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Effects of Creatine Supplementation and Resistance Training on Muscle Strength and Weightlifting Performance
Abstract
Creatine monohydrate has become the supplement of choice for many athletes striving to improve sports performance. Recent data indicate that athletes may not be using creatine as a sports performance booster per se but instead use creatine chronically as a training aid to augment intense resistance training workouts. Although several studies have evaluated the combined effects of creatine supplementation and resistance training on muscle strength and weightlifting performance, these data have not been analyzed collectively. The purpose of this review is to evaluate the effects of creatine supplementation on muscle strength and weightlifting performance when ingested concomitant with resistance training. The effects of gender, interindividual variability, training status, and possible mechanisms of action are discussed. Of the 22 studies reviewed, the average increase in muscle strength (1, 3, or 10 repetition maximum [RM]) following creatine supplementation plus resistance training was 8% greater than the average increase in muscle strength following placebo ingestion during resistance training (20 vs. 12%). Similarly, the average increase in weightlifting performance (maximal repetitions at a given percent of maximal strength) following creatine supplementation plus resistance training was 14% greater than the average increase in weightlifting performance following placebo ingestion during resistance training (26 vs. 12%). The increase in bench press 1RM ranged from 3 to 45%, and the improvement in weightlifting performance in the bench press ranged from 16 to 43%. Thus there is substantial evidence to indicate that creatine supplementation during resistance training is more effective at increasing muscle strength and weightlifting performance than resistance training alone, although the response is highly variable.
... Strategic use of dietary supplements has gained prominence in the weightlifting world. Creatine supplementation is one of the most extensively researched ergogenic aids recognized for its ability to increase intramuscular phosphocreatine stores, which enhance power output during short-duration, high-intensity activities [14,15]. Similarly, beta-alanine is widely used to buffer muscle acidity during repeated high-intensity efforts, thereby delaying the onset of muscle fatigue [16,17]. ...
... Creatine plays a key role in the adenosine triphosphatecreatine phosphate (ATP-PC) system by promoting ATP synthesis in muscles to provide rapid bursts of energy [14]. Studies have shown that athletes who take creatine supplements can sustain high-intensity training and recover from fatigue more quickly [2,14,15,74,75]. ...
... Related studies have suggested that the loading phase can rapidly saturate muscle creatine stores, leading to an improved high-intensity performance in athletes. Furthermore, long-term supplementation has been associated with enhanced recovery and increased lean body mass, supporting its application in short-term competition preparations and prolonged training [15,[75][76][77]. ...
Weightlifting demands explosive power and neuromuscular coordination in brief, repeated intervals. These physiological demands underscore the critical role of nutrition, not only in optimizing performance during competitions but also in supporting athletes’ rigorous training adaptations and ensuring effective recovery between sessions. As weightlifters strive to enhance their performance, well-structured nutritional strategies are indispensable. In this comprehensive review, we explored how weightlifters can optimize their performance through targeted nutritional strategies, including carbohydrate intake for glycogen replenishment and proteins for muscle growth and recovery. Additionally, the roles of key supplements, such as creatine, beta-alanine, and branch-chained amino acids in enhancing strength, delaying fatigue, and supporting muscle repair were discussed. A comprehensive literature review was conducted using PubMed, Google Scholar, and Web of Science to gather studies on nutritional strategies for weightlifting performance and training adaptation. The review focused on English-language articles relevant to weightlifters, including studies on powerlifting, while excluding those involving non-human subjects. Weightlifting requires explosive power, and proper nutrition is vital for performance and recovery, emphasizing the role of carbohydrate, protein, and fat intake. Nutrient timing and personalized strategies, informed by genetic and metabolomic analyses, enhance recovery and performance, while supplements like creatine, caffeine, and beta-alanine can significantly improve results when used correctly. Sustainable nutritional strategies are essential for enhancing weightlifter performance, emphasizing a balanced approach over extreme diets or excessive supplements. Further research is needed to refine these strategies based on individual athlete characteristics, ensuring consistent top-level performance throughout competitive seasons.
... Still today, creatine is one of the most popular nutritional ergogenic aids for athletes and recreational performers [1,3,4]. In addition to its popularity in the consumer realm, creatine's ability to enhance or augment some types of exercise performance has arguably been one of the most researched topics in the sport nutrition literature for the past 25 years [1,3,7,[9][10][11]. In this regard, creatine has yielded predominantly positive effects regarding exercise performance measures with no ergolytic effects and minimal to no side effects in populations ranging from adolescents to the elderly [3,9]. ...
... In addition to these tables, results from previous selected original investigations and review papers surrounding the ergogenic potential of creatine supplementation are summarized throughout this paper in tables. Finally, the interested reader is directed to other reviews that have outlined the impact of creatine supplementation on exercise performance [3,9,10,12,13,18]. The purpose of this review is to summarize the existing literature surrounding the efficacy of creatine supplementation on exercise and sports performance, along with recovery factors in healthy populations. ...
... Creatine's ability to increase various parameters of acute exercise performance is well documented [3,9,10]. A review by Kreider in 2003 summarized the literature and concluded that approximately 70% of these studies had reported an improvement in some aspect of exercise performance [9]. ...
Creatine is one of the most studied and popular ergogenic aids for athletes and recreational weightlifters seeking to improve sport and exercise performance, augment exercise training adaptations, and mitigate recovery time. Studies consistently reveal that creatine supplementation exerts positive ergogenic effects on single and multiple bouts of short-duration, high-intensity exercise activities, in addition to potentiating exercise training adaptations. In this respect, supplementation consistently demonstrates the ability to enlarge the pool of intracellular creatine, leading to an amplification of the cell’s ability to resynthesize adenosine triphosphate. This intracellular expansion is associated with several performance outcomes, including increases in maximal strength (low-speed strength), maximal work output, power production (high-speed strength), sprint performance, and fat-free mass. Additionally, creatine supplementation may speed up recovery time between bouts of intense exercise by mitigating muscle damage and promoting the faster recovery of lost force-production potential. Conversely, contradictory findings exist in the literature regarding the potential ergogenic benefits of creatine during intermittent and continuous endurance-type exercise, as well as in those athletic tasks where an increase in body mass may hinder enhanced performance. The purpose of this review was to summarize the existing literature surrounding the efficacy of creatine supplementation on exercise and sports performance, along with recovery factors in healthy populations.
... Historically, supplements have had the earliest push to sports where strength and power have a critical role in performance, with the prime examples being football and basketball. The drive to use supplements for performance gains received the most significant push from increased reliance on strength and associated training to develop more powerful and faster athletes [18][19][20][21][22][23][24]. Thus, compounds like creatine monohydrate and whey protein have had a substantial ramp-up in use starting in the 1980s. ...
... Protein supplementation and the use of creatine monohydrate received their primary usage justification from enhancing this part of the physiological profile. The research summarizes that these supplements can boost strength gains with sufficient training intensity [20][21][22][23][24]. They do not have strong efficacy results in moderate or cardio-vascular dominated activities, like distance running. ...
Over the last decade, there has been a dramatic increase in martial arts participation driven by health and physical fitness benefits and the expansion of martial arts into Olympic sports. Additionally, the broad popularity of mixed martial arts (MMA), particularly, the Ultimate Fighting Championships (UFC) has also fueled interest. Martial Arts is a broad-based term describing various disciplines and techniques implemented in self-defense, fighting and utilization of weaponry. Is there a coming intersection of the martial arts category and sports nutrition? The answer to this question depends upon first dissecting the components of training and competition in the martial arts arena and then comparing them to activities requiring the same components. The application of sports nutrition in those related areas should provide clues for this pathway and potential in training and performance relevance.
... Muscle creatine uptake is increased by 15%-40% [14,19] by high-dose short-term and lower-dose longer-term creatine monohydrate supplementation. Increased muscle creatine and phosphocreatine, resulting from supplementation, can improve the quality of high-intensity exercise performance [24,26], resistance exercise performance [32], and increase lean body mass [5]. Beneficial effects of supplementation are independent of age, as ergogenic effects have been observed in adolescents, younger adults, and older individuals [25]. ...
... Two observations widely found in the literature are the increase in body mass [5,25,37,39] and strength gain [5,17,24,26,32,38]. Most studies, in animals and humans that performed creatine supplementation for more than 3 days, report significant increases in body mass, being attributed to fluid retention by the hygroscopic effect of creatine in the initial days [19], but later by increased synthesis and reduced degradation of contractile proteins in skeletal muscle [9,20,28,41]. ...
PurposeThe safety of creatine supplementation has been investigated, however, the safety of a high-dose/short-term or low-dose/long-term supplementation dosing scheme, combined with a resistance training program, a commonly used dosing scheme, has not yet studied. The aim of this study was to evaluate physical performance and the safety of the cited creatine supplementation dosing scheme in a double-blind placebo-controlled study by assessing blood and urine health indicators in subjects undertaking resistance training.Method
Thirty-four healthy male subjects were randomly assigned to creatine supplement (CREA/7 days, 0.3 g/kg body mass + 21 days, 0.03 g/kg) or placebo (PLA) group and both groups participated in a resistance training intervention (6 exercises, 3 sets of 8–12 repetitions per exercise at 85% of 1RM, 3 d/week). Blood and urine samples were collected pre-, 7 and 30 days post-supplementation. For blood (26 parameters) and urine markers (15), between-group differences were calculated by using 2 groups (CREA and PLA) × 2 measures (“POST7 minus PRE” and “POST30 minus PRE”) terms.ResultsThe CREA group exhibited significant body weight and 1RM increase (POST30 minus PRE) of all evaluated exercises, when compared to PLA group. Regarding the blood and urine health markers, only hematocrit, LDL, Uric Acid, Phosphatase Alkaline and Creatinine exhibited between-group differences, but with small magnitude of differences and maintained into the range of clinical reference values.Conclusion
Our data suggest that creatine supplementation the used dosing scheme, concomitantly with resistance training, improves physical performance with no evident risk or protection to health for young weightlifters.
... Povećanje snage u bench press-u nakon konzumacije CR je zabilježeno u nekim od izdvojenih radova (Amirsasan et al., 2018;Vilar-Neto et al., 2018;Bjelica et al., 2020;Mills et al., 2020). Ostala istraživanja su demonstrirala slična poboljšanja u bench press-u performanse (Camic et al., 2014;Kilduff et al., 2002;Rawson & Volek, 2003). Kada je u pitanju sportovi, koji zahtijevaju kombinaciju aerobnih i anaerobnih izvora uz učešće snage i izdržljivosti, dolazi do umora i smanjenja efikasnosti. ...
... Increased strength on bench press after CR supplementation was mentioned in some of the papers (Amirsasan et al., 2018;Vilar-Neto et al., 2018;Bjelica et al., 2020;Mills et al., 2020). Other research demonstrated similar improvements in bench press performances (Camic et al., 2014;Kilduff et al., 2002;Rawson & Volek, 2003). Regardng sports which require combination of aerobic and anaerobic sources with participation of strength and endurance, fatigue may occur and hence efficiency reduces. ...
In football, the knee joint is one of the most stressed joints during the
game itself, especially for professional football players where there are higher
physical requirements. Factors such as race, weight, vitamin contribution, metabolic
/ hormone disorders, environment and football practice can affect the knee angle.
The aim of the study was to determine the impact of playing football on changes in
the knee joint. The following electronic databases were used to search the literature:
PubMed, MEDLINE, Google Scholar, EBSCO in the period from 2006 to 2019. The
sample of respondents included the male participants who played football, who
were of different training status and age categories. The studies were included only
if there were differences in the angle of the knee – genu varum or genu valgum in
football players. Most researchers concluded that there are significant differences in
the knee joint in respondents who played football and respondents who play no
sports. The authors believe that the most critical period in which deformities can
occur is the period of adolescence, while later this process slows down. People who
have played other sports, as well as football players, have an increased risk of
developing knee deformities. From the reviewed works, we can conclude that
intense physical exercise and frequent competition can encourage the development
of deformities.
... Povećanje snage u bench press-u nakon konzumacije CR je zabilježeno u nekim od izdvojenih radova (Amirsasan et al., 2018;Vilar-Neto et al., 2018;Bjelica et al., 2020;Mills et al., 2020). Ostala istraživanja su demonstrirala slična poboljšanja u bench press-u performanse (Camic et al., 2014;Kilduff et al., 2002;Rawson & Volek, 2003). Kada je u pitanju sportovi, koji zahtijevaju kombinaciju aerobnih i anaerobnih izvora uz učešće snage i izdržljivosti, dolazi do umora i smanjenja efikasnosti. ...
... Increased strength on bench press after CR supplementation was mentioned in some of the papers (Amirsasan et al., 2018;Vilar-Neto et al., 2018;Bjelica et al., 2020;Mills et al., 2020). Other research demonstrated similar improvements in bench press performances (Camic et al., 2014;Kilduff et al., 2002;Rawson & Volek, 2003). Regardng sports which require combination of aerobic and anaerobic sources with participation of strength and endurance, fatigue may occur and hence efficiency reduces. ...
Nutritional analysis is a very important segment in monitoring the growth
and development of school-age children. The aim of this study was to define the
nutritional status based on the results of previous studies with samples taken from
the population of primary school students in Montenegro. The analysis included 11
studies with a total of 8619 respondents of both sexes, which mainly dealt with the
assessment of the nutritional status of respondents aged 6 to 15 years. Based on the
analysis of the research results, it was determined that malnutrition and obesity are
significantly present in children of primary school age of both sexes in Montenegro.
Taking into account malnutrition and obesity together, the percentages range from
20-40%, which is typical for the Mediterranean countries of Europe, including
Montenegro. Also, it was found that the application of different nutrition assessment
standards gives different results that sometimes differ significantly on the same
sample of respondents.
... Povećanje snage u bench press-u nakon konzumacije CR je zabilježeno u nekim od izdvojenih radova (Amirsasan et al., 2018;Vilar-Neto et al., 2018;Bjelica et al., 2020;Mills et al., 2020). Ostala istraživanja su demonstrirala slična poboljšanja u bench press-u performanse (Camic et al., 2014;Kilduff et al., 2002;Rawson & Volek, 2003). Kada je u pitanju sportovi, koji zahtijevaju kombinaciju aerobnih i anaerobnih izvora uz učešće snage i izdržljivosti, dolazi do umora i smanjenja efikasnosti. ...
... Increased strength on bench press after CR supplementation was mentioned in some of the papers (Amirsasan et al., 2018;Vilar-Neto et al., 2018;Bjelica et al., 2020;Mills et al., 2020). Other research demonstrated similar improvements in bench press performances (Camic et al., 2014;Kilduff et al., 2002;Rawson & Volek, 2003). Regardng sports which require combination of aerobic and anaerobic sources with participation of strength and endurance, fatigue may occur and hence efficiency reduces. ...
Nutritional analysis is a very important segment in monitoring the growth
and development of school-age children. The aim of this study was to define the
nutritional status based on the results of previous studies with samples taken from
the population of primary school students in Montenegro. The analysis included 11
studies with a total of 8619 respondents of both sexes, which mainly dealt with the
assessment of the nutritional status of respondents aged 6 to 15 years. Based on the
analysis of the research results, it was determined that malnutrition and obesity are
significantly present in children of primary school age of both sexes in Montenegro.
Taking into account malnutrition and obesity together, the percentages range from
20-40%, which is typical for the Mediterranean countries of Europe, including
Montenegro. Also, it was found that the application of different nutrition assessment
standards gives different results that sometimes differ significantly on the same
sample of respondents.
... Muscle creatine uptake is increased by 15%-40% [14,19] by high-dose short-term and lower-dose longer-term creatine monohydrate supplementation. Increased muscle creatine and phosphocreatine, resulting from supplementation, can improve the quality of high-intensity exercise performance [24,26], resistance exercise performance [32], and increase lean body mass [5]. Beneficial effects of supplementation are independent of age, as ergogenic effects have been observed in adolescents, younger adults, and older individuals [25]. ...
... Two observations widely found in the literature are the increase in body mass [5,25,37,39] and strength gain [5,17,24,26,32,38]. Most studies, in animals and humans that performed creatine supplementation for more than 3 days, report significant increases in body mass, being attributed to fluid retention by the hygroscopic effect of creatine in the initial days [19], but later by increased synthesis and reduced degradation of contractile proteins in skeletal muscle [9,20,28,41]. ...
Background:
Creatine represents a natural supplement and ergogenic aid for sport performance, but there are several concerns regarding its safety for health. The present double-blind placebo-controlled study evaluated the effect of creatine monohydrate supplementation on a panel of blood and urine health indicators in resistance training practitioners.
Methods:
Eighteen males performing resistance training three times per week were supplemented with 0.3 g/kg per day creatine monohydrate for 7 days and compared with matched controls supplemented with dextrosol. Blood and urine samples were collected pre- and 30 days post-supplementation to evaluate 41 biochemical parameters and renal function.
Results:
Creatine monohydrate supplementation did not cause adverse events and, as expected, promoted an increase of the performance and body weight. No modification of red blood cells parameters, white blood cells profile, blood lipid profile, metabolic and urine markers, hepatic and renal function were observed in the supplemented group.
Conclusions:
Despite the expected weight increase, the creatine monohydrate supplementation is safe for health and no detrimental effects on different organs and physiological systems were observed in our cohort of volunteers.
... It is well-established that creatine supplementation, primarily when combined with exercise training, increases measures of muscle performance, specifically muscle strength, Nutrients 2025, 17, 95 4 of 20 muscle power, and the ability to repeat sprints, across a variety of populations [14]. Creatine supplementation may also aid in faster recovery from intense exercise by reducing muscle cell damage and inflammation [15]. The varied evidence supporting the efficacy of creatine supplementation as a performance-enhancing substance has made creatine a very popular ergogenic aid in recent decades [16]. ...
Creatine monohydrate supplementation is widely used by athletes in high-intensity, power-based sports due to its ability to enhance short-term performance by increasing intramuscular phosphocreatine (PCr) stores, which aid in ATP resynthesis during intense muscle contractions. However, emerging evidence suggests that creatine monohydrate offers benefits beyond athletic performance. This narrative review explores the literature supporting the advantages of creatine supplementation in women, vegans, and clinical populations. In women, who typically have lower baseline intramuscular creatine levels, supplementation may help alleviate fatigue-related symptoms associated with the menstrual cycle, particularly during the early follicular and luteal phases. For vegans and vegetarians, who often have reduced creatine stores due to the absence of creatine-rich animal products in their diet, supplementation can improve both physical and cognitive performance while supporting adherence to plant-based diets. Additionally, creatine supplementation holds potential for various clinical populations. It may mitigate muscle wasting in conditions such as sarcopenia and cachexia, support neuroprotection in neurodegenerative diseases such as Parkinson’s and Huntington’s, improve exercise capacity in cardiovascular diseases, and enhance energy metabolism in chronic fatigue syndrome. Creatine may also aid recovery from traumatic brain injury by promoting brain energy metabolism and reducing neuronal damage. In conclusion, creatine monohydrate supplementation can enhance physical performance, cognitive function, and overall health in women, vegans, and clinical populations by addressing creatine deficiencies, improving energy metabolism, and supporting recovery from physical and neurological challenges. Most available evidence supports the effectiveness of creatine monohydrate, which should be considered the preferred form of creatine supplementation over other variants. Additionally, proper creatine dosing is essential to maximize benefits and minimize potential adverse effects that may arise from chronic ingestion of excessively high doses.
... This system primarily supports activities lasting less than 10 seconds, after which anaerobic glycolysis begins to contribute energy for slightly longer-duration efforts ( Figure 2). Supplementing with creatine increases phosphocreatine stores, reducing muscle fatigue and enhancing performance in brief, high-intensity exercises and resistance training [14,15]. Authors' own image. ...
Depression, affecting millions of people worldwide, is a leading cause of disability globally. It affects not only daily functioning but also interpersonal relationships and overall health by increasing the risks of chronic physical and mental illnesses. Creatine, traditionally recognized for boosting physical performance through its role in producing adenosine triphosphate, has recently shown potential as an adjunctive therapy for treating depression. Creatine’s ability to enhance brain energy metabolisms and provide neuroprotection suggests that it can alleviate mood disorders by improving mitochondrial function, increasing cellular resilience, and modulating neurotransmitter systems that regulate mood.
This narrative review aims to critically evaluate the research on creatine supplementation for depression, focusing on its efficacy, mechanism of action, risks, and benefits as a treatment for mood disorders. It analyzes preclinical and clinical studies to understand creatine’s potential as an adjunctive or alternative therapy for major depressive disorder and bipolar depression and underscores any gaps in current research. Both animal models and human trials indicate creatine’s efficacy for the treatment of depression. Creatine supplementation reduces depressive symptoms, particularly when combined with selective serotonin reuptake inhibitors, and may improve brain energy metabolism and neuroplasticity. It is generally well tolerated, though caution is warranted due to potential side effects such as manic episodes in bipolar disorder and renal function impairment in patients with kidney dysfunction. Overall, creatine presents a promising addition to current depression treatments, though further research is needed to establish optimal dosing, long-term efficacy, and safety across diverse patient populations.
... I 2 = 23%; p < 0.00001). This result aligns with the study by Rawson and Volek, who reported that creatine enhances memory performance in complex tasks (34). Similarly, Avgerinos et al.'s systematic review noted positive effects of creatine on cognitive and memory functions, especially in tasks requiring high cognitive control (15). ...
Background
This study aimed to evaluate the effects of creatine monohydrate supplementation on cognitive function in adults and explore its potential role in preventing and delaying cognitive impairment-related diseases.
Methods
Following the PRISMA 2020 guidelines, a systematic review with meta-analysis was conducted. Randomized controlled trials (RCTs) published between 1993 and 2024 were retrieved from PubMed, Scopus, and Web of Science databases. The study protocol was registered with PROSPERO (registration number: CRD42024533557). The impact of creatine supplementation on overall cognitive function, memory, executive function, attention, and information processing speed was assessed using standardized mean differences (SMD) and Hedge’s g with 95% confidence intervals (CI).
Results
Sixteen RCTs involving 492 participants aged 20.8–76.4 years, including healthy individuals and patients with specific diseases, were selected. Creatine monohydrate was the form used in all included studies. Creatine supplementation showed significant positive effects on memory (SMD = 0.31, 95% CI: 0.18–0.44, Hedges’s g = 0.3003, 95% CI: 0.1778–0.4228) and attention time (SMD = −0.31, 95% CI: −0.58 to −0.03, Hedges’s g = −0.3004, 95% CI: −0.5719 to −0.0289), as well as significantly improving processing speed time (SMD = −0.51, 95% CI: −1.01 to −0.01, Hedges’s g = −0.4916, 95% CI: −0.7852 to −0.1980). However, no significant improvements were found on overall cognitive function or executive function. Subgroup analyses revealed that creatine supplementation was more beneficial in individuals with diseases, those aged 18–60 years, and females. No significant differences were found between short- (<4 weeks) and long-term (≥4 weeks) interventions for improving cognitive function. Low-to-moderate risk of bias was found, and no significant publication bias was detected. The GRADE assessment indicates that the certainty of evidence for memory function is moderate, suggesting a reasonable level of confidence in the positive effects of creatine on memory. However, the evidence for processing speed, overall cognitive function, executive function, and attention is of low certainty, indicating that further research is needed to confirm these potential benefits.
Conclusion
Current evidence suggests that creatine monohydrate supplementation may confer beneficial effects on cognitive function in adults, particularly in the domains of memory, attention time, and information processing speed. Larger robust clinical trials are warranted to further validate these findings. Furthermore, future research should investigate the influence of different populations and intervention durations on the effects of creatine monohydrate supplementation, as well as elucidate the precise mechanisms underlying its potential cognitive-enhancing properties.
... Studies have shown that skeletal muscle contraction stimulates intramyocellular uptake of creatine, and that a combination of creatine supplementation and resistance training may maximize its accretion [76]. As results, creatine supplementation combined with resistance training increases LBM and muscle strength [75,[77][78][79][80]. However, there is no evidence to suggest that creatine supplementation independent of resistance training can increase muscle strength. ...
Maintaining skeletal muscle mass is important for improving muscle strength and function. Hence, maximizing lean body mass (LBM) is the primary goal for both elite athletes and fitness enthusiasts. The use of amino acids as dietary supplements is widespread among athletes and physically active individuals. Extensive literature analysis reveals that branched-chain amino acids (BCAA), creatine, glutamine and β-alanine may be beneficial in regulating skeletal muscle metabolism, enhancing LBM and mitigating exercise-induced muscle damage. This review details the mechanisms of these amino acids, offering insights into their efficacy as supplements. Recommended dosage and potential side effects are then outlined to aid athletes in making informed choices and safeguard their health. Lastly, limitations within the current literature are addressed, highlighting opportunities for future research.
... In addition to previous works, handgrip strength was seen to increase with creatine in our primary analysis, a finding replicated in athletes in the sports science literature. 88 Multimorbidity and aging are associated with functional disability because of muscle wasting. 11,13 The shared common pathway is an F I G U R E 5 Forest plot of studies reporting body composition outcomes demonstrated as a standardized mean difference using frequentist meta-analysis. ...
Background
The efficacy of creatine replacement through supplementation for the optimization of physical function in the population at risk of functional disability is unclear.
Methods
We conducted a systematic literature search of MEDLINE, EMBASE, the Cochrane Library, and CINAHL from inception to November 2022. Studies included were randomized controlled trials (RCTs) comparing creatine supplementation with placebos in older adults and adults with chronic disease. The primary outcome was physical function measured by the sit‐to‐stand test after pooling data using random‐effects modeling. We also performed a Bayesian meta‐analysis to describe the treatment effect in probability terms. Secondary outcomes included other measures of physical function, muscle function, and body composition. The risk of bias was assessed using the Cochrane risk‐of‐bias tool.
Results
We identified 33 RCTs, comprising 1076 participants. From six trials reporting the primary outcome, the pooled standardized mean difference (SMD) was 0.51 (95% confidence interval [CI]: 0.01–1.00; I ² = 62%; P = 0.04); using weakly informative priors, the posterior probability that creatine supplementation improves physical function was 66.7%. Upper‐body muscle strength (SMD: 0.25; 95% CI: 0.06–0.44; I ² = 0%; P = 0.01), handgrip strength (SMD 0.23; 95% CI: 0.01–0.45; I ² = 0%; P = 0.04), and lean tissue mass (MD 1.08 kg; 95% CI: 0.77–1.38; I ² = 26%; P < 0.01) improved with creatine supplementation. The quality of evidence for all outcomes was low or very low because of a high risk of bias.
Conclusion
Creatine supplementation improves sit‐to‐stand performance, muscle function, and lean tissue mass. It is crucial to conduct high‐quality prospective RCTs to confirm these hypotheses (PROSPERO number, CRD42023354929).
... The mechanism behind this improvement is believed to be related to the increase in phosphocreatine (PCr) availability, which plays a critical role in the resynthesis of adenosine triphosphate (ATP) during high-intensity exercise [1]. A study conducted by Rawson and Volek [5] reported that creatine supplementation had a significant effect on muscular performance during high-intensity exercise. Similarly, a study conducted by Johnston et al. [6] reported improvements in body composition, strength, and sprint performance in healthy males following creatine supplementation. ...
This review article provides an overview of the mechanisms behind creatine's performance-enhancing and health-boosting effects in people of all ages. Creatine is a widely-used dietary supplement among athletes and fitness enthusiasts due to its ability to improve high-intensity exercise performance. Recent research has highlighted its potential health benefits, such as improving bone health in older adults and enhancing renal function. The paper concludes by discussing the safety concerns associated with creatine supplementation and emphasizes the need for further research to identify potential applications in various populations.
... Failing to meet these demands can result in fatigue, cognitive dysfunction, weight loss, Creatine is a popular ergogenic aid among athletes, known for enhancing performance and promoting exercise adaptations. It is particularly beneficial for short-duration, highintensity exercises [66][67][68][69][70]. The International Society of Sports Nutrition (ISSN) suggests that healthy individuals can use creatine supplements safely, and recent evidence refutes the notion that they could lead to dehydration or muscle cramping [71,72]. ...
Background:
More than 270 million participants and 128,893 professional players play soccer. Although UEFA recommendations for nutrition in elite football exist, implementing these guidelines among professional and semiprofessional soccer players remains suboptimal, emphasizing the need for targeted and individualized nutritional strategies to improve adherence to established recommendations.
Methods:
We conducted a comprehensive search in PubMed, Scopus, Web of Science, and clinical trial registers. Inclusion criteria focused on professional or semiprofessional soccer players, nutrition or diet interventions, performance improvement outcomes, and randomized clinical trial study types. We assessed quality using the Risk of Bias 2 (RoB 2) tool. We identified 16 eligible articles involving 310 participants. No nutritional interventions during the recovery period effectively improved recovery. However, several performance-based interventions showed positive effects, such as tart cherry supplementation, raw pistachio nut kernels, bicarbonate and mineral ingestion, creatine supplementation, betaine consumption, symbiotic supplements, and a high-carbohydrate diet. These interventions influenced various aspects of soccer performance, including endurance, speed, agility, strength, power, explosiveness, and anaerobic capacity.
Conclusions:
Specific strategies, such as solutions with bicarbonate and minerals, high carbohydrate diets, and supplements like creatine, betaine, and tart cherry, can enhance the performance of professional soccer players. These targeted nutritional interventions may help optimize performance and provide the competitive edge required in professional soccer. We did not find any dietary interventions that could enhance recovery.
... Exercise further promotes the body's metabolic process, improves lipid metabolism, and increases energy consumption [41,42]. In several meta-analyses and review articles related to creatine supplementation, creatine supplementation was found to be readily and positively associated with muscle endurance and exercise performance [43][44][45][46][47]. It was also possible that creatine supplements increase calcium reuptake by the sarcoplasmic reticulum, which would lead to faster actin-myosin cross-bridge cycling during repeated muscle contractions [48]. ...
The present study aimed to assess the changes in muscle strength and plasma metabolites in athletes with β-glucan supplementation. A total of 29 athletes who met the inclusion criteria were recruited for this study (ChiCTR2200058091) and were randomly divided into a placebo group (n = 14) and β-glucan group (n = 15). During the trial, the experimental group received β-glucan supplementation (2 g/d β-glucan) for 4 weeks and the control group received an equal dose of placebo supplementation (0 g/d β-glucan), with both groups maintaining their regular diet and exercise habits during the trial. The athletes’ exercise performance, muscle strength, and plasma metabolome changes were analyzed after 4 weeks of β-glucan supplementation. The results showed a significant increase in mean grip strength (kg), right hand grip strength (kg), left triceps strength (kg), and upper limb muscle mass (kg) in the experimental group after the 4-week intervention compared to the preintervention period (p < 0.05). A comparison of the difference between the two groups after the intervention showed that there were significant differences between the control group and the experimental group in mean grip strength (kg) and right-hand grip strength (kg) (p < 0.05). Athletes in the experimental group showed significant improvements in 1 min double rocking jump (pcs), VO2max (ml/kg-min) (p < 0.05). The β-glucan intake increased the creatine-related pathway metabolites in plasma. Overall, these results suggest that 4 weeks of β-glucan supplementation can improve muscle strength in athletes, with the potential to increase aerobic endurance and enhance immune function, possibly by affecting creatine-related pathways.
... As a result, most reviews conducted in the past decades provide us with limited information on which mechanical or metabolic stimuli has the most expedited effect on muscle strength gains. Typical categorizations reviewed include loading level (66), type of muscle contraction (i.e., eccentric vs concentric; 65), type of training focus (i.e., strength vs. power; (8)), supplementation (64), and blood flow restriction (BFR; 47); but because the timeline of muscle strength adaptation has not been considered in these reviews, only the overall benefit to exposure (effect of the intervention) is known of selected mechanical and metabolic stimuli. ...
A fundamental task in exercise physiology is to determine and ultimately improve the adaptations that take place in the human body, an integrated network of various physiological systems, for example, muscle, tendon, and bone. Investigating the temporal dynamics (time course) of adaptations in these diverse systems may help us gain new knowledge about the functioning of the neuromotor system in healthy and pathological conditions. The aim of this review was to explore the temporal dynamics of muscular strength adaptations in studies implementing a resistance training intervention. In addition, we categorized these studies under mechanical or metabolic stimuli to identify whether certain stimuli cause faster muscle strength gains. Searches were performed using PubMed and Google Scholar databases. The review comprised 708 subjects from 57 training groups within 40 studies that met the inclusion criteria. The results revealed that the mean time point of first significant increase in muscle strength of all studies was 4.3 weeks, and the corresponding increase was on average about 17%. A plateau in muscle strength increase (∼25%) was found to occur between weeks 8 and 12. Categorization into stimuli groups revealed that performing training in a hypoxic environment is likely to produce a leftward shift (∼25% increase at ∼2.8 weeks) in the dose-response relationship compared with blood flow restriction and supplementation. However, stimuli that cause faster muscle strength gains may also induce imbalanced adaptation between the muscle and the surrounding biological structures, potentially triggering a degradation in some parts of the network (i.e., leading to an increased risk of injury).
... [15][16][17] Even in non diseased (normal blood flow) persons (eg athletes), an increase on metabolic function is capable to improve performance, as seen in studies with Cr supplementation, corroborating the data. 27,28 The ingestion of 20g/day of Cr for 5 days can lead to increase more than 20% of muscle Cr content, of which approximately 20% can be attributable to PCr form. 1 As reviewed previously by Rawson and Persky 27 (2007), in the context of exercise performance, Cr supplementation can act as an ergogenic aid through some mechanisms, mainly: a) increased storages of glycogen and PCr pre-exercise; b) reduced time to PCr resynthesys; c) reduced post exercise muscle damage and inflammation; d) increased training intensity, volume, and sensitivity of contractile muscle fibers to Ca++; e) acts in oxidative stress prevention via direct and indirect antioxidant action; f) maintains the ATP/ ADP ratio and maintains cellular pH via H+ buffering; and g) provide activation of glycolysis and glycogenolysis through Pi release thereby integrating the carbohydrate and Cr degradation to provide energy at the early stage of exercises. ...
Creatine (Cr) Supplementation has been efficient and safely used as a therapeutic aid in many health and sickness conditions including muscle weakness, atrophy and metabolic disturbances. In Peripheral arterial obstructive disease (PAOD), chronic ischemia leads to muscle fiber atrophy and denervation, negative muscle metabolism alterations, thus reducing strength and endurance, impairing general physical fitness. Adding the studied benefits of Cr supplementation and the clinical frame of PAOD, it presents Cr Supplementation as a potential therapeutic aid to be considered. Objective: To make a systematic review in scientific literature, searching for studies involving Cr supplementation in PAOD individuals. Method: A search for Portuguese and English written articles, published over the last ten years, including terms related to PAOD and Cr supplementation, was conducted on PubMed SciELO, and LILACS. Results: Only one study evaluated the influence of Cr supplementation in the desired sample (PAOD), describing positive effects in walking distance and blood properties. Due to lack of scientific data, the use Cr supplementation in PAOD population, including metabolic, functional and structural considerations was discussed. Conclusion: Despite the presented discussion for using Cr supplementation in PAOD as a potential therapeutic aid, only one previous study could verify its benefits. Therefore, it still has a gap in scientific literature, leaving several possibilities for future studies researching for possible benefits to counteract the loss of functional fitness and impairments in musculoskeletal structure and metabolism of diseased individuals.
... Creatine was the major component of organic acid, which is a central constituent in muscle energy metabolism and most prevalent in meat products (Dobenecker & Braun, 2015). The role of creatine in producing energy and enhancing muscle strength leads to the common use in people under high energy demand, such as professional athletes (Rawson & Volek, 2003). Creatine has been studied in relation to energy status at slaughter of animals and meat quality (Nissen & Young, 2006;Young, Bertram, Rosenvold, Lindahl, & Oksbjerg, 2005). ...
To explore the chemical composition of chicken meat during different growth and development periods, the dynamic alterations of the metabolite composition were determined using LC-MS/MS-based metabolomics. Together, 573 metabolites were identified in chicken meat from five age stages. Generally, pentadecanoic acid, stearic acid, creatine, carnosine, IMP, L-histidine and L-isoleucine presented an upward trend with age, while anserine, DHA, L-aspartic acid, LPA 18:1 and LPI 18:1 decreased with age. The main pathways of chicken meat metabolism affected by age were fructose and mannose metabolism, arachidonic acid metabolism, steroid hormone biosynthesis, riboflavin metabolism, biosynthesis of unsaturated fatty acids, and linoleic acid metabolism. Using transcriptomic profiling data, we conducted Pearson correlation analysis between gene expression and metabolite profile data in each age comparison. Integration analysis of metabolome and transcriptome would be helpful to understand the biological processes underlying the development of meat quality and explore valuable biomarkers for specific metabolite accumulation.
... A number of mechanisms have been proposed to explain the benefit that CrM has on resistance traininginduced adaptations, including larger lean body mass [18], increased protein expression and synthesis [19], changes in myogenic transcription factors [20], and elevated mitotic activity of satellite cells [21]. Above all, the most likely benefit appears to be due to improved performance during resistance training sessions by increasing intra-muscular phosphocreatine stores, thereby allowing a greater work capacity and thus training stimuli for enhanced chronic training adaptation [22,23]. Recent evidence also suggests the potential for CrM supplementation to attenuate muscle damage markers as an acute response to exercise [24]. ...
Background
Several studies have examined the effect of creatine monohydrate (CrM) on indirect muscle damage markers and muscle performance, although pooled data from several studies indicate that the benefits of CrM on recovery dynamics are limited.
Objective
This systematic review and meta-analysis determined whether the ergogenic effects of CrM ameliorated markers of muscle damage and performance following muscle-damaging exercises.
Methods
In total, 23 studies were included, consisting of 240 participants in the CrM group (age 23.9 ± 10.4 years, height 178 ± 5 cm, body mass 76.9 ± 7.6 kg, females 10.4%) and 229 participants in the placebo group (age 23.7 ± 8.5 years, height 177 ± 5 cm, body mass 77.0 ± 6.6 kg, females 10.0%). These studies were rated as fair to excellent following the PEDro scale. The outcome measures were compared between the CrM and placebo groups at 24–36 h and 48–90 h following muscle-damaging exercises, using standardised mean differences (SMDs) and associated p -values via forest plots. Furthermore, sub-group analyses were conducted by separating studies into those that examined the effects of CrM as an acute training response (i.e., after one muscle-damaging exercise bout) and those that examined the chronic training response (i.e., examining the acute response after the last training session following several weeks of training).
Results
According to the meta-analysis, the CrM group exhibited significantly lower indirect muscle damage markers (i.e., creatine kinase, lactate dehydrogenase, and/or myoglobin) at 48–90 h post-exercise for the acute training response (SMD − 1.09; p = 0.03). However, indirect muscle damage markers were significantly greater in the CrM group at 24 h post-exercise (SMD 0.95; p = 0.04) for the chronic training response. Although not significant, a large difference in indirect muscle damage markers was also found at 48 h post-exercise (SMD 1.24) for the chronic training response. The CrM group also showed lower inflammation for the acute training response at 24–36 h post-exercise and 48–90 h post-exercise with a large effect size (SMD − 1.38 ≤ d ≤ − 1.79). Similarly, the oxidative stress markers were lower for the acute training response in the CrM group at 24–36 h post-exercise and 90 h post-exercise, with a large effect size (SMD − 1.37 and − 1.36, respectively). For delayed-onset muscle soreness (DOMS), the measures were lower for the CrM group at 24 h post-exercise with a moderate effect size (SMD − 0.66) as an acute training response. However, the inter-group differences for inflammation, oxidative stress, and DOMS were not statistically significant ( p > 0.05).
Conclusion
Overall, our meta-analysis demonstrated a paradoxical effect of CrM supplementation post-exercise, where CrM appears to minimise exercise-induced muscle damage as an acute training response, although this trend is reversed as a chronic training response. Thus, CrM may be effective in reducing the level of exercise-induced muscle damage following a single bout of strenuous exercises, although training-induced stress could be exacerbated following long-term supplementation of CrM. Although long-term usage of CrM is known to enhance training adaptations, whether the increased level of exercise-induced muscle damage as a chronic training response may provide potential mechanisms to enhance chronic training adaptations with CrM supplementation remains to be confirmed.
... Approximately 95% of synthesized creatine is included in skeletal muscle and is used primarily as an energy source for muscles [47]. The effects of creatine on muscle mass and strength have been reported in many studies, especially in young individuals [48,49]. It has been reported that the effect is ambiguous on the elderly [50,51] and no adverse events were reported [51]. ...
Cachexia is one of the most common, related factors of malnutrition in cancer patients. Cancer cachexia is a multifactorial syndrome characterized by persistent loss of skeletal muscle mass and fat mass, resulting in irreversible and progressive functional impairment. The skeletal muscle loss cannot be reversed by conventional nutritional support, and a combination of anti-inflammatory agents and other nutrients is recommended. In this review, we reviewed the effects of nutrients that are expected to combat muscle loss caused by cancer cachexia (eicosapentaenoic acid, β-hydroxy-β-methylbutyrate, creatine, and carnitine) to propose nutritional approaches that can be taken at present. Current evidence is based on the intake of nutrients as supplements; however, the long-term and continuous intake of nutrients as food has the potential to be useful for the body. Therefore, in addition to conventional nutritional support, we believe that it is important for the dietitian to work with the clinical team to first fully assess the patient’s condition and then to safely incorporate nutrients that are expected to have specific functions for cancer cachexia from foods and supplements.
... De acordo com Volek e Rawson (2004), a suplementação com creatina, e associado ao treino de resistência de alta intensidade melhora o desempenho físico, eleva a massa muscular e hidratação muscular. De acordo com Rawson & Volek (2003), praticantes de treinamento resistido que ingeriram creatina, melhoraram em média + 8% e + 14% no desempenho da força máxima (1RM) ou resistência (repetições máximas em uma determinada porcentagem de 1RM), quando comparados aos grupos de placebos. Jakobi, et al., (2000), relataram não verificar nenhum efeito de um protocolo de suplementação com creatina de curto prazo na força isométrica no exercício de flexão do cotovelo durante a ativação muscular e recuperação. ...
O consumo de creatina pode potencializar os efeitos do treinamento resistido promovendo resultados fisiológicas que podem interferir de forma positiva, gerando o aumento de força muscular, hipertrofia muscular e resistência. Este artigo objetivou verificar os principais efeitos e os benefícios da suplementação de creatina em praticantes de treinamento resistido. Quanto aos métodos para a elaboração deste, buscou-se a revisão de literatura, qualitativa, de caráter descritivo, a partir de documentos secundários para o alcance do objetivo. Conclui-se que a suplementação de creatina por praticantes de treinamento resistido, poderá influenciar nos resultados fisiológicos de tal maneira a melhorar a força muscular, a hidratação celular, o aumento de massa muscular e a resistência muscular.
... Increased strength on bench press after CR supplementation was mentioned in some of the papers (Amirsasan et al., 2018;Vilar-Neto et al., 2018;Bjelica et al., 2020;Mills et al., 2020). Other research demonstrated similar improvements in bench press performances (Camic et al., 2014;Kilduff et al., 2002;Rawson & Volek, 2003). Regardng sports which require combination of aerobic and anaerobic sources with participation of strength and endurance, fatigue may occur and hence efficiency reduces. ...
Kreatin je postao popularan dodatak prehrani među sportistima. Najnovija istraživanja takođe s sugerišu da postoji veliki broj potencijalnih terapijskih primjena kreatina. Cilj ovog sistematskog pregleda je da se ispitaju efekti CR na mišićnu snagu i tjelesnu kompoziciju, na temelju prikupljenih podataka i analiziranih radova objavljenih u periodu 2018.-2020 godine. Pretraživanje literature izvršeno je pomoću sledećih baza: PubMed, Scholar Google, DOAJ. Radovi su odabrani na osnovu više kriterijuma. Rezultati ukazuju da CR u kombinaciji sa nekim programom vježbanja rezultira povećanjem mišićne mase, povećava snagu, smanjuje vrijeme izvođenja određene aktivnosti. Promjene u tjelesnoj kompoziciji ogledaju se u povećanju ukupne mase i mišićne mase kao i količine vode u sastavu tijela. Korišćenje CR u omjeru 10-20gr na dnevnom nivou i učestalosti korišćenja od 4-5 dana nedeljno, predstavlja efikasno sredstvo za poboljšanje sportskih performansi i pozitivnih promjena u sastavu tijela.
... These findings are in line with the result of the current meta-analysis. CitMal's magnitude of effect appears to be slightly lower than effects observed for other ergogenic supplements on repetitions to failure, such as caffeine (SMD: 0.38; Polito et al., 2016), sodium bicarbonate (SMD: 0.37; Grgic et al., 2020), or long-term use of creatine (14%; Rawson & Volek, 2003), but similar to the effect of short-term beta-alanine supplementation on anaerobic performance (SMD: 0.18; Saunders et al., 2016). ...
Citrulline malate (CitMal) is a dietary supplement that is suggested to enhance strength training performance. However, there is conflicting evidence on this matter. Thus, the purpose of this meta-analysis was to determine whether supplementing with CitMal prior to strength training could increase the total number of repetitions performed before reaching voluntary muscular failure. A systematic search was conducted wherein the inclusion criteria were double-blind, placebo-controlled studies in healthy participants that examined the effect of CitMal on repetitions to failure during upper body and lower body resistance exercises. The Hedges’s g standardized mean differences (SMD) between the placebo and CitMal trials were calculated and used in a random effect model. Two separate subanalyses were performed for upper body and lower body exercises. Eight studies, including 137 participants who consisted of strength-trained men ( n = 101) and women ( n = 26) in addition to untrained men ( n = 9), fulfilled the inclusion criteria. Across the studies, 14 single-joint and multijoint exercises were performed with an average of 51 ± 23 total repetitions during 5 ± 3 sets per exercise at ∼70% of one-repetition maximum. Supplementing with 6–8 g of CitMal 40–60 min before exercise increased repetitions by 3 ± 5 (6.4 ± 7.9%) compared with placebo ( p = .022) with a small SMD (0.196). The subanalysis for the lower body resulted in a tendency for an effect of the supplement (8.1 ± 8.4%, SMD: 0.27, p = .051) with no significant effect for the upper body (5.7 ± 8.4%, SMD: 0.16, p = .131). The current analysis observed a small ergogenic effect of CitMal compared with placebo. Acute CitMal supplementation may, therefore, delay fatigue and enhance muscle endurance during high-intensity strength training.
... Creatine supplementation studies often administer creatine at doses around 20-25 g·d −1 during the loading phase (43) and about 3-5 g·d −1 during the maintenance phase (44). In this study, the amount of creatine supplemented was 5 g daily, with no higher-dose loading phase (10,45). It is possible that creatine-induced increases in TBW would not have been detected in the early weeks of this study, but perhaps changes in TBW may have been appreciated toward the end of the 10 wk as a result of increased intramuscular water content. ...
Introduction:
Resistance exercise training (RET) induces muscle hypertrophy that, when combined with co-temporal protein ingestion, is enhanced. However, fewer studies have been conducted when RET is combined with multi-ingredient supplements.
Purpose:
We aimed to determine the effect of a high-quality multi-ingredient nutritional supplement (SUPP) versus an isonitrogenous (lower protein quality), isoenergetic placebo (PL) on RET-induced gains in lean body mass (LBM), muscle thickness and muscle cross-sectional area (CSA). We hypothesized that RET-induced gains in lean body mass (LBM) and muscle CSA would be greater in SUPP versus PL.
Methods:
In a double-blind randomized controlled trial, twenty-six (13 male, 13 female) healthy young adults (22 ± 2 years [mean ± SD]) were randomized to either the SUPP group (n=13; 20g whey protein, 2g leucine, 2.5g creatine monohydrate, 300 mg calcium citrate, 1000 IU vitamin D) or the PL group (n=13; 20g collagen peptides, 1.4 g alanine, 0.6 g glycine) groups, ingesting their respective supplements twice daily. Measurements were obtained before and after a 10-week linear progressive RET program.
Results:
Greater increases in LBM were observed for SUPP versus PL (SUPP: +4.1 ± 1.3kg, PL: +2.8 ± 1.7kg, p<0.05). No additive effect of the supplement could be detected on vastus lateralis muscle CSA, but SUPP did result in increased biceps brachii muscle CSA and thickness (p<0.05).
Conclusion:
We conclude that when combined with RET, the consumption of SUPP increased lean body mass and upper body cross-sectional area and thickness to a greater extent than to that observed in the PL group of healthy young adults.
... Increased strength on bench press after CR supplementation was mentioned in some of the papers (Amirsasan et al., 2018;Vilar-Neto et al., 2018;Bjelica et al., 2020;Mills et al., 2020). Other research demonstrated similar improvements in bench press performances (Camic et al., 2014;Kilduff et al., 2002;Rawson & Volek, 2003). Regardng sports which require combination of aerobic and anaerobic sources with participation of strength and endurance, fatigue may occur and hence efficiency reduces. ...
Creatine has become highly popular supplement among athletes. Contemporary research also suggests that there is also a large number of potential therapeutic applications of creatine. Aim of this systematic overview is to test the effects of CR to muscle strength and body composition on the basis of the collected data and analysed papers published in the period 2018–2020. Literature research was performed in the following data bases: PubMed, Scholar Google and DOAJ. Papers were selected according to multiple criteria and they suggest that CR in combination with an exercise program produces results in increase of muscle mass and strength and it reduces time required for execution of a specific activity. Changes in body composition were observed in increase of total mass and muscle mass, as well as amount of water in body composition. Use of CR in amount of 10–20 g per day and frequency of 4–5 days a week is an efficient tool used for increase in sport performances and positive changes in body composition.
... 90 Furthermore, supplementation with vitamin D, creatine, and other pharmacologic interventions has been investigated over the years, with conflicting evidence due to the large variability of dose of supplementation used and population investigated and discussed at length elsewhere. [91][92][93][94][95][96][97][98][99][100] A major concern of most dietary intervention studies relies on the fact the clinical trials were typically of short duration and of limited sample size, ultimately preventing the determination of the effects on clinical outcomes. Considering the major role of MusS in modifying CV risk, however, we could speculate that dietary interventions resulting in improved MusS have the potential to improve clinical outcomes. ...
This review discusses the associations of muscular strength (MusS) with cardiovascular disease (CVD), CVD-related death, and all-cause mortality, as well as CVD risk factors, such as metabolic syndrome, diabetes, obesity, and hypertension. We then briefly review the role of resistance exercise training in modulating CVD risk factors and incident CVD.The role of MusS has been investigated over the years, as it relates to the risk to develop CVD and CVD risk factors. Reduced MusS, also known as dynapenia, has been associated with increased risk for CVD, CVD-related mortality, and all-cause mortality. Moreover, reduced MusS is associated with increased cardiometabolic risk. The majority of the studies investigating the role of MusS with cardiometabolic risk, however, are observational studies, not allowing to ultimately determine association versus causation. Importantly, MusS is also essential for the identification of nutritional status and body composition abnormalities, such as frailty and sarcopenia, which are major risk factors for CVD.
... The differences in dietary preferences between men and women may result from different dietary requirements of both sexes. For men, meat consumption may have a specific nutritional value (e.g., [106][107][108]). Women, on the other hand, may need a plant-based diet, which is high in specific carbohydrates responsible for the storage of excess energy as fat (e.g., [109][110][111]). ...
Limiting meat consumption has recently become one of the key issues linked to public health and environmental sustainability. This is reflected in the strong emphasis on increasing promotion of plant-based nutritional styles, such as vegan and vegetarian diets. Vegan/vegetarian diets appeal to certain demographic groups more than to others. The most striking difference, however, is found between the sexes. Men and women differ in their preferences for plant products and in their attitudes to meat consumption. There are also differences between their motivations to start and/or follow a vegan/vegetarian diet. Major differences have also been observed in men's and women's attitudes towards people following plant-based diets. Vegetarian diets are generally considered to be less masculine than meat-based diets, and omnivores exhibit more prejudice against vegetarian men than women. This study follows the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) systematic literature review model. The Web of Science and PubMed databases were searched (up to January 2020) to identify studies, which analysed variables directly or indirectly related to inter-sex differences with regard to the vegan/vegetarian diet. After the screening process based on the relevance and quality criteria, 29 articles were included in the study. The purpose of this review is to raise awareness of these gender differences, not only as regards social perceptions, but also in terms of individual attitudes to vegetarian/vegan diets. Ignoring those differences hinders the promotion of plant-based diets and may explain the relatively meager success of previous efforts to promote sustainable nutritional styles.
... The overall lack of improvement in peak power, average power, and fatigue index after 7 days of oral creatine supplementation irrespective of transdermal treatment was unexpected Table 5 Average power (W) outputs pre and post 7-day administration.* because most research supports the efficacy of orally consumed creatine in both sexes (1,2,16,22,23,28,33). Despite this, improvements in muscular power in the current study were only observed in the limbs of male subjects that had been topically loaded with the transdermal cream. ...
Whinton, AK, Donahoe, K, Gao, R, Thompson, KMA, Aubry, R, Saunders, TJ, Johnston, A, Chilibeck, PD, and Burr, JF. Repeated application of a novel creatine cream improves muscular peak and average power in male subjects. J Strength Cond Res 34(9): 2482-2491, 2020-Using a multicenter, randomized controlled trial, (N = 123, age 23 ± 4 years) we sought to determine whether administration of a novel, topical creatine supplement could improve muscular performance after acute and repeated (7-day) exposure. To study the acute performance enhancing effects of the supplement, subjects completed 5 sets of 15 maximal concentric single-leg knee extensions with and without the application of a low- (low dose [LD]-3.5 ml) or high-dose (high dose [HD]-7 ml) topical creatine cream. After a wash-out period, subjects had one leg randomized to receive either the creatine or placebo cream, with further randomization into an oral creatine or placebo supplement group. Subjects completed 5 sets of 15 maximal concentric single leg knee extensions before and after the supplementation protocol. After acute application, no significant differences in peak power (LD: 252 ± 93 W, HD: 261 ± 100 W, p = 0.21), average power (LD: 172 ± 65 W, HD: 177 ± 69 W, p = 0.78), or fatigue index (LD: 13.4 ± 10.6%, HD: 14 ± 11.9%, p = 0.79) were observed between experimental and placebo creams (peak power: LD: 244 ± 76 W, HD: 267 ± 109 W; average power: LD: 168 ± 57 W, HD: 177 ± 67 W; fatigue index: LD: 12.4 ± 9.6%, HD: 12.8 ± 10.6%) or when controlling for sex. After the 7-day supplementation protocol, a significant increase in average power (creatine: 203 ± 61-220 ± 65 W, placebo: 224 ± 61-214 ± 61 W) and peak power (creatine: 264 ± 73-281 ± 80 W, placebo: 286 ± 79-271 ± 73 W) in the leg receiving creatine cream was observed in male subjects. No differences were observed in female subjects. The topical creatine cream did not enhance measures of muscle performance after acute application, but was able to improve peak and average power in male subjects after 7 consecutive days of application.
... The greater increase in muscle strength ( Figure 2) and endurance ( Figure 3) from creatine supplementation supports the findings of several meta-analyses and review articles [4,[20][21][22][23]. While the mechanistic actions of creatine were not measured in this study, creatine supplementation has been shown to increase intramuscular PCr levels which may have accelerated ATP resynthesis and/or PCr recovery following each set. ...
The purpose was to examine the effects of creatine supplementation during resistance training sessions on skeletal muscle mass and exercise performance in physically active young adults. Twenty-two participants were randomized to supplement with creatine (CR: n = 13, 26 ± 4 yrs; 0.0055 g·kg−1 post training set) or placebo (PLA: n = 9, 26 ± 5 yrs; 0.0055 g·kg−1 post training set) during six weeks of resistance training (18 sets per training session; five days per week). Prior to and following training and supplementation, measurements were made for muscle thickness (elbow and knee flexors/extensors, ankle plantarflexors), power (vertical jump and medicine ball throw), strength (leg press and chest press one-repetition maximum (1-RM)) and muscular endurance (one set of repetitions to volitional fatigue using 50% baseline 1-RM for leg press and chest press). The creatine group experienced a significant increase (p < 0.05) in leg press, chest press and total body strength and leg press endurance with no significant changes in the PLA group. Both groups improved total body endurance over time (p < 0.05), with greater gains observed in the creatine group. In conclusion, creatine ingestion during resistance training sessions is a viable strategy for improving muscle strength and some indices of muscle endurance in physically active young adults.
... Tras un periodo de suplementación de 5 días de carga y 30-90 días de mantenimiento, los valores de creatina en el organismo humano pueden quedar elevados hasta 30 días o más una vez suspendida la toma 308 . ...
... Although the specific composition of MIPS varies, the primary ingredients frequently include creatine monohydrate, caffeine, beta-alanine (BA), and branched-chain amino acids (BCAAs) (36). Both individually (15,37) and in combination (along with the addition of other ingredients such as caffeine and leucine) (41), BA and creatine monohydrate are known to elicit muscle strength increases when combined with a resistance training program in trained (15) and untrained (41) individuals. ...
... The effects of creatine supplementation on resistance training and subsequent gains in strength and muscle hypertrophy have been extensively investigated ( 110 ). ...
... Two of three muscular strength measurements, bench press and squat, was also increased to a greater extant in males that supplemented with creatine + protein compared to those that received a placebo (9). Creatine supplementation during resistance training is more effective at increasing muscle strength and weightlifting performance than resistance training alone (10). ...
Creatine is one of the legal ergogenic aids which are used by athletes here and there. A number of studies assured that it has a positive effect in high intensity short duration intensity exercise performances. This study tried to evaluate the effect of creatine monohydrate supplements on muscle strength and muscle endurance. Twenty subjects (CG= 10 and EG= 10) were participated in three months of exercise training. In this study complete randomized design was used. The EG consumed creatine and the placebo (CG) used water 45 minutes before exercise. The results indicated that Muscle endurance was improved better in the EG. In curl up performance, the CG showed 35% change while the EG improved by 87%. In addition, 44% improvement in CG and 91% improvement in EG were recorded for push up performance. However, muscle strength was highly enhanced in the EG. In one repetition maximum test, the CG and EG shown 18% and 41% change, respectively. Bench press performance of the CG and EG were improved by 11% and 39%, respectively. Barbell squat performance was improved by 22% for the CG and 51% for the EG. Hence, supplementation of creatine is useful to improve both muscular strength and muscular endurance.
... Likewise, Cr supplementation with 0.03 g/kg/day (~2-3 g/day) will increase muscle Cr stores over a 3-4 weeks period [31]. These protocols are important since Cr levels in the human body can be elevated for up to 30 days [31,32]. Likewise, it has to be taken into to account that about 20-30% of individuals do not respond to Cr loading [33]. ...
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.
This research paper provides a comprehensive review of the effects of creatine supplementation on memory function. Creatine, a compound traditionally associated with muscle energy metabolism, has garnered attention for its potential cognitive benefits. The paper synthesizes findings from various studies exploring creatine’s impact on different types of memory, including short-term, long-term, and working memory, in healthy individuals and those with cognitive impairments. The review aims to clarify the conditions under which creatine supplementation may enhance memory performance by analyzing experimental designs, dosage variations, and participant demographics. Additionally, the paper discusses the underlying mechanisms, such as creatine’s role in cellular energy production and neuroprotection, which may contribute to its cognitive effects. The review concludes with recommendations for future research directions, highlighting the need for standardized protocols and long-term studies to fully understand creatine’s potential as a cognitive enhancer.
In this alphabetically arranged chapter, supplements from acarbose through creatine are discussed in detail. For each supplement, this chapter defines what it is and how it works in the body. Further, this chapter discusses the supplement’s recommended dosage as well as the evidence for or against its different usages. Safety concerns, side effects, and precautions are next discussed as well as any potential interactions with other medications. References are provided for the data provided. The goal is for the healthcare provider to be able to reference each supplement and come away with a full, balanced, evidence-based understanding of these topics.
Background/Objectives: Firefighters, tactical police officers, and warriors often engage in periodic, intermittent, high-intensity physical work in austere environmental conditions and have a heightened risk of premature mortality. In addition, tough decision-making challenges, routine sleep deprivation, and trauma exacerbate this risk. Therefore, identifying strategies to bolster these personnel’s health and occupational performance is critical. Creatine monohydrate (CrM) supplementation may offer several benefits to firefighters and tactical athletes (e.g., police, security, and soldiers) due to its efficacy regarding physical performance, muscle, cardiovascular health, mental health, and cognitive performance. Methods: We conducted a narrative review of the literature with a focus on the benefits and application of creatine monohydrate among firefighters. Results: Recent evidence demonstrates that CrM can improve anaerobic exercise capacity and muscular fitness performance outcomes and aid in thermoregulation, decision-making, sleep, recovery from traumatic brain injuries (TBIs), and mental health. Emerging evidence also suggests that CrM may confer an antioxidant/anti-inflammatory effect, which may be particularly important for firefighters and those performing tactical occupations exposed to oxidative and physiological stress, which can elicit systemic inflammation and increase the risk of chronic diseases. Conclusions: This narrative review highlights the potential applications of CrM for related tactical occupations, with a particular focus on firefighters, and calls for further research into these populations.
Creatine is consumed by athletes to increase strength and gain muscle. The aim of this study was to evaluate the effects of creatine supplementation on maximal strength and strength endurance. Twelve strength-trained men (25.2 ± 3.4 years) supplemented with 20 g Creatina + 10g maltodextrin or placebo (20g starch + 10g maltodextrin) for five days in randomized order. Maximal strength and strength endurance (4 sets 70% 1RM until concentric failure) were determined in the bench press. In addition, blood lactate, rate of perceived effort, fatigue index, and mood state were evaluated. All measurements were performed before and after the supplementation period. There were no significant changing in maximal strength, blood lactate, RPE, fatigue index, and mood state in either treatment. However, the creatine group performed more repetitions after the supplementation (Cr: Δ = +3.4 reps, p = 0.036, g = 0.53; PLA: Δ = +0.3reps, p = 0.414, g = 0.06), and higher total work (Cr: Δ = +199.5au, p = 0.038, g = 0.52; PLA: Δ = +26.7au, p = 0.402, g = 0.07). Creatine loading for five days allowed the subjects to perform more repetitions, resulting in greater total work, but failed to change the maximum strength.
Introdução: O uso de suplementos alimentares na musculação é uma prática comum entre praticantes em busca de maximizar os resultados do treinamento. Materiais e Métodos: Este artigo consistiu em uma revisão da literatura científica disponível sobre os suplementos alimentares mais utilizados na musculação. A seleção dos artigos foi baseada na atualidade e veracidade das informações, utilizando bancos de dados científicos como PubMed, Google Scholar e Scopus. Os termos de pesquisa incluíram "creatina", "whey protein", "BCAAs", "suplementos alimentares" e "musculação". Resultados e Discussão: Creatina: A creatina demonstrou consistentemente melhorar o desempenho físico e promover ganhos de massa muscular magra, com um perfil de segurança bem estabelecido. Whey Protein: O whey protein mostrou-se eficaz na recuperação muscular e na estimulação da síntese proteica muscular, contribuindo para o crescimento muscular. Aminoácidos de Cadeia Ramificada (BCAAs): Os BCAAs desempenham um papel importante na regulação da síntese proteica muscular, mas sua eficácia isolada na promoção do crescimento muscular pode ser limitada. Conclusão: Uma abordagem informada e baseada em evidências é essencial para otimizar os benefícios da suplementação na musculação, maximizando os resultados do treinamento enquanto se mantém a saúde e o bem-estar geral dos praticantes.
Background
The efficacy of creatine replacement through supplementation for the optimisation of physical function in the population at risk of functional disability is unclear.
Methods
We conducted a systematic literature search of MEDLINE, EMBASE, Cochrane Library and CINAHL until November 2022. Studies included were randomised controlled trials comparing the use of creatine supplementation with placebo in older adults and adults with chronic disease. The primary outcome was physical function measured by the sit-to-stand test after pooling data using random effects modelling. We also performed a Bayesian meta-analysis to describe the treatment effect in probability terms. Secondary outcomes included other measures of physical function, muscle function and body composition. The risk of bias was assessed using the Cochrane risk-of-bias tool.
Results
We identified 33 RCTs, comprising 1076 participants. From 6 trials reporting the primary outcome, the pooled standardised mean difference was 0.51 (95% CI 0.01 to 1.00; I2=62%; p=0.04); using weakly informative priors, the posterior probability that creatine supplementation improves physical function was 66.7%. Upper body muscle strength (SMD 0.25, 95% CI 0.06 to 0.44; I2=0%; p=0.01), handgrip strength (SMD 0.23, 95% CI 0.01 to 0.45; I2=0%; p=0.04) and lean tissue mass (MD 1.08kg; 95% CI 0.77 to 1.38; I2=26%; p<0.01) improved with creatine supplementation. The quality of evidence for all outcomes was low or very low due to a high risk of bias.
Conclusion
Creatine supplementation improves sit-to-stand performance, muscle function and lean tissue mass. It is crucial to conduct high-quality prospective RCTs to confirm these hypotheses (Prospero number, CRD42023354929).
Accepting a continued rise in the prevalence of vegan type diets in the general population is also likely to occur in athletic populations, it is of importance to assess the potential impact on athletic performance, adaptation and recovery. Nutritional consideration for the athlete requires optimisation of energy, macro- and micro- nutrient intakes, and potentially the judicious selection of dietary supplements, all specified to meet the individual athlete's training and performance goals. The purpose of this review is to assess whether adopting a vegan diet is likely to impinge on such optimal nutrition and, where so, consider evidence based yet practical and pragmatic nutritional recommendations. Current evidence does not support that a vegan-type diet will enhance performance, adaptation or recovery in athletes, but equally suggests that an athlete can follow a (more) vegan diet without detriment. A clear caveat, however, is that vegan diets consumed spontaneously, may induce suboptimal intakes of key nutrients, most notably quantity and/or quality of dietary protein and specific micronutrients (e.g., iron, calcium, vitamin B12 and vitamin D). As such, optimal vegan sports nutrition requires (more) careful consideration, evaluation and planning. Individual/seasonal goals, training modalities, athlete type, and sensory/cultural/ethical preferences, among other factors, should all be considered when planning and adopting a vegan diet.
Background:
An increase in intra-muscular creatine through supplementation has been proposed as a strategy for improving muscle performance and recovery, with studies showing some benefit for adult athletes who rely on short, explosive movements. We reviewed and summarized the current literature on creatine supplementation in a pediatric and adolescent population.
Methods:
The databases PubMed and EMBASE were queried to identity articles related to the use of creatine supplementation in a healthy pediatric and adolescent population according to the guidelines established by PRISMA. The abstracts of all articles were reviewed to determine relevancy, with those meeting the pre-defined criteria included in the final review.
Results:
A combined total of 9393 articles were identified. Following application of filters and review of abstracts, 13 articles were found to meet criteria and were included in the final review. There was a total of 268 subjects across all studies, with mean age ranging from 11.5 to 18.2 years. More than 75% of the studies were randomized-controlled trials, and 85% involved either soccer players or swimmers. The overall quality of the studies was poor, and there were no consistent findings regarding creatine supplementation and improvements in athletic performance. No studies were designed to address the topic of safety.
Conclusions:
There is a gap in the study of the safety and efficacy of creatine supplementation in adolescents. Additional studies are needed to evaluate the effects of alterations in muscle composition on the growth, development, and performance of the developing athlete. Orthopedic providers should counsel their pediatric and adolescent patients on the current limitations in trying to assess the true risk and benefit of creatine supplementation for the aspiring athlete.
Level of evidence:
Review, III.
Bu çalışma, adölesan voleybol oyuncularının beslenme bilgi düzeyleri, beslenme durumları ile sıvı tüketimlerine beslenme eğitiminin etkisinin saptanması amacıyla planlanmıştır. Araştırma, Türkiye Voleybol Federasyonu bünyesindeki TVF Proje takımında oynayan yaşları 15-17 arası olan 13 erkek profesyonel voleybol oyuncusu ile yapılmıştır. Araştırma kapsamında çalışmaya katılan adölesan sporculara 4 hafta boyunca haftada bir saat, sağlıklı beslenme ve sporcu beslenmesi konularında eğitim verilmiştir. Eğitimlerden önce çalışmaya katılan adölesan sporculardan genel bilgi alınmıştır. Sporculara eğitim öncesinde ve sonrasında besin tüketim sıklığı ve beslenme bilgi düzeyi formu ile 2 günlük fiziksel aktivite kayıt formu uygulanmıştır. Aynı şekilde eğitim öncesi ve sonrası olmak üzere voleybolcuların vücut ağırlığı ve boy uzunlukları ölçülmüştür. Ayrıca voleybolcuların vücut yağ yüzdeleri, vücut yağ kütleleri, yağsız doku kütleleri ve vücut sıvı kütleleri biyoelektirik impedans cihazı ile ölçülmüştür. Çalışmaya katılan voleybolcuların yaş ortalamaları 16.4±0.77 yıldır. Sporcuların profesyonel olarak voleybol oynama süreleri ortalama 5±3.54 yıldır. Voleybolcuların eğitim öncesi ortalama (Beden Kütle İndeksi) BKİ'leri 21.8±1.70 kg/m2 iken, eğitim sonrası 22.8±1.85 kg/m2 olarak değişmiştir (p<0.05).Voleybolcuların eğitim öncesi ortalama vücut yağ yüzdeleri %11.8±4.52 iken, eğitim sonrası %11.7±4.41 olarak değişmiştir (p>0.05). Sporcuların eğitim öncesi ortalama yağsız doku kütleleri 70.4±5.19 kg iken, eğitim sonrası 71.2±5.63 kg olarak değişmiştir (p>0.05). Voleybolcuların ortalama günlük total enerji gereksinimleri Harris-Benedict denklemine göre 3108.2±240.7 kkal, Schofield denklemine göre 3188.4±257.10 kkal olarak bulunmuştur. Voleybolcuların eğitim öncesi karbonhidratlardan gelen enerji yüzdeleri ortalama %47±6.59 iken eğitim sonrası %42.2±5.04 olarak bulunmuştur (p<0.05). Sporcuların eğitim öncesi ortalama protein alımları 108.1±41.08 g iken eğitim sonrası 136.1±29.73 g olarak saptanmıştır (p<0.05). Voleybolcuların enerjinin proteinden gelen oranlarının ortalaması eğitim öncesi %15.3±3.64 iken, eğitim sonrası %18.8±2.37 olarak belirlenmiştir (p<0.05). Sporcuların eğitim öncesi ortalama sükroz alımları 76.0±50.86 g iken eğitim sonrası 52.6±33.32 g'a azalmıştır (p<0.05). Eğitim öncesi fruktoz alımları da 21.2±13.89 g iken eğitim sonrası 12.9±6.29 g olarak belirlenmiştir (p<0.05). Eğitim sonrası ortalama B2, niasin ve B12 vitamini alımları artmıştır (p<0.05). Voleybolcuların süt ve süt ürünleri grubundan tükettikleri besinlerin ortalama miktarları eğitim öncesi 522.6±409.18 g iken eğitim sonrası 861.0±356.25 g olarak belirlenmiştir (p<0.05). Sporcuların et, balık, tavuk ve kurubaklagil grubundan tükettikleri besinlerin ortalama miktarları eğitim öncesi 155.0±75.06 g iken eğitim sonrası 202.3±53.11 g olarak artmıştır (p<0.05). Sporcuların ortalama su tüketimleri eğitim öncesi 1769.0±897.23 ml iken eğitim sonrası 2369.2±534.58 ml olarak artmıştır (p<0.05). Voleybolcuların beslenme bilgi düzeyi sorularına verdikleri doğru cevap sayısı eğitim öncesi 8.2±2.16 iken, eğitim sonrası 12.6±2.17'dir (p<0.05). Sonuç olarak 4 hafta boyunca haftada bir saat verilen beslenme eğitimi, adölesan voleybol oyuncularının beslenme bilgi düzeylerini anlamlı şekilde artırmış, besin tüketimlerinin olumlu yönde değişmesini sağlamıştır. Anahtar kelimeler: Adölesan, voleybol, beslenme, beslenme bilgi düzeyi, beslenme eğitimi Bu çalışma için Başkent Üniversitesi Tıp ve Sağlık Bilimleri Araştırma Kurulu tarafından KA16/339 nolu ve 30/11/2016 tarihli 'Etik Kurul Onayı' alınmıştır.
This study was planned to determine the effect of nutrition education program on nutrition knowledge, nutrition status and fluid intake of adolescent volleyball players. Research was conducted with 13 male professional volleyball players aged between 15 and 17, who were participant of TVF Project team in Turkish Volleyball Federation. Within the scope of the research, nutrition education including healthy diet and sport nutrition subjects, is provided to adolescent volleyball players for 1 hour per week along 4 weeks as an intervention. Before the intervention, general information related to the participants was collected. Before and after the intervention, food consumption frequency questionnaire, nutrition knowledge assessment and two-day physical activity form were applied by the researcher. Volleyball players' body weight and height ware measured. In the same way, body fat percentage, body fat mass, fat free mass and body water mass of the adolescent volleyball players were measured with bioelectrical impedance device. Mean age of the volleyball players was 16.46±0.776 years. As professionals, the players had been playing volleyball for 5±3.54 years in average. While the players' mean BMI was 21.8±1.70 kg/m2, after the intervention, it changed to 22.8±1.85 kg/m2 (p<0.05). Before the intervention, mean body fat percentage of the players was %11.8±4.52 and it changed to %11.7±4.41 after the intervention (p>0.05). While mean fat free mass of the players was 70.4±5.19 kg, it changed to 71.2±5.63 kg after the intervention. According to Harris-Benedict equation, mean energy requirement of the players was 3108.2±240.7 kcal and according to Schofield equation, it was 3188.4±257.10 kcal. It was found that the players' mean percentage of energy arising from carbohydrates was %47±6.59 before the intervention and that it was %42.2±5.04 after the intervention (p<0.05). It was detected that the mean protein intake of the players was 108.1±41.08 g before the intervention and that it was 136.1±29.73 g (p<0.05) after the intervention. While the players' mean percentage of energy arising from protein was %15.3±3.64, it was determined that it was %18.8±2.37 after intervention (p<0.05). It was designated that the players mean sucrose intake was 76.0±50.86 g before the intervention, and that it decreased to 52.6±33.32 g after the intervention (p<0.05). It was determined that the players' fructose intake was 21.2±13.89 g before the intervention, and it was 12.9±6.29 g after the intervention (p<0.05). While average niacin, B12, and B2 intake of the volleyball players increased when compared to before intervention (p<0.05). Average amount of dairy products that the volleyball players consumed was 522.6±409.18 g before the intervention and it increased to 861.0±356.25 g (p<0.05). It was designated that average amount of consumed nutrition from meat, fish, chicken and legume groups was 155.0±75.06 g before the intervention and it was 202.3±53.11 g after the intervention (p<0.05). While the average water intake of the players was 1769.0±897.23 ml before the intervention, it increased to 12.6±2.17 (p<0.05). As a result, providing 4-week nutrition education for one hour per week significantly increased nutrition knowledge of the adolescent volleyball players and it led dietary intake of the players to change in a positive way. Keywords: Adolescent, volleyball, nutrition, nutrition knowledge, nutrition education KA16/339 numbered and 30/11/2016 dated 'Ethics Committee Approval' is received by Başkent University Medical and Health Sciences Research Council.
Consumption of pre-workout supplements (PWS) has increased substantially in recent years. However, dosages of ingredients vary between manufacturers. Therefore, the aim of this study was to analyze ingredients from various products and to survey past and present (4 weeks) consumption behavior. Analysis of ingredients was performed in 30 products according to manufacturer's specifications. Subsequently, online questionnaire was used to assess reasons for taking, timing and dosing of PWS in 39 recreational athletes (4 females; 35 males; 25.15 ± 3.67 years). Most prevalent ingredients in PWS were caffeine, beta-alanine, L-citrulline, L-arginine, L-tyrosine, taurine and creatine. Average dosing per serving were 254mg caffeine (125-410 mg), 2513 mg beta-alanine (500-4000 mg), L-citrulline 3506 mg (500-8000 mg), L-arginine 2726 mg (500-8000 mg), L-tyrosine 1227 mg (150-3000 mg), taurine 1211 mg (90-2500 mg) and creatine 3031 mg (1000-5000 mg). Average values were in (63%) or below (36%) the recommended ergogenic dosage. Major motives for PWS use were improved concentration, increased blood flow and delayed onset of fatigue. Most subjects consumed PWS 1-3 times per month. In most cases consumption took place 15-30 min before training. Manufacturers' recommendations for consumption were generally followed. A large number of subjects (82%) reported minor side effects from PWS consumption (e. g. paresthesia, insomnia, headache). Based on current research only caffeine, L-citrulline, L-arginine and taurine show relevant direct performance-enhancing effects, while the benefit of beta-alanine, L-tyrosine and creatine in PWS seems highly questionable. Dosages of ingredients were safe, but often too low to increase performance.
Multiple studies have been conducted, many within the last 3-5 years, to develop a deeper understanding into how certain chemical substances enhance and improve certain aspects of our performance, both mental and physical. The successful synthesis, isolation and purification of such human performance enhancing substances have led to breakthroughs not only in the treatment of debilitating diseases such as Alzheimer’s and Parkinson’s disease, but also have a significant impact on endurance training. While the chief use of such performance enhancing agents is in the treatment of diseases like anaemia, depression, attention deficit and neurodegenerative disorders, such substances are also misused and sometimes abused in sport. This review highlights 6 major substances used as performance enhancers, namely, creatine, racetams, melatonin, caffeine, cholinergics and EPO. The six substances enhance different features of human performance. The chemistry of these substances, their chemical biology, methods of synthesis and latest data obtained from various clinical trials are discussed.
Currently, sport researchers try to identify the proper dietary supplements, that is essential for modern sports. Therefore, most professional athletes to maximize their performance, use these supplements. Creatine recognized as a supplement for enhancing the effectiveness of athletes. So, due to its widespread use among athletes, study of its possible positive or negative impact on the body is a necessity. The researcher in this study investigated the effect of short-term creatine supplementation on markers of cardiovascular risk factor after exhaustive exercise in elite karate athletes. For this purpose, 8 karate ka athletes (age 21.0±5.1 yr., weight 71.2±9.6 kg, height 180.4±4.7 cm) participated in the study, voluntarily. Study method was double-blind. Cardiovascular and respiratory data were gathered by incremental exercise test on treadmill with gas analyzer system and cardio screen at rest and Wingate test, before and after creatine supplementation. Data analysis was performed by SPSS software and repeated measure technique. Subjects consumed 20 grams of creatine or placebo per day for 5 days in 4 steps. Between the use of creatine or placebo supplement for 10 days was considered to body clean. The results showed that short-term creatine supplementation have desirable but non-significant effects on cardiovascular and respiratory function.
Background and Objectives: A few studies have conducted on the effect of protein and creatine supplementation combined with resistance training on the fitness, speed, and strength and muscle hypertrophy of untrained young women. The purpose of the present study was investigating the effect of whey protein, creatine supplements and resistance training on fitness, velocity and muscle hypertrophy in untrained young women. Materials and Methods: The present study was as a quasi-experimental. Thirty-sixth non-active healthy women (weight 61.39±5.92 kg, age 23.91±1.89 year) volunteered to participate in this research. They were randomly assign into three groups: Experimental group 1: Supplementation (protein 1260gr and creatine 450gr) + 6 weeks of strength training, Experimental group 2: placebo + 6 weeks of strength training, and control group. Duration of training was 6 weeks; 4 sessions per week, and each session lasted 50-70 minutes with the intensity of 60-75 percent of maximal reserve heart rate. Data analysis with use of inferential statistics (repeated ANOVA, and Bonferroni post hoc test, when necessary) and employing the SPSS software (version 18). Significance level of p≤0/05 considered. Results: No significant changes in speed, percent body fat, and maximum oxygen uptake have occurred. A significant increase has observed in the maximum power in both groups of supplementation and placebo, and there was a significant increase in the Supplementation group in the variables of weight, BMI and muscle hypertrophy compared to the pre-test and the control groups, as well as the placebo group compared to the pre-test group. The variables of power and muscular endurance have increased no significantly in both groups of supplementation and placebo. Conclusion: Strength training alone can increase power, but to further increase the strength, weight and hypertrophy in heavy exercises, long-term consumption of supplements of creatine and protein recommended. A greater undersetting of these pathways and consequences of concurrent consumption protein and creatine supplementation in females might certainly boost their performance and could use as a dietary supplement to optimize and enhance health outcomes for women.
Objectives
The production and sale of performance-enhancing drugs (PEDs) with annual increase in number and diversity have now become a beneficial industry. At present, there is a kind of creatine supplement, called as creatine hydrochloride (CHCL), which is claimed to have a much higher absorption compared to creatine monohydrate (CRM) supplementation and does not require a loading period. However, this claim has not been fully examined yet. Therefore, the present study aimed to compare the effects of two types of creatine (CHCL and CRM) on physical activity, plasma levels of testosterone (T), and cortisol (Cor) in trained young men.
Equipment and methods
The statistical population of this study included 36 healthy subjects selected by purposive sampling method and with at least six months of resistance training. The subjects were randomly divided into four groups (Group 1: 20 g of CRM, Group 2: 3 g of CRM, Group 3: 3 g of CHCl per day for a week, and Group 4: placebo). The supplements were given to subjects by double-blind manner. Physical performance variables were evaluated on the morning of the first day and before the supplementation, and blood samples (5 cc) were taken in fasting conditions (8–10 hours) to measure the plasma levels of T and Cor. The blood samples were taken again after seven days for physical performance measurements.
Results
The results showed that there were no significant differences between the effects of 3 and 20 g of CRM and 3 g of CHCL on the vigor, power, plasma levels of T and Cor, and T/C ratio. In other words, 3 g of CHCL did not result in improved performance and hormonal changes compared to 20 g of CRM.
Conclusion
According to the results, the multi-day period of supplementation with CHCL in comparison to CRM cannot have much effect on performance and improve the hormonal status of individuals in the short term.
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.
The purpose of this study was to examine the changes in bench press strength (BPS), vertical jump (VJ), 100 yd dash time, and fat-free weight (FFW) in football players following 8 weeks of supplementation with a carbohydrate placebo (CHO), creatine monohydrate (CM), or CM plus CHO. Using a double blind random design, 24 college football players were placed into one of three treatment conditions: CHO) 35g CHO; CM) 5.25g CM plus 1g CHO; or CM+CHO) 5.25g CM and 33g CHO. All treatments were similar in taste and were ingested four times per day for five consecutive days and twice daily thereafter. All subjects weight trained for 1 h and participated in 30 min of speed drills four times per week for 8 weeks. The CM+CHO group experienced significant (p<0.05) improvement in BPS, VJ, 100 yd dash time and FFW when compared to the CHO group. However, delta scores for the CM group were not significantly different from the CHO group. These data suggest that CHO taken with CM during training may be superior to training alone for enhancing exercise performance and FFW.
Nine male subjects performed two bouts of 30-s maximal isokinetic cycling before and after ingestion of 20 g creatine (Cr) monohydrate/day for 5 days. Cr ingestion produced a 23.1 +/- 4.7 mmol/kg dry matter increase in the muscle total creatine (TCr) concentration. Total work production during bouts 1 and 2 increased by approximately 4%, and the cumulative increases in both peak and total work production over the two exercise bouts were positively correlated with the increase in muscle TCr. Cumulative loss of ATP was 30.7 +/- 12.2% less after Cr ingestion, despite the increase in work production. Resting phosphocreatine (PCr) increased in type I and II fibers. Changes in PCr before exercise bouts 1 and 2 in type II fibers were positively correlated with changes in PCr degradation during exercise in this fiber type and changes in total work production. The results suggest that improvements in performance were mediated via improved ATP resynthesis as a consequence of increased PCr availability in type II fibers.
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.
To determine the effects of 28 d of creatine supplementation during training on body composition, strength, sprint performance, and hematological profiles.
In a double-blind and randomized manner, 25 NCAA division IA football players were matched-paired and assigned to supplement their diet for 28 d during resistance/agility training (8 h x wk[-1]) with a Phosphagen HP (Experimental and Applied Sciences, Golden, CO) placebo (P) containing 99 g x d(-1) of glucose, 3 g x d(-1) of taurine, 1.1 g x d(-1) of disodium phosphate, and 1.2 g x d(-1) of potassium phosphate (P) or Phosphagen HP containing the P with 15.75 g x d(-1) of HPCE pure creatine monohydrate (HP). Before and after supplementation, fasting blood samples were obtained; total body weight, total body water, and body composition were determined; subjects performed a maximal repetition test on the isotonic bench press, squat, and power clean; and subjects performed a cycle ergometer sprint test (12 x 6-s sprints with 30-s rest recovery).
Hematological parameters remained within normal clinical limits for active individuals with no side effects reported. Total body weight significantly increased (P < 0.05) in the HP group (P 0.85 +/- 2.2; HP 2.42 +/- 1.4 kg) while no differences were observed in the percentage of total body water. DEXA scanned body mass (P 0.77 +/- 1.8; HP 2.22 +/- 1.5 kg) and fat/bone-free mass (P 1.33 +/- 1.1; HP 2.43 +/- 1.4 kg) were significantly increased in the HP group. Gains in bench press lifting volume (P -5 +/- 134; HP 225 +/- 246 kg), the sum of bench press, squat, and power clean lifting volume (P 1,105 +/- 429; HP 1,558 +/- 645 kg), and total work performed during the first five 6-s sprints was significantly greater in the HP group.
The addition of creatine to the glucose/taurine/electrolyte supplement promoted greater gains in fat/bone-free mass, isotonic lifting volume, and sprint performance during intense resistance/agility training.
To investigate the effects of an oral creatine supplementation in older adults, 32 elderly subjects (67-80 years; 16 females, 16 males) were randomly assigned to four equivalent subgroups (control-creatine; control-placebo; trained-creatine; trained-placebo) based on whether or not they took part in an 8-week strength training programme and an 8-week oral creatine monohydrate creatine supplementation programme. The strength training programme consisted of three sets of eight repetitions at 80% of one-repetition maximum, for leg press, leg extension and chest press, 3 days a week. The 52-day supplementation programme consisted of 20 g of creatine monohydrate (or glucose) and 8 g of glucose per day for the initial 5 days followed by 3 g of creatine monohydrate (or glucose), and 2 g of glucose per day. Prior to and after the training and supplementation periods, body mass, body fat, lower limb muscular volume, 1-, 12-repetitions maxima and isometric intermittent endurance tests for leg press, leg extension and chest press were determined. In all groups, no significant changes in anthropometric parameters were observed. For all movements, the increases in 1- and 12-repetitions maxima were greater (P < 0.02) in trained than control subjects. No significant interactions (supplementation/training/time) were observed for the 1-, 12-repetitions maxima, and the isometric intermittent endurance, whatever the movement considered. We conclude that oral creatine supplementation does not provide additional benefits for body composition, maximal dynamical strength, and dynamical and isometric endurances of healthy elderly subjects, whether or not it is associated with an effective strength training.
We examined the effect of glycogen-depleting exercise on subsequent muscle total creatine (TCr) accumulation and glycogen resynthesis during postexercise periods when the diet was supplemented with carbohydrate (CHO) or creatine (Cr) + CHO. Fourteen subjects performed one-legged cycling exercise to exhaustion. Muscle biopsies were taken from the exhausted (Ex) and nonexhausted (Nex) limbs after exercise and after 6 h and 5 days of recovery, during which CHO (CHO group, n = 7) or Cr + CHO (Cr+CHO group, n = 7) supplements were ingested. Muscle TCr concentration ([TCr]) was unchanged in both groups 6 h after supplementation commenced but had increased in the Ex (P < 0.001) and Nex limbs (P < 0.05) of the Cr+CHO group after 5 days. Greater TCr accumulation was achieved in the Ex limbs (P < 0.01) of this group. Glycogen was increased above nonexercised concentrations in the Ex limbs of both groups after 5 days, with the concentration being greater in the Cr+CHO group (P = 0.06). Thus a single bout of exercise enhanced muscle Cr accumulation, and this effect was restricted to the exercised muscle. However, exercise also diminished CHO-mediated insulin release, which may have attenuated insulin-mediated muscle Cr accumulation. Ingesting Cr with CHO also augmented glycogen supercompensation in the exercised muscle.
Creatine (Cr) supplementation has become a common practice among professional, elite, collegiate, amateur, and recreational athletes with the expectation of enhancing exercise performance. Research indicates that Cr supplementation can increase muscle phosphocreatine (PCr) content, but not in all individuals. A high dose of 20 g x d(-1) that is common to many research studies is not necessary, as 3 g x d(-1) will achieve the same increase in PCr given time. Coincident ingestion of carbohydrate with Cr may increase muscle uptake; however, the procedure requires a large amount of carbohydrate. Exercise performance involving short periods of extremely powerful activity can be enhanced, especially during repeated bouts of activity. This is in keeping with the theoretical importance of an elevated PCr content in skeletal muscle. Cr supplementation does not increase maximal isometric strength, the rate of maximal force production, nor aerobic exercise performance. Most of the evidence has been obtained from healthy young adult male subjects with mixed athletic ability and training status. Less research information is available related to the alterations due to age and gender. Cr supplementation leads to weight gain within the first few days, likely due to water retention related to Cr uptake in the muscle. Cr supplementation is associated with an enhanced accrual of strength in strength-training programs, a response not independent from the initial weight gain, but may be related to a greater volume and intensity of training that can be achieved. There is no definitive evidence that Cr supplementation causes gastrointestinal, renal, and/or muscle cramping complications. The potential acute effects of high-dose Cr supplementation on body fluid balance has not been fully investigated, and ingestion of Cr before or during exercise is not recommended. There is evidence that medical use of Cr supplementation is warranted in certain patients (e.g.. neuromuscular disease); future research may establish its potential usefulness in other medical applications. Although Cr supplementation exhibits small but significant physiological and performance changes, the increases in performance are realized during very specific exercise conditions. This suggests that the apparent high expectations for performance enhancement, evident by the extensive use of Cr supplementation, are inordinate.
The purpose of this investigation was to examine the effects of 6 wk of oral creatine supplementation during a periodized program of arm flexor strength training on arm flexor IRM, upper arm muscle area, and body composition.
Twenty-three male volunteers with at least 1 yr of weight training experience were assigned in a double blind fashion to two groups (Cr, N = 10; Placebo, N = 13) with no significant mean pretest one repetition maximum (IRM) differences in arm flexor strength. Cr ingested 5 g of creatine monohydrate in a flavored, sucrose drink four times per day for 5 d. After 5 d, supplementation was reduced to 2 g x d(-1). Placebo ingested a flavored, sucrose drink. Both drinks were 500 mL and made with 32 g of sucrose. IRM strength of the arm flexors, body composition, and anthropometric upper arm muscle area (UAMA) were measured before and after a 6-wk resistance training program. Subjects trained twice per week with training loads that began at 6RM and progressed to 2RM.
IRM for Cr increased (P < 0.01) from (mean +/- SD) 42.8 +/- 17.7 kg to 54.7 +/- 14.1 kg, while IRM for Placebo increased (P < 0.01) from 42.5 +/- 15.9 kg to 49.3 +/- 15.7 kg. At post-test IRM was significantly (P < 0.01) greater for Cr than for Placebo. Body mass for Cr increased (P < 0.01) from 86.7 +/- 14.7 kg to 88.7 +/- 13.8 kg. Fat-free mass for Cr increased (P < 0.01) from 71.2 +/- 10.0 kg to 72.8 +/- 10.1 kg. No changes in body mass or fat-free mass were found for Placebo. There were no changes in fat mass and percent body fat for either group. UAMA increased (P < 0.01) 7.9 cm2 for Cr and did not change for Placebo.
Creatine supplementation during arm flexor strength training lead to greater increases in arm flexor muscular strength, upper arm muscle area, and fat-free mass than strength training alone.
This study investigated the effect of creatine supplementation in conjunction with protein and/or carbohydrate (CHO) ingestion on plasma creatine and serum insulin concentrations and whole body creatine retention. Twelve men consumed 4 x 5 g of creatine on four occasions in combination with 1) 5 g of CHO, 2) 50 g of protein and 47 g of CHO, 3) 96 g of CHO, or 4) 50 g of CHO. The increase in serum insulin was no different when the protein-CHO and high-CHO treatments were compared, but both were greater than the response recorded for the low-CHO treatment (both P < 0.05). As a consequence, body creatine retention was augmented by approximately 25% for protein-CHO and high-CHO treatments compared with placebo treatment. The areas under creatine- and insulin-time curves were related during the first oral challenge (r = -0.920, P < 0.05) but not after the fourth (r = -0.342). It is concluded, first, that the ingestion of creatine in conjunction with approximately 50 g of protein and CHO is as effective at potentiating insulin release and creatine retention as ingesting creatine in combination with almost 100 g of CHO. Second, the stimulatory effect of insulin on creatine disposal was diminished within the initial 24 h of supplementation.
A survey was used to collect anonymous cross-sectional data on demographics, exercise habits, and use of creatine and other supplements by exercisers in civilian (C) and military (M) health clubs. M (n = 133) reported more aerobic training and less use of creatine and protein supplements than C (n = 96, p <.05). Supplement users (SU, n = 194) and nonusers (SNU, n = 35) engaged in similar frequency and duration of aerobic exercise, as well as number of resistance exercise repetitions, but SU completed more sets for each resistance exercise (x- +/- SE, 5 +/- 1) than SNU (3 +/- 1, p < or =.05). Significant (p < or =.05) associations were observed between SU and resistance training goal of strength (as opposed to endurance), as well as greater frequency of resistance training. Male gender, resistance training goal of strength, lower frequency and duration of aerobic training, and use of protein, b-hydroxy-b-methyl butyrate, and androstenedione/dehydroepiandrosterone supplements were all associated with creatine use (p <.05). For creatine users, the dose and length of creatine supplementation was 12.2 +/- 2.7 g.day-1 for 40 +/- 5 weeks. Popular magazines were the primary source of information on creatine (69%) compared to physicians (14%) or dietitians (10%, p < or =.0001). This study underscores two potential public health concerns: (a) reliance on popular media rather than allied-health professionals for information on creatine, and (b) use of creatine, a popular supplement with unknown long-term effects, in combination with other anabolic supplements of questionable efficacy and/or safety.
This study was conducted to investigate the effects of giving short-term doses of creatine by mouth to healthy older male subjects, taking into account their training status. A group of 42 volunteers was divided into three: a sedentary group composed of elderly sedentary men [n = 14, mean age 70.1 (SEM 1.2) years], a trained group composed of elderly trained cyclists [n = 14, mean age 66.4 (SEM 1.4) years] and a young group composed of young sedentary men [n = 14, mean age 26.0 (SEM 1.2) years]. In each group, double-blind randomization was carried out: one half was given creatine (3x5 g x day(-1)), and the other was given an iso-nitrogenated placebo (3x10 g x day(-1)). Before and after the 5 days during which the supplements were given, all subjects performed five all-out 10-s sprints separated by 60-s intervals of passive recovery, seated on a cycle ergometer. Power output, work done and heart rate data were recorded during each sprint. The elderly and the young sedentary subgroups given creatine showed significant (P < 0.05) improvements in maximal power (+3.7% and +2.0%, respectively) and work done (+4.1% and +5.1%, respectively) in the subsequent tests. In contrast, no significant change in pedalling performances was observed in the trained elderly subjects. The creatine did not change the exercise and recovery heart rate profiles, in any group. Our study suggested that creatine given by mouth increases the anaerobic power and work capacity of sedentary people of different ages during maximal pedalling tasks. However, the level of physical activity seems to be a determinant of the ergogenic effect of creatine in older subjects.
Creatine monohydrate (CrM) supplementation during resistance exercise training results in a greater increase in strength and fat-free mass than placebo. Whether this is solely due to an increase in intracellular water or whether there may be alterations in protein turnover is not clear at this point. We examined the effects of CrM supplementation on indexes of protein metabolism in young healthy men (n = 13) and women (n = 14). Subjects were randomly allocated to CrM (20 g/day for 5 days followed by 5 g/day for 3-4 days) or placebo (glucose polymers) and tested before and after the supplementation period under rigorous dietary and exercise controls. Muscle phosphocreatine, creatine, and total creatine were measured before and after supplementation. A primed-continuous intravenous infusion of L-[1-(13)C]leucine and mass spectrometry were used to measure mixed-muscle protein fractional synthetic rate and indexes of whole body leucine metabolism (nonoxidative leucine disposal), leucine oxidation, and plasma leucine rate of appearance. CrM supplementation increased muscle total creatine (+13.1%, P < 0.05) with a trend toward an increase in phosphocreatine (+8.8%, P = 0.09). CrM supplementation did not increase muscle fractional synthetic rate but reduced leucine oxidation (-19.6%) and plasma leucine rate of appearance (-7.5%, P < 0.05) in men, but not in women. CrM did not increase total body mass or fat-free mass. We conclude that short-term CrM supplementation may have anticatabolic actions in some proteins (in men), but CrM does not increase whole body or mixed-muscle protein synthesis.
This study examined the effects of 26 days of oral creatine monohydrate (Cr) supplementation on near-maximal muscular strength, high-intensity bench press performance, and body composition. Eighteen male powerlifters with at least 2 years resistance training experience took part in this 28-day experiment. Pre and postmeasurements (Days 1 and 28) were taken of near-maximal muscular strength, body mass, and % body fat. There were two periods of supplementation: Days 2 to 6 and Days 7 to 27. ANOVA and t-tests revealed that Cr supplementation significantly increased body mass and lean body mass with no changes in % body fat. Significant increases in 3-RM strength occurred in both groups, both absolute and relative to body mass; the increases were greater in the Cr group. The change in total repetitions also increased significantly with Cr supplementation both in absolute terms and relative to body mass, while no significant change was seen in the placebo (P) group. Creatine supplementation caused significant changes in the number of BP reps in Sets 1, 4, and 5. No changes occurred in the P group. It appears that 26 days of Cr supplementation significantly improves muscular strength and repeated near-maximal BP performance, and induces changes in body composition.
Purpose:
To study the effect of creatine (Cr) supplementation combined with resistance training on muscular performance and body composition in older men.
Methods:
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.
Results:
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.
Conclusion:
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.
The use of creatine monohydrate supplementation by athletes to increase strength and lean body mass has great anecdotal support. There has also been great interest in the use of lower doses of creatine monohydrate for extended periods during heavy resistance training. The purpose of this investigation was to document the long-term effects of creatine monohydrate supplementation on resistance-trained athletes. Sixteen collegiate football players were randomly separated into creatine monohydrate and placebo groups. Supplementation in capsule form consisted of 5 g/d of creatine mono-hydrate or placebo (no loading phase) throughout a 10-week supervised resistance training program. Pretesting and post-testing consisted of the following: weight; body fat estimation; 1 repetition maximum bench press, squat, and power clean; and Cybex testing. Results revealed the creatine monohydrate group was able to significantly increase measures of strength and power and increase body mass without a change in percent body fat, whereas the placebo group showed no significant changes. The results indicate that 10 weeks of creatine monohydrate supplementation while participating in a resistance training program significantly increases strength and power indices compared with placebo supplementation. These data also indicate that lower doses of creatine monohydrate may be ingested (5 g/d), without a short-term, large-dose loading phase (20 g/d), for an extended period to achieve significant performance enhancement.
(C) 1999 National Strength and Conditioning Association
Sixteen collegiate women lacrosse players consumed either creatine (C, n = 7) or a placebo (P, n = 9) for 5 weeks during their preseason conditioning program (20 g [middle dot] d-1 for 1 week and 2 g [middle dot] d-1 for 4 weeks). Pre-and posttesting consisted of body composition, muscle endurance test, blood lactate response to the endurance test, 1 repetition maximum (1RM) bench press and leg extension, and blood glutamyltransferase (GGL) and blood urea nitrogen (BUN). Testing revealed that 1RM bench press significantly increased in both groups, with the C group improving significantly more than the P group (6.2 +/- 2.0 and 2.8 +/- 1.8 kg). Percent body fat by skin-fold decreased significantly more in C than the P group (-1.2 +/- 0.9 and 0.3 +/- 0.8), but was not different by group by hydrodensitometry. No significant differences between groups were found for all other measures, but significant time effects were noted for body weight gain (0.5 +/- 3.2 kg), 1RM leg extension (1.4 +/- 4.1 kg), BUN (0.07 +/- 0.03 mmol [middle dot] L-1), total work during the muscle endurance test (283.5 +/- 387.3 watts), and fat-free mass by skinfold (0.7 +/- 1.2 kg). In summary, a regime of dietary creatine supplementation significantly improved upper-body strength gain and decreased the percent body fat as assessed by skinfold in women athletes engaged in a resistance-training program.
(C) 2000 National Strength and Conditioning Association
A self-administered questionnaire examining creatine monohydrate (Cr[middle dot]H2O) use was sent to 82 elite Australian power lifters, of which 61% (n = 50) questionnaires were returned. Ninety-six percent of respondents (n = 48) were aware of Cr[middle dot]H2Q. Seventy-four percent (n = 37) identified themselves as current or former users, and 26% (n = 13) as nonusers. Power lifters agreed that Cr[middle dot]H2O improved the quality of their training and competitive performance. An increase in body mass was the most common side effect. Seventy percent of users (n = 26) reported a cyclic method of intake, 14% (n = 5) reported a regular intake, and 16% (n = 6) reported an intermittent intake. Cyclic users displayed a median of 5.8 and 38.5 days for the loading and maintenance phases, respectively. During the loading phase, cyclic users reported a median loading dose of 5 g. During the maintenance phase, cyclic users reported a mean of 6.0 +/- 2.4 g per dose. This study has found that awareness and use of Cr[middle dot]H2O is widespread among elite Australian power lifters and that most use a cyclic method of Cr[middle dot]H2O administration.
(C) 2000 National Strength and Conditioning Association
This study compared the effects of different dosages of creatine relative to fat free mass on strength, % body fat, body mass (BM), fat free mass (FFM), 40-yd dash time, and vertical jump (VJ) height. In a true experimental double-blind design, 39 male college athletes were given either 5 g creatine mono-hydrate or a placebo 4 times a day for 5 days. For the rest of the 8 weeks they were given either a placebo or 100 or 300 mg * kg-1 FFM of creatine. During this period all subjects undertook a conditioning program 4 times a week emphasizing weight training and speed drills. Pre- and posttesting was conducted on all 6 variables. Both experimental groups had significant improvements in the bench press; the group ingesting 300 mg * kg-1 FFM of creatine improved significantly more than the control group (p < 0.05). Forty-yard dash improvement was significantly better as a result of ingesting 100 mg * kg-1 FFM of creatine compared to the control group. Only the 100-mg group significantly improved 40-yd time. No significant differences among groups were noted in BM, % body fat, FFM, or VJ. In conclusion, ingestion of 100 or 300 mg * kg-1 FFM of creatine for 8 weeks in conjunction with weight training and speed training significantly improved 40-yd dash time and bench press strength, respectively.
(C) 1998 National Strength and Conditioning Association
We investigated the effects of creatine (Cr) supplementation on muscle strength and body composition during 13 weeks of training in female collegiate soccer players. Fourteen athletes were randomly assigned to receive either Cr supplementation (7.5 g, 2 times a day for 1 week and 5 g per day thereafter) or placebo dissolved in a fluid-replacement beverage. Baseline measurements were made 1-2 weeks before and at 5 and 13 weeks after beginning supplementation. The Cr group demonstrated greater improvements in bench press and full-squat maximal strength (the trial by group interaction) compared with the placebo group, which were significantly different between baseline and 5 weeks for the bench press and between 5 and 13 weeks for the full squat. Fat-and bone-free lean masses measured by dual-energy x-ray absorptiometry increased with training (main effect) but were not enhanced by Cr supplementation. These results suggest that female soccer players increase strength as well as lean tissue during off-season training. Cr supplementation, however, appears to be associated with significantly greater increases in muscle strength but not lean tissue.
(C) 2000 National Strength and Conditioning Association
The use of creatine as an ergogenic aid for athletic performance is growing in popularity, despite limited scientific support for its efficacy. The purpose of this study was to determine the effect of creatine (Cr) monohydrate (CrM) and creatine phosphate (CrP) supplementation on strength, body composition, and blood pressure over a 6-week period. Thirty-five males (age range = 19-29 years) with at least 2 years of strength training experience were tested on three separate occasions (pretest, 3 weeks, 6 weeks). Strength tests performed were the one-repetition maximum (1-RM) bench press, 1-RM leg press, and maximal repetitions on the seated preacher bar curl with a fixed amount of weight. Subjects were divided into three groups matched for strength: placebo (Pl), CrM, and CrP. All subjects were provided a standardized strength training regimen and ingested a loading dosage of 20 g per day for the first 3 days of the study, followed by a maintenance dose of 10 g per day for the remainder of the 6-week supplementation period. Significant differences were noted between the Pl group and the two Cr groups for changes in lean body mass, body weight, and 1-RM bench press. These results suggest that oral Cr supplementation will result in greater strength and fat-free mass development. In addition, CrP may be as effective as CrM in achieving these desired outcomes.
(C) 1999 National Strength and Conditioning Association
Twenty-one men (20-26 years old) were randomly assigned to one of 3 groups: an acute creatine monohydrate (Cr) 5-day load and maintenance placebo (AL); an acute Cr 5-day load and 32-day maintenance dose (ALM), and a placebo group (PL). The AL and ALM groups received Cr dissolved in a flavored drink at a dosage of 0.3g[middle dot]kg-1[middle dot]d-1 for 5 days for the acute load and the ALM group ingested Cr at 0.03g[middle dot]kg-1[middle dot]d-1 for the maintenance phase. The PL group ingested the drink only. While supplementing, all groups participated in a periodized resistance training program performing the same relative load and volume of training regardless of their assigned experimental group. Bench press (BP) and incline leg press (ILP) absolute strength (1 repetition maximum [1RM]), total lifting volume (80% of 1RM to failure), and strength per mass ratio were assessed initially (T1), after a 5-day acute load (T2), and following the 32-day maintenance phase (T3). No differences were observed in 1RMs, total lifting volume, or strength per mass ratio between experimental groups over time except in the AL group, which showed a significant improvement in the total lifting volume for BP after the acute Cr load. All groups significantly improved 1RM, total lifting volume, and strength per mass ratio from T1 to T3, with no changes observed from T1 to T2 in BP and ILP. The findings suggest that Cr supplementation combined with resistance training when relative loads and volumes are the same as a placebo group does not result in a training advantage in absolute or relative strength performance.
(C) 2000 National Strength and Conditioning Association
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.
The purpose of this study was to determine if using a new form of creatine monohydrate (Phosphagems -EAS) could increase muscular strength and favorably alter body composition. Twenty-seven college-aged Ss were randomly placed into a placebo or creatine group. Subjects in the creatine group were required to ingest 20 grams maintenance of the supplement for 5 days (loading phase) and 5 grams everyday thereafter (phase), while the placebo group took an identical looking and tasting product. The supplement or placebo was distributed in a double-blind protocol. Ss performed 1 RMs for the bench press and squat, and body composition was measured using hydrostatic weighing before and after supplementation/training. For the training program, both groups participated in a 6 week, 4 day split, resistance training program. Supplementation began the first week of the resistance program. The posttests were performed the week following the completion of the resistance program. Data were analyzed using a 2-way ANOVA with repeated measures and a Tukey's post hoc test. Both groups increased significantly (p < .05) in bench press and squat strength. The placebo group increased 22.9 lbs in the bench press and 59.6 lbs in the squat, while the creatine group increased 30.0 lbs in the bench press and 46.2 lbs in the squat in 6 weeks. Differences between groups were not statistically significant (p > .05). Total body and lean body weight increased significantly in the creatine group only (p < .05). Total body weight increased 5.4 lbs, with 4.8 lbs being lean body weight. No changes were found in % body fat or fat weight in either group. The results of this study indicate that creatine monohydrate does not improve muscular strength and/or body composition. However, the results of this research suggest that through a scientifically sound resistance training program, significant strength gains will occur along with slight improvements in body composition. Further research with the effects of creatine supplementation on muscular strength and body composition is needed.
The time course of phosphorylcreatine (PC) resynthesis in the human m. quadriceps femoris was studied during recovery from exhaustive dynamic exercise and from isometric contraction sustained to fatigue. The immediate postexercise muscle PC content after either form of exercise was 15–16% of the resting muscle content. The time course of PC resynthesis during recovery was biphasic exhibiting a fast and a slow recovery component. The half-time for the fast component was 21–22 s but this accounted for a smaller fraction of the total PC restored during recovery from the isometric contraction than after the dynamic exercise. The half-time for the slow component was in each case more than 170 s. After 2 and 4 min recovery the total amounts of PC resynthesized after the isometric exercise were significantly lower than from the dynamic exercise.
Occlusion of the circulation to the quadriceps completely abolished the resynthesis of PC. Restoration of resynthesis occurred only after release of occlusion.
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.
1. A method is described enabling the determination of fat, water, electrolytes, protein, DNA, RNA and total creatine in a single sample of human muscle obtained by the percutaneous needle-biopsy technique. The amino acid content can also be analysed in the same muscle sample.
2. Fifty healthy subjects were studied: 29 between 19 and 40 years of age, 11 between 41 and 60 years of age, and 10 between 61 and 85 years of age. The two groups aged less than 60 years showed only marginal differences in muscle composition, whereas the highest age group showed increases in muscle fat content in relation to tissue weight and decreases in alkali-soluble protein content in relation to both tissue weight and tissue DNA content. Also, potassium, magnesium, total creatine and RNA contents were decreased in this age group when related to tissue DNA content. When alkali-soluble protein was used as a reference base, only magnesium content was decreased.
3. A comparison was also made between female (n = 23) and male (n = 18) subjects in the age groups below 60 years. Differences observed included a higher fat content in female muscle, and an increase in total creatine content in relation to tissue weight. The alkali-soluble protein content was lower per muscle cell in the females when calculated on the basis of DNA content.
4. The results show that in the assessment of muscle constituents, age and sex must be taken into account.
There is evidence that cellular hydration state is an important factor controlling cellular protein turnover; protein synthesis and protein degradation are affected in opposite directions by cell swelling and shrinking. An increase in cellular hydration (swelling) acts as an anabolic proliferative signal, whereas cell shrinkage is catabolic and antiproliferative. The cellular hydration state is mainly determined by the activity of ion and substrate transport systems in the plasma membrane. Hormones, substrates, and oxidative stress can change the cellular hydration state within minutes, thereby affecting protein turnover. We postulate that a decrease in cellular hydration in liver and skeletal muscle triggers the protein catabolic states that accompany various diseases.
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.
Blood and urine samples were obtained from four groups of healthy male subjects (A-D, total n = 22) before, during and after ingesting the following: group A, 5 g of creatine in solution; groups B and C, 5 g of creatine and 93 g of simple carbohydrate in solution: group D, a creatine- and carbohydrate-free solution. Subjects ingested the above preparations every 4 h for the remainder of the day and throughout the next day (total daily creatine dose = 20 g), and reported back to the laboratory on day 3 to undergo the same procedures as on day 1. Throughout this time, subjects weighed and recorded all dietary intake, and those in groups B and C ingested a prescribed isoenergetic high carbohydrate diet. Subjects in group C also performed 1 h of cycling exercise at 70% of their maximal oxygen consumption on the morning of each day. On both days 1 and 3, peak plasma creatine concentration, the area under the plasma creatine concentration/time curve and urinary creatine concentration were lower in groups B and C than in group A. Conversely, serum insulin concentration was higher in groups B and C than in A. No differences were evident when comparing groups B and C. These data suggest carbohydrate ingestion augmented creatine retention during creatine feeding and that creatine retention was not further increased when exercise was performed prior to ingestion.
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.
This study investigated the effect of insulin on plasma and muscle creatine accumulation and limb blood flow in humans after creatine administration. Seven men underwent a 300-min euglycemic insulin clamp combined with creatine administration on four separate occasions. Insulin was infused at rates of 5, 30, 55, or 105 mU. m-2. min-1, and on each occasion 12.4 g creatine was administered. During infusion of insulin at rates of 55 and 105 mU. m-2. min-1, muscle total creatine concentration increased by 4.5 +/- 1.4 (P < 0. 05) and 8.3 +/- 1.0 mmol/kg dry mass (P < 0.05), and plasma creatine concentrations were lower at specific time points compared with the 5 mU. m-2. min-1 infusion rate. The magnitude of increase in calf blood flow (plethysmography) was the same irrespective of the rate of insulin infusion, and forearm blood flow increased to the same extent as the three highest infusion rates. These findings demonstrate that insulin can enhance muscle creatine accumulation in humans but only when present at physiologically high or supraphysiological concentrations. This response is likely to be the result of an insulin-mediated increase in muscle creatine transport rather than creatine delivery.
The purpose of this study was to examine nutritional and supplemental habits among international alpine- and cross-country skiers and power sport athletes in Norway. Data from all the athletes of the National alpine skiing team (ALP; n = 33, 19 men and 14 women) and the National cross-country skiing team (CRO; n = 34, 17 men and 17 women) plus a mixed group of power sport athletes (POW: n = 33, all men) from the National teams of boxers, weightlifters and track and field athletes, were collected through a semi-structured interview during their annual medical examination. Twenty percent of all the athletes reported unsatisfactory nutritional habits (CRO 6%, ALP 27% and POW 27%; CRO vs. ALP/POW P < 0.05). Eight-four percent used one or more micronutrient supplement (ALP 70%, POW 88%, CRO 95%; ALP vs. CRO/POW P < 0.01). Power sport athletes had the most frequent use of supplemental creatine (45%), proteins/amino acids (30%), vitamins (88%) and minerals (82%), and CRO had the most frequent intake of iron (94%), vitamin C (88%) and fish oils (91%). Among ALP, only 7% of the female athletes supplemented iron regularly compared to 37% of male ALP (P < 0.05) Overall, male athletes supplemented mostly on a regular basis and female athletes more on an occasional basis. The results show that in spite of differences between sport groups, many elite athletes report unsatisfactory nutritional habits. Micronutrient supplementation was prevalent, but varied between both groups of sports and gender.
The purpose of this investigation was to study the efficacy of two dietary supplements on measures of body mass, body composition, and performance in 42 American football players. Group CM (n = 9) received creatine monohydrate, Group P (n = 11) received calcium pyruvate, Group COM (n = 11) received a combination of calcium pyruvate (60%) and creatine (40%), and Group PL received a placebo. Tests were performed before (T1) and after (T2) the 50 week supplementation period, during which the subjects continued their normal training schedules. Compared to P and PL, CM and COM showed significantly greater increases for body mass, lean body mass, 1 repetition maximum (RM) bench press, combined 1 RM squat and bench press, and static vertical jump (SVJ) power output. Peak rate of force development for SVJ was significantly greater for CM compared to P and PL. Creatine and the combination supplement enhanced training adaptations associated with body mass/composition, maximum strength, and SVJ; however, pyruvate supplementation alone was ineffective.
In this investigation we evaluated the effects of oral creatine (Cr) supplementation on body composition, strength of the elbow flexors, and fatigue of the knee extensors in 20 males aged 60-82 years who were randomly administered Cr or placebo (P) in a double-blind fashion. Subjects ingested either 20 g of Cr or P for 10 days, followed by either 4 g of Cr or P, respectively, for 20 days. Tests were conducted pre-supplementation and following 10 and 30 days of supplementation. Leg fatigue was determined using an isokinetic dynamometer; subjects performed 5 sets of 30 maximal voluntary contractions at 180 degrees x s(-1), with 1 min of recovery between sets. The strength of the elbow flexors was assessed using a modified preacher bench attached to a strain gauge. There was a significant interaction (P < 0.05; group x time) in leg fatigue following supplementation. However, this interaction appears to have resulted from a combination of the improved fatigue score by the Cr-supplemented group and the decreased fatigue score by the P-supplemented group, because when the simple main effects were analyzed for the groups individually, there was no significant difference over time for either of the groups. There were no significant differences in body mass, body density, or fat-free mass as assessed by hydrostatic weighing, or strength between the Cr-supplemented or P-supplemented groups. These data suggest that 30 days of Cr-supplementation may have a beneficial effect on reducing muscle fatigue in men over the age of 60 years, but it does not affect body composition or strength.
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.
To determine the prevalence and pattern of creatine use among varsity athletes at a National Collegiate Athletic Association (NCAA) Division I athletic program.
Anonymous descriptive survey.
Institutional.
Collegiate varsity and junior varsity athletes.
Self-reports of creatine use, including pattern of use and dose, source of information on creatine, and expected and perceived effects from creatine use.
Surveys were obtained from 93% of 806 eligible athletes. Overall, 68% of athletes had heard of creatine and 28% reported using it. Forty-eight percent of men reported having used creatine as compared with 4% of women. With two exceptions, all men's teams had at least 30% of athletes who reported a history of creatine use. Of athletes that had used creatine, about one-third had first used it in high school. Friends and teammates were the most common sources of creatine information. Increased strength and muscle size were the most common effects the athletes expected and perceived from creatine use.
In this population of collegiate athletes, creatine use was widespread among men but was minimal among women. Athletes learned about creatine supplementation primarily from their peers, and substantial numbers began to take creatine while still in high school. Most athletes could not report their dosing of creatine. This study reported findings at one location for one academic year. Studies are needed at multiple locations and over time to further delineate creatine use patterns.
The hypothesis of this study was that short term creatine (Cr) ingestion in older individuals would increase body mass and exercise performance, as has been shown in younger subjects. Seventeen males 60-78 years old were randomly placed into two groups, Cr and placebo (P), and supplemented in double-blind fashion for 5 days. Subjects ingested either 5 g of Cr plus 1 g of sucrose 4x per day or 6 g of a sucrose placebo 4x per day. Isometric strength of the elbow flexors was assessed using a modified preacher bench attached to a strain gauge. Isokinetic exercise performance was assessed using an intermittent fatigue test of the knee extensors. Subjects performed 3 sets of 30 repetitions with 60 sec rest between sets. There was a small (0.5 kg) but statistically significant increase in body mass (p < 0.05) in the Cr group after supplementation. There was a significant overall interaction between groups in isokinetic performance from pre to post supplementation (group x time x set, p < 0.05). However, analysis of the groups separately revealed that the subjects in the Cr group demonstrated a small non-significant increase in isokinetic performance while subjects in the P group demonstrated a small non-significant performance decrement. There was no significant difference in isometric strength between groups from pre to post supplementation. These data suggest that acute oral Cr supplementation does not increase isometric strength and only produces small increases in isokinetic performance and body mass in men over the age of 60.
Nutritional status influences muscle growth and athletic performance, but little is known about the effect of nutritional supplements, such as creatine, on satellite cell mitotic activity. The purpose of this study was to examine the effect of oral creatine supplementation on muscle growth, compensatory hypertrophy, and satellite cell mitotic activity. Compensatory hypertrophy was induced in the rat plantaris muscle by removing the soleus and gastrocnemius muscles. Immediately following surgery, a group of six rats was provided with elevated levels of creatine monohydrate in their diet. Another group of six rats was maintained as a non-supplemented control group. Twelve days following surgery, all rats were implanted with mini-osmotic pumps containing the thymidine analog 5-bromo-2'-deoxyuridine (BrdU) to label mitotically active satellite cells. Four weeks after the initial surgery the rats were killed, plantaris muscles were removed and weighed. Subsequently, BrdU-labeled and non-BrdU-labeled nuclei were identified on enzymatically isolated myofiber segments. Muscle mass and myofiber diameters were larger (P < 0.05) in the muscles that underwent compensatory hypertrophy compared to the control muscles, but there were no differences between muscles from creatine-supplemented and non-creatine-supplemented rats. Similarly, compensatory hypertrophy resulted in an increased (P < 0.05) number of BrdU-labeled myofiber nuclei, but creatine supplementation in combination with compensatory hypertrophy resulted in a higher (P < 0.05) number of BrdU-labeled myofiber nuclei compared to compensatory hypertrophy without creatine supplementation. Thus, creatine supplementation in combination with an increased functional load results in increased satellite cell mitotic activity.
Creatine monohydrate (CrM) administration may enhance high intensity exercise performance and increase body mass, yet few studies have examined for potential adverse effects, and no studies have directly considered potential gender differences.
The purpose of this study was to examine the effect of acute creatine supplementation upon total and lean mass and to determine potential side effects in both men and women.
The effect of acute CrM (20 g x d(-1) x 5 d) administration upon systolic, diastolic, and mean BP, plasma creatinine, plasma CK activity, and body composition was examined in 15 men and 15 women in a randomized, double-blind experiment. Additionally, ischemic isometric handgrip strength was measured before and after CrM or placebo (PL).
CrM did not affect blood pressure, plasma creatinine, estimated creatinine clearance, plasma CK activity, or handgrip strength (P > 0.05). In contrast, CrM significantly increased fat-free mass (FFM) and total body mass (P < 0.05) as compared with PL, with no changes in body fat. The observed mass changes were greater for men versus women.
These findings suggest that acute CrM administration does not affect blood pressure, renal function, or plasma CK activity, but increases FFM. The effect of CrM upon FFM may be greater in men as compared with that in women.
To describe patterns of creatine use in select Division I collegiate athletes based on recommended dosages according to body weight. Further, to report the perceived effects noted with creatine supplementation.
Anonymous open-ended self-report descriptive questionnaire.
National Collegiate Athletic Association Division I institution.
Two-hundred and nineteen male and female collegiate athletes representing eight varsity sports.
An open-ended questionnaire was administered to determine patterns of creatine use during the loading and maintenance phases of this nutritional supplement. In addition, perceived positive, negative, and no effects associated with creatine usage patterns were determined from athlete responses on this self-report measure.
Considering this select group of collegiate athletes, highly variable patterns of creatine supplementation were noted for loading/maintenance phases based on recommended dosages/days and body weight. Of the 219 athletes surveyed, 90 (41%) reported using creatine, while creatine supplementation was more prevalent among men than women. Creatine users (80 athletes, 89%) reporting perceived positive effects were primarily at or below recommended dosages for the loading phase but above recommended dosages in the maintenance phase. Creatine users (34 athletes, 38%) reporting perceived negative effects were primarily at or below recommended dosages in the loading phase but noticeably above recommended dosages in the maintenance phase. Ironically, all creatine users who reported negative side effects also reported positive effects. Creatine users (10 athletes, 11%) reporting no effects were below recommended loading dosages but above recommended maintenance dosages.
The perceived positive effects noted support current research (strength/weight gains), while the perceived negative effects (cramping/gastrointestinal distress) were consistent with anecdotal reports surrounding creatine supplementation. Apparently, collegiate athletes in this study are in need of education regarding the proper use of creatine supplementation. Additional studies are needed to ascertain creatine supplementation patterns of collegiate athletes in various settings.
Creatine monohydrate supplementation has been shown to enhance high-intensity exercise performance in some but not all studies. Part of the controversy surrounding the ergogenic effect(s) of creatine monohydrate supplementation may relate to design issues that result in low statistical power. A further question that remains unresolved in the creatine literature is whether or not males and females respond in a similar manner to supplementation. We studied the effect of creatine supplementation upon high intensity exercise performance in 24 subjects (n = 12 males, n = 12 females). Creatine monohydrate (Cr; 5g, 4x/d 3 4d) and placebo (Pl; glucose polymer 3 4d) were provided using a randomized, double-blind crossover design (7 week washout). Outcome measures included: 2 3 30-s anaerobic cycle test, with plasma lactate pre- and post-test; dorsi-flexor: maximal voluntary contraction (MVC), 2-min fatigue test, and electrically stimulated peak and tetanic torque; isokinetic knee extension torque and 1-min ischemic handgrip strength. Significant main effects of Cr treatment included: increased peak and relative peak anaerobic cycling power ( 3.7%; p <. 05), dorsi-flexion MVC torque ( 6.6%; p <.05), and increased lactate ( 20.8%; p <.05) with no gender specific responses. We concluded that short-term Cr supplementation can increase indices of high-intensity exercise performance for both males and females.
We investigated whether creatine (CR) and beta-hydroxy-beta-methylbutyrate (HMB) act by similar or different mechanisms to increase lean body mass (LBM) and strength in humans undergoing progressive resistance-exercise training. In this double-blind, 3-wk study, subjects (n = 40) were randomized to placebo (PL; n = 10), CR (20.0 g of CR/d for 7 d followed by 10.0 g of CR/d for 14 d; n = 11), HMB (3.0 g of HMB/d; n = 9), or CR-and-HMB (CR/HMB; n = 10) treatment groups. Over 3 wk, all subjects gained LBM, which was assessed by bioelectrical impedance analysis. The CR, HMB and CR/HMB groups gained 0.92, 0.39, and 1.54 kg of LBM, respectively, over the placebo group, with a significant effect with CR supplementation (main effect P = 0.05) and a trend with HMB supplementation (main effect P = 0.08). These effects were additive because there was no interaction between CR and HMB (CR x HMB main effect P = 0.73). Across all exercises, HMB, CR, and CR/HMB supplementation caused accumulative strength increases of 37.5, 39.1, and 51.9 kg, respectively, above the placebo group. The exercise-induced rise in serum creatine phosphokinase was markedly suppressed with HMB supplementation (main effect P = 0.01). However, CR supplementation antagonized the HMB effects on serum creatine phosphokinase (CR x HMB interactive effect P = 0.04). Urine urea nitrogen and plasma urea were not affected by CR supplementation, but both decreased with HMB supplementation (HMB effect P < 0.05), suggesting a nitrogen-sparing effect. In summary, CR and HMB can increase LBM and strength, and the effects are additive. Although not definitive, these results suggest that CR and HMB act by different mechanisms.
This study examined 12 wk of creatine (Cr) supplementation and heavy resistance training on muscle strength and myosin heavy chain (MHC) isoform mRNA and protein expression.
Twenty-two untrained male subjects were randomly assigned to either a control (CON), placebo (PLC), or Cr (CRT) group in a double-blind fashion. Muscle biopsies were obtained before and after 12 wk of heavy resistance training. PLC and CRT trained thrice weekly using three sets of 6-8 repetitions at 85-90% 1-RM on the leg press, knee extension, and knee curl exercises. CRT ingested 6 g.d-1 of Cr for 12 wk, whereas PLC consumed the equal concentration of placebo.
There were no significant differences for percent body fat (P > 0.05). However, for total body mass, fat-free mass, thigh volume, muscle strength, and myofibrillar protein, CRT and PLC exhibited significant increases after training when compared to CON (P < 0.05), whereas CRT was also significantly greater than PLC (P < 0.05). For Type I, IIa, and IIx MHC mRNA expression, CRT was significantly greater than CON and PLC, whereas PLC was greater than CON (P < 0.05). For MHC protein expression, CRT was significantly greater than CON and PLC for Type I and IIx (P < 0.05) but was equal to PLC for IIa.
Long-term Cr supplementation increases muscle strength and size, possibly as a result of increased MHC synthesis.
This investigation assessed the effects of a 9-wk regimen of creatine monohydrate (Cr x H2O) supplementation coupled with resistance training on body composition and neuromuscular performance in NCAA Division I football athletes.
Twenty-five subjects were randomly assigned in a double-blind, randomized placebo-controlled design, to a treatment (Cr, N = 9), placebo (P, N = 8), or control group (C, N = 8). The Cr group received 20 g.d(-1) of creatine for the first 5 d in 5-g doses, four times daily, followed by 5 g.d(-1) for the remainder of the study. Each 5-g dose was mixed with 500 mL of glucose solution (Gatorade). The P group received a placebo (sodium phosphate monohydrate; NaH2PO4 x H2O) following the exact protocol as the Cr group. The C group received no supplementation. All subjects resistance trained 4 d.wk(-1). Measurements of neuromuscular performance and body composition were made pre- and post-training after supplementation while monitoring dietary intakes.
Repeated measures ANOVA indicated significant differences occurred between the Cr group and the other two groups (P and C) for total body weight, lean body mass, cell hydration, strength, peak torque at 300 degrees.s(-1) knee flexion, percent torque decrement, and anaerobic power and capacity. However, percent body fat, peak torque during both knee flexion and extension at 60 and 180 degrees.s(-1), peak torque at 300 degrees.s(-1) during knee extension, global muscular strength (power clean), and extracellular fluid remained statistically unchanged for all groups.
Our findings indicate that creatine, supplemented concurrently with resistance and anaerobic training, may positively affect cell hydration status and enhance performance variables further than augmentation seen with training alone.
We tested the null hypothesis that creatine monohydrate loading (20 g per day for 7 days, n = 18) would not alter resistance exercise performance, isometric strength, or in vivo contractile properties of the quadriceps femoris muscle compared with loading with placebo (n = 13) in resistance-trained subjects. For the entire study group, the 1 repetition maximum (1RM) and 5-set performance (the number of repetitions) for unilateral, dynamic knee extension increased slightly (2% and 5%, respectively) after dietary supplementation, and these responses did not differ by condition. Maximal voluntary isometric torque and the rate of torque development did not change. During electromyostimulation, torque development and relaxation time were also unaffected. Our data suggest that creatine loading does not augment unilateral strength or multiset resistance exercise performance for knee extensions compared with placebo loading.
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.