as a training and research tool, is also discussed.
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Affiliation(s)
- Matt Spencer
- Team Sport Research Group, School of Human Movement and Exercise Science, The University of Western Australia, Crawley, Western Australia, Australia.
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Glaister M. Multiple sprint work : physiological responses, mechanisms of fatigue and the influence of aerobic fitness. Sports Med 2005; 35:757-77. [PMID: 16138786 DOI: 10.2165/00007256-200535090-00003] [Citation(s) in RCA: 289] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The activity patterns of many sports (e.g. badminton, basketball, soccer and squash) are intermittent in nature, consisting of repeated bouts of brief (<or=6-second) maximal/near-maximal work interspersed with relatively short (<or=60-second) moderate/low-intensity recovery periods. Although this is a general description of the complex activity patterns experienced in such events, it currently provides the best means of directly assessing the physiological response to this type of exercise. During a single short (5- to 6-second) sprint, adenosine triphosphate (ATP) is resynthesised predominantly from anaerobic sources (phosphocreatine [PCr] degradation and glycolysis), with a small (<10%) contribution from aerobic metabolism. During recovery, oxygen uptake (V-O2) remains elevated to restore homeostasis via processes such as the replenishment of tissue oxygen stores, the resynthesis of PCr, the metabolism of lactate, and the removal of accumulated intracellular inorganic phosphate (Pi). If recovery periods are relatively short, V-O2 remains elevated prior to subsequent sprints and the aerobic contribution to ATP resynthesis increases. However, if the duration of the recovery periods is insufficient to restore the metabolic environment to resting conditions, performance during successive work bouts may be compromised. Although the precise mechanisms of fatigue during multiple sprint work are difficult to elucidate, evidence points to a lack of available PCr and an accumulation of intracellular Pi as the most likely causes. Moreover, the fact that both PCr resynthesis and the removal of accumulated intracellular Pi are oxygen-dependent processes has led several authors to propose a link between aerobic fitness and fatigue during multiple sprint work. However, whilst the theoretical basis for such a relationship is compelling, corroborative research is far from substantive. Despite years of investigation, limitations in analytical techniques combined with methodological differences between studies have left many issues regarding the physiological response to multiple sprint work unresolved. As such, multiple sprint work provides a rich area for future applied sports science research.
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Affiliation(s)
- Mark Glaister
- School of Human Sciences, St Mary's College, a College of the University of Surrey, Strawberry Hill, Twickenham, UK.
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Peyrebrune MC, Stokes K, Hall GM, Nevill ME. Effect of creatine supplementation on training for competition in elite swimmers. Med Sci Sports Exerc 2005; 37:2140-7. [PMID: 16331142 DOI: 10.1249/01.mss.0000179101.38913.73] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE The study was conducted to examine the effects of oral creatine supplementation on training for competition in 20 elite swimmers. METHODS Subjects performed a maximal sprint test (8 x 50 yd (45.72 m), T1) before loading with creatine (Cr, 20 g.d Cr monohydrate for 5 d), 1 wk later (T2), and following a 22- to 27-wk period of training and competition (T3). Following T2, subjects supplemented with either Cr (3 g + glucose 7 g.d) or placebo (glucose 10 g.d; double blind) for the remainder of the 22- to 27-wk season and then both groups supplemented once more with 20 g.d Cr monohydrate for 5 d before their major competition. Venous and capillary blood samples were obtained pre- and posttest during the repeated sprint tests to determine blood metabolites and hormones. Competition times were recorded, and changes in subjects' best times were used to compare the effect of training and supplementation on competitive performance. RESULTS Mean competition times in the Cr and control groups changed by+1.90 +/-1.91 and+0.72+/-1.64% for short course (SC, 25-m pool) and by+0.14+/-1.14 and -0.59+/-0.82% long course (LC, 50-m pool), respectively (Cr vs control, NS). No differences between groups were found in blood metabolites, although the human growth hormone (hGH) response to repeated sprints was blunted following Cr loading (T1, 30.42+/-14.60 and 28.95+/-18.27 microg.L; T2, 21.48+/-13.96 and 14.24+/-7.32 microg.L for Cr and control groups, respectively P<0.05). CONCLUSION No statistically significant differences in performance were observed between groups after long-term maintenance during training, although small differences were observed that might be meaningful for elite performers.
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Affiliation(s)
- Michael C Peyrebrune
- English Institute of Sport, EIS Pool, Loughborough University, Leicestershire, ENGLAND.
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Mendel RW, Blegen M, Cheatham C, Antonio J, Ziegenfuss T. Effects of creatine on thermoregulatory responses while exercising in the heat. Nutrition 2005; 21:301-7. [PMID: 15797670 DOI: 10.1016/j.nut.2004.06.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2004] [Accepted: 06/21/2004] [Indexed: 11/16/2022]
Abstract
OBJECTIVE We hypothesized that creatine supplementation would interfere with normal body fluid shifts that occur during exercise in a hot environment due to its osmotic effect intracellularly. This study examined the effects of acute creatine loading (20 g/d for 5 d) on the thermoregulatory response of the body during a bout of exercise at 39 degrees C. METHODS Subjects (15 men and 1 woman) performed a cycle test of maximum oxygen consumption to determine the proper work rate for the heat-stress test (40 min at 55% maximum oxygen consumption at 39 degrees C) and were assigned to a creatine group (n = 8) or a placebo group (n = 8) in a double-blind fashion. Each group performed the heat-stress test on two separate occasions: before supplementation and after supplementation (20 g/d of creatine with Gatorade or Solka-floc plus Gatorade). Dependent variables included rectal temperature, mean skin temperature, mean body temperature, and perceived thermal sensation. RESULTS Repeated measure analysis of variance showed a significant (P < or = 0.05) increase in body weight in the group supplemented with Gatorade. Core temperature was significantly lower after supplementation for both groups combined (before supplementation at 37.85 degrees C and after supplementation at 37.7 degrees C), with no difference between groups. A significant three-way interaction (group x trial x time) was also found for rectal temperature, with both groups having significantly lower rectal temperature after supplementation. Mean body and mean skin temperatures showed no differences. CONCLUSIONS Short-term creatine supplementation (20 g/d for 5 d) did not have a negative effect on thermoregulatory responses during exercise at 39 degrees C.
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Javierre C, Barbany JR, Bonjorn VM, Lizárraga MA, Ventura JL, Segura R. Creatine supplementation and performance in 6 consecutive 60 meter sprints. J Physiol Biochem 2005; 60:265-71. [PMID: 15957245 DOI: 10.1007/bf03167072] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Creatine is an ergogenic aid used in individual and team sports. The aim of this study is to analyze the effect of monohydrate creatine supplementation on physical performance during 6 consecutive maximal speed 60 meter races, and the changes induced in some characteristic biochemical and ventilatory parameters. The study was carried out on nineteen healthy and physically active male volunteers, and randomly distributed into two groups: Group C received a supplement of creatine monohydrate (20 g/day for 5 days) and group P received placebo. Tests were performed before and after supplementation. No significant changes were observed in weight or body water measured by bioimpedance or the sum of 7 skinfold or performance during the 60 meter races. Group C showed a statistically significant increase in plasma creatinine from 69.8 +/- 12.4 to 89.3 +/- 12.4 micromol x L(-1) (p<0.05). In group C in the second control day (after creatine supplementation), expiratory volume V(E), O2 uptake and CO2 production were lower after 2 minutes of active recovery period. These results indicate that creatine monohydrate supplementation does not appear to improve the performance in 6 consecutive 60 meter repeated races but may modify ventilatory dynamics during the recovery after maximal effort.
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Affiliation(s)
- C Javierre
- Depto. de Ciencias Fisiológicas II, Facultad de Medicina (Campus de Bellvitge), (IDIBELL), Universidad de Barcelona, Ctra. Feixa Llarga s./n., 08907 L'Hospitalet de Llobregat, Spain.
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Harris P, Harris R. Ergogenic potential of nutritional strategies and substances in the horse. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/j.livprodsci.2004.11.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Murphy RM, Stephenson DG, Lamb GD. Effect of creatine on contractile force and sensitivity in mechanically skinned single fibers from rat skeletal muscle. Am J Physiol Cell Physiol 2004; 287:C1589-95. [PMID: 15282195 DOI: 10.1152/ajpcell.00276.2004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Increasing the intramuscular stores of total creatine [TCr = creatine (Cr) + creatine phosphate (CrP)] can result in improved muscle performance during certain types of exercise in humans. Initial uptake of Cr is accompanied by an increase in cellular water to maintain osmotic balance, resulting in a decrease in myoplasmic ionic strength. Mechanically skinned single fibers from rat soleus (SOL) and extensor digitorum longus (EDL) muscles were used to examine the direct effects on the contractile apparatus of increasing [Cr], increasing [Cr] plus decreasing ionic strength, and increasing [Cr] and [CrP] with no change in ionic strength. Increasing [Cr] from 19 to 32 mM, accompanied by appropriate increases in water to maintain osmolality, had appreciable beneficial effects on contractile apparatus performance. Compared with control conditions, both SOL and EDL fibers showed increases in Ca2+ sensitivity (+0.061 ± 0.004 and +0.049 ± 0.009 pCa units, respectively) and maximum Ca2+-activated force (to 104 ± 1 and 105 ± 1%, respectively). In contrast, increasing [Cr] alone had a small inhibitory effect. When both [Cr] and [CrP] were increased, there was virtually no change in Ca2+ sensitivity of the contractile apparatus, and maximum Ca2+-activated force was ∼106 ± 1% compared with control conditions in both SOL and EDL fibers. These results suggest that the initial improvement in performance observed with Cr supplementation is likely due in large part to direct effects of the accompanying decrease in myoplasmic ionic strength on the properties of the contractile apparatus.
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Affiliation(s)
- Robyn M Murphy
- Department of Zoology, La Trobe University, Melbourne, Victoria 3086, Australia.
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Tokish JM, Kocher MS, Hawkins RJ. Ergogenic aids: a review of basic science, performance, side effects, and status in sports. Am J Sports Med 2004; 32:1543-53. [PMID: 15310585 DOI: 10.1177/0363546504268041] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The use of drugs and supplements to enhance performance has become a part of mainstream athletics. Many team physicians and sports medicine practitioners are unfamiliar with the benefits and risks of these products and thus are unable to educate young athletes on this topic. In spite of numerous reports on the health risks of anabolic steroid use, 1 to 3 million Americans have used them. Human growth hormone has been tried by up to 5% of 10th graders, although no scientific study has shown that it is an effective performance-enhancing drug. Amphetamines and similar compounds may be the most widely abused drug in baseball; recently, they have come under increased scrutiny in sport. Erythropoietin is a highly effective aerobic enhancer that has been linked to multiple deaths in cyclists and other endurance athletes. The neutraceutical industry, led by supplements such as creatine, ephedra, and androstenedione, remains unregulated by the Food and Drug Administration and has serious issues with quality and side effects. An understanding of these products is essential for the sports medicine practitioner to provide sound, safe advice to the athlete.
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Affiliation(s)
- John M Tokish
- US Air Force Academy, Colorado Springs, Colorado, USA
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Mendes RR, Pires I, Oliveira A, Tirapegui J. Effects of creatine supplementation on the performance and body composition of competitive swimmers. J Nutr Biochem 2004; 15:473-8. [PMID: 15302082 DOI: 10.1016/j.jnutbio.2003.12.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2003] [Revised: 10/29/2003] [Accepted: 12/15/2003] [Indexed: 11/17/2022]
Abstract
The objective of this study was to determine the effect of creatine supplementation on performance and body composition of swimmers. Eighteen swimmers were evaluated in terms of post-performance lactate accumulation, body composition, creatine and creatinine excretion, and serum creatinine concentrations before and after creatine or placebo supplementation. No significant differences were observed in the marks obtained in swimming tests after supplementation, although lactate concentrations were higher in placebo group during this period. In the creatine-supplemented group, urinary creatine, creatinine, and body mass, lean mass and body water were significantly increased, but no significant difference in muscle or bone mass was observed. These results suggest that creatine supplementation cannot be considered to be an ergogenic supplement ensuring improved performance and muscle mass gain in swimmers.
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Affiliation(s)
- Renata Rebello Mendes
- Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of São Paulo-Av, Lineu Prestes, São Paulo, SP, Brazil.
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Berg EP, Maddock KR, Linville ML. Creatine monohydrate supplemented in swine finishing diets and fresh pork quality: III. Evaluating the cumulative effect of creatine monohydrate and alpha-lipoic acid1,2. J Anim Sci 2003; 81:2469-74. [PMID: 14552373 DOI: 10.2527/2003.81102469x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The objective of this study was to evaluate short-duration supplementation of alpha-lipoic acid (ALA) and creatine monohydrate (CMH) to improve fresh pork quality. Forty-eight commercial hybrid barrows were blocked by BW and randomly allotted to one of four treatments: 1) no CMH or ALA; 2) supplementation of 24 g of CMH(-1) x pig(-1) x d(-1); 3) supplementation of 600 mg ALA(-1) x pig(-1) x d(-1); or 4) combined CMH and ALA supplements. Twelve pigs per treatment were individually penned with ad libitum access to water and a finishing diet. Treatments were hand-fed to individual pigs daily (divided into three equal doses) for 5 d before slaughter at 113 kg BW in two separate groups of 24 pigs each. Intramuscular pH was recorded at 45 min postmortem and again at 24 h in the ham semimembranosus (SM) and the longissimus muscle (LM) between the 10th and 11th rib. A Meatcheck (SFK Technology, Peosta, IA) conductivity probe was inserted in the same anatomical locations as pH measurement, providing an index value (PY) from 0 to 100 (a higher index value indicates more intact muscle cells and higher water-holding capacity). Color (L, a, b values) measurements were obtained at 24 h postmortem on the ham gluteus medius (GM), SM, and LM. Two 2.54-cm-thick loin chops were removed from the loin for determination of Warner-Bratzler shear force and glycolytic potential. The intact SM and the posterior portion of the boneless loin were vacuum-packaged and stored for 7 d to determine purge loss. Creatine-supplemented pigs had a higher (P = 0.03) PY value in the SM (66.67) at 45 min postmortem than either ALA, singularly (63.50), or in the combined CMH/ALA (62.27) treatments. (A higher PY index indicates superior water-holding capacity.) Lipoic acid supplementation resulted in the highest pH at 45 min (P = 0.029). These results justify further evaluation of the potential positive influence of supplementing alpha-lipoic acid to improve pork quality.
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Affiliation(s)
- E P Berg
- Department of Animal Science, University of Missouri, Columbia 65211-5300, USA.
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Ferrauti A, Remmert H. The effects of creatine supplementation: A review with special regards to ballgames. Eur J Sport Sci 2003. [DOI: 10.1080/17461390300073309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Bishop D, Lawrence S, Spencer M. Predictors of repeated-sprint ability in elite female hockey players. J Sci Med Sport 2003; 6:199-209. [PMID: 12945626 DOI: 10.1016/s1440-2440(03)80255-4] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The ability to maintain maximal power over a series of sprints may depend, in part, on the resynthesis of PCr and the buffering of hydrogen ions (H+). As a result, repeated-sprint ability may be related to VO2peak and changes in plasma pH. Fourteen elite female field-hockey players (Mean +/- SD body mass: 61.1 +/- 5.9 kg and VO2pea: 55.7 +/- 3.2 mL x kg(-1) x min(-1)) participated in this investigation. Tests consisted of a repeated-sprint ability test (5 x 6-s all-out sprints every 30 s) and a VO2peak test. Capillary and venous blood was sampled before and after the 5 x 6-s cycle test for the determination of lactate concentration and pH. There were no significant correlations between VO2peak (mL x kg(-1) x min(-1)) and total work (J.kg(-1); r = 0.35), or power decrement (r = 0.30) during the repeated-sprint ability test. There was, however, a significant correlation between power decrement and change in plasma [H+] (r = 0.66; P < 0.05). The results of this study show that in a homogenous group of elite, team-sport athletes, VO2peak (mL x kg(-1) x min(-1)) is not a strong predictor of repeated-sprint ability. However, in this group, there is a significant correlation between change in plasma [H+] and repeated-sprint ability.
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Affiliation(s)
- D Bishop
- The University of Western Australia
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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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Robinson DM, Loiselle DS. Effect of creatine manipulation on fast-twitch skeletal muscle of the mouse. Clin Exp Pharmacol Physiol 2002; 29:1105-11. [PMID: 12390299 DOI: 10.1046/j.1440-1681.2002.03782.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
1. The effect of short-term, reversible alteration of muscle total creatine content (Crtot) on force development was sought in fast-twitch extensor digitorum longus (EDL) muscles of female mice. 2. Three in vivo interventions were investigated: 1% creatine-supplementation, treatment with the creatine-uptake inhibitor beta-guanidino propionic acid (beta-GPA; 1%) or beta-GPA treatment followed by creatine supplementation for 5 days. 3. The Crtot of isolated muscles, determined using reverse-phase high-performance liquid chromatography, was 133 +/- 38 mmol/kg dry in 11 EDL control muscles and was not significantly affected by dietary creatine-supplementation (152 +/- 25 mmol/kg dry; n = 8). Significant creatine depletion was observed in the beta-GPA-fed group (65 +/- 6 mmol/kg dry; n = 9) and this was reversed by 5 days of creatine supplementation (133 +/- 21 mmol/kg dry; n = 10). 4. Creatine depletion did not affect maximum tetanic stress. However, when muscle creatine was restored by creatine supplementation, a substantial increase in tetanic stress was observed. Significant correlations were observed between Crtot and maximum tetanic stress (r = 0.56) and relaxation rate (r = 0.43). The enhancement of force was not due to effects of creatine on muscle fibre type because neither mechanical tests of fibre characteristics nor the fibre types of the muscles were affected. 5. We conclude that, in muscles that contain large numbers of fast-twitch fibres, maximum tetanic stress is determined, in part, by muscle creatine stores.
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Affiliation(s)
- Dean M Robinson
- Department of Physiology, Faculty of Medicine and Health Sciences, University of Auckland, Auckland, New Zealand.
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Abstract
BACKGROUND In an age of highly competitive sports, whether it be the high school student, the weekend warrior, or the professional athlete, more individuals are using "performance-enhancing" nutritional supplements. Many feel they are gaining a "competitive edge," without thinking of the potential consequences. Consumers are inundated with claims of strength, weight loss, and improved body definition, but they are rarely given information on the potentially harmful side effects. There are few large, multicenter, randomized trials of these various nutritional supplements that look at the purported claims and potential side effects. STUDY We reviewed the available studies, including case reports, and researched data on five of the most popular performance-enhancing supplements, including androstenedione, creatine, chromium, ephedra, and protein and amino acid supplements. CONCLUSIONS Of the reviewed supplements, only creatine may be marginally beneficial. The potential benefit would probably only be useful to the professional athlete and not the average person. All of the supplements reviewed have potentially harmful side effects; however, certain supplements clearly show harmful effects, and use should strongly be cautioned. In addition, ephedra should be withdrawn from the marketplace. At this time, without better-designed studies, these agents cannot be recommended.
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Affiliation(s)
- Marvin E Lawrence
- Department of Medicine, Psychiatry, Biochemistry, and Molecular Physics, Medical college of Virginia Hospitals and Physiciands of the virginia Commonwealth University Care System, Richmond, Virginia 23298-0711, USA
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Svensson MB, Ekblom B, Cotgreave IA, Norman B, Sjöberg B, Ekblom O, Sjödin B, Sjödin A. Adaptive stress response of glutathione and uric acid metabolism in man following controlled exercise and diet. ACTA PHYSIOLOGICA SCANDINAVICA 2002; 176:43-56. [PMID: 12193218 DOI: 10.1046/j.1365-201x.2002.01008.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Ergometer cycling performance as well as acute exercise-induced changes in the metabolism of energy-intermediates and glutathione (GSH) were investigated in skeletal muscle (SM) of 15 healthy young male subjects (VO(2max) approximately 54.7 mL kg(-1) min(-1), age approximately 25 years), before and after 3 days of controlled 'ìoverload-training' in combination with either high (62% of energy intake) or low (26% of energy intake) dietary intake of carbohydrates. The intake of a carbohydrate-rich diet clearly reduced the depletion of SM glycogen following the short-term training period, paralleled with a positive effect on the endurance performance, but not on high-intensity work-performance. An 'delayed over-reaching effect', defined as impaired work-performance, was observed after 2.5 days of recovery from the short-term training period, irrespective of the carbohydrate content of the diet and basal glycogen level in SM. Taken together, the main and novel findings of present investigation are: (1) an acute decrease of reduced GSH content and altered thiol-redox homeostasis in SM induced by strenuous high-intensity exercise; (2) an adaptive elevation of basal GSH level following the short-term training period; (3) an adaptive decrease of basal GSH level following 2.5 days recovery from training; (4) evidence of a relationship between the SM fibre type, physical performance capacity and GSH turnover during acute bouts of exercise; and (5) no evident effect of the level of carbohydrate intake on metabolism of GSH or energy intermediates. Furthermore, the induction of acute oxidative stress in exercising human SM and the adaptive responses to training are suggested to provide a protective antioxidant phenotype to the exercising SM during periods with repeated intense intermittent training.
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Affiliation(s)
- M B Svensson
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
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Jones AM, Carter H, Pringle JSM, Campbell IT. Effect of creatine supplementation on oxygen uptake kinetics during submaximal cycle exercise. J Appl Physiol (1985) 2002; 92:2571-7. [PMID: 12015375 DOI: 10.1152/japplphysiol.01065.2001] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The purpose of this study was to test the effect of oral creatine (Cr) supplementation on pulmonary oxygen uptake (VO(2)) kinetics during moderate [below ventilatory threshold (VT)] and heavy (above VT) submaximal cycle exercise. Nine subjects (7 men; means +/- SD: age 28 +/- 3 yr, body mass 73.2 +/- 5.6 kg, maximal VO(2) 46.4 +/- 8.0 ml. kg(-1). min(-1)) volunteered to participate in this study. Subjects performed transitions of 6-min duration from unloaded cycling to moderate (80% VT; 8-12 repeats) and heavy exercise (50% change; i.e., halfway between VT and maximal VO(2); 4-6 repeats), both in the control condition and after Cr loading, in a crossover design. The Cr loading regimen involved oral consumption of 20 g/day of Cr monohydrate for 5 days, followed by a maintenance dose of 5 g/day thereafter. VO(2) was measured breath by breath and modeled by using two (moderate) or three (heavy) exponential terms. For moderate exercise, there were no differences in the parameters of the VO(2) kinetic response between control and Cr-loaded conditions. For heavy exercise, the time-based parameters of the VO(2) response were unchanged, but the amplitude of the primary component was significantly reduced with Cr loading (means +/- SE: control 2.00 +/- 0.12 l/min; Cr loaded 1.92 +/- 0.10 l/min; P < 0.05) as was the end-exercise VO(2) (control 2.19 +/- 0.13 l/min; Cr loaded 2.12 +/- 0.14 l/min; P < 0.05). The magnitude of the reduction in submaximal VO(2) with Cr loading was significantly correlated with the percentage of type II fibers in the vastus lateralis (r = 0.87; P < 0.01; n = 7), indicating that the effect might be related to changes in motor unit recruitment patterns or the volume of muscle activated.
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Affiliation(s)
- Andrew M Jones
- Department of Exercise and Sport Science, Manchester Metropolitan University, Alsager ST7 2HL, United Kingdom.
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