Article

Effect of Creatine and Weight Training on Muscle Creatine and Performance in Vegetarians

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Abstract

To compare the change in muscle creatine, fiber morphology, body composition, hydration status, and exercise performance between vegetarians and nonvegetarians with 8 wk of creatine supplementation and resistance training. Eighteen VG and 24 NV subjects (19-55 yr) were randomly assigned (double blind) to four groups: VG + creatine (VGCr, N=10), VG + placebo (VGPl, N=8), NV + creatine (NVCr, N=12), and NV + placebo (NVPl, N=12). Before and at the end of the study, muscle biopsies were taken from the vastus lateralis m, body composition was assessed by DXA, and strength was assessed using 1-RM bench press and leg press. Subjects participated in the same 8-wk resistance-training program. Creatine dosage was based on lean tissue mass (0.25 g.kg(-1) LTM.d(-1) x 7 d; 0.0625 g.kg(-1) LTM.d(-1) x 49 d). Biopsy samples indicated that total creatine (TCr=free Cr + PCr) was significantly lower in VG compared with NV at baseline (VG=117 mmol.kg(-1); NV=130 mmol.kg(-1); P<0.05). For Cr subjects, there was a greater increase in PCr, TCr, bench-press strength, isokinetic work, Type II fiber area, and whole-body lean tissue compared with subjects on placebo (P<0.05). Vegetarians who took Cr had a greater increase in TCr, PCr, lean tissue, and total work performance than nonvegetarians who took Cr (P<0.05). The change in muscle TCr was significantly correlated with initial muscle TCr, and the change in lean tissue mass and exercise performance. These findings confirm an ergogenic effect of Cr during resistance training and suggest that subjects with initially low levels of intramuscular Cr (vegetarians) are more responsive to supplementation.

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... A potential negative impact of the vegan diet on exercise performance might be attributed to a lower consume of creatine and b-alanine. A poor consumption of creatine is associated with a reduction in intramuscular creatine and phosphorylcreatine (PCr) content in vegetarians (13)(14)(15)(16). In the skeletal muscle, PCr regenerates the adenosine-triphosphate (ATP) to maintain muscle contraction, mainly during intense exercise (17). ...
... The higher level of intramuscular PCr is associated with a higher peak power (37,38). Although no study has measured the intramuscular Cr and PCr concentration specifically in vegans, cross-sectional studies have shown lower levels of intramuscular Cr and PCr in vegetarians than in the omnivores (13,14). Studies of intervention have also shown that 3 months (16) or even 21 days (15) under lacto-ovo-vegetarian diet were enough to reduce intramuscular creatine and PCr levels. ...
... Intramuscular total creatine content in vegetarians ranges from 115 to 120 mmol.kg À1 dry muscle (13,41), which is only slightly lower than that reported for omnivores (118 to 130 mmol.kg À1 dry muscle) (13,(41)(42)(43)(44)(45). ...
Article
Objective The impact of a vegan diet on sprint interval exercise performance is unknown. Thus, the purpose of the present study was to compare performance during a sprint interval exercise between omnivores and vegans. Methods Nine healthy omnivores (4 men and 5 women) and nine healthy vegans (4 men and 5 women), with similar levels of daily physical activity, performed four bouts (5-min rest between bouts) of a 30-s all-out sprint exercise on a cycle ergometer. Peak power, mean power, fatigue index, and time to reach maximal power output in each bout were recorded. Results There was a higher peak power in bouts 1 and 2 compared with bouts 3 and 4 (p < 0.02), and a higher mean power in bout 1 compared with bouts 2, 3 and 4 (p < 0.02). However, for all bouts, there were no significant difference between omnivores and vegans in peak power (7.60 ± 1.55 vs. 8.16 ± 1.27, 7.52 ± 1.6 vs 7.61 ± 0.73, 7.00 ± 1.44 vs. 7.00 ± 1.05 and 6.95 ± 1.42 vs. 6.49 ± 0.90 W.kg⁻¹, all p > 0.05) and in mean power (5.35 ± 0.93 vs. 5.69 ± 0.84, 5.10 ± 0.88 vs. 5.21 ± 0.49, 4.79 ± 0.81 vs. 4.79 ± 0.45 and 4.81 ± 0.81 vs. 4.69 ± 0.47 W.kg⁻¹, all p > 0.05). Fatigue index and time to reach maximal power output were not affected by diet or bouts (all p > 0.05). Conclusions These findings indicate that a vegan diet does not compromise sprint interval exercise performance.
... Creatine (21 g/day) combined with resistance training for 5 days improved the muscle anabolic environment (mRNA, GLUT4, Myosin heavy chain IIA) in 9 healthy men [61] . Creatine injection mixed with intensive resistance exercise increased the levels of insulin-like growth factor 1 (IGF-1) in muscle and muscle hypertrophy [65] . In the same study, vegetarians had a higher gain in lean mass than nonvegetarians (2.4 and 1.9 kg, respectively) [65] . ...
... Creatine injection mixed with intensive resistance exercise increased the levels of insulin-like growth factor 1 (IGF-1) in muscle and muscle hypertrophy [65] . In the same study, vegetarians had a higher gain in lean mass than nonvegetarians (2.4 and 1.9 kg, respectively) [65] . These findings, according to the authors, do not support the theory that a low-amino-acid standard vegetarian diet reduces IGF-1 production [65] . ...
... In the same study, vegetarians had a higher gain in lean mass than nonvegetarians (2.4 and 1.9 kg, respectively) [65] . These findings, according to the authors, do not support the theory that a low-amino-acid standard vegetarian diet reduces IGF-1 production [65] . On the whole, creatine administration and subsequent increases in total creatine and PCr may result in increased muscle IGF-1 production and protein synthesis, resulting in greater muscular hypertrophy [66][67][68] . ...
Article
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Athletes take nutritional supplements because they believe it will provide them with a convenient and effective source of nutrients. Creatine and ß-hydroxy-ß-methyl-butyrate (HMB) are two of the most popular and legal ergogenic dietary supplements. These two compounds may have a comparable ergogenic effect since they favor muscle protein synthesis and proteolysis during exercise. This narrative review seeks to offer the most recent scientific literature on these two ergogenic aids in detail. HMB has been found to improve strength and lean muscle mass by acting as an anti-catabolic agent, reducing muscle breakdown and protein degradation following exercise. In terms of muscle absorption and the ability to boost high-intensity exercise capacity, creatine monohydrate (CM) is the most clinically effective nutritional supplement. Athletes utilize creatine pills to boost their exercise performance. The combination of CM and HMB has the potential to increase fat-free mass while lowering fat mass.
... The study of Shomrat et al. (2000) with creatine supplementation resulted in an increase in body mass and power. The study of Burke et al. (2003), based on creatine supplementation, obtained an increase of phosphocreatine (PCr), total creatine (TCr), strength, type II muscle fibers, and lean tissue. These changes were significant in vegetarians. ...
... De acuerdo con la escala PEDro, la metodología de aquellos estudios con una puntuación de 9-10 es considerada «excelente», con una puntuación de 6-8 es considerada «buena» y aquellos estudios con una puntuación de 4-5 es considerada como «regular». En la presente revisión un estudio tenía una excelente metodología (Burke et al., 2003), otro una calidad buena (Burke et al., 2008) y uno de ellos una calidad metodológica considerada como regular (Shomrat, Weinstein, & Katz, 2000). ...
... El consumo de Cr incrementa significativamente la masa corporal (˜1 Kg) y potencia media (˜5 %). Pico W solo en NVC, no en VC. Burke et al. (2003) El entrenamiento incrementa el IGF-1 en un 67% con mayor acumulación para los de creatina respecto a placebo. No diferencias entre V y NV en el IGF-1 (se incrementa con la suplementación independientemente de la dieta). ...
Article
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Resumen: El objetivo del estudio fue investigar los efectos de un entrenamiento de fuerza más una suplementación adicional sobre deportistas adultos no profesionales y vegetarianos. Una revisión sistemática de las bases de datos MEDLINE (PubMed), Scopus, SportDiscus y WOS (Web of Science) fue realizada siguiendo el modelo PICO, utilizando términos que representasen a personas vegetarianas de entre 18 y 64 años que hubiesen realizado una intervención basada en un entrenamiento de fuerza más suplementación. Siguiendo el procedimiento PRISMA, de los 62 estudios encontrados tan solo 3 cumplieron todos los criterios por lo que fueron analizados en su totalidad para poder ser incluidos en la revisión. La calidad metodológica de los estudios se evaluó mediante la escala PEDro. El estudio de Shomrat et al. (2000) la suplementación con creatina provocó un incremento de la masa corporal y potencia media. El estudio de Burke et al. (2003) obtuvo con la suplementación de creatina incrementos en la fosfocreatina (PCr), creatina total (TCr), fuerza, fibras musculares de tipo II y tejido magro, siendo estos cambios más significativos en las personas vegetarianas. Por último, en el estudio de Burke et al. (2008), el factor de crecimiento insulínico de tipo 1 (IGF-1) se incrementó en un 67%, con mayor acumulación en el grupo que fue suplementado con creatina. A raíz de estos resultados se puede concluir que la suplementación con creatina puede provocar efectos positivos en el rendimiento de los deportistas vegetarianos, ya que puede cubrir ciertas carencias derivadas de la dieta vegetariana. Palabras clave: vegetarianos; adultos; entrenamiento de fuerza; suplementación; creatina. Abstract: The aim of the study was to investigate the effects of strength training plus additional supplementation on non-professional adult athletes who are vegetarian. A systematic review of MEDLINE (PubMed), Scopus, SportDiscus, and WOS (Web of Science) databases was performed following the PICO model, using terms related to vegetarians aged between 18 and 64 years who realized an intervention based on strength training and supplementation. Following the PRISMA statement, of the 62 studies found only 3 met all the inclusion criteria and were analyzed entirely to be included in the review. The methodological quality of the studies was performed using the PEDro scale. The study of Shomrat et al. (2000) with creatine supplementation resulted in an increase in body mass and power. The study of Burke et al. (2003), based on creatine supplementation, obtained an increase of phosphocreatine (PCr), total creatine (TCr), strength, type II muscle fibers, and lean tissue. These changes were significant in vegetarians. Finally, in a study of Burke et al. (2008), insulin-like growth factor-1 (IGF-1) increased by 67%, with higher accumulation in the group that was supplemented with creatine. As a consequence of these results we can conclude that creatine supplementation could have positive effects on the performance of vegetarians due to the fact that it could cover certain shortcomings derived from the vegetarian diet.
... The synthesis of such high amounts of creatine diverts onto itself a large part of the body's methylation potential causing appreciable metabolic stress. 25 Despite this metabolic stress, the amount of creatine in vegetarian subjects is decreased (compared to the nonvegetarian subjects) in the serum 41,42 and in the muscle, 43,45 but not in the brain. 46 Beside lack of intake with the diet, another possible reason for low creatine levels in subjects following a vegetarian or vegan diet is that creatine synthesis is impaired in subjects having vitamin B 12 deficiency, 47 a condition that is not infrequent among vegans and vegetarians. ...
... 48,49 Creatine administration has a greater ergogenic effect in vegetarian subjects than in nonvegetarian ones. 43,45 The administration of creatine at a dose of 0.3 g/kg/d (21 g in a man of 70 kg) for 5 days was able to normalize creatine muscle content, which was beforehand reduced by a lacto-ovo vegetarian diet. 42 A similar result was obtained with a loading dose of 0.25 g/(kg of lean tissue mass)/d for 7 days followed by 0.0625 g/(kg of lean tissue mass)/d for 49 days. ...
... 42 A similar result was obtained with a loading dose of 0.25 g/(kg of lean tissue mass)/d for 7 days followed by 0.0625 g/(kg of lean tissue mass)/d for 49 days. 45 Despite the aforementioned cerebral normality, creatine administration at a dose of 20 g/d for 5 days improved memory test performance in vegetarians, not in omnivorous subjects. 50 The authors speculate that creatine supplementation may have positively affected memory in vegetarians by a possible improvement in glucose homeostasis, although this is a purely speculative hypothesis. ...
Article
Creatine is pivotal in energy metabolism of muscle and brain cells, both in physiological and in pathological conditions. Additionally, creatine facilitates the differentiation of muscle and neuronal cells. Evidence of effectiveness of creatine supplementation in improving several clinical conditions is now substantial, and we review it in this paper. In hereditary diseases where its synthesis is impaired, creatine has a disease‐modifying capacity, especially when started soon after birth. Strong evidence, including a Cochrane meta‐analysis, shows that it improves muscular strength and general well‐being in muscular dystrophies. Significant evidence exists also of its effectiveness in secondary prevention of statin myopathy and of treatment‐resistant depression in women. Vegetarians and vegans do not consume any dietary creatine and must synthesize all they need, spending most of their methylation capacity. Nevertheless, they have a lower muscular concentration of creatine. Creatine supplementation has proved effective in increasing muscular and neuropsychological performance in vegetarians or vegans and should, therefore, be recommended especially in those of them who are athletes, heavy‐duty laborers or who undergo intense mental effort. Convincing evidence also exists of creatine effectiveness in muscular atrophy and sarcopenia in the elderly, and in brain energy shortage (mental fatigue, sleep deprivation, environmental hypoxia as in mountain climbing, and advanced age). Furthermore, we review more randomized, placebo‐controlled trials showing that creatine supplementation is safe up to 20 g/d, with a possible caveat only in people with kidney disease. We trust that the evidence we review will be translated into clinical practice and will spur more research on these subjects.
... Dietary intake of creatine is significantly reduced in individuals following a vegetarian diet (egg and dairy products may contribute to provide very small amounts of creatine), while in vegan diets, almost no exogenous source of creatine is consumed [15]. The amount of creatine is lower in serum, plasma, red blood cells, and muscle, but not in the brain in vegetarians versus omnivores [16][17][18][19]. Further, vitamin B12 deficiency (common in vegetarians) is linked with impairment in methionine production, and this may lead to lower creatine biosynthesis [20]. ...
... The majority of data provide strong support indicating creatine supplementation is beneficial, in particular, for increasing upper and lower body strength [27][28][29], high-intensity anaerobic activities (especially when done in a repeated, intermittent fashion [23,25]), muscle mass [23,25,27], and recovery from exercise [25]; however, creatine supplementation is unlikely to improve aerobic exercise performance [24]. When combined with resistance training, creatine supplementation enables athletes to train at a higher intensity, leading to greater training adaptations, which result in greater anabolic gains [18,30]. During high-intensity and short-term exercise which relies mainly on anaerobic energy system pathways, it may be advantageous to have a larger creatine pool to increase anaerobic exercise capacity and shorten recovery time between bouts of exercise [25]. ...
... Muscle biopsies from the vastus lateralis indicate that total creatine (i.e., creatine + phosphocreatine), phosphocreatine, and creatine concentrations are lower by 10-15%, 7-10%, and 7-26%, respectively, in vegetarians compared to omnivores [17,18,34,37]. In the lateral gastrocnemius, phosphocreatine levels, as assessed by 31 P-MRS, are similar in vegetarians and omnivores (i.e., a reduction in vegetarians by~5% that was not statistically significant) [33]; therefore, differences between vegetarians and omnivores seem to be muscle-specific. ...
Article
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Background: Creatine monohydrate is a nutritional supplement often consumed by athletes in anaerobic sports. Creatine is naturally found in most meat products; therefore, vegetarians have reduced creatine stores and may benefit from supplementation. Objective: to determine the effects of creatine supplementation on vegetarians. Data sources: PubMed and SPORTDiscus. Eligibility criteria: Randomized controlled trials (parallel group, cross-over studies) or prospective studies. Participants: Vegetarians. Intervention: Creatine supplementation. Study appraisal and synthesis: A total of 64 records were identified, and eleven full-text articles (covering nine studies) were included in this systematic review. Results: Creatine supplementation in vegetarians increased total creatine, creatine, and phosphocreatine concentrations in vastus lateralis and gastrocnemius muscle, plasma, and red blood cells, often to levels greater than omnivores. Creatine supplementation had no effect on brain levels of phosphocreatine. Creatine supplementation increased lean tissue mass, type II fiber area, insulin-like growth factor-1, muscular strength, muscular endurance, Wingate mean power output, and brain function (memory and intelligence) in vegetarian participants. Studies were mixed on whether creatine supplementation improved exercise performance in vegetarians to a greater extent compared to omnivores. Limitations: Studies that were reviewed had moderate-high risk of bias. Conclusions: Overall, it appears vegetarian athletes are likely to benefit from creatine supplementation.
... All participants had engaged in structured resistance training programmes for at least three months before the commencement of the study, they were technically competent in the back squat exercise, and they were free from illness and musculoskeletal injuries. Participants were excluded from the study if they were vegetarians or vegans since it has been shown that vegetarians have lower muscle creatine stores than omnivores (Maccormick et al., 2004;Burke et al., 2003;Shomrat et al., 2000). Participants refrained from taking any form of performance enhancing substances and supplements including creatine and sodium bicarbonate for at least four weeks before the onset of the study. ...
... Strict dietary controls and carefully chosen inclusion/exclusion criteria were put in place in an attempt to reduce the chances of heterogeneity between groups. For example, participants with low initial creatine stores such as vegans or vegetarians (Maccormick et al., 2004;Burke et al., 2003;Shomrat et al., 2000) are more likely to respond positively when supplemented with creatine (responders) compared to individuals with high baseline creatine stores (nonresponders) (Cooper et al., 2012). Energy and macronutrient intakes were also carefully monitored and controlled since an increase in the carbohydrate intake in particular would have enhanced muscle creatine uptake (Steenge et al., 1998). ...
... Although limited in number, select studies have demonstrated that creatine supplementation is an effective nutritional strategy to promote increases in the phosphocreatine content and energy status of the cell among pediatric populations [9,10]; however, some evidence suggests this is potentially so, but to a lesser extent when compared to what is commonly reported in adult populations [1]. Depending on baseline levels of creatine content, which tend to be heavily influenced by exogenous creatine intake [11], increases of 10-40% in creatine or phosphocreatine content within skeletal muscle tissue are routinely reported following periods of creatine supplementation in adult populations [1]. Interestingly, preliminary evidence suggests that an age-dependent effect of creatine supplementation may exist regarding intramuscular creatine uptake, thereby indicating that the development of age-specific supplementation strategies may be warranted [9,10]. ...
... It is also worth noting that a growing body of evidence exists demonstrating that creatine may also confer a variety of physiological benefits for multiple clinical conditions in adult populations, such as mitochondrial disease, neurological disorders, and autoimmune disorders [47,74], but the extent to which these findings may extend to pediatric populations requires more research due to the limited data currently available. Lastly, and a point that is beyond the scope of this review, all of these findings may hold particular importance for any clinical population (adult or adolescent) who are vegetarians as they may be susceptible to low daily creatine intake through diet alone, as has been reported in adults [3,11,61]. ...
Article
Full-text available
Creatine is a popular ergogenic aid among athletic populations with consistent evidence indicating that creatine supplementation also continues to be commonly used among adolescent populations. In addition, the evidence base supporting the therapeutic benefits of creatine supplementation for a plethora of clinical applications in both adults and children continues to grow. Among pediatric populations, a strong rationale exists for creatine to afford therapeutic benefits pertaining to multiple neuromuscular and metabolic disorders, with preliminary evidence for other subsets of clinical populations as well. Despite the strong evidence supporting the efficacy and safety of creatine supplementation among adult populations, less is known as to whether similar physiological benefits extend to children and adolescent populations, and in particular those adolescent populations who are regularly participating in high-intensity exercise training. While limited in scope, studies involving creatine supplementation and exercise performance in adolescent athletes generally report improvements in several ergogenic outcomes with limited evidence of ergolytic properties and consistent reports indicating no adverse events associated with supplementation. The purpose of this article is to summarize the rationale, prevalence of use, performance benefits, clinical applications, and safety of creatine use in children and adolescents.
... It is composed outside of the muscle itself and then carried to the muscle via the bloodstream. Human studies have demonstrated that Cr supplementations increment slender tissue mass and muscle fiber measure [6]. The expanded concentration of intramuscular phosphocreatine attract water into the muscle cell and increase the cell amount [7]. ...
... CHM had no affect feed conversion ratio (FCR) [21]. The results in a table (6) show the effect of supplemental Creatine monohydrate on performance and nutrient digestibility of broiler chicks fed on diets during 1 day to 42 days. Creatine monohydrate had no Effect on mortality at T2, T3 and T4 was no significant difference in mortality compared their control (T1).at ...
... Burke et al. [26] avaliaram 42 voluntários, sendo 24 não vegetarianos e 18 vegetarianos, divididos em quatro grupos: vegetarianos suplementados com creatina ou com placebo, e não vegetarianos suplementados com creatina ou com placebo. O intuito foi investigar os efeitos da suplementação com creatina sobre diversas variáveis, dentre elas, a concentração muscular de creatina e performance em dois tipos de testes: 1 RM e leg press. ...
... Também foi observado efeito significativo da suplementação de creatina, em ambos os grupos suplementados com esse nutriente, sobre a performance em teste de 1RM, porém, não houve diferenças significativas entre os quatro grupos no que se refere ao leg press. É importante ressaltar que em ambos trabalhos acima citados [25,26] as amostras não foram compostas exclusivamente por indivíduos veganos; considerando-se que os ovolactovegetarianos consomem alguns alimentos de fontes animais, ainda que forneçam quantidades reduzidas de creatina, supõe-se que os estoques de creatina seriam ainda menores nos veganos [22]. Desta forma, veganos poderiam apresentar resposta diferente à suplementação de creatina, uma vez que a dieta tem influência direta nos estoques de creatina muscular. ...
Article
Full-text available
Introdução: A creatina tem sido considerada agente ergogênico para indivíduos onívoros e vegetarianos, porém, nota-se lacuna importante sobre o efeito dessa suplementação sobre a performance de veganos, grupo que apresenta maiores restrições nutricionais dentre os vegetarianos. Objetivo: Analisar o efeito da suplementação de creatina sobre performance em teste de força e composição corporal de veganas. Métodos: Quatorze veganas não-atletas foram randomicamente distribuídas em grupo creatina (n = 7) e placebo (n = 7). Antes e depois da suplementação (0,3 g kg-1 d-1 por 7 dias) foram realizados testes de performance em leg press (3 séries de repetições máximas até falha, a 80% de uma repetição máxima, 60 segundos de intervalo), e antropometria. Resultados: Após suplementação, houve diferenças significativa no número de repetições na primeira série e no somatório das três séries para ambos grupos, porém, com o o tamanho do efeito (effect size) e delta percentual superiores para grupo creatina. Na segunda série, não houve diferenças significativas entre grupos e momentos, porém, effect size e delta percentual também foram superiores para grupo creatina. Não foi observada alteração significativa na composição corporal. Conclusão: A suplementação de creatina apresentou maior efeito sobre performance em teste de força para membros inferiores, quando comparadas ao placebo, sem alterar composição corporal.
... There is evidence of responders and nonresponders to Cr supplementation. Subjects with low initial levels of intramuscular Cr exhibit a more significant response to Cr supplementation, which may account for varying degrees of performance and body composition changes seen in the above studies (5,39). Because vegetarians have lower total Cr levels compared to nonvegetarians, the overall increase in muscle Cr content is likely to be greater and therefore elicit a more ergogenic response (5). ...
... Subjects with low initial levels of intramuscular Cr exhibit a more significant response to Cr supplementation, which may account for varying degrees of performance and body composition changes seen in the above studies (5,39). Because vegetarians have lower total Cr levels compared to nonvegetarians, the overall increase in muscle Cr content is likely to be greater and therefore elicit a more ergogenic response (5). Despite evidence of dietary creatine affecting intramuscular creatine levels, none of the articles included in this review used dietary restricted subjects, nor did they separate vegetarians from nonvegetarians for independent analysis. ...
... Although limited in number, select studies have demonstrated that creatine supplementation is an effective nutritional strategy to promote increases in creatine content and energy status of the cell among pediatric populations [9,10]; however, some evidence suggest potentially to a lesser extent when compared to what is commonly reported in adult populations [1]. Depending on baseline levels of creatine content, which tends to be heavily influenced by exogenous creatine intake [11], increases of 10-40% in creatine content within skeletal muscle tissue are routinely reported following periods of creatine supplementation in adult populations [1]. Interestingly, there is preliminary evidence suggesting there may be an age-dependent effect of creatine supplementation on intramuscular creatine uptake, thereby indicating that the development of age-specific supplementation strategies may be warranted [9,10]. ...
... It is also worth noting, there is a growing body of evidence demonstrating that creatine may also confer a variety of physiological benefits for multiple clinical conditions in adult populations, such as mitochondrial disease, neurological disorders, and autoimmune disorders [49,65], but the extent to which these findings may extend to pediatric populations requires more research due to the limited data currently available. Lastly, and a point that is beyond the scope of this review, all of these findings may hold particular importance for any clinical populations (adult or adolescent) who are vegetarians as they may be susceptible to low daily creatine intake through diet alone, as has been reported in adults [3,11,66]. ...
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Creatine is a popular ergogenic aid among athletic populations with consistent evidence indicating that creatine supplementation also continues to be commonly used among adolescent populations. In addition, the evidence base supporting the therapeutic benefits of creatine supplementation for a plethora of clinical applications in both adults and children continues to grow. Among pediatric populations, a strong rationale exists for creatine to afford therapeutic benefits pertaining to multiple neuromuscular and metabolic disorders, with preliminary evidence for other subsets of clinical populations as well. Despite the strong evidence supporting the efficacy and safety of creatine supplementation among adult populations, less is known as to whether similar physiological benefits extend to children and adolescent populations, and in particular those adolescent populations who are regularly participating in high-intensity exercise training. While limited in scope, studies involving creatine supplementation and exercise performance in adolescent athletes generally report improvements in a number of ergogenic outcomes with limited evidence of ergolytic properties and consistent reports indicating no adverse events associated with supplementation. The purpose of this article is to summarize the rationale, prevalence of use, performance benefits, clinical applications, and safety of creatine use in children and adolescents.
... Creatine supplementation has been reported to increase muscle creatine and PCr levels, enhance acute exercise capacity, and improve training adaptations [44, 66,69,. The improvement in performance has generally been 10-20% on various high-intensity exercise tasks [97] that include lifetime fitness activities like fitness/weight training [77,84,91,[98][99][100][101][102][103][104][105][106][107][108], golf [109], volleyball [110], soccer [82,111,112], softball [113], ice hockey [114], running [115][116][117][118][119], and swimming [73,74,[120][121][122][123], among others. Ergogenic benefits have been reported in men and women from children to elderly populations, although the majority of studies have been conducted on men [74,111,113,[124][125][126][127][128]. ...
Article
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Although creatine has been mostly studied as an ergogenic aid for exercise, training, and sport, several health and potential therapeutic benefits have been reported. This is because creatine plays a critical role in cellular metabolism, particularly during metabolically stressed states, and limitations in the ability to transport and/or store creatine can impair metabolism. Moreover, increasing availability of creatine in tissue may enhance cellular metabolism and thereby lessen the severity of injury and/or disease conditions, particularly when oxygen availability is compromised. This systematic review assesses the peer-reviewed scientific and medical evidence related to creatine’s role in promoting general health as we age and how creatine supplementation has been used as a nutritional strategy to help individuals recover from injury and/or manage chronic disease. Additionally, it provides reasonable conclusions about the role of creatine on health and disease based on current scientific evidence. Based on this analysis, it can be concluded that creatine supplementation has several health and therapeutic benefits throughout the lifespan.
... High-intensity exercise performance is generally increased by 10-20% with greater improvements seen in individuals starting the supplementation protocol with lower muscle creatine and PCr content [102]. Improvements in performance have been reported in individuals participating in weight training [55,89,95,[103][104][105][106][107][108][109][110][111][112][113], running [114][115][116][117][118], soccer [87,119,120], swimming [79,80,[121][122][123][124], volleyball [125], softball [126], ice hockey [127], golf [128], among others [24]. Men and women have been reported to benefit from CrM supplementation in populations ranging from children to elderly populations [47,80,119,126,[129][130][131][132][133]. ...
Article
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In 2011, we published a paper providing an overview about the bioavailability, efficacy, and regulatory status of creatine monohydrate (CrM), as well as other “novel forms” of creatine that were being marketed at the time. This paper concluded that no other purported form of creatine had been shown to be a more effective source of creatine than CrM, and that CrM was recognized by international regulatory authorities as safe for use in dietary supplements. Moreover, that most purported “forms” of creatine that were being marketed at the time were either less bioavailable, less effective, more expensive, and/or not sufficiently studied in terms of safety and/or efficacy. We also provided examples of several “forms” of creatine that were being marketed that were not bioavailable sources of creatine or less effective than CrM in comparative effectiveness trials. We had hoped that this paper would encourage supplement manufacturers to use CrM in dietary supplements given the overwhelming efficacy and safety profile. Alternatively, encourage them to conduct research to show their purported “form” of creatine was a bioavailable, effective, and safe source of creatine before making unsubstantiated claims of greater efficacy and/or safety than CrM. Unfortunately, unsupported misrepresentations about the effectiveness and safety of various “forms” of creatine have continued. The purpose of this critical review is to: (1) provide an overview of the physiochemical properties, bioavailability, and safety of CrM; (2) describe the data needed to substantiate claims that a “novel form” of creatine is a bioavailable, effective, and safe source of creatine; (3) examine whether other marketed sources of creatine are more effective sources of creatine than CrM; (4) provide an update about the regulatory status of CrM and other purported sources of creatine sold as dietary supplements; and (5) provide guidance regarding the type of research needed to validate that a purported “new form” of creatine is a bioavailable, effective and safe source of creatine for dietary supplements. Based on this analysis, we categorized forms of creatine that are being sold as dietary supplements as either having strong, some, or no evidence of bioavailability and safety. As will be seen, CrM continues to be the only source of creatine that has substantial evidence to support bioavailability, efficacy, and safety. Additionally, CrM is the source of creatine recommended explicitly by professional societies and organizations and approved for use in global markets as a dietary ingredient or food additive.
... Furthermore, it is importnat to highlight that the participants in the current study were omnivores. Within skeletal muscle, vegetarians have a lower creatine content and are more responsive to creatine supplementation (Burke et al., 2003). With regards to cognitive function, a previous randomized controlled trial revealed that word recall response declined after creatine supplementation (20 g/d of creatine for 5 days) in meat-eaters, as opposed to vegan and vegetarian participants, and post supplementation comparisons were significantly greater in vegetarians compared to omnivores (Benton and Donohoe, 2011). ...
Article
Aims: The purpose was to examine the relationship between habitual dietary creatine intake obtained in food and visuo-spatial short-term memory (VSSM). Methods: Forty-two participants (32 females, 10 males; > 60 yrs of age) completed a 5-day dietary recall to estimate creatine intake and performed a cognitive assessment which included a visuospatial short-term memory test (forward and reverse corsi block test) and a mini-mental state examination (MMSE). Pearson correlation coefficients were determined. Further, cohorts were derived based on the median creatine intake. Results: There was a significant correlation between the forward Corsi (r = 0.703, P < 0.001), reverse Corsi (r = 0.715, P < 0.001), and the memory sub-component of the MMSE (r = 0.406, P = 0.004). A median creatine intake of 0.382 g/day was found. Participants consuming greater than the median had a significantly higher Corsi (P = 0.005) and reverse Corsi (P < 0.001) scores compared to participants ingesting less than the median. Conclusions: Dietary creatine intake is positively associated with measures of memory in older adults. Clinical Implications: Older adults should consider food sources containing creatine (i.e. red meat, seafood) due to the positive association with visuospatial short-term memory.
... These supplement does not doing any miracle without exercise, proper sleep, macro micro nutrients full fill diet these supplement work as support primary is natural diet, exercise, add water in 5 -6 litre. In this article we discussed about all supplement their advantage, fat loss goal journey schedule in last main conclusion is supplement only work when person take low calorie in diet, full nutritional, sleep, workout then any individual achieve goal 3 -4 months [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. ...
Article
There are several myths about obesity management or fat loss program from longer time. In USA every 1/3 Person is suffering obesity due to unhealthy diet follow and other unhealthy food habit like taking to much fast food. In this article we are focusing in natural way how we can manage obesity or remove fat layer from the body. In this article we are focusing keto diet, essential nutrition from food, omega 3, L-Arginine, BCAA (essential three amino acid) in ratio 2:2:1 form, whey protein [fast digest protein] apart from meat, soya protein. Obesity is very dangerous disease itself or we can also triggered a term for obesity a powerhouse of fat that helps to metabolism slow and occurring several serious disease. Such as diabetes, blood pressure [High], Blood Clot, Cholesterol, hormone imbalance, low libido in male, Erectile dysfunction, low testosterone, heart attack, joint pain, vision problem, skin problem, water retention, sickness etc. We have only the way to minimize the fat proper sleep, nutrition, exercise with high intensity highly recommended this is the only way to minimize the severe conditions comes from obesity. In India epidemic range is around 5% of total population and the common age 22 - 38 Male/female. Keywords: Obesity; Fat Loss; Keto Diet; BCAA; L-Arginine
... For example, creatine has been studied extensively for its ability to enhance athletic performance (Cooper et al., 2012), but creatine also plays an important role in cognition (Avgerinos et al., 2018). As creatine is found only in animal foods, vegans and vegetarians often have lower bodily stores (Burke et al., 2003), and vegetarians provided with supplemental creatine showed substantial improvements in memory tasks (Benton and Donohoe, 2011). Similarly, the antioxidants anserine, carnosine, and taurine are found (almost) exclusively in animal foods (Hou et al., 2019). ...
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There is wide scale concern about the effects of red meat on human health and climate change. Plant-based meat alternatives, designed to mimic the sensory experience and nutritional value of red meat, have recently been introduced into consumer markets. Plant-based meats are marketed under the premise of environmental and human health benefits and are aimed appeal to a broad consumer base. Meat production is critiqued for its overuse of water supplies, landscape degradation, and greenhouse gas emission, and depending on production practices, environmental footprints may be lower with plant-based meat alternatives. Life-cycle analyses suggest that the novel plant-based meat alternatives have an environmental footprint that may be lower than beef finished in feedlots, but higher than beef raised on well-managed pastures. In this review, we discuss the nutritional and ecological impacts of eating plant-based meat alternatives vs. animal meats. Most humans fall on a spectrum of omnivory: they satisfy some nutrient requirements better from plant foods, while needs for other nutrients are met more readily from animal foods. Animal foods also facilitate the uptake of several plant-derived nutrients (zinc and iron), while plant nutrients can offer protection against potentially harmful compounds in cooked meat. Thus, plant and animal foods operate in symbiotic ways to improve human health. The mimicking of animal foods using isolated plant proteins, fats, vitamins, and minerals likely underestimates the true nutritional complexity of whole foods in their natural state, which contain hundreds to thousands of nutrients that impact human health. Novel plant-based meat alternatives should arguably be treated as meat alternatives in terms of sensory experience, but not as true meat replacements in terms of nutrition. If consumers wish to replace some of their meat with plant-based alternatives in the diet (a “flexitarian approach”) this is unlikely to negatively impact their overall nutrient status, but this also depends on what other foods are in their diet and the life stage of the individual.
... As dietas vegetarianas tendem a diminuir as reservas de creatina muscular, visto não haver compensação pelo aumento da produção endógena (61,62 ...
Article
There has been a growing adoption of the vegetarian dietary pattern, four times higher than ten years ago. Nowadays, the benefits of vegetable food consumption and its role in the prevention of several highly prevalent diseases in the population are known, such as type 2 diabetes mellitus, hypertension and cardiovascular diseases. When a large amount of food is included daily in the diet and the energy intake is adequate, vegetarian athletes can meet their protein needs through vegetable sources. Nutrients to consider avoiding nutritional deficiencies in vegetarians include proteins, n-3 fatty acids, iron, zinc, calcium, iodine, vitamin D and vitamin B12. With the increase of the number of athletes who follow the vegetarian diet, it is pertinent to question its effect on sports performance. This work brings together an existent proof of a nutritional approach in vegetarian athletes, identifying scientific studies from 1997 to 2019. The purpose of this paper is to examine and discuss the possible impacts of the vegetarian dietary pattern on sports performance. Current scientific evidence demonstrates that the adoption of this dietary pattern does not positively or negatively affect athletes' performance. Thus, it will be necessary to conduct further studies to examine the effects of the vegetarian dietary pattern on athletes to ensure the optimization of health and performance.
... Vegetarians generally present with lower total creatine levels. However, this difference appears to make them more receptive to creatine supplementation and its effects, as vegetarian participants receiving a creatine supplement exhibited greater increases in total creatine, phosphocreatine, lean body mass, and total work performed doing leg extensions and flexions on an isokinetic dynamometer compared to omnivores receiving creatine supplementation and undergoing the same training program [118]. There were no significant differences in total work output at baseline between groups, in spite of the lower total creatine levels. ...
Article
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Plant-based diets provide well-established physical and environmental health benefits. These benefits stem in part from the degree of restriction of animal-derived foods. Historically, meat and other animal-derived proteins have been viewed as an integral component of athletes’ diets, leading some to question the adequacy of vegetarian or vegan diets for supporting athletic performance. The purpose of this review is to examine the impact of plant-based diets on human physical health, environmental sustainability, and exercise performance capacity. Based on currently available literature, it is unlikely that plant-based diets provide advantages, but do not suffer from disadvantages, compared to omnivorous diets for strength, anaerobic, or aerobic exercise performance. However, plant-based diets typically reduce the risk of developing numerous chronic diseases over the lifespan and require fewer natural resources for production compared to meat-containing diets. As such, plant-based diets appear to be viable options for adequately supporting athletic performance while concurrently contributing to overall physical and environmental health. Given the sparse literature comparing omnivore, vegetarian, and vegan athletes, particularly at the elite level, further research is warranted to ascertain differences that might appear at the highest levels of training and athletic performance.
... terest in vegetarian kinds of diet in relation to their potential for enhancing or hampering sports performance, a brief/short outline of the recent focus on vegetarian and vegan diets in sports affecting both anaerobic and aerobic exercise performance is given. This includes dietary antioxidants and exercise-induced oxidative stress [18,211,266,267]; kinds of plant protein such as soy, rice, pea, hemp, and wheat [268][269][270]; creatine [271,272], l-carnitine [273,274]; muscle carnosine [275]; and dietary nitrate supplementation from beet root juice for example [276][277][278], among others [2] (p. 426). ...
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https://clinmedjournals.org/International-Journal-of-Sports-and-Exercise-Medicine.php?fbclid=IwAR2VOazGWyn0X6pk574PNVzXRy3yOFjpLkSQ3SmcJxFe68cyEBZs2a641JI or directly from https://clinmedjournals.org/articles/ijsem/international-journal-of-sports-and-exercise-medicine-ijsem-6-165.pdf?fbclid=IwAR0-UxOUaOZySmOSRGWTPj267VkDhJPwQIH8elrmQHtG6IgdnMXBzR-ieZg
... Briefly, creatine supplementation may be more efficacious in those with lower pre-supplementation intramuscular creatine stores [48]. The vast majority of dietary creatine is found in animal-based foods (i.e., meat, seafood, and poultry) and those who consume little to no animal-based products (i.e., vegan, vegetarian) would potentially respond more favorably to creatine supplementation [49]. Furthermore, individuals with the greatest quantity and crosssectional area of type II muscle fibers appear to respond optimally to creatine supplementation [48]. ...
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High-intensity interval training (HIIT) involves short bursts of intense activity interspersed by periods of low-intensity exercise or rest. HIIT is a viable alternative to traditional continuous moderate-intensity endurance training to enhance maximal oxygen uptake and endurance performance. Combining nutritional strategies with HIIT may result in more favorable outcomes. The purpose of this narrative review is to highlight key dietary interventions that may augment adaptations to HIIT, including creatine monohydrate, caffeine, nitrate, sodium bicarbonate, beta-alanine, protein, and essential amino acids, as well as manipulating carbohydrate availability. Nutrient timing and potential sex differences are also discussed. Overall, sodium bicarbonate and nitrates show promise for enhancing HIIT adaptations and performance. Beta-alanine has the potential to increase training volume and intensity and improve HIIT adaptations. Caffeine and creatine have potential benefits, however, longer-term studies are lacking. Presently, there is a lack of evidence supporting high protein diets to augment HIIT. Low carbohydrate training enhances the upregulation of mitochondrial enzymes, however, there does not seem to be a performance advantage, and a periodized approach may be warranted. Lastly, potential sex differences suggest the need for future research to examine sex-specific nutritional strategies in response to HIIT.
... Уровни креатина в плазме крови и мышцах у вегетарианцев, как правило, ниже, чем у ТПЛ [67,68]. Результаты исследования [69] показали низкую обеспеченность креатином у взрослых лакто-ово-вегетарианцев. Причем дети и взрослые, получающие веганский рацион, вообще не могут получать креатин из пищи [70]. ...
... Numerous studies have shown that oral creatine supplementation with doses of 20-25 g/d for 5-7 days followed by a maintenance dose of 4-5 g/g for several weeks increases intramuscular phosphocreatine (PCr) concentration by stimulating phosphagen metabolism [2][3][4][5]. These metabolic and training adaptations may explain the significant improvements in performance during high-intensity continuous exercise, as in prolonged sprints (400 m dash), or short lasting (5-10 m) repeated bouts of exercise, such as in team sport games or combat sports [6][7][8]. Metabolically, PCr serves as an important energy contributor during high-intensity exercise. Theoretically, it seems that increasing the availability of PCr should speed endurance, speed as well as changes in body mass and chosen biochemical variables related to buffering capacity. ...
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Aim: The aim of the study was to evaluate the effects of 16 weeks of a low dose of magnesium creatine chelate supplementation on repeated sprint ability test (RAST) results in elite soccer players. Materials: Twenty well-trained soccer players participated in the study. The players were divided randomly into two groups: the supplemented group (SG = 10) and placebo group (PG = 10). Out of the 20 subjects selected for the study, 16 (SG = 8, PG = 8) completed the entire experiment. The SG ingested a single dose of 5500 mg of magnesium creatine chelate (MgCr-C), in 4 capsules per day, which was 0.07 g/kg/d. The PG received an identical 4 capsules containing corn starch. Before and after the study, the RAST was performed. In the RAST, total time (TT), first and sixth 35 m sprint length (s), average power (AP) and max power (MP) were measured. Additionally, before and after the test, lactate LA (mmol/L) and acid-base equilibrium pH (-log(H+)), bicarbonates HCO3- (mmol/L) were evaluated. Also, in serum at rest, creatinine (mg/dL) concentration was measured. Results: After the study, significantly better results in TT, AP and MP were observed in the SG. No significant changes in the RAST results were observed in the PG. After the study, significant changes in the first 35 m sprint, as well as the sixth 35 m sprint results were registered in the SG, while insignificant changes occurred in the PG. A significantly higher creatinine concentration was observed. Also, a higher post-RAST concentration of LA, HCO3- and lower values of pH were observed in April, May and June compared with baseline values. Conclusions: The long timeframe, i.e., 16 weeks, of the low dose of magnesium creatine chelate supplementation improved the RAST results in the SG. Despite the long period of MgCr-C supplementation, in the end of the study, the creatinine level in the SG reached higher but still reference values.
... Por tanto, el efecto de la suplementación con Cr, se ha visto especialmente interesante en la mejora del rendimiento de ejercicios de alta intensidad que duran menos de 30 segundos, siendo más evidente, cuando hay periodos repetidos de ejercicio intenso, como por ejemplo, el entrenamiento de fuerza 11 . Además, el entrenamiento de fuerza junto con la ingesta de Cr permite aumentar la intensidad del entrenamiento, lo que conlleva mayores adaptaciones y ganancias de masa muscular 12,13 . ...
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José Manuel Jurado-Castro, et al. 48 Arch Med Deporte 2021;38(1):48-53 Revisión Resumen La creatina es un suplemento deportivo con una elevada evidencia científica sobre sus efectos en el rendimiento y con resul-tados emergentes en la salud, incluida la de deportistas vegetarianos y adultos mayores. El tipo de creatina y las dosis efectivas, han sido bien estudiadas presentando resultados consistentes. Sin embargo, no son muchos los estudios que han evaluado el momento de la ingesta en cuanto a su interacción con los efectos de la creatina. El objetivo de esta revisión, es analizar la diferente literatura científica existente sobre los protocolos de suplementación con creatina y su interacción con el momento de la ingesta, con el fin de evaluar si existe un efecto mayor de la dosis ergogénica considerada efectiva de creatina cuando esta es ingerida antes, después del entrenamiento o en otro momento del día. Los resultados de este trabajo presentaron diferentes tipos de protocolos y dosis en la suplementación con creatina, a pesar de ser diversos los protocolos mostrados en la literatura, el más efectivo constó de un consumo de 0,3 g/kg/d durante cinco días, seguido de un consumo de 0,03 g/kg/d consiguiendo de esta forma, una mayor reserva de PCr en el músculo esquelético. Los estudios mostraron mayores beneficios cuando la ingesta de creatina se realizó en los momentos cercanos al entreno debido al mayor flujo sanguíneo, apuntando los estudios a mejoras significativas en un consumo post-entreno, debido a que la creatina puede aumentar la formación de de glucógeno en el músculo y aumentar la sensibilidad a la insulina. Palabras clave: Creatina. Deporte. Suplementos dietéticos. Rendimiento deportivo. Summary Creatine is a sports supplement with high scientific evidence on its effects on performance and with emerging health's results, including for vegetarian athletes and older adults. The creatine type and effective doses have been well studied, presenting consistent results. However, not many studies have evaluated the ingestion timing in terms of its interaction with the creatine effects. The aim of this review is to analyze the different existing scientific literature on creatine supplementation protocols and their interaction with the timing of ingestion, in order to assess whether there is a greater effect of the ergogenic dose of creatine considered effective when It is ingested before, post workout or at another time of the day. The results of this work presented different types of protocols and doses in creatine supplementation, despite being diverse the protocols shown in the literature, the most effective consisted of a consumption of 0.3 g/kg/d for five days, followed by a consumption of 0.03 g/kg/d, thus achieving a greater reserve of PCr in skeletal muscle. Studies showed greater benefits when creatine intake was carried out in the moments close to workout due to greater blood flow, the studies pointing to significant improvements in post-workout consumption, since creatine can increase the rate of glycogen uptake in muscle and increase insulin sensitivity.
... Therefore, the effect of Cr supplementation has been viewed with particular interest in terms of improving performance in high-intensity exercises lasting less than 30 seconds, proving most evident where there are repeated periods of intense exercise, such as strength training, for example 11 . Furthermore, strength training combined with taking Cr, allows for an increase in the intensity of the training, which entails greater adaptations and muscle mass gains 12,13 . ...
Article
Full-text available
Creatine is a sports supplement with high scientific evidence on its effects on performance and with emerging health’s results, including for vegetarian athletes and older adults. The creatine type and effective doses have been well studied, presenting consistent results. However, not many studies have evaluated the ingestion timing in terms of its interaction with the creatine effects. The aim of this review is to analyze the different existing scientific literature on creatine supplementation protocols and their interaction with the timing of ingestion, in order to assess whether there is a greater effect of the ergogenic dose of creatine considered effective when It is ingested before, post workout or at another time of the day. The results of this work presented different types of protocols and doses in creatine supplementation, despite being diverse the protocols shown in the literature, the most effective consisted of a consumption of 0.3 g/kg/d for five days, followed by a consumption of 0.03 g/kg/d, thus achieving a greater reserve of PCr in skeletal muscle. Studies showed greater benefits when creatine intake was carried out in the moments close to workout due to greater blood flow, the studies pointing to significant improvements in post-workout consumption, since creatine can increase the rate of glycogen uptake in muscle and increase insulin sensitivity
... Por tanto, el efecto de la suplementación con Cr, se ha visto especialmente interesante en la mejora del rendimiento de ejercicios de alta intensidad que duran menos de 30 segundos, siendo más evidente, cuando hay periodos repetidos de ejercicio intenso, como por ejemplo, el entrenamiento de fuerza 11 . Además, el entrenamiento de fuerza junto con la ingesta de Cr permite aumentar la intensidad del entrenamiento, lo que conlleva mayores adaptaciones y ganancias de masa muscular 12,13 . ...
Article
Full-text available
La creatina es un suplemento deportivo con una elevada evidencia científica sobre sus efectos en el rendimiento y con resul- tados emergentes en la salud, incluida la de deportistas vegetarianos y adultos mayores. El tipo de creatina y las dosis efectivas, han sido bien estudiadas presentando resultados consistentes. Sin embargo, no son muchos los estudios que han evaluado el momento de la ingesta en cuanto a su interacción con los efectos de la creatina. El objetivo de esta revisión, es analizar la diferente literatura científica existente sobre los protocolos de suplementación con creatina y su interacción con el momento de la ingesta, con el fin de evaluar si existe un efecto mayor de la dosis ergogénica considerada efectiva de creatina cuando esta es ingerida antes, después del entrenamiento o en otro momento del día. Los resultados de este trabajo presentaron diferentes tipos de protocolos y dosis en la suplementación con creatina, a pesar de ser diversos los protocolos mostrados en la literatura, el más efectivo constó de un consumo de 0,3 g/kg/d durante cinco días, seguido de un consumo de 0,03 g/kg/d consiguiendo de esta forma, una mayor reserva de PCr en el músculo esquelético. Los estudios mostraron mayores beneficios cuando la ingesta de creatina se realizó en los momentos cercanos al entreno debido al mayor flujo sanguíneo, apuntando los estudios a mejoras significativas en un consumo post-entreno, debido a que la creatina puede aumentar la formación de de glucógeno en el músculo y aumentar la sensibilidad a la insulina.
... To be noted that, at least in muscles, data suggest that individuals consuming a lowmeat diet (who normally show reduced Cr/PCr content) experience greater Cr/PCr accretion following supplementation of this metabolite [39,40]. Additionally, it is important to carefully evaluate a potential age-dependent effect that might be responsible of a different intramuscular Cr uptake by age groups [35]. ...
Article
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Background: Creatine (Cr) levels are strongly dependent on diets, including animal-derived proteins. Cr is an important metabolite as it represents a source of stored energy to support physical performance and potentially sustain positive effects such as improving memory or intelligence. This study was planned to assess Cr levels in PKU children adhering to a diet low in phenylalanine (Phe) content and compared with those of children with mild hyperphenylalaninemia (MHP) on a free diet. Methods: This retrospective pilot study analyzed Cr levels from Guthrie cards in 25 PKU and 35 MHP subjects. Anthropomorphic and nutritional data of the study populations were assessed, compared and correlated. Results: Cr levels of PKU subjects were significantly lower than those of MHP subjects and correlated to the low intake of animal proteins. Although no deficiencies in PKU subjects were identified, PKU subjects were found to have a 26-fold higher risk of displaying Cr levels <25° percentile than MHP counterparts. Conclusions: This pilot study suggests that Cr levels might be concerningly low in PKU children adhering to a low-Phe diet. Confirmatory studies are needed in PKU patients of different age groups to assess Cr levels and the potential benefits on physical and intellectual performance of Cr supplementation.
... Here, I bring into focus possible advantages of creatine use in the general public and medicine while extensive evidence about its application in sports and exercise nutrition is available elsewhere (Kreider et al., 2017); coadministration studies that provided creatine along with exercise regimen or other therapeutics were not included in this summary. Still, the health benefits of creatine are often augmented when it is combined with resistance training in clinical and non-clinical populations (Burke et al., 2003;Candow, Forbes, Kirk, & Duque, 2021;Forbes, Candow, Ferreira, & Souza-Junior, 2021). ...
Article
Creatine is a non-proteinogenic amino acid available from various animal-based foods or synthesized endogenously in the human body. A number of recent population-based studies demonstrate a lower-than-expected dietary creatine intake across age- and gender-specific cohorts, with low creatine consumption accompanied by various health risks. Those studies suggest that the general public may benefit from creatine to prevent and manage various health conditions or to ensure advanced growth. Favorable safety and promising impact of supplemental creatine on human well-being and functioning emanated from plenty of small-sampled interventional studies perhaps suggest a need for recommending creatine to the general public. In this opinion paper, I have outlined the possible rationales for endorsing supplemental creatine ubiquitously, and discussed opportunities and challenges for population-wide creatine use.
... However, there has been a recent focus on vegetarian and vegan diets in sports affecting both anaerobic and aerobic exercise performance, for example, blood acid-base status (pH-value), because diet and exercise may affect acid-base balance (Hietavala et al., 2012); dietary antioxidants and exercise-induced oxidative stress (Trapp et al., 2010;Yavari et al., 2015); kinds of plant protein such as soy, rice, pea, hemp, and wheat (Hartman et al., 2007;Joy et al., 2013;Tang et al., 2009); creatine (Burke et al., 2003;Shomrat et al., 2000), l-carnitine (Novakova et al., 2015;Stephens et al., 2011); muscle carnosine (Baguet et al., 2011), and dietary nitrate supplementation from beet root juice for example (Callahan et al., 2017;Clements et al., 2014;Jones, 2014); hypertrophic potential of a resistive exercise training in terms of strength gain (does not seem to be influenced by plant protein) (Campbell et al., 1999;Haub et al., 2002Haub et al., , 2005Wells et al., 2003), which together reflects a growing scientific interest in plant-based diets related to their potential for enhancing or hindering performance. ...
Chapter
Technology-supported food development is an important aspect of modern societies. At the same time, there is a strong trend towards natural and whole plant-food diets as practicable tools to be implemented in everyday life. In ancient times, gladiators and prominent philosophers already knew that plant-based diets (vegetarian, vegan) lead to peak performance. This chapter presents data on a highly underestimated body of evidence-based scientific information, still mostly neglected by nutrition science, and provides a more basic but dual approach to food bio-engineering and human development. This comprehensive overview of vegetarian and vegan diets ranges from the myths about meat and early studies into the effect of vegetarian diets on sports, through the flood of studies published on the health-threatening effects of foods from animal sources, to current studies showing the benefits of of predominantly plant-based diets on human health and sports performance, but without claim of completeness. What does this chapter add?  This chapter reminds of the fact that vegan diets not only supply all nutrients in adequate amounts (except for vitamin B12), but has enabled recreational as well as professional athletes to achieve top performances in their chosen disciplines. How might this impact daily dietary practice?  The knowledge about the benefits of a vegan diet on mental and physical performance can motivate conventional consumers to change to some kind of vegetarian diet, which would be beneficial, in addition to health, also to the environment, the climate and animal welfare.
... However, it should be noted that not all individuals will respond to exogenous creatine intake vis-à-vis significantly increasing muscle creatine content [135,136]. In particular, "responders" tend to be those who have a larger type II muscle fiber area (i.e., those with an innate proclivity for sprinting and/or strength/power sports) [137,138] and/or those with lower initial creatine levels, perhaps due to lack of intake (e.g., those who have not been supplementing with creatine or who are non-supplementing vegetarians) [139]. ...
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Bodybuilding is a competitive endeavor where a combination of muscle size, symmetry, “conditioning” (low body fat levels), and stage presentation are judged. Success in bodybuilding requires that competitors achieve their peak physique during the day of competition. To this end, competitors have been reported to employ various peaking interventions during the final days leading to competition. Commonly reported peaking strategies include altering exercise and nutritional regimens, including manipulation of macronutrient, water, and electrolyte intake, as well as consumption of various dietary supplements. The primary goals for these interventions are to maximize muscle glycogen content, minimize subcutaneous water, and reduce the risk abdominal bloating to bring about a more aesthetically pleasing physique. Unfortunately, there is a dearth of evidence to support the commonly reported practices employed by bodybuilders during peak week. Hence, the purpose of this article is to critically review the current literature as to the scientific support for pre-contest peaking protocols most commonly employed by bodybuilders and provide evidence-based recommendations as safe and effective strategies on the topic.
... Moreover, it has been suggested that people with low levels of intramuscular creatine respond better to creatine supplementation. 21 We did not check the intramuscular creatine levels. ...
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Int J Cur Res Rev | Vol 13 • Issue 12 • June 2021150Efficacy and Safety of Creatine Supplementation on Strength and Muscle Mass in Resistance Trained Individuals: A Prospective StudyPriyanka Mirdha1, Vivek Nalgirkar2, Anant Patil3, Vijaykumar Gupta41Assistant Lecturer, Department of Physiology, Dr. DY Patil Medical College, Navi Mumbai, Maharashtra, India; 2Professor and Head, Depart-ment of Physiology, Dr. DY Patil Medical College, Navi Mumbai, Maharashtra, India; 3Assistant Professor, Department of Pharmacology, DY Patil University, School of medicine, Navi Mumbai, India; 4Assistant Professor, Department of Physiology, Dr. DY Patil Medical College, Navi Mumbai, Maharashtra, India.Corresponding Author:Dr. Priyanka Mirdha, Assistant Lecturer, Department of Physiology, Dr. DY Patil Medical College, Navi Mumbai, Maharashtra, India.Email: mirdha.priyanka@gmail.comISSN: 2231-2196 (Print) ISSN: 0975-5241 (Online)Received: 06.11.2020 Revised: 02.01.2021 Accepted: 18.02.2021 Published: 22.06.2021INTRODUCTIONWith the increasing number of cases of obesity and asso-ciated diseases, the importance of physical fitness is ever-growing.1 Several interventions including diet, exercise and its combination are being tried to reduce weight and improve physical fitness.2 With increased adaptation to automation and changes in lifestyle, physical fitness awareness among the public is becoming very important. Among adults and students, sports and exercise science is gaining popularity over the years. People are becoming interested in knowing how the body responds and adapts to exercise and strategies to improve performance for enjoying a longer and healthi (2) (PDF) Efficacy and Safety of Creatine Supplementation on Strength and Muscle Mass in Resistance Trained Individuals: A Prospective Study. Available from: https://www.researchgate.net/publication/352657496_Efficacy_and_Safety_of_Creatine_Supplementation_on_Strength_and_Muscle_Mass_in_Resistance_Trained_Individuals_A_Prospective_Study [accessed Nov 26 2021].
... A parallel may be drawn with creatine supplementation. Vegetarians and vegans who consume diets poorest in creatine (meat, fish, and eggs) have the lowest levels of muscle creatine phosphate, and the effect of creatine supplementation on performance is significantly more pronounced in this population versus omnivores [73]. ...
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Nitrates have become increasingly popular for their potential role as an ergogenic aid. The purpose of this article was to review the current scientific evidence of nitrate supplementation on human performance. The current recommendation of nitrate supplementation is discussed, as well as possible health complications associated with nitrate intake for athletes, and dietary strategies of covering nitrate needs through sufficient intake of nitrate-rich foods alone are presented. Pubmed, Scopus, and Web of Science were searched for articles on the effects of nitrate supplementation in humans. Nitrates are an effective ergogenic aid when taken acutely or chronically in the range of ~5–16.8 mmol (~300–1041 mg) 2–3 h before exercise and primarily in the case of exercise duration of ~10–17 min in less trained individuals (VO2max < 65 mL/kg/min). Nitrate needs are most likely meet by ingesting approximately 250–500 g of leafy and root vegetables per day; however, dietary supplements might represent a more convenient and accurate way of covering an athlete’s nitrate needs. Athletes should refrain from mouthwash usage when nitrate supplementation benefits are desired. Future research should focus on the potential beneficial effects of nitrate supplementation on brain function, possible negative impacts of chronic nitrate supplementation through different nitrate sources, and the effectiveness of nitrate supplementation on strength and high-intensity intermittent exercise.
... Furthermore, consuming creatine immediately before (0.05 g·kg -1 of body weight) and immediately after (0.05 g·kg -1 of body weight) resistance training sessions (3 days/week, 10 weeks) resulted in greater muscle accretion (2.0 ± 0.3 cm) compared to placebo (0.8 ± 0.3 cm) in healthy older males (59-77 years; 8 ). These results support previous findings of a significant increase in lean tissue mass (6%), type II muscle fiber area (29%), and insulin growthfactor I (78%) in adults (19-55 years) who ingested creatine before (0.03 g·kg -1 of body weight) and after (0.03 g·kg -1 of body weight) resistance training for 8 weeks 23,26 . In addition, a creatine supplement (1 g·kg -1 : supplement per 100 g = 40 g protein, 43 g glucose, 7 g creatine and <0.5 g fat) immediately before and immediately after resistance training sessions for 10 weeks significantly increased intramuscular creatine content, lean tissue mass, muscle cross sectional-area of type II fibers and maximal strength in resistance trained body-builders compared to consuming creatine > 5 hours before and after exercise (i.e., before breakfast and immediately prior to sleep; 9 ). ...
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The combination of creatine monohydrate supplementation and resistance training increases muscle mass and strength. In this brief narrative review, we propose that the timing of creatine supplementation in relation to resistance training may be an important factor to optimize hypertrophy and strength gains. Meta-analyses indicated that creatine supplementation immediately after resistance training was superior for increasing muscle mass compared to creatine supplementation immediately before resistance training (3 studies, standard mean difference 0.52, 95% CI 0.03-1.00, p = 0.04); however, this did not translate into greater muscular strength (p > 0.05). Further research is needed to confirm these limited findings and to determine the mechanisms explaining the potential greater increase in muscle mass from post-exercise creatine.
... This nutrient distribution can also be found in European populations [11], with a more pronounced deficiency in vitamin D intake. Total creatine concentration measured in skeletal muscle tissue differs between vegetarians and omnivores, with omnivores showing the highest total creatine concentrations [12]. As the body synthesizes approximately 1 g per day of creatine endogenously, food, in the form of meat, fish and poultry, provides an additional 1 g [13]. ...
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Muscular adaptations can be triggered by exercise and diet. As vegan and vegetarian diets differ in nutrient composition compared to an omnivorous diet, a change in dietary regimen might alter physiological responses to physical exercise and influence physical performance. Mitochondria abundance, muscle capillary density, hemoglobin concentration, endothelial function, functional heart morphology and availability of carbohydrates affect endurance performance and can be influenced by diet. Based on these factors, a vegan and vegetarian diet possesses potentially advantageous properties for endurance performance. Properties of the contractile elements, muscle protein synthesis, the neuromuscular system and phosphagen availability affect strength performance and can also be influenced by diet. However, a vegan and vegetarian diet possesses potentially disadvantageous properties for strength performance. Current research has failed to demonstrate consistent differences of performance between diets but a trend towards improved performance after vegetarian and vegan diets for both endurance and strength exercise has been shown. Importantly, diet alters molecular signaling via leucine, creatine, DHA and EPA that directly modulates skeletal muscle adaptation. By changing the gut microbiome, diet can modulate signaling through the production of SFCA.
... Female athletes with restricted intake and amenorrhea (i.e., low energy availability) [233] may require additional calcium (1500 mg/day along with 1500-2000 IU vitamin D) to optimize bone health [234]. Maintaining adequate vitamin D status is important for athletes due to its role in immune function, inflammatory modulation, physical performance, and overall health [235][236][237][238]. Vegetarian athletes may have lower blood and muscle creatinine and carnitine concentrations [239][240][241][242] compared to omnivores due to lower dietary intake. Athletes participating in resistance training and bouts of high-intensity exercise may benefit from creatine supplementation [243], but there is no recognized benefit to carnitine supplementation. ...
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Plant-based diets, defined here as including both vegan and lacto-ovo-vegetarian diets, are growing in popularity throughout the Western world for various reasons, including concerns for human health and the health of the planet. Plant-based diets are more environmentally sustainable than meat-based diets and have a reduced environmental impact, including producing lower levels of greenhouse gas emissions. Dietary guidelines are normally formulated to enhance the health of society, reduce the risk of chronic diseases, and prevent nutritional deficiencies. We reviewed the scientific data on plant-based diets to summarize their preventative and therapeutic role in cardiovascular disease, cancer, diabetes, obesity, and osteoporosis. Consuming plant-based diets is safe and effective for all stages of the life cycle, from pregnancy and lactation, to childhood, to old age. Plant-based diets, which are high in fiber and polyphenolics, are also associated with a diverse gut microbiota, producing metabolites that have anti-inflammatory functions that may help manage disease processes. Concerns about the adequate intake of a number of nutrients, including vitamin B12, calcium, vitamin D, iron, zinc, and omega-3 fats, are discussed. The use of fortified foods and/or supplements as well as appropriate food choices are outlined for each nutrient. Finally, guidelines are suggested for health professionals working with clients consuming plant-based diets.
... Tarnopolsky et al 8 found that 4-month creatine intake (0.10 g/kg/day) led to an increase in DXA-derived fat-free mass and reduction in bone breakdown among 31 children with DMD. Creatine also attenuated body fat accumulation in children with acute lymphoblastic leukemia during maintenance chemotherapy, 13 and adolescent combat athletes, 14 and increased whole-body lean body mass in cohorts that included adolescent vegetarians, 15 resistancetrained male and female teenagers, [16][17][18] and young soccer players. 19 Our findings back up a conclusion from above interventional trials about a tie-in linking creatine intake and body composition while extending this line of evidence to the populational level. ...
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Several small-scale trials indicate a positive correlation between dietary creatine intake and fat-free mass in the pediatric population; whether this connection occurs at the population-wide level remains currently unknown. The main purpose of this cross-sectional study was to calculate the amount of creatine consumed through a regular diet among U.S. boys and girls aged 8 to 19 years, and investigate the link between creatine consumption and dual-energy X-ray absorptiometry (DXA)-derived body composition indices in this population. Data were obtained from the National Health and Nutrition Examination Survey 2017-2018 round, with dietary information and whole-body DXA body composition measures extracted for respondents aged 8 to 19 years (1273 participants, 649 boys and 624 girls). Individual values for total grams of creatine consumed per day for each participant were computed using the average amount of creatine (3.88 g/kg) across all creatine-containing foods. The primary exposure was the mean daily intake of creatine; the primary and secondary outcomes comprised lean mass excluding bone mineral content (BMC), and bone mineral density, BMC, lean mass including BMC, fat mass, and percent body fat, respectively. The average intake of creatine across the sample was 0.65 ± 0.72 g/day (95% CI, from 0.61 to 0.69). Creatine positively correlated with lean mass (excluding BMC) and BMC across the whole sample ( r = .18 and .20, respectively; P
... W piśmiennictwie znaleźć można różne opinie na temat stosowania diety wegetariańskiej wśród sportowców, zwłaszcza kobiet odbywających ciężkie treningi, jeżeli nie jest ona odpowiednio zbilansowana pod kątem podaży białka, żelaza i kreatyniny, ponieważ może sprzyjać rozregulowaniu cyklów menstruacyjnych [34,35,36]. Jednocześnie istnieją pojedyncze prace, które wskazują, że odpowiednio zbilansowana dieta może poprawić wydolność organizmu, dzięki czemu mogą z niej korzystać zawodowi sportowcy [37]. ...
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... PB individuals can increase their phosphocreatine levels with creatine supplementation to a greater extent than omnivores due to a "super-compensation" effect, despite no differences in the muscle creatine transporter (Watt et al. 2004). Some studies indicate that vegetarians can enhance their physical performance (i.e., work output during a repeated-contraction isokinetic test) compared to omnivores following creatine supplementation (Burke et al. 2003), while others show no greater benefit for enhancement in exercise performance in vegetarians compared to omnivores when supplementing with creatine (Watt et al. 2004). Although a minimum of 1 g of supplemental creatine per day is necessary to match creatine intakes consumed in the average omnivorous diet (Kaviani et al. 2020a), supplementation with 5 g/day is associated with optimal tissue saturation (Maughan et al. 2018). ...
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Individuals may opt to follow a plant-based diet for a variety of reasons, such as religious practices, health benefits or concerns for animal or environmental welfare. Such diets offer a broad spectrum of health benefits including aiding in the prevention and management of chronic diseases. In addition to health benefits, a plant-based diet may provide performance-enhancing effects for various types of exercise due to high carbohydrate levels and the high concentration of antioxidants and phytochemicals found in a plant-based diet. However, some plant-based foods also contain anti-nutrional factors, such as phytate and tannins, which decrease the bioavailability of key nutrients, such as iron, zinc, and protein. Thus, plant-based diets must be carefully planned to ensure adequate intake and absorption of energy and all essential nutrients. The current narrative review summarizes the current state of the research concerning the implications of a plant-based diet for health and exercise performance. It also outlines strategies to enhance the bioavailability of nutrients, sources of hard-to-get nutrients, and sport supplements that could interest plant-based athletes.
... meat, seafood, poultry; (15,19) typically have low intramuscular creatine concentrations and would therefore respond more favorably to creatine supplementation. For example, Burke et al. (50) showed that vegetarians experienced the greatest increase in intramuscular total creatine (PCr, free Cr) from 8 weeks of creatine supplementation (0.25 g/kg lean tissue mass/day for 7 days + 0.0625 g/kg lean tissue mass/day for 49 days) compared to non-vegetarians who supplemented with creatine. Furthermore, in examining the effects of short-term creatine supplementation (0.3 g/day for 7 days) in omnivorous younger adults (n = 17, 29.18 ± 7.81 yrs) and aging individuals (n = 18, 71.78 ± 6.97 yrs), Solis et al. (47) showed that omnivores had higher dietary creatine intake presupplementation. ...
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Sarcopenia is an age-related muscle condition characterized by a reduction in muscle quantity, force generating capacity and physical performance. Sarcopenia occurs in 8–13% of adults ≥ 60 years of age and can lead to disability, frailty, and various other diseases. Over the past few decades, several leading research groups have focused their efforts on developing strategies and recommendations for attenuating sarcopenia. One potential nutritional intervention for sarcopenia is creatine supplementation. However, research is inconsistent regarding the effectiveness of creatine on aging muscle. The purpose of this perspective paper is to: (1) propose possible reasons for the inconsistent responsiveness to creatine in aging adults, (2) discuss the potential mechanistic actions of creatine on muscle biology, (3) determine whether the timing of creatine supplementation influences aging muscle, (4) evaluate the evidence investigating the effects of creatine with other compounds (protein, conjugated linoleic acid) in aging adults, and (5) provide insight regarding the safety of creatine for aging adults.
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Studies have shown that creatine supplementation increases intramuscular creatine concentrations, favoring the energy system of phosphagens, which may help explain the observed improvements in high-intensity exercise performance. However, research on physical performance in soccer has shown controversial results, in part because the energy system used is not taken into account. The main aim of this investigation was to perform a systematic review and meta-analysis to determine the efficacy of creatine supplementation for increasing performance in skills related to soccer depending upon the type of metabolism used (aerobic, phosphagen, and anaerobic metabolism). A structured search was carried out following the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines in the Medline/PubMed and Web of Science, Cochrane Library, and Scopus databases until January 2019. The search included studies with a double-blind and randomized experimental design in which creatine supplementation was compared to an identical placebo situation (dose, duration, timing, and drug appearance). There were no filters applied to the soccer players’ level, gender, or age. A final meta-analysis was performed using the random effects model and pooled standardized mean differences (SMD) (Hedges’s g). Nine studies published were included in the meta-analysis. This revealed that creatine supplementation did not present beneficial effects on aerobic performance tests (SMD, −0.05; 95% confidence interval (CI), −0.37 to 0.28; p = 0.78) and phosphagen metabolism performance tests (strength, single jump, single sprint, and agility tests: SMD, 0.21; 95% CI, −0.03 to 0.45; p = 0.08). However, creatine supplementation showed beneficial effects on anaerobic performance tests (SMD, 1.23; 95% CI, 0.55–1.91; p <0.001). Concretely, creatine demonstrated a large and significant effect on Wingate test performance (SMD, 2.26; 95% CI, 1.40–3.11; p <0.001). In conclusion, creatine supplementation with a loading dose of 20–30 g/day, divided 3–4 times per day, ingested for 6 to 7 days, and followed by 5 g/day for 9 weeks or with a low dose of 3 mg/kg/day for 14 days presents positive effects on improving physical performance tests related to anaerobic metabolism, especially anaerobic power, in soccer players.
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Creatine availability in adipose tissue has been shown to have profound effects on thermogenesis and energy balance in mice. However, whether dietary creatine supplementation affects brown adipose tissue (BAT) activation in humans is unclear. In the present study, we report the results of a double-blind, randomized, placebo-controlled, cross-over trial (NCT04086381) in which 14 young, healthy, vegetarian adults, who are characterized by low creatine levels, received 20 g of creatine monohydrate per day or placebo. Participants were eligible if they met the following criteria: male or female, white, aged 18–30 years, consuming a vegetarian diet (≥6 months) and body mass index 20–25 kg m⁻². BAT activation after acute cold exposure was determined by calculating standard uptake values (SUVs) acquired by [¹⁸F]fluorodeoxyglucose positron emission tomography–magnetic resonance imaging. BAT volume (−31.32 (19.32) SUV (95% confidence interval (CI) −73.06, 10.42; P = 0.129)), SUVmean (−0.34 (0.29) SUV (95% CI −0.97, 0.28; P = 0.254)) and SUVmax (−2.49 (2.64) SUV (95% CI −8.20, 3.21; P = 0.362)) following acute cold exposure were similar between placebo and creatine supplementation. No side effects of creatine supplementation were reported; one participant experienced bowel complaints during placebo, which resolved without intervention. Our data show that creatine monohydrate supplementation in young, healthy, lean, vegetarian adults does not enhance BAT activation after acute cold exposure.
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Handball performance is a team-sport characterized by high intensity efforts interspersed with recovery periods. Due to high demands of handball performance, the use of ergogenic aids is a common strategy of handball players with the aim of enhancing handball performance, to allow more effective training, and to increase the rate of recovery. Although the use of ergogenic aids is generalized in the whole spectrum of competitive handball (e.g., from recreational to professional players), only a few ergogenic aids have been investigated to test their effectiveness to increase handball performance. In addition, no previous study has summarized the scientific literature on this topic to determine the ergogenic aids with good level of evidence regarding their effectiveness to increase handball physical performance. Thus, the aim of this narrative review was to describe the prevalence in the use of ergogenic aids in handball players and to analyse this information to identify which of these substances may increase physical performance in an intermittent sport such as competitive handball
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Our purpose was to assess muscular adaptations during 6 weeks of resistance training in 36 males randomly assigned to supplementation with whey protein (W; 1.2 g/kg/day), whey protein and creatine monohydrate (WC; 0.1 g/kg/day), or placebo (P; 1.2 g/kg/day maltodextrin). Measures included lean tissue mass by dual energy x-ray absorptiometry, bench press and squat strength (1-repetition maximum), and knee extension/flexion peak torque. Lean tissue mass increased to a greater extent with training in WC compared to the other groups, and in the W compared to the P group (p < .05). Bench press strength increased to a greater extent for WC compared to W and P (p < .05). Knee extension peak torque increased with training for WC and W (p < .05), but not for P. All other measures increased to a similar extent across groups. Continued training without supplementation for an additional 6 weeks resulted in maintenance of strength and lean tissue mass in all groups. Males that supplemented with whey protein while resistance training demonstrated greater improvement in knee extension peak torque and lean tissue mass than males engaged in training alone. Males that supplemented with a combination of whey protein and creatine had greater increases in lean tissue mass and bench press than those who supplemented with only whey protein or placebo. However, not all strength measures were improved with supplementation, since subjects who supplemented with creatine and/or whey protein had similar increases in squat strength and knee flexion peak torque compared to subjects who received placebo.
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The effect of dietary creatine and supplementation on skeletal muscle creatine accumulation and subsequent degradation and on urinary creatinine excretion was investigated in 31 male subjects who ingested creatine in different quantities over varying time periods. Muscle total creatine concentration increased by approximately 20% after 6 days of creatine supplementation at a rate of 20 g/day. This elevated concentration was maintained when supplementation was continued at a rate of 2 g/day for a further 30 days. In the absence of 2 g/day supplementation, total creatine concentration gradually declined, such that 30 days after the cessation of supplementation the concentration was no different from the presupplementation value. During this period, urinary creatinine excretion was correspondingly increased. A similar, but more gradual, 20% increase in muscle total creatine concentration was observed over a period of 28 days when supplementation was undertaken at a rate of 3 g/day. In conclusion, a rapid way to "creatine load" human skeletal muscle is to ingest 20 g of creatine for 6 days. This elevated tissue concentration can then be maintained by ingestion of 2 g/day thereafter. The ingestion of 3 g creatine/day is in the long term likely to be as effective at raising tissue levels as this higher dose.
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The effects of oral creatine supplementation on muscle phosphocreatine (PCr) concentration, muscle strength, and body composition were investigated in young female volunteers (n = 19) during 10 wk of resistance training (3 h/wk). Compared with placebo, 4 days of high-dose creatine intake (20 g/day) increased (P < 0.05) muscle PCr concentration by 6%. Thereafter, this increase was maintained during 10 wk of training associated with low-dose creatine intake (5 g/day). Compared with placebo, maximal strength of the muscle groups trained, maximal intermittent exercise capacity of the arm flexors, and fat-free mass were increased 20-25, 10-25, and 60% more (P < 0. 05), respectively, during creatine supplementation. Muscle PCr and strength, intermittent exercise capacity, and fat-free mass subsequently remained at a higher level in the creatine group than in the placebo group during 10 wk of detraining while low-dose creatine was continued. Finally, on cessation of creatine intake, muscle PCr in the creatine group returned to normal within 4 wk. It is concluded that long-term creatine supplementation enhances the progress of muscle strength during resistance training in sedentary females.
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This investigation evaluated the effects of oral beta-hydroxy-beta-methylbutyrate (HMB) supplementation on training responses in resistance-trained male athletes who were randomly administered HMB in standard encapsulation (SH), HMB in time release capsule (TRH), or placebo (P) in a double-blind fashion. Subjects ingested 3 g x day(-1) of HMB or placebo for 6 weeks. Tests were conducted pre-supplementation and following 3 and 6 weeks of supplementation. The testing battery assessed body mass, body composition (using dual energy x-ray absorptiometry), and 3-repetition maximum isoinertial strength, plus biochemical parameters, including markers of muscle damage and muscle protein turnover. While the training and dietary intervention of the investigation resulted in significant strength gains (p < .001) and an increase in total lean mass (p = .01), HMB administration had no influence on these variables. Likewise, biochemical markers of muscle protein turnover and muscle damage were also unaffected by HMB supplementation. The data indicate that 6 weeks of HMB supplementation in either SH or TRH form does not influence changes in strength and body composition in response to resistance training in strength-trained athletes.
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Purpose: The purpose of this study was to examine the effects of age and gender on the strength response to strength training (ST and detraining. Methods: Eighteen young (20-30 yr) and 23 older (65-75 yr) men and women had their one-repetition maximum (1 RM) and isokinetic strength measured before and after 9 wk of unilateral knee extension ST (3 d.wk(-1)) and 31 wk of detraining. Results: The young subjects demonstrated a significantly greater (P < 0.05) increase in 1 RM strength (34 +/- 3%; 73 +/- 5 vs 97 +/- 6 kg; P < 0.01) than the older subjects (28 +/- 3%; 60 +/- 4 vs 76 +/- 5 kg, P < 0.01). There were no significant differences in strength gains between men and women in either age group with 9 wk of ST or in strength losses with 31 wk of detraining. Young men and women experienced an 8 +/- 2% decline in 1 RM strength after 31 wk of detraining (97 +/- 6 vs 89 +/- 6 kg, P < 0.05). This decline was significantly less than the 14 +/- 2% decline in the older men and women (76 +/- 5 vs 65 +/- 4 kg, P < 0.05). This strength loss occurred primarily between 12 and 31 wk of detraining with a 6 +/- 2% and 13 +/- 2% decrease in the young and older subjects, respectively, during this period. Discussion: These results demonstrate that changes in 1 RM strength in response to both ST and detraining are affected by age. However, ST-induced increases in muscular strength appear to be maintained equally well in young and older men and women during 12 wk of detraining and are maintained above baseline levels even after 31 wk of detraining in young men, young women, and older men.
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Anaerobic working capacity (AWC) estimated from the critical power test provides a theoretically and experimentally valid estimate of work capacity associated with muscle energy reserves adenosine triphosphate and phosphocreatine. Creatine monohydrate (CM) supplementation has been shown to increase phosphocreatine stores in skeletal muscle and, in theory should increase AWC. Therefore, the purpose of this study was to examine the effects of supplementation with CM, CM plus carbohydrate (CHO), or CHO alone on AWC. Using a double-blind random design, 26 young men (mean age +/- SD, 19.9 +/-1.6 years) were assigned to 1 of 3 treatment conditions: (a) 35 g of flavored CHO powder as a placebo (PL, n = 8); (b) 5.25 g of CM and 1 g of CHO in a flavored powder blend (CM, n = 9); and (c) 5.25 g of CM and 33 g of CHO in flavored powder blend (CM-CHO, n = 9). The subjects completed 3 phases of testing on an electronically braked cycle ergometer: (a) familiarization (3 learning trials to establish power outputs for subsequent testing); (b) pretesting (4 bouts performed at power outputs selected to elicit fatigue in 1-10 minutes); and (c) posttesting (4 bouts performed at the same power outputs as pretesting but completed after ingesting the supplements 4 times per day for 6 consecutive days). The results indicated that CM and CM-CHO supplementation significantly (p <= 0.05) increased AWC by 9.4 and 30.7%, respectively These data suggest that 33 g of CHO may augment the effects of CM supplementation on AWC. (C) 1999 National Strength and Conditioning Association
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1. We investigated the effect of oral creatine supplementation during leg immobilization and rehabilitation on muscle volume and function, and on myogenic transcription factor expression in human subjects. 2. A double-blind trial was performed in young healthy volunteers (n = 22). A cast was used to immobilize the right leg for 2 weeks. Thereafter the subjects participated in a knee-extension rehabilitation programme (3 sessions week _1 , 10 weeks). Half of the subjects received creatine monohydrate (CR; from 20 g down to 5 g daily), whilst the others ingested placebo (P; maltodextrin). 3. Before and after immobilization, and after 3 and 10 weeks of rehabilitation training, the cross- sectional area (CSA) of the quadriceps muscle was assessed by NMR imaging. In addition, an isokinetic dynamometer was used to measure maximal knee-extension power (W max), and needle biopsy samples taken from the vastus lateralis muscle were examined to asses expression of the myogenic transcription factors MyoD, myogenin, Myf5, and MRF4, and muscle fibre diameters. 4. Immobilization decreased quadriceps muscle CSA (~10 %) and W max (~25 %) by the same magnitude in both groups. During rehabilitation, CSA and Wmax recovered at a faster rate in CR than in P (P < 0.05 for both parameters). Immobilization changed myogenic factor protein expression in neither P nor CR. However, after rehabilitation myogenin protein expression was increased in P but not in CR (P < 0.05), whilst MRF4 protein expression was increased in CR but not in P (P < 0.05). In addition, the change in MRF4 expression was correlated with the change in mean muscle fibre diameter (r = 0.73, P < 0.05). 5. It is concluded that oral creatine supplementation stimulates muscle hypertrophy during rehabilitative strength training. This effect may be mediated by a creatine-induced change in MRF4 and myogenin expression.
Article
1. The present study was undertaken to test whether creatine given as a supplement to normal subjects was absorbed, and if continued resulted in an increase in the total creatine pool in muscle. An additional effect of exercise upon uptake into muscle was also investigated. 2. Low doses (1 g of creatine monohydrate or less in water) produced only a modest rise in the plasma creatine concentration, whereas 5 g resulted in a mean peak after 1 h of 795 (sd 104) μmol/l in three subjects weighing 76–87 kg. Repeated dosing with 5 g every 2 h sustained the plasma concentration at around 1000 μmol/l. A single 5 g dose corresponds to the creatine content of 1.1 kg of fresh, uncooked steak. 3. Supplementation with 5 g of creatine monohydrate, four or six times a day for 2 or more days resulted in a significant increase in the total creatine content of the quadriceps femoris muscle measured in 17 subjects. This was greatest in subjects with a low initial total creatine content and the effect was to raise the content in these subjects closer to the upper limit of the normal range. In some the increase was as much as 50%. 4. Uptake into muscle was greatest during the first 2 days of supplementation accounting for 32% of the dose administered in three subjects receiving 6 × 5 g of creatine monohydrate/day. In these subjects renal excretion was 40, 61 and 68% of the creatine dose over the first 3 days. Approximately 20% or more of the creatine taken up was measured as phosphocreatine. No changes were apparent in the muscle ATP content. 5. No side effects of creatine supplementation were noted. 6. One hour of hard exercise per day using one leg augmented the increase in the total creatine content of the exercised leg, but had no effect in the collateral. In these subjects the mean total creatine content increased from 118.1 (sd 3.0) mmol/kg dry muscle before supplementation to 148.5 (sd 5.2) in the control leg, and to 162.2 (sd 12.5) in the exercised leg. Supplementation and exercise resulted in a total creatine content in one subject of 182.8 mmol/kg dry muscle, of which 112.0 mmol/kg dry muscle was in the form of phosphocreatine.
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Methods are described for the determination of glycogen, glycolytic intermediates, and high-energy phosphates in muscle biopsy samples. Initial freezedrying of samples and extraction of metabolites with relatively weak acid are preferred. Normal values in muscle are similar to those found by other workers. Variation in muscle content of ATP, ATP + ADP + AMP, phosphorylcreatine (PC), creatine (Cr), PC + Cr, and glycogen, between legs, between sites on the same muscle, or as a result of error introduced during analysis, was small compared with the between-individuals variance. The importance of the different sources of variance on taking a biopsy is discussed.
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A method for increasing the size of a percutaneous needle biopsy specimen of skeletal muscle is described. Suction (700 TORR) is applied to the inner bore of the biopsy needle after the needle has been inserted into the subject's muscle. The suction pulls the surrounding muscle tissue into the needle, thus insuring the taking of a larger piece (X = 78.5 mg). In most cases, this technique will eliminate the need for repeated biopsies because of inadequate muscle sample size and enhance the validity of subsequent analysis procedures.
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Gyrate atrophy of the choroid and retina is a disease characterized by progressive constriction of visual fields, a 10-fold to 20-fold elevation in plasma ornithine, and depressed activity of L-ornithine:2 oxoacid aminotransferase. Morphologically conspicuous but clinically unimportant atrophy of Type II muscle fibers progresses concomitantly with the eye disease. A pathogenic component of the disease may be deficient formation of creatine, caused by hyperornithinemia, which leads to a shortage of cellular phosphocreatine energy stores. To test the therapeutic value of replenishing the postulated deficiency of creatine, we supplemented the diet of seven patients with 1.5 g of creatine daily. During one year of this treatment the diameters of Type II muscle fibers increased from 34.1 +/- 7.1 to 49.9 +/- 7.0 micron (mean +/- S.D.) (P less than 0.001). There was no significant increase in the diameters of Type I fibers. The visual-field tests showed no further constriction during the therapy. Fundus photography revealed slow impairment at an age otherwise associated with rapid progression of the disease. These promising preliminary results need further evaluation with long-term follow-up studies.
Article
Biopsy samples were obtained from the vastus lateralis muscle of eight subjects after 0, 20, 60, and 120 s of recovery from intense electrically evoked isometric contraction. Later (10 days), the same procedures were performed using the other leg, but subjects ingested 20 g creatine (Cr)/day for the preceding 5 days. Muscle ATP, phosphocreatine (PCr), free Cr, and lactate concentrations were measured, and total Cr was calculated as the sum of PCr and free Cr concentrations. In five of the eight subjects, Cr ingestion substantially increased muscle total Cr concentration (mean 29 +/- 3 mmol/kg dry matter, 25 +/- 3%; range 19-35 mmol/kg dry matter, 15-32%) and PCr resynthesis during recovery (mean 19 +/- 4 mmol/kg dry matter, 35 +/- 6%; range 11-28 mmol/kg dry matter, 23-53%). In the remaining three subjects, Cr ingestion had little effect on muscle total Cr concentration, producing increases of 8-9 mmol/kg dry matter (5-7%), and did not increase PCr resynthesis. The data suggest that a dietary-induced increase in muscle total Cr concentration can increase PCr resynthesis during the 2nd min of recovery from intense contraction.
Article
This study examined the effect of (a) creatine supplementation on exercise metabolism and performance and (b) changes in intramuscular total creatine stores following a 5 day supplementation period and a 28 day wash-out period. Six men performed four exercise trials, each consisting of four 1 min cycling bouts, punctuated by 1 min of rest followed by a fifth bout to fatigue, all at a workload estimated to require 115 or 125% VO2,max. After three familiarization trials, one trial was conducted following a creatine monohydrate supplementation protocol (CREAT); the other after 28 d without creatine supplementation, in which the last 5 d involved placebo ingestion (CON). Intramuscular TCr was elevated (P < 0.05) in CREAT compared with the final familiarization trial (FAM 3) and CON. Concentrations of this metabolite in these latter trials were not different. In addition, a main effect (P < 0.05) for treatment was observed for PCr when the data from CREAT were compared with CON. In contrast, no differences were observed in the total adenine nucleotide pool (ATP+ADP+AMP), inosine 5'-monophosphate, ammonia, lactate or glycogen when comparing CREAT with CON. Despite the differences in TCr and PCr concentrations when comparing CREAT with other trials, no difference was observed in exercise duration in the fifth work bout. These data demonstrate that creatine supplementation results in an increase in TCr but this has no effect on performance during exercise of this nature, where the creatine kinase system is not the principal energy supplier. In addition 28 d without supplementation is a sufficient time to return intramuscular TCr stores to basal levels.
Article
This study investigated the effect of carbohydrate (CHO) ingestion on skeletal muscle creatine (Cr) accumulation during Cr supplementation in humans. Muscle biopsy, urine, and plasma samples were obtained from 24 males before and after ingesting 5 g Cr in solution (group A) or 5 g Cr followed, 30 min later, by 93 g simple CHO in solution (group B) four times each day for 5 days. Supplementation resulted in an increase in muscle phosphocreatine (PCr), Cr, and total creatine (TCr; sum of PCr and Cr) concentration in groups A and B, but the increase in TCr in group B was 60% greater than in group A (P < 0.01). There was also a corresponding decrease in urinary Cr excretion in group B (P < 0.001). Creatine supplementation had no effect on serum insulin concentration, but Cr and CHO ingestion dramatically elevated insulin concentration (P < 0.001). These findings demonstrate that CHO ingestion substantially augments muscle Cr accumulation during Cr feeding in humans, which appears to be insulin mediated.
Article
To investigate the time-dependent effects of ischemia, as modified by muscle fiber type composition, on sarcoplasmic reticulum (SR) function, Ca(2+)-ATPase activity (total minus basal) was measured in homogenates prepared from samples obtained from rat soleus and extensor digitorum longus (EDL) muscle of ischemic and contralateral controls. Ischemia was induced by occlusion of blood flow to one hindlimb for periods of 1, 2, and 3 h (n = 10 per group). In EDL, maximal Ca(2+)-ATPase activity (expressed in mumol.g wet wt-1.min-1) was higher (P < 0.05) in ischemic than in control at 1 h (80 +/- 10 vs. 56.5 +/- 5.3) and increased progressively with ischemia at both 2 h (88 +/- 4.6 vs. 53.1 +/- 2.8) and 3 h (116 +/- 3.8 vs. 67.8 +/- 3.2). In contrast, in soleus, increases (P < 0.05) in Ca(2+)-ATPase activity with ischemia were observed at 2 h (19.2 +/- 0.86 vs. 14.0 +/- 0.56) and 3 h (19.9 +/- 1.4 vs. 12.4 +/- 0.62) but not at 1 h (10.7 +/- 1.5 vs. 10.0 +/- 0.83). In both EDL and soleus, basal Mg(2+)-ATPase was unchanged with ischemia. On the basis of these findings, it can be concluded that ischemia results in an increase in the maximal SR Ca(2+)-ATPase activity but that the time course of the change is dependent on the fiber type composition of the muscle.
Article
The purpose of this study was to examine the effect of creatine supplementation in conjunction with resistance training on physiological adaptations including muscle fiber hypertrophy and muscle creatine accumulation. Nineteen healthy resistance-trained men were matched and then randomly assigned in a double-blind fashion to either a creatine (N = 10) or placebo (N = 9) group. Periodized heavy resistance training was performed for 12 wk. Creatine or placebo capsules were consumed (25 g x d(-1)) for 1 wk followed by a maintenance dose (5 g x d(-1)) for the remainder of the training. After 12 wk, significant (P < or = 0.05) increases in body mass and fat-free mass were greater in creatine (6.3% and 6.3%, respectively) than placebo (3.6% and 3.1%, respectively) subjects. After 12 wk, increases in bench press and squat were greater in creatine (24% and 32%, respectively) than placebo (16% and 24%, respectively) subjects. Compared with placebo subjects, creatine subjects demonstrated significantly greater increases in Type I (35% vs 11%), IIA (36% vs 15%), and IIAB (35% vs 6%) muscle fiber cross-sectional areas. Muscle total creatine concentrations were unchanged in placebo subjects. Muscle creatine was significantly elevated after 1 wk in creatine subjects (22%), and values remained significantly greater than placebo subjects after 12 wk. Average volume lifted in the bench press during training was significantly greater in creatine subjects during weeks 5-8. No negative side effects to the supplementation were reported. Creatine supplementation enhanced fat-free mass, physical performance, and muscle morphology in response to heavy resistance training, presumably mediated via higher quality training sessions.
Article
This study investigated creatine supplementation (CrS) effects on muscle total creatine (TCr), creatine phosphate (CrP), and intermittent sprinting performance by using a design incorporating the time course of the initial increase and subsequent washout period of muscle TCr. Two groups of seven volunteers ingested either creatine [Cr; 6 x (5 g Cr-H(2)O + 5 g dextrose)/day)] or a placebo (6 x 5 g dextrose/day) over 5 days. Five 10-s maximal cycle ergometer sprints with rest intervals of 180, 50, 20, and 20 s and a resting vastus lateralis biopsy were conducted before and 0, 2, and 4 wk after placebo or CrS. Resting muscle TCr, CrP, and Cr were unchanged after the placebo but were increased (P < 0.05) at 0 [by 22.9 +/- 4.2, 8.9 +/- 1.9, and 14.0 +/- 3.3 (SE) mmol/kg dry mass, respectively] and 2 but not 4 wk after CrS. An apparent placebo main effect of increased peak power and cumulative work was found after placebo and CrS, but no treatment (CrS) main effect was found on either variable. Thus, despite the rise and washout of muscle TCr and CrP, maximal intermittent sprinting performance was unchanged by CrS.
Article
The effect of creatine supplementation on exercise performance in vegetarians was examined. Creatine was ingested for 1 week by a group of vegetarians (VC) and meat-eaters (MC); a control group of meat-eaters was fed only glucose (MG). Exercise performance during three, 20-s maximal cycling tests (modified Wingate anaerobic test, WAnT) was determined before and after creatine supplementation. Blood samples were also drawn before and after exercise prior to and after supplementation. Basal plasma creatine (after an overnight fast) averaged (SE) 11 (2) microM in VC, and 24 (2) and 23 (7) microM in MG and MC, respectively (P < 0.05 for VC vs meat-eaters). These findings were expected, since most of the body's exogenous creatine source is meat. There was no significant difference in any other parameter between groups prior to supplementation. Creatine feedings significantly increased body mass (approximately 1 kg) and mean power output during the WAnTs (approximately 5%) to a similar extent in the VC and MC groups (P < 0.05-0.001). These parameters were not affected by supplementation in the MG group. Peak power output was also significantly increased by supplementation in MC (approximately 5%, P < 0.05), but not in VC. It is concluded that vegetarians and meat-eaters respond to creatine feedings with similar increases in mean power output during short-term, maximal exercise.
Article
Dietary supplementation (SUP) has become a significant part of athletic training. Studies indicate that creatine (Cr) can enhance short-duration, high-intensity activities. This study examined the effect of 21 days of low dose Cr SUP ( approximately 7.7 g/day) and resistance training on force output, power output, duration of mean peak power output, and total work performed until fatigue. A double-blind protocol was used, where an individual, who was not part of any other aspect of the study, randomly assigned subjects to creatine and placebo groups. Forty-one male university athletes were randomly assigned to either Cr (n = 20) or placebo (n = 21) SUP. On the first and last day of the study, subjects were required to perform concentric bench press movements until exhaustion on an isokinetic dynamometer. The dynamometer was hard-wired to a personal computer, which provided force, velocity, and duration measures. Force and power output until fatigue, were used to determine total work, force-time, and power-time relationships. ANOVA results revealed that the Cr subjects performed more total work until fatigue, experienced significantly greater improvements in peak force and peak power, and maintained elevated mean peak power for a longer period of time. These results indicate that Cr SUP can significantly improve factors associated with short-duration, high-intensity activity.
Article
To study the effect of creatine (Cr) supplementation combined with resistance training on muscular performance and body composition in older men. Thirty men were randomized to receive creatine supplementation (CRE, N = 16, age = 70.4 +/- 1.6 yr) or placebo (PLA, N = 14, age = 71.1 +/- 1.8 yr), using a double blind procedure. Cr supplementation consisted of 0.3-g Cr.kg(-1) body weight for the first 5 d (loading phase) and 0.07-g Cr.kg(-1) body weight thereafter. Both groups participated in resistance training (36 sessions, 3 times per week, 3 sets of 10 repetitions, 12 exercises). Muscular strength was assessed by 1-repetition maximum (1-RM) for leg press (LP), knee extension (KE), and bench press (BP). Muscular endurance was assessed by the maximum number of repetitions over 3 sets (separated by 1-min rest intervals) at an intensity corresponding to 70% baseline 1-RM for BP and 80% baseline 1-RM for the KE and LP. Average power (AP) was assessed using a Biodex isokinetic knee extension/flexion exercise (3 sets of 10 repetitions at 60 degrees.s(-1) separated by 1-min rest). Lean tissue (LTM) and fat mass were assessed using dual energy x-ray absorptiometry. Compared with PLA, the CRE group had significantly greater increases in LTM (CRE, +3.3 kg; PLA, +1.3 kg), LP 1-RM (CRE, +50.1 kg; PLA +31.3 kg), KE 1-RM (CRE, +14.9 kg; PLA, +10.7 kg), LP endurance (CRE, +47 reps; PLA, +32 reps), KE endurance (CRE, +21 reps; PLA +14 reps), and AP (CRE, +26.7 W; PLA, +18 W). Changes in fat mass, fat percentage, BP 1-RM, and BP endurance were similar between groups. Creatine supplementation, when combined with resistance training, increases lean tissue mass and improves leg strength, endurance, and average power in men of mean age 70 yr.
Article
The purpose of this investigation was to examine the effects of preceding oral creatine monohydrate with a lacto-ovo-vegetarian diet on muscle creatine concentration. Thirty-two healthy men, who regularly consumed an omnivorous diet, were randomly assigned to consume a weight maintaining, lacto-ovo-vegetarian (LOV; n = 16) or omnivorous (Omni; n = 16) diet for 26 days. In addition to their assigned diet, on day 22 of the study, subjects were assigned in a double-blind manner to receive either creatine monohydrate (CM; 0.3 g kg d 1 + 20 g Polycose) or an equivalent dose of placebo (PL) for 5 days. There were no significant differences between the LOV and Omni groups at baseline with respect to age, height, and weight. The results demonstrated that consuming a LOV diet for 21 days was an effective procedure to decrease muscle creatine concentration (p <.01) in individuals who normally consume meat and fish in their diet. However, muscle total creatine (TCr) following creatine supplementation did not differ statistically between LOV and Omni diet groups (148.6 4.5 vs. 141.7 4.5 mmol kg-1 d.m.).
Article
Creatine monohydrate (CrH2O) supplementation has been demonstrated to increase skeletal muscle power output in men. However, its effect upon women is not as clearly defined. This study investigated the effect of oral creatine supplementation upon muscle function, thigh circumference, and body weight in women. Twenty-two consenting college-age women were assigned to 1 of 2 groups matched for dietary and exercise habits, phase of menstrual cycle, and fat-free mass (FFM). After familiarization with testing procedures, pretrial measures of muscle function (5 repetitions 60 deg x s(-1) and 50 repetitions 180 deg x s(-1) were conducted during maximal voluntary concentric contraction of the preferred quadriceps muscle using an isokinetic dynamometer. Subjects then ingested 0.5 g x kg(-1) FFM of either CrH2O or placebo (one fourth dosage 4 times daily) in a double-blind design for 5 days. Resistance exercise was prohibited. After the ingestion phase was completed, all measures were repeated at the same time of day as during pretrials. Statistical analysis revealed time to peak torque in quadriceps extension decreased from pre-test values of 255 +/- 11 ms (mean +/- SEM) to post-test values of 223 +/- 3 ms; average power in extension increased from 103 +/- 7 W pre-test to 112 +/- 7 W post-test; and, during flexion, average power increased from 59 +/- 5 W pre-test to 65 +/- 5 W post-test in the creatine group as compared to controls (p .05). FFM, percent body fat, mid-quadriceps circumference, skinfold thickness of the measured thigh, and total body weight did not change for both groups between trials. We conclude that CrH2O improves muscle performance in women without significant gains in muscle volume or body weight.