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Leale I, Di Stefano V, Costanza C, Brighina F, Roccella M, Palma A, Battaglia G. Telecoaching: a potential new training model for Charcot-Marie-Tooth patients: a systematic review. Front Neurol 2024; 15:1359091. [PMID: 38784904 PMCID: PMC11112069 DOI: 10.3389/fneur.2024.1359091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Accepted: 04/24/2024] [Indexed: 05/25/2024] Open
Abstract
Introduction Charcot-Marie-Tooth disease (CMT) is an inherited neuropathy that affects the sensory and motor nerves. It can be considered the most common neuromuscular disease, with a prevalence of 1/2500. Methods Considering the absence of a specific medical treatment and the benefits shown by physical activity in this population, a systematic review was completed using several search engines (Scopus, PubMed, and Web of Science) to analyze the use, effectiveness, and safety of a training program performed in telecoaching (TC). TC is a new training mode that uses mobile devices and digital technology to ensure remote access to training. Results Of the 382 studies identified, only 7 met the inclusion criteria. The effects of a TC training program included improvements in strength, cardiovascular ability, and functional abilities, as well as gait and fatigue. However, the quality of the studies was moderate, the size of the participants in each study was small, and the outcome measured was partial. Discussion Although many studies have identified statistically significant changes following the administration of the TC training protocol, further studies are needed, with appropriate study power, better quality, and a higher sample size.
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Affiliation(s)
- Ignazio Leale
- Sport and Exercise Research Unit, Department of Psychology, Educational Sciences and Human Movement, University of Palermo, Palermo, Italy
- Ph.D. Program in Health Promotion and Cognitive Sciences, University of Palermo, Palermo, Italy
- Department of Psychology, Educational Science and Human Movement, University of Palermo, Palermo, Italy
| | - Vincenzo Di Stefano
- Neurology Unit, Department of Biomedicine, Neuroscience, and Advanced Diagnostics (BiND), University of Palermo, Palermo, Italy
| | - Carola Costanza
- Department of Sciences for Health Promotion and Mother and Child Care “G. D’Alessandro”, University of Palermo, Palermo, Italy
| | - Filippo Brighina
- Neurology Unit, Department of Biomedicine, Neuroscience, and Advanced Diagnostics (BiND), University of Palermo, Palermo, Italy
| | - Michele Roccella
- Department of Psychology, Educational Science and Human Movement, University of Palermo, Palermo, Italy
| | - Antonio Palma
- Sport and Exercise Research Unit, Department of Psychology, Educational Sciences and Human Movement, University of Palermo, Palermo, Italy
- Department of Psychology, Educational Science and Human Movement, University of Palermo, Palermo, Italy
| | - Giuseppe Battaglia
- Sport and Exercise Research Unit, Department of Psychology, Educational Sciences and Human Movement, University of Palermo, Palermo, Italy
- Department of Psychology, Educational Science and Human Movement, University of Palermo, Palermo, Italy
- Regional Sports School of Italian National Olympic Committee (CONI) Sicilia, Palermo, Italy
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Supplementation and Performance for Wheelchair Athletes: A Systematic Review. Adapt Phys Activ Q 2022; 39:268-282. [PMID: 34758458 DOI: 10.1123/apaq.2020-0241] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Revised: 08/20/2021] [Accepted: 09/02/2021] [Indexed: 12/29/2022] Open
Abstract
This systematic review aimed to identify nutritional interventions and supplements that improve the performance for wheelchair athletes. Intervention trials involving high-performance wheelchair athletes were analyzed, including those that comprised a nutritional intervention, defined as any intervention related to food, beverages, and supplementation aiming at evaluating the performance of wheelchair athletes. Of the included studies, four evaluated caffeine supplementation, of which one also evaluated sodium citrate supplementation; two studies evaluated vitamin D supplementation; one study assessed creatine monohydrate supplementation; and one assessed carbohydrate supplementation. Most studies were conducted on athletes with spinal cord injury. Athletes who consumed caffeine exhibited an improvement in performance, but this finding is not strong enough to become a recommendation.
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Fielding RA, Rivas D, Grosicki GJ, Ezzyat Y, Ceglia L, Price LL, Orhan C, Sahin K, Fowler K, White T, Durkee S, Kritsch K, Bellamine A. Effects of Low Doses of L-Carnitine Tartrate and Lipid Multi-Particulate Formulated Creatine Monohydrate on Muscle Protein Synthesis in Myoblasts and Bioavailability in Humans and Rodents. Nutrients 2021; 13:3985. [PMID: 34836240 PMCID: PMC8625796 DOI: 10.3390/nu13113985] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 11/02/2021] [Accepted: 11/05/2021] [Indexed: 11/18/2022] Open
Abstract
The primary objective of this study was to investigate the potential synergy between low doses of L-carnitine tartrate and creatine monohydrate to induce muscle protein synthesis and anabolic pathway activation in primary human myoblasts. In addition, the effects of Lipid multi-particulates (LMP) formulation on creatine stability and bioavailability were assessed in rodents and healthy human subjects. When used individually, L-carnitine tartrate at 50 µM and creatine monohydrate at 0.5 µM did not affect myoblast protein synthesis and signaling. However, when combined, they led to a significant increase in protein synthesis. Increased AKT and RPS6 phosphorylation were observed with 50 µM L-carnitine tartrate 5 µM creatine in combination in primary human myoblasts. When Wistar rats were administered creatine with LMP formulation at either 21 or 51 mg/kg, bioavailability was increased by 27% based on the increase in the area under the curve (AUC) at a 51 mg/kg dose compared to without LMP formulation. Tmax and Cmax were unchanged. Finally, in human subjects, a combination of LMP formulated L-carnitine at 500 mg (from L-carnitine tartrate) with LMP formulated creatine at 100, 200, or 500 mg revealed a significant and dose-dependent increase in plasma creatine concentrations. Serum total L-carnitine levels rose in a similar manner in the three combinations. These results suggest that a combination of low doses of L-carnitine tartrate and creatine monohydrate may lead to a significant and synergistic enhancement of muscle protein synthesis and activation of anabolic signaling. In addition, the LMP formulation of creatine improved its bioavailability. L-carnitine at 500 mg and LMP-formulated creatine at 200 or 500 mg may be useful for future clinical trials to evaluate the effects on muscle protein synthesis.
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Affiliation(s)
- Roger A. Fielding
- Nutrition, Exercise Physiology, and Sarcopenia Laboratory, Jean Mayer USDA Human Nutrition Research Center, Aging Tufts University, Boston, MA 02111, USA; (D.R.); (G.J.G.); (Y.E.)
| | - Donato Rivas
- Nutrition, Exercise Physiology, and Sarcopenia Laboratory, Jean Mayer USDA Human Nutrition Research Center, Aging Tufts University, Boston, MA 02111, USA; (D.R.); (G.J.G.); (Y.E.)
| | - Gregory J. Grosicki
- Nutrition, Exercise Physiology, and Sarcopenia Laboratory, Jean Mayer USDA Human Nutrition Research Center, Aging Tufts University, Boston, MA 02111, USA; (D.R.); (G.J.G.); (Y.E.)
- Biodynamics and Human Performance Center, Georgia Southern University, Armsrong Campus, Savannah, GA 31419, USA
| | - Yassine Ezzyat
- Nutrition, Exercise Physiology, and Sarcopenia Laboratory, Jean Mayer USDA Human Nutrition Research Center, Aging Tufts University, Boston, MA 02111, USA; (D.R.); (G.J.G.); (Y.E.)
| | - Lisa Ceglia
- Division of Endocrinology, Tufts Medical Center, Boston, MA 02111, USA;
| | - Lori Lyn Price
- The Institute for Clinical Research and Health Policy Studies, Tufts Medical Center, Boston, MA 02111, USA;
- Tufts Clinical and Translational Science Institute, Tufts University, Boston, MA 02111, USA
| | - Cemal Orhan
- Department of Animal Nutrition, Faculty of Veterinary Medicine, Firat University, Elazig 23119, Turkey; (C.O.); (K.S.)
| | - Kazim Sahin
- Department of Animal Nutrition, Faculty of Veterinary Medicine, Firat University, Elazig 23119, Turkey; (C.O.); (K.S.)
| | - Kelli Fowler
- R&D Innovation, Lonza Consumer Health, Morristown, NJ 07960, USA; (K.F.); (T.W.); (S.D.); (A.B.)
| | - Tyler White
- R&D Innovation, Lonza Consumer Health, Morristown, NJ 07960, USA; (K.F.); (T.W.); (S.D.); (A.B.)
| | - Shane Durkee
- R&D Innovation, Lonza Consumer Health, Morristown, NJ 07960, USA; (K.F.); (T.W.); (S.D.); (A.B.)
| | - Katja Kritsch
- R&D Lonza Specialty Ingredients, Alpharetta, GA 30004, USA;
| | - Aouatef Bellamine
- R&D Innovation, Lonza Consumer Health, Morristown, NJ 07960, USA; (K.F.); (T.W.); (S.D.); (A.B.)
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Billingsley HE, Rodriguez-Miguelez P, Del Buono MG, Abbate A, Lavie CJ, Carbone S. Lifestyle Interventions with a Focus on Nutritional Strategies to Increase Cardiorespiratory Fitness in Chronic Obstructive Pulmonary Disease, Heart Failure, Obesity, Sarcopenia, and Frailty. Nutrients 2019; 11:nu11122849. [PMID: 31766324 PMCID: PMC6950118 DOI: 10.3390/nu11122849] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 11/03/2019] [Accepted: 11/15/2019] [Indexed: 12/11/2022] Open
Abstract
Cardiorespiratory fitness (CRF) is an independent predictor for all-cause and disease-specific morbidity and mortality. CRF is a modifiable risk factor, and exercise training and increased physical activity, as well as targeted medical therapies, can improve CRF. Although nutrition is a modifiable risk factor for chronic noncommunicable diseases, little is known about the effect of dietary patterns and specific nutrients on modifying CRF. This review focuses specifically on trials that implemented dietary supplementation, modified dietary pattern, or enacted caloric restriction, with and without exercise training interventions, and subsequently measured the effect on peak oxygen consumption (VO2) or surrogate measures of CRF and functional capacity. Populations selected for this review are those recognized to have a reduced CRF, such as chronic obstructive pulmonary disease, heart failure, obesity, sarcopenia, and frailty. We then summarize the state of existing knowledge and explore future directions of study in disease states recently recognized to have an abnormal CRF.
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Affiliation(s)
- Hayley E. Billingsley
- Department of Internal Medicine, VCU Pauley Heart Center, Virginia Commonwealth University, Richmond, VA 23284, USA; (H.E.B.); (A.A.)
- Department of Kinesiology & Health Sciences, College of Humanities & Sciences, Virginia Commonwealth University, Richmond, VA 23284, USA;
| | - Paula Rodriguez-Miguelez
- Department of Kinesiology & Health Sciences, College of Humanities & Sciences, Virginia Commonwealth University, Richmond, VA 23284, USA;
| | - Marco Giuseppe Del Buono
- Department of Cardiovascular and Thoracic Sciences, Catholic University of the Sacred Heart, 00168 Rome, Italy;
| | - Antonio Abbate
- Department of Internal Medicine, VCU Pauley Heart Center, Virginia Commonwealth University, Richmond, VA 23284, USA; (H.E.B.); (A.A.)
| | - Carl J. Lavie
- Department of Cardiovascular Diseases, Ochsner Clinical School, New Orleans, LA 70121, USA;
| | - Salvatore Carbone
- Department of Internal Medicine, VCU Pauley Heart Center, Virginia Commonwealth University, Richmond, VA 23284, USA; (H.E.B.); (A.A.)
- Department of Kinesiology & Health Sciences, College of Humanities & Sciences, Virginia Commonwealth University, Richmond, VA 23284, USA;
- Correspondence: ; Tel.: +1-804-628-3980
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Myoprotective Potential of Creatine Is Greater than Whey Protein after Chemically-Induced Damage in Rat Skeletal Muscle. Nutrients 2018; 10:nu10050553. [PMID: 29710855 PMCID: PMC5986433 DOI: 10.3390/nu10050553] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 04/26/2018] [Accepted: 04/27/2018] [Indexed: 12/28/2022] Open
Abstract
The myoprotective effects of creatine monohydrate (CR) and whey protein (WP) are equivocal, with the use of proxy measures of muscle damage making interpretation of their effectiveness limited. The purpose of the study was to determine the effects of CR and WP supplementation on muscle damage and recovery following controlled, chemically-induced muscle damage. Degeneration of the extensor digitorum longus (EDL) muscle was induced by bupivacaine in rats supplemented with either CR, WP, or standard rat chow (CON). At day 7 and 14 post-myotoxic injury, injured EDL muscles were surgically removed and tested for isometric contractile properties, followed by the contralateral, non-injured EDL muscle. At the completion of testing, muscles were snap-frozen in liquid nitrogen and stored for later analysis. Data were analyzed using analysis of variance. Creatine-supplemented muscles displayed a greater proportion of non-damaged (intact) fibers (p = 0.002) and larger cross-sectional areas of regenerating and non-damaged fibers (p = 0.024) compared to CON muscles at day 7 post-injury. At day 14 post-injury, CR-supplemented muscles generated higher absolute forces concomitant with greater contractile protein levels compared to CON (p = 0.001, p = 0.008) and WP-supplemented muscles (p = 0.003, p = 0.006). Creatine supplementation appears to offer an element of myoprotection which was not observed following whey protein supplementation.
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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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Gualano B, Roschel H, Lancha AH, Brightbill CE, Rawson ES. In sickness and in health: the widespread application of creatine supplementation. Amino Acids 2011; 43:519-29. [DOI: 10.1007/s00726-011-1132-7] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Accepted: 10/20/2011] [Indexed: 12/12/2022]
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Greydanus DE, Patel DR. Sports doping in the adolescent: the Faustian conundrum of Hors de Combat. Pediatr Clin North Am 2010; 57:729-50. [PMID: 20538154 DOI: 10.1016/j.pcl.2010.02.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The drive toward success in sports and the need for a cosmetically acceptable appearance have driven many adolescents to take a wide variety of so-called doping substances. The consumption of these chemicals in the hope and hype of improved sports performance, fueled by the easing of government restrictions on their proof of safety and efficacy, has resulted in an explosion of so-called ergogenic products available to our youth. Agents that have been used include anabolic steroids, anabolic-like agents, designer steroids, creatine, protein and amino acid supplements, minerals, antioxidants, stimulants, blood doping, erythropoietin, beta-blockers, and others. The use of these agents has considerable potential to cause physical and psychological damage. Use and misuse of drugs in this sports doping process should be discouraged. This discussion reviews some of the agents that are currently being used. Clinicians providing sports medicine care to youth, whether through anticipatory guidance or direct sports medicine management, should educate their young patients about the hype and hyperbole of these products that may keep them out instead of in the game at considerable financial cost to the unwary consumer.
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Affiliation(s)
- Donald E Greydanus
- Department of Pediatrics & Human Development, Michigan State University College of Human Medicine, Kalamazoo, MI 49008-1284, USA.
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Tarnopolsky MA. Caffeine and Creatine Use in Sport. ANNALS OF NUTRITION AND METABOLISM 2010; 57 Suppl 2:1-8. [DOI: 10.1159/000322696] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Bourgeois JM, Nagel K, Pearce E, Wright M, Barr RD, Tarnopolsky MA. Creatine monohydrate attenuates body fat accumulation in children with acute lymphoblastic leukemia during maintenance chemotherapy. Pediatr Blood Cancer 2008; 51:183-7. [PMID: 18421708 DOI: 10.1002/pbc.21571] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Corticosteroids are an important component of the treatment of acute lymphoblastic leukemia (ALL), with known significantly negative effects on bone and muscle. Creatine monohydrate (CrM) supplementation may be an adjunctive therapeutic strategy to attenuate some of these adverse effects. PROCEDURE Nine children with ALL in the maintenance phase of treatment on the Dana-Farber Cancer Institute (DFCI) protocol 2000-2001 were treated with CrM (0.1 g/kg/day) for two sequential periods of 16 weeks (16 weeks treat > 6 weeks wash-out > 16 weeks treat). A cohort of children (N = 50) who were receiving the same chemotherapy at the same time served as natural history controls. Measurements included height, weight, body mass index (BMI), and lumbar spine bone mineral density (LS-BMD), whole body bone mineral content (WB-BMC), fat-free mass (FFM), and percent body fat (%BF) using dual-energy X-ray absorptiometry. RESULTS Despite the long course of corticosteroid treatment for ALL, children showed significant increases in height, LS-BMD, WB-BMC and FFM over approximately 38 weeks (P < 0.05) during the study. There was an increase in BMI over time, but children taking CrM had a reduction, while the natural history group showed an increase in % BF (P < 0.05 for interaction). CONCLUSIONS Children with ALL treated with corticosteroids as part of a maintenance protocol of chemotherapy showed an increase in % BF that was attenuated by CrM supplementation.
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Affiliation(s)
- Jacqueline M Bourgeois
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada.
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Deacon SJ, Vincent EE, Greenhaff PL, Fox J, Steiner MC, Singh SJ, Morgan MD. Randomized controlled trial of dietary creatine as an adjunct therapy to physical training in chronic obstructive pulmonary disease. Am J Respir Crit Care Med 2008; 178:233-9. [PMID: 18420964 DOI: 10.1164/rccm.200710-1508oc] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Skeletal muscle strength and bulk are reduced in patients with chronic obstructive pulmonary disease (COPD) and influence quality of life, survival, and utilization of health care resources. Exercise training during pulmonary rehabilitation (PR) can reverse some of these effects. In athletes and healthy elderly individuals, dietary creatine supplementation (CrS) has been shown to augment high-intensity exercise training, thereby increasing muscle mass. OBJECTIVES This article examines the effect of CrS on functional exercise capacity and muscle performance in people with COPD. METHODS One hundred subjects with COPD (mean [SD] age, 68.2 [8.2] yr; FEV(1), 44.0 [19.6] %predicted) were randomized to a double-blind, placebo-controlled, parallel group trial of CrS during 7 weeks of PR encompassing aerobic and resistance exercises. Subjects ingested creatine (22 g/d loading for 5 d; maintenance, 3.76 g/d throughout PR) or placebo. Baseline, postloading, and postrehabilitation measurements included pulmonary function, body composition, peripheral muscle strength, and functional performance (shuttle walking tests). A volunteer subgroup (n = 44) had pre- and postloading quadriceps muscle biopsies. MEASUREMENTS AND MAIN RESULTS Eighty subjects completed the trial (38 creatine, 42 placebo). All outcome measures significantly improved after PR. There were no significant differences between groups post-PR (mean [SD] change in incremental shuttle walk distance, 84 [79] m in the creatine group vs. 83.8 [60] m in the placebo group; P = 1.0; knee extensor work, 19.2 [16] Nm [Newton meters] in the creatine group vs. 19.5 [17] Nm in the placebo group; P = 0.9). Muscle biopsies showed evidence of creatine uptake. CONCLUSIONS This adequately powered, randomized, placebo-controlled trial shows that CrS does not augment the substantial training effect of multidisciplinary PR for patients with COPD. Clinical trial registered with https://portal.nihr.ac.uk/Pages/NRRArchiveSearch.aspx (NO123138126).
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Affiliation(s)
- Sarah J Deacon
- Institute for Lung Health, Department of Respiratory Medicine, Allergy and Thoracic Surgery, University Hospitals of Leicester NHS Trust, Glenfield Hospital, Leicester LE39QP, UK.
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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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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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Ellis AC, Rosenfeld J. The role of creatine in the management of amyotrophic lateral sclerosis and other neurodegenerative disorders. CNS Drugs 2004; 18:967-80. [PMID: 15584767 DOI: 10.2165/00023210-200418140-00002] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Creatine is consumed in the diet and endogenously synthesised in the body. Over the past decade, the ergogenic benefits of synthetic creatine monohydrate have made it a popular dietary supplement, particularly among athletes. The anabolic properties of creatine also offer hope for the treatment of diseases characterised by weakness and muscle atrophy. Moreover, because of its cellular mechanisms of action, creatine offers potential benefits for diseases involving mitochondrial dysfunction. Recent data also support the hypothesis that creatine may have a neuroprotective effect. Amyotrophic lateral sclerosis (ALS) is characterised by progressive degeneration of motor neurons, resulting in weakening and atrophy of skeletal muscles. In patients with this condition, creatine offers potential benefits in terms of facilitating residual muscle contractility as well as improving neuronal function. It may also help stabilise mitochondrial dysfunction, which plays a key role in the pathogenesis of ALS. Indeed, the likely multifactorial aetiology of ALS means the combined pharmacodynamic properties of creatine offer promise for the treatment of this condition. Evidence from available animal models of ALS supports the utility of treatment with creatine in this setting. Limited data available in other neuromuscular and neurodegenerative diseases further support the potential benefit of creatine monohydrate in ALS. However, few randomised, controlled trials have been conducted. To date, two clinical trials of creatine monohydrate in ALS have been completed without demonstration of significant improvements in overall survival or a composite measure of muscle strength. These trials have also posed unanswered questions about the optimal dosage of creatine and its beneficial effects on muscle fatigue, a measure distinct from muscle strength. A large, multicentre, clinical trial is currently underway to further investigate the efficacy of creatine monohydrate in ALS and address these unresolved issues. Evidence to date shows that creatine supplementation has a good safety profile and is well tolerated by ALS patients. The purpose of this article is to provide a short, balanced review of the literature concerning creatine monohydrate in the treatment of ALS and related neurodegenerative diseases. The pharmacokinetics and rationale for the use of creatine are described along with available evidence from animal models and clinical trials for ALS and related neurodegenerative or neuromuscular diseases.
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Affiliation(s)
- Amy Cameron Ellis
- Carolinas Neuromuscular/ALS Center, Charlotte, North Carolina 28203, USA.
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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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16
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Jordan AN, Jurca R, Abraham EH, Salikhova A, Mann JK, Morss GM, Church TS, Lucia A, Earnest CP. Effects of oral ATP supplementation on anaerobic power and muscular strength. Med Sci Sports Exerc 2004; 36:983-90. [PMID: 15179168 DOI: 10.1249/01.mss.0000128198.97260.8b] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE We examined 14 d of oral adenosine 5'-triphosphate (ATP) supplementation on indices of anaerobic capacity and muscular strength. METHODS Twenty-seven healthy males successfully completed the trial, after randomly receiving in a double-blind manner an oral dose of low dose (150 mg) or high dose (225 mg) ATP, or matched placebo. To improve absorption characteristics, the ATP was enterically coated. Total blood ATP (whole blood and plasma ATP) concentrations, two Wingate anaerobic power tests (30 s), and muscular strength (1RM and three sets of repetitions to fatigue at 70% of 1RM) were measured under three conditions: (i) baseline; (ii) acutely (7d later, no prior supplementation and 75 min after ATP ingestion); and (iii) after 14 d of daily ingestion (post). RESULTS Statistical analyses showed no significant between or within group treatment effects for whole blood ATP or plasma ATP concentrations for any treatment condition. We also did not observe any treatment effects for any Wingate testing parameter including peak PO, total work, average PO for 30 s, or post-Wingate lactate accumulation. Overall, we observed no significant between group treatment effects for any muscular strength parameter. We did observe several within group differences for the group ingesting the high ATP dosage including 1RM (6.6%; P < 0.04) and repetitions to fatigue during set 1 of posttesting (18.5%; P < 0.007) and total lifting volume at post (22%; P < 0.003). CONCLUSIONS We conclude that enterically coated oral ATP supplementation may provide small ergogenic effects on muscular strength under some treatment conditions.
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Affiliation(s)
- Alexander N Jordan
- The Cooper Institute Centers for Integrated Health Research, Center for Human Performance and Nutrition Research, Dallas, TX, USA
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17
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Abstract
OBJECTIVE To describe opportunities and obligations for pharmacists regarding doping control in sports, and to present information and resources on drugs and dietary supplements that are popular among athletes for performance enhancement. DATA SOURCES Sports medicine journals and articles in English obtained from Medline (1966 through June 2003) using the search terms doping in sports, drugs in sports, dietary supplements, sports, amphetamine, stimulants, ephedrine, ephedra, caffeine, anabolic steroids, human growth hormone, erythropoietin, darbepoetin, androstenedione, dehydroepiandrosterone, and creatine. Information was also obtained from sports-governing agencies, such as the National Collegiate Athletic Association and the International Olympic Committee. STUDY SELECTION Studies and reports that were credible and scientifically sound that evaluated the ergogenic effects of drugs and dietary supplements. DATA EXTRACTION By the author. DATA SYNTHESIS Pharmacists can participate in doping control programs in a number of ways. Pharmacists also have an obligation when counseling, advising, and treating athletes to help them avoid banned substances. Athletes use a host of drugs for their performance-enhancing effects, many of which are banned by major sports-governing bodies. Myriad dietary supplements are marketed to athletes, claiming to have ergogenic effects. Some of these popular supplements have proven performance-enhancing effects, while others do not. Adverse effects of these drugs and dietary supplements are discussed. CONCLUSION A variety of drugs and dietary supplements have proven performance-enhancing effects in athletes. However, many of these substances have adverse effects and are banned by various sports-governing organizations. Pharmacists can play a key role in participating in doping control programs, and can prevent athletes from inadvertently consuming a banned substance.
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Affiliation(s)
- Peter J Ambrose
- Department of Clinical Pharmacy, School of Pharmacy, University of California, San Francisco, USA.
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18
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Tyler TF, Nicholas SJ, Hershman EB, Glace BW, Mullaney MJ, McHugh MP. The effect of creatine supplementation on strength recovery after anterior cruciate ligament (ACL) reconstruction: a randomized, placebo-controlled, double-blind trial. Am J Sports Med 2004; 32:383-8. [PMID: 14977662 DOI: 10.1177/0363546503261731] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Creatine supplementation has been shown to augment training-induced strength gains. The purpose of this study was to examine the effect of creatine supplementation on recovery of muscle strength after anterior cruciate ligament (ACL) reconstruction. HYPOTHESIS Creatine supplementation will facilitate strength gains after ACL reconstruction. STUDY DESIGN Double-blind, prospective, and randomized clinical trial. METHODS Sixty patients were randomized into creatine or placebo groups. Quadriceps and hamstring strength and power were measured isokinetically. Hip flexor, abductor, and adductor strengths were measured with a handheld dynamometer prior to surgery and at 6 weeks, 12 weeks, or 6 months after surgery. RESULTS From 6 weeks to 12 weeks after surgery, there were significant increases in strength on the involved side for knee extension (47%), knee flexion (27%), hip flexion (20%), hip abduction (9%), and hip adduction (17%). These strength improvements were unaffected by creatine supplementation with similar effects in the creatine and placebo groups. From 6 weeks to 12 weeks after surgery, there were significant increases in power on the involved side for knee extension (46%) and knee flexion (26%), but these effects were not affected by creatine supplementation. At 6 months, creatine supplementation did not affect outcome as measured by the single leg hop test for distance or the knee outcome score. CONCLUSIONS The results demonstrate that patients do not benefit from creatine supplementation during the first 12 weeks of rehabilitation after ACL reconstruction.
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Chetlin RD, Gutmann L, Tarnopolsky MA, Ullrich IH, Yeater RA. Resistance training exercise and creatine in patients with Charcot-Marie-Tooth disease. Muscle Nerve 2004; 30:69-76. [PMID: 15221881 DOI: 10.1002/mus.20078] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Resistance exercise and creatine supplementation independently improve strength and function in patients with certain neuromuscular diseases. The purpose of this study was to examine the effects of resistance training with and without creatine supplementation on muscle, strength, and function in patients with Charcot-Marie-Tooth (CMT) disease. Twenty patients with CMT consumed 5 g/day creatine or placebo while participating in resistance training for 12 weeks. Energy metabolites, muscle fiber type and size, strength, and timed activities of daily living were measured before and after training. There were no differences between creatine or placebo groups for any outcome. For the groups combined, exercise training increased type I muscle fiber diameter (48.2 +/- 14.2 microm vs. 55.4 +/- 14.8 microm), strength, and activities of daily living (ADL) times. Thus, patients respond to resistance training with muscle fiber adaptations, and improvements in strength and function. Creatine was not beneficial.
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Affiliation(s)
- Robert D Chetlin
- Department of Human Performance and Applied Exercise Science, West Virginia University, P.O. Box 9139, Morgantown, West Virginia 26506-9139, USA.
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20
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Kinugasa R, Akima H, Ota A, Ohta A, Sugiura K, Kuno SY. Short-term creatine supplementation does not improve muscle activation or sprint performance in humans. Eur J Appl Physiol 2003; 91:230-7. [PMID: 14574579 DOI: 10.1007/s00421-003-0970-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/11/2003] [Indexed: 10/26/2022]
Abstract
The purpose of this study was to examine the influence of short-term creatine (Cr) supplementation on exercise-induced transverse relaxation time (T2) and sprint performance during maximum intermittent cycling exercise using the muscle functional magnetic resonance imaging (mfMRI) technique. Twelve men were divided into a Cr supplementation group [the Cr group, taking 4 x (5 g Cr monohydrate + 2.5 g maltodextrin)/day], or a placebo supplementation group (the P group, taking 4 x 7.5 g maltodextrin/day). The allocation to the groups was based on cycling tests and the subject's physical characteristics, and thus was not randomized. A double-blind research design was employed for a 5-day supplementation period. mfMR images of the right thigh were collected at rest and immediately after two, five, and ten 6-s sprint bouts of maximum intermittent cycling exercise with a 30-s recovery interval between sets. Before and after supplementation, blood was taken to calculate lactate accumulation, and the muscle volume of the thigh was determined by MRI. Following supplementation, there was significant body mass gain in the Cr group ( P<0.05), whereas the P group did not change. The exercise-induced T2, blood lactate levels and sprint performance were not affected by Cr supplementation in any sprint bouts. These results suggest that short-term Cr supplementation does not influence short duration repetitive sprint performance and muscle activation and/or metabolic state during sprint cycling evaluated by mfMRI of the skeletal muscle in humans.
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Affiliation(s)
- Ryuta Kinugasa
- Graduate School of Health and Sport Science, Nippon Sport Science University, 7-1-1 Fukasawa, Setagaya, 158-8508, Tokyo, Japan.
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21
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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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22
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Vierck JL, Icenoggle DL, Bucci L, Dodson MV. The effects of ergogenic compounds on myogenic satellite cells. Med Sci Sports Exerc 2003; 35:769-76. [PMID: 12750586 DOI: 10.1249/01.mss.0000065005.96298.01] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
PURPOSE A series of studies were conducted in which compounds commonly shown to be ergogenic aids for strength athletes if taken orally were evaluated for their ability to directly induce postnatal muscle stem cell proliferation or differentiation/fusion in vitro. METHODS Compounds tested were creatine monohydrate, creatine pyruvate, L-glutamine, dehydroepiandrosterone (DHEA), androstenedione, Ma Huang (Ephedra sinensis) extract, and Zhi Shi (Citrus aurantium) extract. Dulbecco's modified eagle medium, supplemented with minimal levels of serum and antibiotics, was used as the initial vehicle for the test compounds. Subsequently, a defined treatment medium termed ITTC was used. Satellite cells were exposed to the test compounds for the indicated times and then evaluated by counting mononucleated and multinucleated (fused) cells. RESULTS In serum-containing media, none of the treatment groups displayed increased proliferation over that of the control. However, in the differentiation cultures, 0.10% creatine monohydrate increased differentiation over that of the control cultures. When 0.10% creatine monohydrate was added to defined media formulations, all treatments but one demonstrated increased differentiation over the 0.5% serum control. Time course experiments, which followed the effect of 0.10% creatine monohydrate contained in ITTC defined media over 120 h, suggested that cells exposed to this treatment differentiated earlier and to a greater level than cells exposed to ITTC alone. CONCLUSIONS Creatine in the monohydrate form induced differentiation of myogenic satellite cells. Other agents examined did not increase satellite cell proliferation or differentiation. These results provide initial evidence for a mechanistic understanding of observed effects in vivo of increased muscular size and strength from creatine supplementation.
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Affiliation(s)
- Janet L Vierck
- Muscle Biology Laboratory, Department of Animal Sciences, Washington State University, Pullman, WA 99164, USA
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23
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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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24
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Abstract
The use of nonanabolic nutritional supplements for the sake of improving athletic performance is common, and the types of supplements used can have significant implications for the medical care of athletes. This review will address the most common and most controversial nonanabolic nutritional supplements, including recommendations regarding their use. Many supplements are marketed and promoted based on various theoretical benefits, often derived from limited animal studies, without any basis for recommending their human use. Physicians are trained to not recommend a nutritional supplement unless it is known to be effective, whereas athletes are oriented toward trying any supplement or ergogenic aid as long as it is safe, with the hope that it may be effective. The built-in error in most study designs is larger than the difference between winning and not qualifying at elite levels of competition, such that research may not always answer the questions raised by athletes. An honest discussion of the limitations of most supplements, and acknowledgment that some supplements may work some of the time in some athletes, may lead the physician to be more credible and useful to athletes in providing medical care and guidance that support their desire to improve their performance.
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Affiliation(s)
- Thomas L Schwenk
- Department of Family Medicine, University of Michigan Health System, Ann Arbor, Michigan 48109, USA
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25
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Abstract
A well-balanced diet with appropriate training is the key to maximizing athletic performance. Nutritional counseling should be an essential part of anticipatory guidance, especially for certain teens, such as those who are vegetarians or those with low-calorie intakes. Other considerations for anticipatory guidance are listed in Box 8. Adequate hydration before, during, and after practice or a game is important to maintain hemodynamic balance, prevent heat disorders, and optimize performance. Cool water is adequate for short-duration activities, while carbohydrate-electrolyte fluids are more desirable for long-term activities, especially those lasting more than an hour. Such drinks are also more palatable and the athlete is more likely to consume them. Carbohydrates (meaning hydrates of carbon) are an important part of the athlete's diet; carbohydrates are rapidly broken down and their energy is quickly supplied to the body. The body stores only a small amount of carbohydrates in the form of glycogen in the liver, while muscle glycogen is an immediate source of energy. Thus, carbohydrate loading has been used to increase glycogen stores and aid the athlete involved in endurance events.
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Affiliation(s)
- Donald E Greydanus
- Pediatrics Program, Michigan State University, Kalamazoo Center for Medical Studies, 49008-1284, USA.
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26
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Balikian P, Lourenção A, Ribeiro LFP, Festuccia WTL, Neiva CM. Consumo máximo de oxigênio e limiar anaeróbio de jogadores de futebol: comparação entre as diferentes posições. REV BRAS MED ESPORTE 2002. [DOI: 10.1590/s1517-86922002000200002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
O grau de desenvolvimento das capacidades físicas no futebol é fator determinante do nível desportivo do jogador. O objetivo do presente estudo foi comparar valores de limiar anaeróbio e consumo máximo de oxigênio entre jogadores profissionais de futebol de diferentes posições. Para tanto, 25 atletas (idade = 22,08 ± 8,28 anos, peso = 76,12 ± 9,8kg, altura = 179,8 ± 7,1cm e relação corporal = 12,21 ± 3,67% de gordura corporal) foram divididos em cinco grupos, como se segue: goleiros (GO), zagueiros (ZA), laterais (LA), meio-campistas (MC) e atacantes (AT). O VO2max foi determinado em esteira ergométrica através de análise direta e a velocidade de corrida correspondente ao limiar anaeróbio fixo de 4mM (V4mM), em teste de campo (2 x 1.000m a 90 e 95% da velocidade máxima para a distância) através de interpolação linear. A V4mM foi menor (p < 0,05) para o grupo GO em relação aos demais grupos. Além disso, os grupos LA e MC apresentaram valores de V4mM significantemente maiores em relação aos grupos ZA e AT. O grupo GO mostrou VO2max significantemente menor em relação a todos os outros grupos, sendo que estes últimos não apresentaram diferença entre si. Uma vez que os atletas de diferentes posições não realizavam treinamento diferenciado, os autores creditam as diferenças encontradas à especificidade da movimentação durante partidas e coletivos.
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27
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Andres LPA, Sacheck J, Tapia S. A Review of Creatine Supplementation: Side Effects and Improvements in Athletic Performance. ACTA ACUST UNITED AC 2002. [DOI: 10.1046/j.1523-5408.1999.00087.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- L. P. Andy Andres
- Nutrition, Exercise Physiology, and Sarcopenia Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts
| | - Jennifer Sacheck
- Nutrition, Exercise Physiology, and Sarcopenia Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts
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28
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Abstract
A creatina vem sendo muito pesquisada devido ao seu potencial efeito no rendimento físico de atletas envolvidos em exercícios de alta intensidade e curta duração, intermitentes e com curtos períodos de recuperação. A creatina fosforilada é uma reserva de energia nas células musculares. Durante um exercício intenso, a sua quebra libera energia é usada para regenerar o trifosfato de adenosina. Aproximadamente 95% do pool de creatina encontra-se na musculatura esquelética e sua regeneração após o exercício é um processo dependente de oxigênio. Estudos mostram que a suplementação com este composto pode aumentar o pool orgânico em 10 a 20%, e este percentual é maior em atletas vegetarianos (até 60%). Ainda existe controvérsia com relação aos benefícios e riscos da suplementação com esta substância. Este estudo revisa alguns dos aspectos relacionados com o metabolismo da creatina e seu uso como substância ergogênica na prática desportiva.
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Bemben MG, Bemben DA, Loftiss DD, Knehans AW. Creatine supplementation during resistance training in college football athletes. Med Sci Sports Exerc 2001; 33:1667-73. [PMID: 11581550 DOI: 10.1097/00005768-200110000-00009] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE This investigation assessed the effects of a 9-wk regimen of creatine monohydrate (Cr x H2O) supplementation coupled with resistance training on body composition and neuromuscular performance in NCAA Division I football athletes. METHODS Twenty-five subjects were randomly assigned in a double-blind, randomized placebo-controlled design, to a treatment (Cr, N = 9), placebo (P, N = 8), or control group (C, N = 8). The Cr group received 20 g.d(-1) of creatine for the first 5 d in 5-g doses, four times daily, followed by 5 g.d(-1) for the remainder of the study. Each 5-g dose was mixed with 500 mL of glucose solution (Gatorade). The P group received a placebo (sodium phosphate monohydrate; NaH2PO4 x H2O) following the exact protocol as the Cr group. The C group received no supplementation. All subjects resistance trained 4 d.wk(-1). Measurements of neuromuscular performance and body composition were made pre- and post-training after supplementation while monitoring dietary intakes. RESULTS Repeated measures ANOVA indicated significant differences occurred between the Cr group and the other two groups (P and C) for total body weight, lean body mass, cell hydration, strength, peak torque at 300 degrees.s(-1) knee flexion, percent torque decrement, and anaerobic power and capacity. However, percent body fat, peak torque during both knee flexion and extension at 60 and 180 degrees.s(-1), peak torque at 300 degrees.s(-1) during knee extension, global muscular strength (power clean), and extracellular fluid remained statistically unchanged for all groups. CONCLUSIONS Our findings indicate that creatine, supplemented concurrently with resistance and anaerobic training, may positively affect cell hydration status and enhance performance variables further than augmentation seen with training alone.
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Affiliation(s)
- M G Bemben
- Neuromuscular Research Lab, Department of Health & Sport Sciences, University of Oklahoma, Norman, OK 73019, USA.
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30
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Abstract
The cellular role of creatine (Cr) and Cr phosphate (CrP) has been studied extensively in neural, cardiac and skeletal muscle. Several studies have demonstrated that alterations in the cellular total Cr (Cr + CrP) concentration in these tissues can produce marked functional and/or structural change. The primary aim of this review was to critically evaluate the literature that has examined the regulation of cellular total Cr content. In particular, the review focuses on the regulation of the activity and gene expression of the Cr transporter (CreaT), which is primarily responsible for cellular Cr uptake. Two CreaT genes (CreaT1 and CreaT2) have been identified and their chromosomal location and DNA sequencing have been completed. From these data, putative structures of the CreaT proteins have been formulated. Transcription products of the CreaT2 gene are expressed exclusively in the testes, whereas CreaT1 transcripts are found in a variety of tissues. Recent research has measured the expression of the CreaT1 protein in several tissues including neural, cardiac and skeletal muscle. There is very little information available about the factors regulating CreaT gene expression. There is some evidence that suggests the intracellular Cr concentration may be involved in the regulatory process but there is much more to learn before this process is understood. The activity of the CreaT protein is controlled by many factors. These include substrate concentration, transmembrane Na+ gradients, cellular location, and various hormones. It is also likely that transporter activity is influenced by its phosphorylation state and by its interaction with other plasma membrane proteins. The extent of CreaT protein glycosylation may vary within cells, the functional significance of which remains unclear.
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Affiliation(s)
- R J Snow
- School of Health Sciences, Deakin University, Burwood, Australia
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31
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Corrigan B. Sir William Refshauge Lecture 1999. Drugs and nutrition. J Sci Med Sport 2000; 3:339-59. [PMID: 11235001 DOI: 10.1016/s1440-2440(00)80002-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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34
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Abstract
The consumption of oral creatine monohydrate has become increasingly common among professional and amateur athletes. Despite numerous publications on the ergogenic effects of this naturally occurring substance, there is little information on the possible adverse effects of this supplement. The objectives of this review are to identify the scientific facts and contrast them with reports in the news media, which have repeatedly emphasised the health risks of creatine supplementation and do not hesitate to draw broad conclusions from individual case reports. Exogenous creatine supplements are often consumed by athletes in amounts of up to 20 g/day for a few days, followed by 1 to 10 g/day for weeks, months and even years. Usually, consumers do not report any adverse effects, but body mass increases. There are few reports that creatine supplementation has protective effects in heart, muscle and neurological diseases. Gastrointestinal disturbances and muscle cramps have been reported occasionally in healthy individuals, but the effects are anecdotal. Liver and kidney dysfunction have also been suggested on the basis of small changes in markers of organ function and of occasional case reports, but well controlled studies on the adverse effects of exogenous creatine supplementation are almost nonexistent. We have investigated liver changes during medium term (4 weeks) creatine supplementation in young athletes. None showed any evidence of dysfunction on the basis of serum enzymes and urea production. Short term (5 days), medium term (9 weeks) and long term (up to 5 years) oral creatine supplementation has been studied in small cohorts of athletes whose kidney function was monitored by clearance methods and urine protein excretion rate. We did not find any adverse effects on renal function. The present review is not intended to reach conclusions on the effect of creatine supplementation on sport performance, but we believe that there is no evidence for deleterious effects in healthy individuals. Nevertheless, idiosyncratic effects may occur when large amounts of an exogenous substance containing an amino group are consumed, with the consequent increased load on the liver and kidneys. Regular monitoring is compulsory to avoid any abnormal reactions during oral creatine supplementation.
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Affiliation(s)
- J R Poortmans
- Physiological Chemistry, Higher Institute of Physical Education and Readaptation, Free University of Brussels, Bruxelles, Belgium.
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35
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Kreis R, Kamber M, Koster M, Felblinger J, Slotboom J, Hoppeler H, Boesch C. Creatine supplementation--part II: in vivo magnetic resonance spectroscopy. Med Sci Sports Exerc 1999; 31:1770-7. [PMID: 10613427 DOI: 10.1097/00005768-199912000-00012] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE Our purpose was to study effects of creatine (Cr) supplementation on muscle metabolites noninvasively by means of magnetic resonance spectroscopy (MRS) before and after supplementation with Cr or placebo. METHODS 1H-MRS was used in a comprehensive, double-blind, cross-over study in 10 volunteers to measure Cr in m. tibialis anterior and m. rectus femoris at rest. PCr/ATP was observed in m. quadriceps femoris by 31P-MRS at rest and after exercise. RESULTS A significant increase in total Cr was observed with Cr intake in m. tibialis anterior (+9.6 +/- 1.7%, P = 0.001) and in m. rectus femoris (+18.0 +/- 1.8%, P < 0.001). PCr/ATP showed a significant increase (+23.9 +/- 2.3%, P < 0.001) in m. quadriceps femoris at rest with Cr supplementation. Post-Cr supplementation recovery rates from exercise were significantly lower (k = 0.029 s(-1), P < 0.01) compared with postplacebo consumption (k = 0.034 s(-1)) and presupplementation (k = 0.037 s(-1)). However, higher levels of PCr/ATP at rest compensate for this reduction of the recovery rate after Cr supplementation. The increase of PCr/ATP determined by 31P-MRS correlates with the increase of Cr observed by 1H-MRS (r = 0.824, P < 0.001). CONCLUSION Noninvasive observation of Cr and PCr after Cr supplementation shows an increase in a muscle specific manner. Higher preexercise levels of PCr/ATP at rest compensate for significantly slower recovery rates of PCr/ATP after Cr supplementation.
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Affiliation(s)
- R Kreis
- Department of Clinical Research, University of Bern, Switzerland
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36
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Kamber M, Koster M, Kreis R, Walker G, Boesch C, Hoppeler H. Creatine supplementation--part I: performance, clinical chemistry, and muscle volume. Med Sci Sports Exerc 1999; 31:1763-9. [PMID: 10613426 DOI: 10.1097/00005768-199912000-00011] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE Our purpose was to study the effects and side effects of creatine (Cr) supplementation on high-intensity, short-term muscle work, on biochemical parameters related to Cr metabolism in blood and urine, and on muscle volume of the lower limb muscles. METHODS A cycling ergometer was used in a double-blind, cross-over study on 10 well-trained male physical education students to measure physical performance with 10 repetitive ergometer sprints (6-s duration, 30-s rest) before and after supplementation (5 d, 20 g x d(-1), washout period 61 +/- 8 d, mean +/- SEM, minimum 28 d) with Cr or placebo. Before and after supplementation, blood and urine were taken and the muscle volume of the lower limb was determined by magnetic resonance imaging (MRI). RESULTS A significant (P << 0.05) increase in performance (+7%) at the end [4-6 s] of the later sprints (4-7 and 8-10) was observed combined with a lower production of blood lactate (-1 mmol x L(-1)) with Cr supplementation. The concentration of Cr was increased significantly in urine (P < 0.001) and serum (P = 0.005), whereas creatinine (Crn) was increased in serum (P < 0.001). Crn in urine and Crn clearance did not change significantly with Cr intake. There were no significant changes in the analyzed blood enzyme activities. A significant gain of body weight (pre-Cr 76.5 +/- 1.7 kg to 77.9 +/- 1.7 kg post-Cr) with Cr supplementation was measured, but no accompanying increase of muscle mass in a limited volume of the lower limb was observed by MRI. CONCLUSION Cr supplementation is effective in improving short-term performance, and the methods used show no detrimental side effects with this supplementation protocol.
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Affiliation(s)
- M Kamber
- Institute of Sport Sciences, Swiss Sports School, Magglingen
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Poortmans J, Francaux M. Les effets indésirables de la créatine exogène: de la fiction à la réalité. Sci Sports 1999. [DOI: 10.1016/s0765-1597(00)86521-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Abstract
The available evidence supports neither a beneficial nor a detrimental effect of a vegetarian diet on physical performance capacity, especially when carbohydrate intake is controlled for. Concerns have been raised that an emphasis on plant foods to enhance carbohydrate intake and optimize body glycogen stores may lead to increases in dietary fiber and phytic acid intake to concentrations that reduce the bioavailability of several nutrients, including zinc, iron, and some other trace minerals. There is no convincing evidence, however, that vegetarian athletes suffer impaired nutrient status from the interactive effect of their heavy exertion and plant-food based dietary practices to the extent that performance, health, or both are impaired. Although there has been some concern about protein intake for vegetarian athletes, data indicate that all essential and nonessential amino acids can be supplied by plant food sources alone as long as a variety of foods is consumed and the energy intake is adequate. There has been some concern that vegetarian female athletes are at increased risk for oligoamenorrhea, but evidence suggests that low energy intake, not dietary quality, is the major cause. In conclusion, a vegetarian diet per se is not associated with improved aerobic endurance performance. Although some concerns have been raised about the nutrient status of vegetarian athletes, a varied and well-planned vegetarian diet is compatible with successful athletic endeavor.
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Affiliation(s)
- D C Nieman
- Department of Health, Leisure, and Exercise Science, Appalachian State University, Boone, NC 28608, USA.
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Abstract
Weight loss in elderly patients is a common clinical problem. Wasting and cachexia are associated with severe physiologic, psychologic, and immunologic consequences, regardless of the underlying causes. Cachexia has been associated with infections, decubitus ulcers, and even death. Multivariate analyses of risk and prognostic factors in community-acquired pneumonia in the elderly have found that age by itself is not a significant factor related to prognosis. Among the significant risk factors, only nutritional status is amenable to medical intervention. Cachexia in the elderly may have profound consequences: medical, cognitive, and psychiatric disorders may diminish self-reliance in activities of daily living, thus reducing quality of life and increasing the frequency of secondary procedures, hospitalizations, and the need for skilled care. Cachexia is associated with higher-than-normal concentrations of tumor necrosis factor alpha (TNF-alpha), interleukin (IL) 1, IL-6, serotonin, and interferon gamma. The role of these proinflammatory cytokines has been established in the cachexia seen in cancer and AIDS patients. Reduction in the concentrations of these cytokines is associated with weight gain. Drugs that promote appetite stimulation and weight gain, such as progestational agents, cyproheptadines, pentoxifylline, and thalidomide may work by down-regulating these proinflammatory cytokines. An understanding of the relation between cachexia and negative regulatory cytokines may point to effective treatment of geriatric cachexia as well.
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Affiliation(s)
- S S Yeh
- Geriatric Division, Department of Medicine, VA Medical Center Northport, NY, USA.
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Michaelis T, Wick M, Fujimori H, Matsumura A, Frahm J. Proton MRS of oral creatine supplementation in rats. Cerebral metabolite concentrations and ischemic challenge. NMR IN BIOMEDICINE 1999; 12:309-314. [PMID: 10484820 DOI: 10.1002/(sici)1099-1492(199908)12:5<309::aid-nbm572>3.0.co;2-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Proton magnetic resonance spectroscopy (MRS) was employed to determine the concentrations of N-acetylaspartate (NAA), total creatine (tCr), choline-containing compounds (Cho), myo-inositol (Ins), glucose (Glc), and lactate (Lac) in rat brain before and after 10 days of oral supplementation of 2.6 g Cr-monohydrate per kg body weight per day. Measurements were performed both in vitro (n = 16) and in vivo (n = 6). The neuroprotective potential of oral Cr was assessed by dynamically monitoring brain Glc and Lac in response to transient global ischemia (12 min). In comparison to controls the in vitro concentrations of Cr (13.1 +/- 9.3%) and Ins (12.7 +/- 14. 0%) were significantly increased in Cr-fed rats. Under in vivo conditions, the data revealed trends for elevated tCr (4.7%) and Ins (10.6%) which were enhanced in the concentration ratios of tCr:Cho (10.2%) and Ins:Cho (17.8%). Together with an increased Glc level (27.3%), the observation of a statistically significant decrease of brain Lac (-38.5 +/- 19.3%) in Cr-fed rats may reflect a shift of the energy metabolism from non-oxidative toward oxidative glycolysis. One hour after global ischemia most of the metabolic differences between Cr-fed rats and controls were retained. The increased Glc level (44.4 +/- 33.3%) reached statistical significance, but the accumulation of Lac and its time course during ischemia and early reperfusion showed no differences between Cr-fed rats and controls.
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Affiliation(s)
- T Michaelis
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, D-37070 Göttingen, Germany.
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Abstract
Creatine supplementation is the most popular nutritional supplement today. Although many questions remain regarding the use and benefits of creatine supplementation, a fast-growing body of literature is starting to define both its acute and chronic effects on human and physiologic performance. The initial data indicate that this energetic boost of the phosphagen energy system also helps to enhance strength and power training. Few documented side effects have been demonstrated in the medical and scientific literature, but further investigation is still required as to long-term use (i.e., beyond several months).
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Affiliation(s)
- W J Kraemer
- Department of Physical Education, Biology, Physiology, and Health Science, Ball State University, Muncie, Indianapolis, Indiana, USA.
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van Leemputte M, Vandenberghe K, Hespel P. Shortening of muscle relaxation time after creatine loading. J Appl Physiol (1985) 1999; 86:840-4. [PMID: 10066694 DOI: 10.1152/jappl.1999.86.3.840] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The effect of creatine (Cr) supplementation on muscle isometric torque generation and relaxation was investigated in healthy male volunteers. Maximal torque (Tmax), contraction time (CT) from 0.25 to 0.75 of Tmax, and relaxation time (RT) from 0.75 to 0.25 of Tmax were measured during 12 maximal isometric 3-s elbow flexions interspersed by 10-s rest intervals. Between the pretest and the posttest, subjects ingested Cr monohydrate (4 x 5 g/day; n = 8) or placebo (n = 8) for 5 days. Pretest Tmax, CT, and RT were similar in Cr and placebo groups. Also in the posttest, Tmax and CT were similar between groups. However, posttest RT was decreased consistently by approximately 20% (P < 0.05) in the Cr group from the first to the last of the 12 contractions. In addition, the mean decrease in RT after Cr loading was positively correlated with pretest RT (r = 0.82). It is concluded that Cr loading facilitates the rate of muscle relaxation during brief isometric muscle contractions without affecting torque production.
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Affiliation(s)
- M van Leemputte
- Department of Kinesiology, Faculty of Physical Education and Physiotherapy, Katholieke Universiteit Leuven, B-3001 Leuven, Belgium
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Abstract
Creatine is an amino acid that plays a vital role as creatine phosphate (phosphocreatine) in regenerating adenosine triphosphate in skeletal muscle to energize muscle contraction. Oral administration increases muscle stores. During the past decade, with notable popularity this past year, creatine has assumed prominence as an ergogenic aid for professional and elite athletes. Safety issues of long-term use, however, have not been addressed satisfactorily.
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Abstract
Creatine, a natural nutrient found in animal foods, is alleged to be an effective nutritional ergogenic aid to enhance sport or exercise performance. Research suggests that oral creatine monohydrate supplementation may increase total muscle creatine [TCr], including both free creatine [FCr] and phosphocreatine [PCr]. Some, but not all, studies suggest that creatine supplementation may enhance performance in high-intensity, short-term exercise tasks that are dependent primarily on PCr (i.e., < 30 seconds), particularly laboratory tests involving repeated exercise bouts with limited recovery time between repetitions; additional corroborative research is needed regarding its ergogenic potential in actual field exercise performance tasks dependent on PCr. Creatine supplementation has not consistently been shown to enhance performance in exercise tasks dependent on anaerobic glycolysis, but additional laboratory and field research is merited. Additionally, creatine supplementation has not been shown to enhance performance in exercise tasks dependent on aerobic glycolysis, but additional research is warranted, particularly on the effect of chronic supplementation as an aid to training for improvement in competitive performance. Short-term creatine supplementation appears to increase body mass in males, although the initial increase is most likely water. Chronic creatine supplementation, in conjunction with physical training involving resistance exercise, may increase lean body mass. However, confirmatory research data are needed. Creatine supplementation up to 8 weeks has not been associated with major health risks, but the safety of more prolonged creatine supplementation has not been established. Creatine is currently legal and its use by athletes is not construed as doping.
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Affiliation(s)
- M H Williams
- Department of Exercise Science, Physical Education, and Recreation, Old Dominion University, Norfolk, Virginia 23529-0196, USA
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Abstract
Amid the surrounding chaos of the supplement blitz, athlete, coach, and physician alike must step back and place the issue of supplements into perspective. There is no legal supplement that can substantially alter performance to date in the same way as illegal drugs. Effectiveness, safety, legality, and purity of compounds are all issues that should be addressed when approaching the use of any supplement. Education about the validity of the claims of supplements is important. Research is lending useful and helpful information despite the many new products continually appearing on the market. Because there is no mechanism for investigations to adequately research every supplement, many of the supplements should be approached with caution and skepticism. In addition, supplements in and of themselves should not be viewed as the sole answer to performance improvement. There is some promise to an extremely small number of supplements that appear to enhance performance, yet they do so in the realm of complete athletic training, including hard work, sports-specific training and strength training, psychological preparedness, and good nutritional intake.
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Affiliation(s)
- P R Stricker
- Department of Orthopaedics and Rehabilitation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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Volek JS, Kraemer WJ, Bush JA, Boetes M, Incledon T, Clark KL, Lynch JM. Creatine supplementation enhances muscular performance during high-intensity resistance exercise. JOURNAL OF THE AMERICAN DIETETIC ASSOCIATION 1997; 97:765-70. [PMID: 9216554 DOI: 10.1016/s0002-8223(97)00189-2] [Citation(s) in RCA: 146] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE This study was undertaken to investigate the influence of oral supplementation with creatine monohydrate on muscular performance during repeated sets of high-intensity resistance exercise. SUBJECTS/DESIGN Fourteen active men were randomly assigned in a double-blind fashion to either a creatine group (n = 7) or a placebo group (n = 7). Both groups performed a bench press exercise protocol (5 sets to failure using each subject's predetermined 10-repetition maximum) and a jump squat exercise protocol (5 sets of 10 repetitions using 30% of each subject's 1-repetition maximum squat) on three different occasions (T1, T2, and T3) separated by 6 days. INTERVENTION Before T1, both groups received no supplementation. From T1 to T2, both groups ingested placebo capsules. From T2 to T3, the creatine group ingested 25 g creatine monohydrate per day, and the placebo group ingested an equivalent amount of placebo. MAIN OUTCOME MEASURES Total repetitions for each set of bench presses and peak power output for each set of jump squats were determined. Other measures included assessment of diet, body mass, skinfold thickness, and preexercise and 5-minute postexercise lactate concentrations. RESULTS Lifting performance was not altered for either exercise protocol after ingestion of the placebos. Creatine supplementation resulted in a significant improvement in peak power output during all 5 sets of jump squats and a significant improvement in repetitions during all 5 sets of bench presses. After creatine supplementation, postexercise lactate concentrations were significantly higher after the bench press but not the jump squat. A significant increase in body mass of 1.4 kg (range = 0.0 to 2.7 kg) was observed after creatine ingestion. CONCLUSION One week of creatine supplementation (25 g/day) enhances muscular performance during repeated sets of bench press and jump squat exercise.
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Affiliation(s)
- J S Volek
- Center for Sports Medicine, Pennsylvania State University, University Park 16802, USA
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Kreis R, Koster M, Kamber M, Hoppeler H, Boesch C. Peak assignment in localized 1H MR spectra of human muscle based on oral creatine supplementation. Magn Reson Med 1997; 37:159-63. [PMID: 9001137 DOI: 10.1002/mrm.1910370202] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
1H-MR spectra of human skeletal muscle feature peak splittings due to dipolar coupling. Quantitative difference spectroscopy in a double-blind cross-over trial testing oral creatine supplementation revealed that most of the resonances affected by dipolar coupling can be assigned to creatine and/or phosphocreatine. The assignment was performed in two different skeletal muscles and confirmed by measurements at the magic angle where dipolar splittings vanish. Numerical spectral simulations revealed that the observed spectra are consistent with partly-averaged dipolar coupling among methylene and methyl protons of (phospho)creatine. The possible nature of the molecular dynamics leading to incomplete dipolar averaging is discussed.
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Affiliation(s)
- R Kreis
- Department for Magnetic Resonance Spectroscopy and Methodology, University Bern, Switzerland
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Williams MH. Ergogenic aids: a means to Citius, Altius, Fortius, and Olympic gold? RESEARCH QUARTERLY FOR EXERCISE AND SPORT 1996; 67:S58-S64. [PMID: 8902909 DOI: 10.1080/02701367.1996.10608854] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Affiliation(s)
- M H Williams
- Department of Health, Physical Education and Recreation at Old Dominion University, USA.
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