Creatine as a dietary supplement (which is also used for treating patients with disturbances of the metabolism of creatine), has had a huge boom in recent years among athletes and among scientists, thus becoming the most studied supplement in recent years. Many scientific studies have investigated the effect of supplementation with creatine monohydrate in a variety of exercises and sports, although not all with good results which may be due to different initial levels of creatine, dose and duration of supplementation (3, 5 or more days), exercise evaluation, gender, duration of exercise, different statistical treatment, etc.

Introduction In 1832, creatine, a molecule of nitrogen, was identified in meat by the French scientist Chevreul. Later, in 1847, Lieberg concluded that the accumulation of creatine in the body is directly involved in the production of muscular work. The investigation of creatine supplementation started using creatine about 1900 extracted from the meat. The production of synthetic creatine starts in the mid-60s and was initially used in the countries that formed the Soviet Union. Some British Olympic athletes were supplemented with creatine in the Barcelona Olympics in 1992. Moreover the Olympic Games in Atlanta were referred to as "The Creatine Games , since a significant number of athletes supplemented with creatine achieved gold medals.

Creatine is a compound that is found in our bodies (95% of contenidototal Creatine is found in the muscles and the rest in the heart and brain), and is formed from three precursor amino acids: glycine , Arginine and Methionine. The normal concentration of creatine in plasma is 50-100 mmol / L and the turnover of the same man in an average of 70 kg is estimated at 2 grams. newspapers which can be covered by the exogenous intake of foods such as meat or fish (the average consumption of creatine from a mixed diet is approximately 1 g.) and the rest is supplemented by endogenous synthesis.

Information on nutritional supplements can be quite confusing in many cases. Today we find enough literature on the information that appears to supplements such as the Internet, in magazines, advertisements, etc.. Still says that many people receive mixed messages. This is especially true in the case of a product has become the "boom" of supplements to boost athletic performance, we're talking, of course, of the creatine.

Every day we receive more queries from interested parties seeking information, questions and questioning the credibility of the press who have published so many conflicting reports.
In the past year, more than 175 television news and more than 900 newspaper articles have included stories about creatine. Although often successfully posted functions creatine, never missing the misleading advertising such as a recent article in Decatur, Illinois, the Herald and Review exaggerating the effects of the supplement to the point of titles such as "magic bullet" .

Furthermore, we find the erroneous information that appeared in St. collude Times, in which the doctor stated that "if not used properly, creatine may even delay the healing of wounds."

Fortunately, in the midst of this chaos caused by the boom of creatine are voices of reason, scientific experts, like Richard Kreider, PhD, who offers an oasis of information on what really sensational creatine " does or does not do "information based on scientific literature, not rumors or hearsay.

People who attended a recent symposium at the National Strength and Conditioning Association's annual meeting at 21 the June 24 in Nashville, Tennessee, could witness a quite understandable overview, summarized by Dr. Kreider, who 4 clearly presented the latest scientific facts about creatine supplementation and its effects on athletic performance. Dr. Kreider has authorized us to publish this presentation, which will undoubtedly help to those who are not familiar with the benefits of creatine, to acquire a knowledge of what the supplement can and can not accomplish and who should use it or not use. We also provide extensive knowledge about the effects of this supplement in sports andalusia muscle growth.

Razonamiento theoretical Creatine supplementation
• During the course of type short and explosive, the biochemical reaction catalyzed by the enzyme refosforilasa from ADP (adenosine diphosphate) is phosphorylated to form ATP (adenosine triphosphate, the basic form of energy used by cells) is determined largely by the amount of fosfocreatina stored in the muscle.
When stocks begin to run out of fosfocreatina, athletic performance deteriorates rapidly due to the inability of ATP resintetizar the pace required.
Creatine supplementation increases total muscle creatine content and fosfocreatina between 10 and 40%. Increasing the bioavailability of
fosfocreatina increasing levels of ATP during intense exercise and the pace at which the ATP is resintetiza after exercise of high intensity and short duration.
Report on the Effects of load creatine on muscle power.
Increases in total muscle creatine by 10 to 25% and fosfocreatina by 20 to 40% (with some variability between different people).
Has been shown that ingestion of glucose (100 grams), creatine (5 grams) increases the concentration of insulin and promotes the increased use of creatine by the muscle as well as the synthesis of glycogen.
ATP increases the bioavailability of explosive and effort during the exercise of high intensity repetitive.
Accelerates the pace at which the ATP is resintetiza after high intensity exercise.
Benefits of creatine supplementation in the short and long term. Increases
1 Repetition Maximum (1RM) and / or maximum stress.
Improves performance in vertical jump and jumps repetitive.
Increases during sets of maximum effort for repetitive muscular contraction. Increases
single effort sprint duration of 6 to 30 seconds. Increases the explosive effort
repetitive (eg, 6 C 6 seconds with 30 seconds rest)
better performance in high intensity events lasting between 90 to 600 seconds. Increases
AT (Anaerobic Threshold) and VO2 max (the body's ability to carry oxygen to muscles).

observed changes in body composition
Changes in body composition:
increase total muscle mass.
Increases lean muscle tissue.
Decreased percentage of adipose tissue.
Theories on the increase in lean muscle tissue:
Fluid retention
protein synthesis.
Improved quality of training.
Theories of yield improvement.
Increase of total creatine and intramuscular fosfocreatina. Mayor
resynthesis of ATP and / or metabolic efficiency during high intensity exercise.
Increase in promoting better quality of the training adaptations to training over time.
Increase lean muscle tissue, promoting more gains force.
Possible side effects. Report
side effects: Weight gain
.

Side Effects anecdotal published by the press:
cramps / dehydration. Muscle Pulls
.
Kidney disorders. Concerns
: Abusos
?
Long-term side effects? Ethics
?

Motion Study
retrospectively evaluate the side effects observed when using a questionnaire survey in two post-test and controlled double-blind randomized study in which the effects of supplementation creatine in sport performance and body composition during training.

Methods
164 questionnaires were evaluated post-test study of two double-blind and random. n
84 people taking placebo, 80 took supplements containing creatine during training.
During the tests, were questioning the people studied to report on problems or side effects observed after ingestion of the supplements.
After the supplementation period was that people study describes the positive and negative aspects of taking the supplements that were administered.
The post-study questionnaires were filled in anonymously.

content questionnaire survey
What impact did the supplements ingested during your workout in the study, compared with a recent training and / or during a competition < BR> In percentage terms, how would that affect the protocol to supplement your training and / or explosive effort in your performance?. (eg No effect 0%, 10% improvement.)
How did you feel was the most positive aspects of taking supplements?. n
What was the most negative aspect of taking supplements?.
Describe any comments you may have about the supplements you took. (Taste, quality, effectiveness, likelihood of purchase and consumption of the product, etc.).. n
Compliance? What group was most affected? What they believed they were taking a supplement? Ratio of confidence in the choice of it.

Protocols Training and Supplementation
Nine days ingesting placebo or 21 grams of carbohydrates per day of creatine in elite junior swimmers male and female during their training (20.5 ± hours week). Fourteen days
placebo ingesting carbohydrates, 16.5 grams of creatine per day, or an A * Supplement containing 15.75 grams of creatine per day in runners, cyclists and triathletes male and female, well trained and desentrenados. (8 to 22 hours / week). Twenty-eight days
placebo ingesting carbohydrate, high-calorie supplements, or ** Supplement B contains 20 grams of creatine per day during resistance training. (7.6 ± 2 hours / week). Twenty-eight days
ingesting carbohydrate or placebo A Supplement containing 15.75 grams of creatine per day in college football off-season / agility training. (8 hours / week). Eighty-four days
ingesting carbohydrate placebo, a popular meal replacement, Supplement B contains 20 grams of creatine per day, or C *** Supplement containing 25 grams of creatine per day for rugby players in the league University USA, off-season training, strength training and agility of rugby season. * A
Supplement: creatine monohydrate DEXTROSE + + + TAURINE PHOSPHATES
** Supplement B: whey protein CASEINATES + CALCIUM + L-Glutamine + TAURINE + + egg albumin creatine monohydrate Maltodextrin + + + DEXTROSE MIXTURE Vitamins / Minerals
*** C Supplement: Supplement B with higher amounts of protein, carbohydrates and creatine

Analysis of post-study questionnaire
The results show that there were no cramps or muscle injuries in athletes who took a placebo or supplements containing creatine during training.
There was an isolated incident but the pain increased gastrointestinal (GI) among the athletes who consumed placebo compared with those who took supplements containing creatine.

post-analysis questionnaire survey
The results indicated that creatine supplementation during several exercises / training does not increase the incidents of muscle cramps, muscle jerks or gastrointestinal pain.
These data are the result of the questionnaire and will require further investigation to assess the reality of these assertions.

Comments on the Controversy of Creatine
was not detected any side effect in the scientific literature / medical.
The controversy has been perpetuated in the press mainly by quoting "experts" who apparently are not familiar with the literature on creatine. Comments on
creatine should be based on scientific literature, not on anecdotal reports, untested assumptions and / or speculation.
Many theories about the negative effects of creatine have no physiological basis.
Where are the data to support their views, and / or theories?.
Direct information for those interested in media, coaches, athletes and family to review scientific research on creatine can be found at
• RB Kreider, "Creatine, the new supplement ergogenic" in Sportscience Training & Technology, Internet Society for Sport Science. Available at: http://www.sportsci.org/traintech/creatine/rbk.html (1998 )
• RBKreider, ² creatine supplementation, analysis of ergogenic value, medical safety and concerns ². Journal of Exercise Physiology Online. Available at: http: / / www.css.edu/users/tboone2/asep/jan.htm (1998).
Know the maximum of literature, provide accurate and timely information that is available to clarify the manner in didactic and clear.
Because many supplements have been ineffective and that only a few nutritional supplements have been shown to have ergogenic value, people have become skeptical.
However, research shows that several nutritional strategies can help improve athletic performance. The paradigm
related to the role of nutritional supplements in health and human performance is changing. People
believes that taking supplements should be linked to information about its effects, risks, side effects, etc.., So that they can choose the most appropriate supplementation.
Supplementation should be voluntary and even creatine, as well as the generality of the dietary products are not drugs, its use should be supervised by medical practitioners, pharmacists or nutrólogos specialized in sports.

minimum acceptable available
Research and clinical studies indicate that short-term supplementation with creatine is very effective in improving the strength and performance on repetitive exercises.
Creatine supplementation during training achieves greater strength gains, lean muscle mass and improve performance in explosive effort.
Although additional research is needed long-term studies are available (up to 2 years) showed that creatine supplementation is safe and presents no health risks.

Critical analysis of studies that showed no ergogenic benefit.
creatine supplementation in various clinical studies produced no improvement in athletic performance. This happens:
• When ingested less than 20 grams a day for 5 days or when ingested 2 to 3 grams per day during training (with or without a high dose or period of initial load.)
• In people who experience less than 20% increase in the content of creatine in the muscle. • In experimental studies
crossed with periods of less than 5 weeks of use. • In efforts
explosive repetitive length between 6 and 60 seconds, when there are prolonged periods of rest between the series of efforts explosives. • In
submáximos aerobic exercise after a period of acute load.
• In high-intensity aerobic exercise after short periods of loading. • When
recovery time is too short to replenish fosfocreatina.

Concerns creatine supplementation
Removal of the natural synthesis of creatine?
Kidney disorders?
Muscle cramps? Pulls
muscle?
Long-term effects? Ethics
in improving sports performance?
Effects of supplementation?
Expenditure? Administrative Control

Could happen to remove the natural synthesis of creatine
has been reported that the natural synthesis of creatine decreases during periods in which increases the content creatine in the diet.
However, the synthesis of creatine seems back to normal upon cessation of supplementation.
There is evidence in animal or human evidence to indicate a long-term suppression of the natural synthesis of creatine.

renal Can appear
Diets high in protein (> 3g/kg/d) increase renal overload in patients with renal failure. Some concerns are based on the possibility that creatine can cause kidney overload. Ingesting
15 to 25 grams per day of creatine increases the protein intake at 0.1 to 0.2 g / kg / d (ie, 8 to 16 grams of protein per day for a 83 kg athlete) No No
There is evidence that adding less than the equivalent of 30 grams of protein per day (0.1 to 0.2 g / kg / d.) to the diet is an overload or renal failure in healthy people.
Although it has been reported that levels creatine rise moderately after creatine supplementation (ie 1.2 to 1.4 umol / L), these are among the normal parameters for high performance athletes.
Increased creatinine may be due to excess creatine eliminated.
There are no studies reporting elevations in liver enzymes in response to creatine supplementation.
Recent studies indicate that creatine supplementation (20 grams daily for 63 days) does not increase the possibility of renal failure. < / P>

Can cause muscle cramps
Some advertisements or articles have suggested the possibility that athletes taking creatine can experience a higher incidence in muscle when train at high temperatures.
The proponents of this theory believe that creatine causes water retention, dehydration and / or electrolyte imbalance leading to cramps when you are training at high temperatures.
The cause of cramps is unknown .
There are no studies that have reported a disproportionate increase in the% of total water in the body, excessive retention of intracellular fluid, changes in plasma volume, and / or electrolyte imbalances in response to creatine supplementation.
There are no studies that have reported the occurrence of cramps in relation to creatine supplementation, although many of these studies have evaluated highly trained athletes during periods of high intensity.
Preliminary reports indicate that there is no relationship between creatine supplementation and dehydration and / or cramps in athletes training for 1 hour at 37 º C (98.6 º F).

Can

muscle jerks appear
has also been suggested that creatine causes a higher incidence of muscle jerks due to the rapid increase in weight and strength however
n The increase in yield strength and explosive efforts usually from 5 to 8% and are accompanied by increases in lean body mass. No study has documented the increase in the number of injuries after creatine supplementation.
There is clinical evidence that supplementation with creatine accelerates recovery after orthopedic surgery.

Concern for cramping and muscle pulls
We are preparing studies to investigate these alleged negative effects.
Logically, if creatine supplementation promotes cramping and / or a higher incidence of muscle pulls, it would be a very popular supplement among athletes because all teams would be injured or cramping, and therefore would not be able to participate in their sporting events.
Most scientists believe that this information is exaggerated.

Concern over the long term effects
athletes take creatine as a nutritional supplement, using the last 10 years.
Creatine has been used to treat errors of creatine synthesis in children, patients with heart failure, and prevent arrhythmias in patients of heart.
Has not been reported any significant side effects in medical studies for up to 2 years.
Although studies are still needed long-term, there is no evidence to date that creatine supplementation may lead to adverse medical situations when taken in recommended doses.

Ethical considerations

Concerns about ethics have emerged because the athletes are taking a nutritional supplement that clearly improves athletic performance.
While creatine supplementation is similar to the loads of carbohydrates, which is fully accepted.
Should all supplements and / or strategies believed to improve performance sports be banned?. Are
the use of scientifically based training and nutritional strategies are not ethical or just part of the assistance to the athlete in a natural way to optimize your athletic performance?.
Ultimately, medical technology, physical, nutritional and psychological applied to sport improved as a result of the investigation (today's cars are the same as in 1920?). Nobody disputes that progress in other areas is ethical, all non-aggressive techniques on health in the short or long term to improve physical performance need not be considered unethical

concern about abuse
The concern started by the possibility that athletes can take high doses of creatine (ie 50 to 100 grams per day) or even that they can take other supplements ineffective or potentially dangerous.
Some people believe that proper education is needed among athletes and coaches to inform them of the effects of nutritional supplementation in the training and the recommended dose for each athlete as a better means of reducing risks.

Need for Administrative Control
legal concerns have emerged regarding the administrative control of supplementation in the equipment and the responsibility of teams, universities and government bodies that provide creatine the athletes.
Most authorities believe that if creatine teams provide their athletes should ingest these supplements on a voluntary basis after having adequate knowledge about the effects they produce.
Is recommended administrative control to ensure that the form is not being administered to athletes excessive amounts of creatine.

Concern spending
Some argue that creatine supplementation is expensive and a waste of limited budget resources of the sport. Although initially
creatine was expensive, now is sold in the market for 4800 ptas. / Kg when buying in bulk (about 100 ptas. andalusia days when taking 20 grams daily).
Accordingly, the cost of the creatine is actually cheaper than most sports drinks. Contents
ergogenic value of creatine.
Total creatine in muscle contributes positively to improving the performance of high intensity training and recovery.
Creatine supplementation (15 to 25 grams per day for 5 to 7 days) may increase the concentrations of total creatine, free creatine in muscle fosfocreatina and about 10 to 40%.
Ingestion of creatine increases the glucose uptake of creatine to a greater degree and improve the synthesis of glycogen.
People with high initial levels do not respond as well to load creatine unless you ingest creatine with glucose, which promotes the absorption of creatine and glycogen.
Creatine supplementation in the short term (15 to 25 grams per daily for 5 to 7 days) can improve aerobic capacity for repetitive series of high-intensity training in a 5 to 10%.

Contents ergogenic value of creatine
has been shown that creatine supplementation during training leads to increases in strength and maximum stress.
Not all studies have shown benefits in athletic performance, possibly due to differences in the time of supplementation, the individual variation in response to creatine supplementation, the evaluation criterion of the training and time recovery observed between the repetitions of the exercise sets.
Has been reported that creatine supplementation in the short run a slightly increased body weight. Studies of supplementation
long-term (2 to 20 weeks) creatine alone, glucose with creatine or creatine added to proteins / carbohydrates have shown to increase lean muscle mass between 1.5 and 6 kg
Based on current data, creatine supplementation appears to be a safe and effective nutritional strategy to improve athletic performance.
Recommendations supplementation.
Improved athletic performance:
- recommended 200 mg / kg / day with carbohydrates during the first three days at the load step
- Then Eat 50 mg / kg / day with carbohydrates to maintain the levels of creatine.
Improved athletic performance and increase lean muscle mass:
- Ingesting 200 mg / kg / day with carbs / protein to which the goals of weight / body composition are achieved, then maintain it with a dose (50 mg / kg / day).
- Reduce or eliminate consumption among macrocyclic competitive training.

References

Sport Nutrition
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• WYSS, M. et. andalusia. I-4 Creatine metabolism and the consequences of creatine depletion in muscle. Mol. and Cellu. Biochem. 133/134 :51-66, 1994 GUERRERO-
• ONTIVEROS, M.L. et. andalusia. Creatine Suplementation in health and disease. Effects of chronic creatine ingestion in vivo: Down-regulation of the expression of creatine transporter isoforms in skeletal muscle. Mol. and Cell. Biochem. 184: 427-437, 1998.
• POORTMANS, J.R. at. andalusia. Long-term oral creatine supplementation does not impair renal function in healthy athletes. Medicine & Science in Sports & Exercise , 1108-1110, 1999.
• VOLEK, J.S. et. andalusia. Performance and muscle fiber adaptations to creatine supplementation and heavy resistance training. Mid & Scie. in Sport & Exerc. 1147-1156, 1999.
• STONE, M.H. et. andalusia. Effects of in-season (5 weeks) Pyruvate and Creatine Supplementation on Anaerobic Performance and Body Composition in American Football Players. Int Journal of Sport. Nut. 9, 146-165, 1999.