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Here is a cut and Paste from Iron Addict...A lot to read, but Tons of Info...
Creatine, shut up, it works
We are CONSTANTLY bombarded with creatine questions. I will say it again, then no more answers but referrals to this thread.
Most people do NOT get the big water weight gains some people do, so they automatically conclude it isn't working. They don't get dramatic strength increases, so they conclude it is not working. Most people are also looking for "steroid type" gains--NOT HAPPENING. What creatine does is allow a rep here and a extra rep there, and a few extra pounds to be lifted, and that is GOLD for the price of it. Most people also do not take enough of it (I have NEVER seen good results with UNDER 10 grams monohydrate a DAY). And they don't take it consistently, and then say it doesn't work. We have literally THOUSANDS of well documented studies, and strength coaches that directly supervise their trainees all will tell you it works. Here are a few more studies. If you want to believe your bio-chemistry is that different from the rest of the world go for it, but quit telling people it doesn't work, because properly applied and looking for REASONABLE results, it works for everyone I have actually seen use it properly.
Creatine Supplementation in Athletes: Review
by Mark A. Jenkins, MD
If you haven't yet heard of creatine supplementation you soon will. It is being promoted as a muscular performance enhancer, and there is scientific evidence to support this. Unfortunately, claims have escalated beyond science, and now athletes from a wide variety of sports have begun taking this substance. The pursuit of performance enhancing potions has historically been like the alchemists dreams turning lead into gold. Too often the latest fad turns out to do nothing or is harmful. Although creatine supplementation offers short-term limited benefits, whether or not it is harmful long term has yet to be fully determined.
Physiology of creatine in exercise
The key to understanding creatine supplementation is to appreciate that it only helps with certain activities. A basic review of what creatine is, and how it is used in the body will help you understand how supplementation might be beneficial. First, the basics. Muscle cells generate mechanical work from an energy liberating chemical reaction -- ATP is split into ADP and P (phosphate). ATP can be used by muscle cells very quickly, but there is only an extremely limited supply -- usually only enough for a few seconds of high intensity work. When the ATP is gone, work stops. Fortunately, the
body has several ways to convert ADP back to ATP. The fastest method is to move the phosphate group off of phosphocreatine and onto ADP. This yields ATP -- which is immediately available for muscular work -- and creatine. There is enough phosphocreatine to keep ATP levels up for several more seconds. So at this point we've moved from 2 - 3 seconds of all-out work (ATP) to almost 10 seconds (ATP + creatine). The body can recharge creatine back to phosphocreatine, but this takes time (approximately 30 - 60 seconds). This ATP + creatine system makes up the fastest component of the anaerobic system, and is most used by power athletes. A good example is trench warfare in football (i.e., 6 seconds of all out force, followed by 45 seconds of standing around).
Diagram 2 illustrates the energy pathwys that are the most important for all-out exercise of differing times. This diagram represents somewhat of an oversimplification since, in reality, aerobic pathways are used even in very short duration, high intensity exercise(e.g., 10 seconds), but to a small degree. The longer that exercise goes on the greater the proportion of energy aquired from aerobic glycolysis.
Aerobic endurance athletes, such as distance runners and triathletes, represent a much different picture from power athletes. Their levels of ATP and phosphocreatine don't change during exercise because ATP is generated at the same rate it is used -- a "pay as you go" mechanism. Aerobic generation of ATP, via oxidation of glucose (and fats), is slower than by anaerobic systems, but the fuel supply is enormous. Aerobic athletes train their muscles differently, and indeed the muscle tissue itself is different from power athletes. Type I muscle fibers are known as "slow-twitch" because they have a slower speed of contraction than type II fibers ("fast-twitch"). Slow twitch fibers have less glycolytic capacity, but increased mitochondria, myoglobin, and aerobic enzyme pathways.
Thus, "slow twitch" athletes cannot generate the speed and force of their "fast twitch" cousins, but they can do their thing for a long time. If an endurance athlete needs to dip into the anaerobic range, for a sprint or hill climb, the needed extra energy primarily comes from anaerobic glycolysis of glucose (yielding lactic acid, and that wonderful muscular "burning" sensation.). The ATP-creatine system is not important for endurance athletes.
Where does creatine come from?
The creatine that is normally present in human muscle may come from two potential sources, dietary (animal flesh), and/or internally manufactured. What isn't present in the diet is easily made by the liver and kidneys from a few amino acids (glycine, arginine, and methionine). A 70kg adult has about 120g of creatine in the muscles, and the daily turnover is roughly 2g. About half of this is replaced by the diet and half synthesized endogenously. The exogenous intake of creatine appears to exert negative feedback on the endogenous production of creatine (i.e., more creatine present in the diet means less production by the body). Creatine is eliminated from the body by the kidneys either as creatine, or as creatinine, which is formed from the metabolism of creatine.
What about creatine supplements and performance?
In the early 1900's it was discovered that increased dietary creatine resulted in increased muscular stores of creatine and phosphocreatine. A study published in 1992, demonstrated approximately a 20% increase in total creatine stores in subjects fed 20 g of creatine per day for several days (1). This increase appears to be the upper limit and it has been shown that, even over a few days, a progressively increasing percentage of supplemented creatine ends up in the urine (1).
Since creatine supplementation increases muscular creatine levels, the next logical step would be to see if this helped athletic performance. From the brief discussion so far, one might expect that power athletes would benefit, and endurance athletes, not. Indeed, the exercise studies to date have confirmed that supposition.
Brief intermittent, high-intensity exercise.
A variety of protocols have been used to study the effect of creatine supplementation of brief, intermittant, high intensity exercise. Some of the exercise protocols which have shown improvements in performance are listed below, with indexed references. The most common method of supplementation used a 5 or 6 day loading period, consisting of approximately 20 grams of creatine per day.
1. Five sets of 30 maximum voluntary knee extensions, with 60 seconds rest between sets. (2)
2. Ten x 6 second bouts with 30 seconds rest. High intensity work on a bicycle ergometer. Placebo controlled, double-blind study design.(3)
3. Bench press; 5 sets to failure (predetermined 10 rep maximum), with 2 minute rest periods. Jump squats; 5 sets of ten, with 2 minute rest periods, using 30% of each subjects predetermined 1 rep. maximum. Placebo controlled, double-blind study design. (4)
4. Maximum continuous jumping exercise; 45 seconds. All-out treadmill running (approx. 60 seconds), at 20 km/hr, 5 degree incline. Placebo controlled, double-blind study design. (5)
5. Cycling to exhaustion at 150% peak VO2 at several different protocols; non-stop (a), 60 seconds work / 120 seconds rest (b), 20 seconds work / 40 seconds rest (c), and 10 seconds work / 20 seconds rest (d). Group D showed the greatest improvement with creatine supplementation. Placebo controlled, double-blind study design. (6)
It is interesting to note that one study, which looked at intermittent, high intensity work, found that caffeine completely abolished the ergogenic effect of creatine supplementation (7). Despite this, some of the commonly available supplements, such as powdered drink mixes possessing many ingredients, contain both creatine and caffeine !
As expected, the studies which looked at endurance exercise failed to show any benefit of creatine compared to placebo. In fact one study, which measured running performance over a 6 km course, found slower times in the creatine supplemented group (8). This effect is possibly related to the weight gain (mean 1 kg ) associated with creatine use. Since the creatine-ATP system is not used by endurance athletes, the weight gain is "dead weight" -- it adds nothing to moving the athlete forward. Instead, the extra weight makes the athlete less efficient.
Side effects and adverse reactions to creatine supplementation
Short term (less than 2 weeks) exercise studies have not reported any adverse events associated with creatine supplementation. There have been no long term studies done to evaluate the safety of prolonged administration. This is unfortunate because increasingly more and more athletes are taking creatine supplements for longer periods. Anecdotal reports have begun to emerge and have noted increased muscle cramping (especially during exercise in the heat), nausea and other gastrointestinal disturbances, elevated liver transaminases, and acute renal injury.
Creatine supplementation, in the dosages commonly used, results in urinary concentrations that are 90 times greater than normal. The long term effects of this have not been investigated, but there is possibility for a variety of nephrotoxic, i.e., kidney damaging, events. There is potential for direct toxicity on renal tubules where urine is formed, and for acceleration of kidney stone formation. Recently, a baseball player for the Houston Astros was determined to have suffered from dehydration, kidney stones, and transient kidney damage as the result of creatine supplementation. Additionally, the deaths of 3 collegiate wrestlers this past year are being investigated to determine what role creatine supplementation may have played.
Impurities are present in virtually every manufactured product, and in some cases, even though the product may be considered harmless, the impurity is not. Such was the case in the late 1980's when an epidemic of cases of eosinophilia-myalgia syndrome, including over 30 deaths, were blamed on a contaminant present in L-tryptophan (9), an amino acid supplement widely taken as a sleep aid. Creatine, and other such supplements, are not regulated by the FDA. No published investigation has been conducted on creatine to determine what impurities might be present in creatine supplements, and what their long term effect might be.
The bottom line is that no one can confidently state that prolonged creatine supplementation is safe, and its use would best be avoided until more data can be compiled. Prolonged administration is, in essence, an uncontrolled toxicity study and one which might yield harmful results. Is it worth the risk? Remember, it's your body!
(1) Elevation of creatine in resting and exercising muscles of normal subjects by creatine supplementation. Harris R. et al . Clin. Sci. 1992: 83: 367-74
(2) Influence of oral creatine supplementation on muscle torque during repeated bouts of maximum voluntary exercise in man. Greenhaff PL, et al. Clin. Sci. 1993: 84: 565-71.
(3) Creatine supplementation and dynamic high-intensity intermittent exercise. Balsom PD, et al. Scand J Med Sci Sports. 1993: 3: 143-9.
(4) Creatine supplementation enhances muscular performance during high-intensity resistance exercise. Volek JS, et al. J Am. Diet. Assoc. 1997; 97; 765-770.
(5) Effect of oral creatine supplementation on jumping and running performance. Bosco C, et. al. Int. J. Sports Med. 1997; 18; 369-372.
(6) Creatine supplementation enhances intermittent work performance. Prevost MC, et al. Res. Quarterly Exerc. Sport. 1997; 68(3); 233-240.
(7) Caffeine counteracts the ergogenic action of muscle creatine loading. Vanderberghe K, et al. J Appl. Physiol. 1996; 80(2); 452-7.
(8) Creatine supplementation per se does not enhance endurance exercise performance. Balsom PD, et al. Acta Physiol Scand. 1993; 149; 521-3.
(9) Tryptophan produced by Showa Denko and epidemic eosinophilia-myalgia syndrome [comment]. [Review] [22 refs]. Kilbourne EM. Philen RM. Kamb ML. Falk H. Journal of Rheumatology - Supplement. 46:81-8; discussion 89-91, 1996 Oct. Institution: Centers for Disease Control and Prevention, US Department of Health and Human Services, Atlanta, Georgia 30333, USA.
Other refernces used in this review
(10) Creatine in Humans with Special Refernce to Creatine Supplementation. Balsom PD, et al. Sports Med 1994; 18(4); 268-280.
Biochemistry: The Chemical Reactions of Living Cells. . David E. Metzler. Academic Press Inc. 1977
Exercise Physiology: Energy, Nutrition, and Human Performance. McArdle, Katch, and Katch. Lea & Febiger. 3rd Edition. 1991
Harrison's : Principles of Internal Medicine. McGraw-Hill. 1998
Creatine is used in muscle cells to store energy for sprinting and explosive exercise. Athletes can increase the amount of creatine in muscle by taking creatine supplements. Although some studies report no ergogenic effect, most indicate that creatine supplementation (e.g. 20 g per day for 5 to 7 days) increases sprint performance by 1-5% and work performed in repeated sprints by up to 15%. These ergogenic effects appear to be related to the extent of uptake of creatine into muscle. Creatine supplementation for a month or two during training has been reported to promote further gains in sprint performance (5-8%), as well as gains in strength (5-15%) and lean body mass (1-3%). The only known side effect is increased body weight. More research is needed on individual differences in the response to creatine, periodic or cyclical use of creatine, side effects, and long-term effects on endurance.
Creatine is an amino acid, like the building blocks that make up proteins. Creatine in the form of phosphocreatine (creatine phosphate) is an important store of energy in muscle cells. During intense exercise lasting around half a minute, phosphocreatine is broken down to creatine and phosphate, and the energy released is used to regenerate the primary source of energy, adenosine triphosphate (ATP). Output power drops as phosphocreatine becomes depleted, because ATP cannot be regenerated fast enough to meet the demand of the exercise. It follows that a bigger store of phosphocreatine in muscle should reduce fatigue during sprinting. Extra creatine in the muscle may also increase the rate of regeneration of phosphocreatine following sprints, which should mean less fatigue with repeated bursts of activity in training or in many sport competitions.
So much for the theory, but can you get a bigger store of creatine and phosphocreatine in muscle? Yes, and it does enhance sprint performance, especially repeated sprints. Extra creatine is therefore ergogenic, because it may help generate more power output during intense exercise. In addition, long term creatine supplementation produces greater gains in strength and sprint performance and may increase lean body mass. In this article I'll summarize the evidence for and against these claims. I'll draw on about 42 refereed research papers and four academic reviews to make conclusions regarding the ergogenic value of creatine supplementation. In addition, I'll provide 25 references to studies published in abstract form, which report the most recent preliminary findings on creatine supplementation.
Effects of Creatine Supplements on Muscle Creatine, Phosphocreatine, and ATP
The daily turnover of creatine is about 2 g for a 70 kg person. About half of the daily needs of creatine are provided by the body synthesizing creatine from amino acids. The remaining daily need of creatine is obtained from the diet. Meat or fish are the best natural sources. For example, there is about 1 g of creatine in 250 g (half a pound) of raw meat. Dietary supplementation with synthetic creatine is the primary way athletes "load" the muscle with creatine. Daily doses of 20 g of creatine for 5-7 days usually increase the total creatine content in muscle by 10-25%. About one-third of the extra creatine in muscle is in the form of phosphocreatine (Harris, 1992; Balsom et al., 1995).
Extra creatine in muscle does not appear to increase the resting concentration of ATP, but it appears to help maintain ATP concentrations during a single maximal effort sprint. It may also enhance the rate of ATP and phosphocreatine resynthesis following intense exercise (Greenhaff et al., 1993a; Balsom et al., 1995; Casey et al., 1996).
There is some evidence that not all subjects respond to creatine supplementation. For example, one study reported that subjects who experienced less of a change in resting muscle creatine (<20 mmol/kg dry mass) did not appear to benefit from creatine supplementation (Greenhaff et al., 1994). However, more recent studies indicate that taking creatine with large amounts of glucose increases muscle creatine content by 10% more than when creatine is taken alone (Green et al., 1996a; Green et al., 1996b). Consequently, ingesting creatine with glucose may increase its ergogenic effect.
Effects on Performance
Researchers first investigated the ergogenic effects of short-term creatine loading. In a typical study, a creatine dose of 5 g is given four times a day for five to seven days to ensure that muscle creatine increases. A control group is given a placebo (glucose or some other relatively inert substance) in a double-blind manner (neither the athletes nor the researchers doing the testing know who gets what until after the tests are performed). Most studies have shown that speed or power output in sprints--all-out bursts of activity lasting a few seconds to several minutes--is enhanced, typically by 5-8%. Repetitive sprint performance is also enhanced when the rests between sprints don't allow full recovery. In this case, total work output can be increased by 5-15%. There is also evidence that work performed during sets of multiple repetition strength tests may be enhanced by creatine supplementation, typically by 5-15%. In addition, one-repetition maximum strength and vertical-jump performance may also be increased with creatine supplementation, typically by 5-10%. The improvement in exercise performance has been correlated with the degree in which creatine is stored in the muscle following creatine supplementation, particularly in Type II muscle fibers (Casey et al., 1996).
Researchers have now turned their attention to longer-term creatine supplementation. In these studies, a week of creatine loading of up to 25 g per day is followed by up to three months of maintenance with reduced or similar dosages (2-25 g per day). Training continues as usual in a group given creatine and in a control group given a placebo. Greater gains are now seen in performance of single-effort sprints, repeated sprints, and strength (5-15%).
Table 1 at the end of this article lists the references to positive effects of creatine on performance. Theoretically, creatine may affect performance through one or more of the following mechanisms (Table 2): an increase in concentrations of creatine and phosphocreatine in resting muscle cells; an increased rate of resynthesis of phosphocreatine between bouts of activity; enhanced metabolic efficiency (lower production of lactate, ammonia, and/or hypoxanthine); and enhanced adaptations through higher training loads. Creatine supplementation during training may also promote greater gains in lean body mass (see Body Composition below).
Not all studies have reported ergogenic benefit of creatine supplementation (Table 3). In this regard, a number of equally well-controlled studies indicate that creatine supplementation does not enhance: single or repetitive sprint performance; work performed during sets of maximal effort muscle contractions; maximal strength; or, submaximal endurance exercise. What's more, one study reported that endurance running speed was slower, possibly because of an increase in body mass (Balsom et al., 1993b).
In analysis of these studies, creatine supplementation appears to be less effective in the following situations: when less than 20 g per day was used for 5 days or less; when low doses (2-3 g per day) were used without an initial high-dose loading period; in crossover studies with insufficient time (less than 5 weeks) to allow washout of the creatine; in studies with relatively small numbers of subjects; and when repeated sprints were performed with very short or very long recovery periods between sprints. It is also possible that subject variability in response to creatine supplementation may account for the lack of ergogenic benefit reported in these studies. In addition, there have been reports that caffeine may negate the benefit of creatine supplementation (Vandenberghe et al., 1996). Consequently, although most studies indicate that creatine supplementation may improve performance, creatine supplementation may not provide ergogenic value for everyone.
Although some studies have found no effect, most indicate that short-term creatine supplementation increases total body mass, by 0.7 to 1.6 kg. With longer use, gains of up to 3 kg more than in matched control groups have been reported (see Table 4 at the end of this article for references). For example, Kreider et al.(1998) reported that 28 days of creatine supplementation (16 g per day) resulted in a 1.1 kg greater gain in lean body mass in college football players undergoing off-season resistance/agility training. In addition, Vandenberghe et al. (1997) reported that untrained females ingesting creatine (20 g per day for 4 days followed by 5 g per day for 66 days) during resistance training observed significantly greater gains in lean body mass (1.0 kg) than subjects ingesting a placebo during training. The gains in lean body mass were maintained while ingesting creatine (5 g per day) during a 10-week period of detraining and in the four weeks after supplementation stopped.
Findings like these suggest that creatine supplementation may promote gains in lean body mass during training, but we don't yet understand how it works. The two prevailing theories are that creatine supplementation promotes either water retention or protein synthesis. More research is needed before we can be certain about the contribution each of these processes makes to the weight gain.
In studies of preoperative and post-operative patients, untrained subjects, and elite athletes, and with dosages of 1.5 to 25 g per day for up to a year, the only side effect has been weight gain (Balsom, Soderlund & Ekblom, 1994). Even so, concern about possible side effects has been mentioned in lay publications and mailing lists. Before discussing these possible side effects, it should be noted that they emanate from unsubstantiated anecdotal reports and may be unrelated to creatine supplementation. We must be careful to base comments regarding side effects of creatine supplementation on factual evidence, not speculation. But we must also understand that few studies have directly investigated any side effects of creatine supplementation. Consequently, discussion about possible side effects is warranted.
Anecdotal reports from some athletic trainers and coaches suggest that creatine supplementation may promote a greater incidence of muscle strains or pulls. Theoretically, the gains in strength and body mass may place additional stress on bone, joints and ligaments. Yet no study has documented an increased rate of injury following creatine supplementation, even though many of these studies evaluated highly trained athletes during heavy training periods. Athletes apparently adapt to the increase in strength, which is modest and gradual.
There have been some anecdotal claims that athletes training hard in hot or humid conditions experience severe muscle cramps when taking creatine, and the cramps have been attributed to overheating and./or changes in the amount of water or salts in muscle. But no study has reported that creatine supplementation causes any cramping, dehydration, or changes in salt concentrations, even though some studies have evaluated highly trained athletes undergoing intense training in hot/humid environments. In my experience with athletes training in the heat (e.g., during 2-a-day football practice in autumn), cramping is related to muscular fatigue and dehydration while exercising in the heat. It is not related to creatine supplementation. Nevertheless, athletes taking creatine while training in hot and humid environments should be aware of this possible side effect and take additional precautions to prevent dehydration.
Some concern has been raised regarding the effects of creatine supplementation on kidney function. The body seems to be able to dispose of the extra creatine without any problem (Poortmans et al., 1997). The extra creatine is eliminated mainly in the urine as creatine, with small amounts broken down and excreted as creatinine or urea. No study has shown that creatine supplementation results in clinically significant increases in liver damage or impaired liver function.
It has also been suggested that creatine supplementation could suppress the body's own creatine synthesis. Studies have reported that it takes about four weeks after cessation of creatine supplementation for muscle creatine (Vandenberghe et al., 1997) and phosphocreatine (Febbraio et al., 1995) content to return to normal. It is unclear whether muscle the content falls below normal thereafter. Although more research is needed, there is no evidence that creatine supplementation causes a long-term suppression of creatine synthesis when supplementation stops (Balsom, Soderlund & Ekblom, 1994; Hultman et al., 1996).
Does creatine supplementation have undiscovered long-term side effects? Trials lasting more than a year have not been performed, but creatine has been used as a nutritional supplement for over 10 years. Although long-term side effects cannot discounted, no significant short-term side effects other than weight gain have been reported. In addition, I am not aware of any significant medical complications that have been linked to creatine supplementation. Furthermore, creatine and phosphocreatine have been used medically to reduce muscle wasting after surgery and to improve heart function and exercise capacity in people with ischemic heart disease (Pauletto & Strumia, 1996; Gordon et al., 1995). Creatine supplementation may even reduce the risk of heart disease by improving blood lipids (Earnest, Almada & Mitchell, 1996; Kreider et al., 1998). On the basis of the available research, I consider creatine supplementation to be a medically safe practice when taken at dosages described in the literature.
Determining whether creatine supplementation has any short- or long-term side effects is an area receiving additional research attention. If there are side effects from long-term creatine supplementation, an important issue will be the liability of coaches, trainers, universities, and athletic governing bodies who provide creatine to their athletes. Anyone advising athletes to take creatine should make it clear that side effects from long-term use cannot be completely ruled out, and that the athletes do not have to take the supplements. It would be wise to have a formal policy for dosages to reduce the chances of athletes taking excessive amounts.
Creatine supplementation is not banned, but is a nutritional practice that enhances performance nevertheless unethical? Anyone pondering this question should consider that creatine supplementation is a practice similar to carbohydrate loading, which is well accepted. Some are also concerned that creatine supplementation could cause a carryover effect, whereby athletes who have learned to take creatine are more likely to use dangerous or banned substances. Proper education among athletes, coaches, and trainers regarding acceptable and unacceptable nutritional practices is probably the best way to reduce any carryover.
How to Use Creatine
A typical loading regime for a 70-kg athlete is a 5-g dose four times a day for a week. Thereafter the dose can be reduced to 2 to 5 g per day in order to maintain elevated creatine content. This supplementation protocol will increase intramuscular creatine and phosphocreatine content and enhance high intensity exercise performance. There is now some evidence that taking glucose (100 g) with the creatine (5 to 7 g) increases the uptake of creatine into muscle (Green et al., 1996a; Green et al., 1996b). Consequently, I recommend that athletes take creatine with carbohydrate (e.g. with grape juice) or ingest commercially available creatine supplements that combine creatine with glucose. For athletes wanting to promote additional gains in lean body mass, I recommend 15 to 25 g per day for 1 to 3 months. Although many athletes cycle on or off creatine, no study has determined whether this practice promotes greater gains in fat free mass or performance than continuous use. More research is needed here.
Creatine supplements are good value
What is creatine?
Creatine is a naturally occurring compound derived from glycine and arginine and found primarily in the heart, brain, and skeletal muscle. It plays a key role in the body's energy system, and has many secondary roles. The average American gets about one gram of creatine per day from their diet, and one gram is produced in the body. Herring, salmon, tuna, and beef are all high in creatine, but you would have to eat very large amounts of these foods to get the benefits achieved through supplementation. Creatine is used primarily to increase athletic performance, but may also be useful in preventing various conditions affecting the brain, heart, and musculature.
2. What application does creatine have?
Creatine supplementation combined with strength training has been shown to cause dramatic improvements in muscle size and strength. A recent meta-analysis at the Medical College of Wisconsin of sixteen placebo-controlled trials on healthy adults showed creatine supplementation to increase the one rep maximum for bench press by an average of 15.07 lbs. (6.85 kg) and squat by an average of 21.47 lbs. (9.76 kg) with a 95% confidence interval (1). Additionally, creatine supplementation causes a significant increase in hypertrophy. A study that measured muscle fiber hypertrophy with creatine supplementation for 12 weeks found a 35%, 36%, and 35% increase in Type I, IIA, and IIAB muscle fiber cross-sectional areas, respectively, compared to 11%, 15%, and 6% in the placebo group (2).
3. How does creatine work?
After being ingested, creatine is absorbed into the bloodstream, most likely by the amino acid transporter (3), and usually reaches a maximum plasma concentration in less than two hours (4). While blood levels are elevated, the creatine transporter (CreaT) actively transports creatine into skeletal muscle, cardiac muscle, and the brain (3). At this point, there are a variety of mechanisms by which creatine may exert its ergogenic effects.
• Modulation of energy metabolism - Creatine operates as an energy and pH buffer during exercise. Creatine kinase catalyzes a reaction between free creatine and phosphor ions (from the breakdown of ATP to ADP), resulting in phosphocreatine (PCr), which is locked into the muscle cell due to its strong negative charge. The PCr can then react with ADP to form ATP during exercise, and during rest periods more PCr is generated. All of this equates to more energy during sets and faster recovery between sets (3).
• Increased protein synthesis - Supplementing with creatine has been shown to increase intracellular water retention (5). Not only does this have the benefit of making the muscles appear larger, it may have an anabolic effect as well. Hyperhydration stimulates protein synthesis and inhibits protein breakdown, and cell volume has a correlation with catabolism in a variety of ailments (6). Numerous studies have confirmed that creatine supplementation prevents protein catabolism (3, 7). There is also evidence that creatine increases satellite cell mitotic activity (8).
• Reduced oxidative stress - In addition to direct effects on energy metabolism and protein synthesis, creatine also has indirect effects on them because it protects against tissue damage, thus increasing the body's ability to regenerate ATP (3) and synthesize protein and protecting against a variety of other harms caused by exercise-induced oxidation. Creatine primarily protects against the peroxynitrite and superoxide free radicals (9).
4. What are some further benefits of creatine use?
• Neuroprotection - Creatine is found in high concentrations in the brain, and is being explored in the treatment of a variety of neurodegenerative diseases. Creatine supplementation increases total creatine levels primarily in grey matter, white matter, the cerebellum, and the thalamus. Similar to its action in skeletal muscle, creatine operates through a variety of pathways in the brain, such as reducing oxidative stress and correcting mitochondrial dysfunction (3). A recent study on mice and rats showed creatine to provide a 36%-50% reduction in cortical damage caused by traumatic brain injury by improving mitochondrial function, decreasing reactive oxygen species, and maintaining ATP levels (10). This is a new area of research, so few human studies have been done on its neuroprotectant effects at this point. One study found that supplementation of creatine at 5 grams a day for 8 days decreased task-evoked mental fatigue and increased oxygen utilization in the brain (11).
• Cardiac health - Since creatine is also found in high concentrations in the heart, its activity there has been studied as well. It protects the heart in a variety of ways, and has been shown to reduce the occurrence of arrhythmia (12), protect cardiac tissue from metabolic stress (13), and reduce plasma cholesterol and triglycerides (14).
5. Are there any side effects?
There are very few side effects associated with creatine use (3, 22). Gastrointestinal discomfort is experienced by some, but generally goes away when dosage is lowered. Weight gain is also a common side effect, however this is mostly water weight (from muscle cell volumization). There are two case reports in the literature of creatine exacerbating renal dysfunction, but multiple studies have shown it to have no impact on healthy individuals (3, 15, 21, 22). You should consult a doctor before using creatine if you have a kidney disorder.
7. How should I take creatine?
According to a study measuring 24-hour urinary excretion of creatine and creatinine, resistance-trained athletes can generally utilize about 50 mg/kg of creatine per day (about 3.5-6 grams) (17). Since creatine is so inexpensive and effective, it is generally best to overshoot this mark. Most users choose to supplement with 5-15 grams daily, spread out over 2-3 doses. There are also a variety of ways to increase creatine uptake. Exercise (18), insulin (19, 20), thyroid hormone (T3) (20), and IGF-1 (20) all increase the amount of creatine uptake into skeletal muscle. This makes pre- and post-workout ideal times to take creatine. Also, because of the effect insulin has on increasing creatine uptake, it is most effective when mixed with a beverage with a high insulin response. Dextrose is ideal, but any non-acidic beverage with a high sugar (non-fructose) content will do. Grape juice is about 50% dextrose.
• Loading - Many creatine users believe it is beneficial to begin use with a "loading" phase in which 20-30 g is taken over 4-6 doses daily for a few days. The literature on loading is conflicting, and the same level of saturation can be achieved with regular, low-dose supplementation, although it may take longer. The decision is ultimately up to the user, as both methods are effective.
• Cycling - This is the idea of taking a week off of creatine every 8-12 weeks to allow natural production of creatine to return to normal levels. This is done because creatine consumption downregulates the creatine transporter, although levels quickly return to normal upon cessation of use (3). Whether or not cycling is beneficial is still up in the air, but it is definitely not necessary.
8. What are some good products to take along with creatine?
Although insulin increases muscle creatine uptake, one should avoid taking high amounts of high glycemic foods on a chronic basis as this could lead to insulin resistance. Supplements that increase insulin sensitivity can be very beneficial in this regard. Alpha lipoic acid is probably the best choice, as it is even better than many prescription drugs at improving insulin sensitivity and also has many other beneficial effects. The recommended dosage is 100-200 mg of ALA every time creatine is consumed.
A Beginners Guide to Creatine
Creatine is a substance found naturally in your body. Every time you perform any type of intense exercise (such as sprinting, or training with weights), your body uses Creatine to provide your body with energy. Unfortunately, creatine stores only last for a maximum of around 10 seconds. That's why you can't sprint "all-out" for very long - your creatine stores become depleted.
Adding Creatine to your diet raises the levels of Creatine in your body.
This dramatically improves your performance in the gym, or on the field of play. Creatine also speeds up muscle growth, leading to gains of 3 or 4 pounds in less than 7 days. Creatine supplementation has been shown in a number of studies to enhance maximal strength , improve sporting performance in soccer players , and accelerate gains in lean muscle mass .
Recent studies have also shown that creatine users gain muscle and strength far more quickly than subjects using a placebo. For example, test subjects given Creatine for 12 weeks in combination with a weight-training programme gained a massive 24% and 32% more strength in the bench press and squat, respectively. What's more, they also gained twice as much lean muscle - despite the fact they did the same amount of training . These kind of results are typical for virtually anyone using Creatine.
Creatine is also perfect if you're impatient for faster gains in muscle strength and size. A study published in the prestigious journal Medicine and Science in Sports and Exercise showed that just five days after using 20 grams of Creatine daily, test subjects gained an impressive 3.1 pounds of lean muscle .
You'll find Creatine in many animal foods, such as salmon, tuna and beef.
Although it is possible to get Creatine from your diet, it would be almost impossible to get enough to have any effect on performance. The Creatine in food can also be "damaged" by cooking. It's because of this that many athletes rely on Creatine supplements to provide them with a competitive edge.
With more research than any other supplement, Creatine has been shown to work amazingly well across a whole range of sports and goals. By adjusting the dosages and how you take it, it can help pack on muscle size and strength fast, yet with a quick change in dosage it can be used for increased endurance, stamina and power.
A recent study showed that Creatine significantly improves the performance of middle distance runners. Scientists at Belgium's Katholieke University also report that elite cyclists were able to improve performance by an impressive 9% during exercise lasting more than two hours.
What's more, there is now hard evidence that Creatine can enhance performance in footballers. A recent study showed that Creatine leads to faster sprinting times and improved jumping performance after only six days. The research team from Spain examined a group of 19 national level players from Athletic Club de Bilbao, one of Europe's leading footballing sides. The players were divided into two groups. Group one were given Creatine for six days. Group two received a 'dummy' supplement that had no effect.
The players were then asked to perform a series of tests. These included a number of sprinting and jumping drills that closely matched the demands of a match. The group who used Creatine were consistently able to outperform the non-Creatine users during both 5 and 15 metre sprints. These improvements in performance were enough to have a big impact on a player's performance. "More than enough", according to the researchers, "to outrun an opponent and attain possession of the ball."
Even the supplement sceptics now admit that Creatine is very impressive.
In fact so impressive is Creatine at improving performance across all athletes, that it is now the most used supplement amongst Olympic athletes, along with protein and energy drinks. Research has now proven that when taken even for several years, Creatine exhibits no side effects or health implications. In fact researchers are now finding it can actually improve health in women, the elderly and people with certain medical conditions.
Scientists recognised that after the age of 30 years there is a progressive decline in muscle mass and function. By the time many people reach old age, this can make normal everyday activities into challenges requiring maximum effort. In relative terms, tasks such as putting shopping on the kitchen table, or walking up a flight of stairs becomes the equivalent of a maximum effort dumbbell curl, or a 200m sprint for a top athlete!
Recognition of these facts prompted several research groups to investigate the effects of creatine supplements in older people. Their findings in the elderly were the same as those in athletes. Creatine supplementation improved strength, muscle power and increased lean body mass - reversing some of the effects of ageing.
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