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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.
... 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. ...
Planiranje je upravljačka akcija kojom se određuju ciljevi i zadaće trenažnog procesa, vremenski ciklusi za njihovo provođenje i potrebni tehnički, materijalni i kadrovski uvjeti. Programiranje je upravljačka akcija u kojoj se na temelju plana vrši izbor, doziranje i raspored trenažnih operatora. Planiranje i programiranje rada u sportu bitan je dio ukupne aktivnosti trenera i stručnog tima. Ono omogućava da se slučajnosti svedu na minimum i da se na siguran i ekonomičan način postignu optimalni sportski rezultati koji odgovaraju individualnim obilježjima sportaša i uvjetima u kojima se provodi trenažni proces. Da bi se napravio dobar plan i program treninga, u ovom slučaju natjecateljskog dijela, potrebno je i dobro isplanirati i pripremni period. Pripremni period trebao bi biti podloga za početak natjecateljskog dijela. Natjecateljski period je jedan od perioda mezociklusa (srednji ciklus treninga) te ima svoje faze (uvodnu, službenu i najvažniju fazu). Jedna godina, točnije godišnji makrociklus, u ženskom nogometu u Hrvatskoj se sastoji od dvije natjecateljske sezone. Jedna traje približno 2 i pol do 3 mjeseca (ovisno o reprezentativnim pauzama) i uključuje 12-15 utakmica različitog karaktera.
... 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.
... As shown, there was a significant difference between the two groups in relation to the range of upper and lower extremity muscle strength changes with a greater improvement in supplement group that is line with some research (10,20,21). Increased peak power in the placebo group can be due to a resistance training program. ...
... In agreement with the results of this research, Bemben et al. (25) reported that cellular water supply, power, and anaerobic power capacity were significantly improved after creatine supplementation and resistance exercises. Despite the relative improvement of the variables in the creatine group compared to placebo, there was no significant difference between the two groups, which is probably due to the professionalism and high intensity training in the futsal players (20). Finally, the results of this study indicated a significant increase in flexibility in both supplement and placebo groups. ...
Objectives: The aim of this study was to determine the effect of 8 weeks resistance training with creatine supplementation on body
composition and physical fitness indexes in male futsal players.
Methods: 20 trained futsal players were selected based on convenience sampling from East Azerbaijan and assigned randomly
either to Ex + Cr group (Exercise + Creatin, n = 10) or Ex + Pl group (Exercise + Placebo, n = 10). All of the subjects performed resistance
training program for 8 weeks. The Ex + Cr group ingested 0.3 g/kg creatine during loading phase 0.1 g/kg in maintenance phase. Body
weight, fat free mass, fat percent, muscular strength, speed, anaerobic power and flexibility were measured before and after training
program. Paired t-test and independent t-test were used to analyze the data.
Results: The results suggested that body weight and fat free mass were significantly increased in both groups with greater improvements
in Ex + Cr group (P� 0.05). Moreover, Ex + Cr group demonstrated greater decrease in fat percent compared with Ex + Pl group
(P � 0.05). Also, muscular strength increased to a greater extent in the Ex + Cr compared with the Ex + Pl group (P � 0.05). Finally,
there was no significant difference between the two groups in speed, anaerobic power and flexibility (P � 0.05).
Conclusions: In general, it seems that resistance training along with creatine supplementation lead to greater increases in body
weight, fat mass and muscular strength as well as greater decrease in fat percent than resistance training alone in trained futsal
players.
... This can be achieved by phosphocreatine's high energy phosphate bonds that are available for immediate ATP replenishment in energy demanding circumstances (Persky and Brazeau, 2001). Based on these properties, it has been widely used to improve performance during anaerobic exercise (Rawson and Volek, 2003). Apart from muscle cells, neurons carry out many processes that require energy. ...
... Apart from muscle cells, neurons carry out many processes that require energy. Ιt has been shown that exogenously administrated creatine increases energy supply to neurons in healthy adults (Persky and Brazeau, 2001;Rawson and Volek, 2003;Klivenyi et al., 1999). Supplementation of creatine can increase its brain's levels up to a threshold, beyond which the excess is being excreted (Joncquel-Chevalier Curt et al., 2015). ...
... 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.
... Some years later, Volek et al. [46] demonstrated a significant increase in muscle fiber cross-sectional areas (e.g., Type I, IIA and IIAB) following 12 weeks of resistance training in conjunction with Cr supplementation, which was much greater than found with resistance training alone, thus showing an important role of Cr supplementation on physiological adaptations of skeletal muscle. Furthermore, in 2003, Rawson and Volek [47] reviewed 22 studies in order to evaluate the response of Cr supplementation associated with resistance training on muscle strength. This review showed an average increase of 8% more than in the groups who performed resistance training alone (i.e., placebo associated with resistance training), therefore confirming the efficacy of Cr supplementation as an ergogenic nutritional supplement. ...
... A systematic review and meta-analyses concluded that Cr supplementation is an effective method in lower-limb strength performance for exercise with a duration of less than 3 min [38]. The increased muscle strength following Cr ingestion plus resistance training could result from several mechanisms, including alteration in the expression of myogenic transcription factors, an increase in satellite cell mitotic activity, or simply an increase in the intensity of individual workouts resulting from a better match between ATP supply and demand during exercise [39]. ...
Creatine supplementation has an ergogenic effect in an acute complex training bout, but the benefits of chronic creatine supplementation during long-term complex training remain unknown. The study aimed to evaluate the effects of 4-week complex training combined with creatine supplementation on sport performances and muscle damage biomarkers. Thirty explosive athletes were assigned to the creatine or placebo group, which consumed 20 g of creatine or carboxymethyl cellulose, respectively, per day for 6 days followed by 2 g of the supplements until the end of the study. After 6 days of supplementation, subjects performed tests of one repetition maximum (1-RM) strength of half squat and complex training bouts to determine the optimal individual post-activation potentiation time. Thereafter, all subjects performed a complex training programme consisting of six sets of 5-RM half squats and plyometric jumps 3 times per week for 4 weeks. Body composition, 30-m sprint and jump performances were assessed before and after the training period. Moreover, blood creatine kinase (CK) activity was analysed at the first and the last training bout. After the training, the 1-RM strength in the creatine group was significantly greater than in the placebo group (p < 0.05). CK activity after the complex training bout in the creatine group was significantly reduced compared with the placebo group (p < 0.05). No differences were noted for other variables. This study concluded that creatine supplementation combined with complex training improved maximal muscular strength and reduced muscle damage during training.
... Células del músculo del atrio; Suplementación de aminoácidos; Entrenamiento anaeróbico; Péptidos natriuréticos Introduction It is well known that feeding athletes before and/or immediately after training with nutritional supplements such as creatine, l-carnitine and l-glutamine positively affects strength development and resistance training recovery (Raastad et al., 2000;Williams et al., 2002;Volek and Rawson, 2002;Rawson and Volek, 2003;Volek, 2004;Kraemer et al., 2007;Bent et al., 2011). Among nutritional supplements, glutamine is one of the most used by athletes (Novelli et al., 2007). ...
We investigated the effects of glutamine supplementation on the secretory apparatus of natriuretic peptides in atrial cardiomyocytes of aged rats undergoing resistance training. Two groups of resistance-trained rats were studied: resistance trained, and resistance trained and supplemented with glutamine group. Both groups of rats were trained to climb a 1.1 m vertical ladder with weights tied to their tail. The cardiomyocytes from resistance trained and supplemented rats showed increased density and sectional area of natriuretic peptides granules, higher relative volumes of the mitochondria, endoplasmic reticulum, Golgi complex and nuclear euchromatin, and nuclear pore density compared with resistance trained rats. In conclusion, glutamine supplementation caused hypertrophy of the secretory apparatus in the cardiomyocytes of aged rats undergoing resistance training.
... Additionally, the Cr-PCr system is proposed to act as a 'spatial energy buffer' whereby the different CK isoforms link the sites of ATP generation (i.e. the mitochondria), to sites of high ATP use (e.g. the sarcomere) (Greenhaff, 2001;Sahlin & Harris, 2011). Subsequently, creatine facilitates the maintenance of ATP homeostasis in tissues with high energy turnover, and supplementation has been shown to enhance performance of brief, high-intensity exercise, typically lasting less than 30 seconds, and resistance exercise performance (reviewed in Branch, 2003;Rawson & Volek, 2003). ...
The ergogenic and therapeutic effects of increasing muscle creatine by supplementation are well-recognized. It appears that similar benefits to brain function and cognitive processing may also be achieved with creatine supplementation, however research in this area is more limited, and important knowledge gaps remain. The purpose of this review is to provide a comprehensive overview of the current state of knowledge about the influence of creatine supplementation on brain function in healthy individuals. It appears that brain creatine is responsive to supplementation, however higher, or more prolonged dosing strategies than those typically used to increase muscle creatine, may be required to elicit an increase in brain creatine. The optimal dosing strategy to induce this response, is currently unknown, and there is an urgent need for studies investigating this. When considering the influence of supplementation strategies on cognitive processes, it appears that creatine is most likely to exert an influence in situations whereby cognitive processes are stressed, e.g. during sleep deprivation, experimental hypoxia, or during the performance of more complex, and thus more cognitively demanding tasks. Evidence exists indicating that increased brain creatine may be effective at reducing the severity of, or enhancing recovery from mild traumatic brain injury, however, only limited data in humans are available to verify this hypothesis, thus representing an exciting area for further research.
... En tan poco tiempo, este aumento, más que al aumento de masa muscular se puede deber a una mayor retención de líquidos, ya que el efecto inmediato de la creatina es la retención de agua por parte del músculo (Juhn & Tarnopolsky, 1998). De acuerdo a estudios realizados, el sexo no parece afectar a la concentración de creatina en la masa muscular ni a la respuesta del organismo, por lo que el hecho de que todos los participantes fuesen varones no debería influir en los resultados del estudio (Bemben & Lamont, 2005;Rawson & Volek, 2003). ...
Resumen: El objetivo del estudio fue investigar los efectos de un entrenamiento de fuerza más una suplementación adicional sobre deportistas adultos no profesionales y vegetarianos. Una revisión sistemática de las bases de datos MEDLINE (PubMed), Scopus, SportDiscus y WOS (Web of Science) fue realizada siguiendo el modelo PICO, utilizando términos que representasen a personas vegetarianas de entre 18 y 64 años que hubiesen realizado una intervención basada en un entrenamiento de fuerza más suplementación. Siguiendo el procedimiento PRISMA, de los 62 estudios encontrados tan solo 3 cumplieron todos los criterios por lo que fueron analizados en su totalidad para poder ser incluidos en la revisión. La calidad metodológica de los estudios se evaluó mediante la escala PEDro. El estudio de Shomrat et al. (2000) la suplementación con creatina provocó un incremento de la masa corporal y potencia media. El estudio de Burke et al. (2003) obtuvo con la suplementación de creatina incrementos en la fosfocreatina (PCr), creatina total (TCr), fuerza, fibras musculares de tipo II y tejido magro, siendo estos cambios más significativos en las personas vegetarianas. Por último, en el estudio de Burke et al. (2008), el factor de crecimiento insulínico de tipo 1 (IGF-1) se incrementó en un 67%, con mayor acumulación en el grupo que fue suplementado con creatina. A raíz de estos resultados se puede concluir que la suplementación con creatina puede provocar efectos positivos en el rendimiento de los deportistas vegetarianos, ya que puede cubrir ciertas carencias derivadas de la dieta vegetariana. Palabras clave: vegetarianos; adultos; entrenamiento de fuerza; suplementación; creatina. Abstract: The aim of the study was to investigate the effects of strength training plus additional supplementation on non-professional adult athletes who are vegetarian. A systematic review of MEDLINE (PubMed), Scopus, SportDiscus, and WOS (Web of Science) databases was performed following the PICO model, using terms related to vegetarians aged between 18 and 64 years who realized an intervention based on strength training and supplementation. Following the PRISMA statement, of the 62 studies found only 3 met all the inclusion criteria and were analyzed entirely to be included in the review. The methodological quality of the studies was performed using the PEDro scale. The study of Shomrat et al. (2000) with creatine supplementation resulted in an increase in body mass and power. The study of Burke et al. (2003), based on creatine supplementation, obtained an increase of phosphocreatine (PCr), total creatine (TCr), strength, type II muscle fibers, and lean tissue. These changes were significant in vegetarians. Finally, in a study of Burke et al. (2008), insulin-like growth factor-1 (IGF-1) increased by 67%, with higher accumulation in the group that was supplemented with creatine. As a consequence of these results we can conclude that creatine supplementation could have positive effects on the performance of vegetarians due to the fact that it could cover certain shortcomings derived from the vegetarian diet.
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.
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.
Nutrition usually makes a small but potentially valuable contribution to successful performance in elite athletes, and dietary supplements can make a minor contribution to this nutrition program. Nonetheless, supplement use is widespread at all levels of sport. Products described as supplements target different issues, including the management of micronutrient deficiencies, supply of convenient forms of energy and macronutrients, and provision of direct benefits to performance or indirect benefits such as supporting intense training regimens. The appropriate use of some supplements can offer benefits to the athlete, but others may be harmful to the athlete's health, performance, and/or livelihood and reputation if an anti-doping rule violation results. A complete nutritional assessment should be undertaken before decisions regarding supplement use are made. Supplements claiming to directly or indirectly enhance performance are typically the largest group of products marketed to athletes, but only a few (including caffeine, creatine, specific buffering agents and nitrate) have good evidence of benefits. However, responses are affected by the scenario of use and may vary widely between individuals because of factors that include genetics, the microbiome, and habitual diet. Supplements intended to enhance performance should be thoroughly trialed in training or simulated competition before implementation in competition. Inadvertent ingestion of substances prohibited under the anti-doping codes that govern elite sport is a known risk of taking some supplements. Protection of the athlete's health and awareness of the potential for harm must be paramount, and expert professional opinion and assistance is strongly advised before embarking on supplement use.
Nutrition usually makes a small but potentially valuable contribution to successful performance in elite athletes, and dietary supplements can make a minor contribution to this nutrition programme. Nonetheless, supplement use is widespread at all levels of sport. Products described as supplements target different issues, including (1) the management of micronutrient deficiencies, (2) supply of convenient forms of energy and macronutrients, and (3) provision of direct benefits to performance or (4) indirect benefits such as supporting intense training regimens. The appropriate use of some supplements can benefit the athlete, but others may harm the athlete’s health, performance, and/or livelihood and reputation (if an antidoping rule violation results). A complete nutritional assessment should be undertaken before decisions regarding supplement use are made. Supplements claiming to directly or indirectly enhance performance are typically the largest group of products marketed to athletes, but only a few (including caffeine, creatine, specific buffering agents and nitrate) have good evidence of benefits. However, responses are affected by the scenario of use and may vary widely between individuals because of factors that include genetics, the microbiome and habitual diet. Supplements intended to enhance performance should be thoroughly trialled in training or simulated competition before being used in competition. Inadvertent ingestion of substances prohibited under the antidoping codes that govern elite sport is a known risk of taking some supplements. Protection of the athlete’s health and awareness of the potential for harm must be paramount; expert professional opinion and assistance is strongly advised before an athlete embarks on supplement use.
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.