| | | Creatine’s most notable trait is its role in the energy production process. It is an organic compound found in muscle fibers that is made from three amino acids: glycine, argininie, and methionine. ATP and CP (creatine phosphate) are stored in muscles and serve as a source of immediate energy. The more ATP and CP that is in the muscles, the more the muscle can lift. Additional creatine can be obtained through consuming meat and fish. Many athletes choose to supplement with creatine, though, because cooking meat converts the creatine into creatinine, which is easily flushed out of the body through the kidneys. |
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When an athlete supplements with creatine, it is usually with creatine monohydrate. Most commonly, athletes start with creatine loading, followed by a maintenance dose. Loading usually consists of 5 grams of creatine 4 times per day. This is done anywhere from 4-7 days. The maintenance dose is anywhere from 2-5 grams per day. Athletes have been using creatine for decades, but it has become popular more recently, once Olympic athletes began sharing their supplement schedules. Most athletes claim their reasons for taking creatine are for enhanced performance, strength, and muscle mass. Advertisers have jumped on the bandwagon and have begun marketing creatine toward specific athletes, including weight lifters, sprinters, and endurance athletes. In this article, I will investigate the accuracy of these claims. The articles I used are referenced at the end of this article.
Research shows that supplementing with creatine has been effective in certain circumstances. When sprinters were tested[1], those who loaded with creatine (25grams for 5 days) increased their sprint power output compared to a group taking a placebo. Football players who did the same increased their weight lifting ability and total body mass.
In one double blind study[2], female volleyball players were studied for 10 weeks. They were divided into 2 groups - a creatine group, and a placebo group. The creatine group ingested 5 grams of creatine 4 times per day, for 5 days. After the initial loading phase, they consumed 5g of creatine per day. The placebo group followed the same pattern using a glucose placebo. Both groups participated in a program including weight training and plyometric training. Before and after the experiment, both groups were measured for body weight, lean body mass, and body fat percentage. They were also tested on the vertical jump and their 1 rep max on the bench press. Predictably, both groups improved but the creatine group had greater gains in the bench press and vertical jump. Furthermore, they experienced greater increases in body weight and lean body mass, although there was no change in body fat percentage.
Another double blind study compared the use of a carbohydrate/protein combination to a carbohydrate/creatine combination. This study included 2 groups of untrained male participants who went through 8 weeks of resistance training. 30 minutes after exercise
they either ingested a combination of 75 grams of carbohydrates +10 grams of protein, or 75 grams of carbohydrates + 10 grams of creatine. After the 8 weeks, the creatine group gained more body mass. A similar study involved participants who did heavy resistance training for 10 weeks. They ingested one of three things: protein only, a protein/carbohydrate combination, or a protein/carbohydrate/creatine combination. This resulted in greater increases in strength and muscle growth for the group that included the creatine.
Those studies[3] indicate that creatine supplementation has a place along with a regular resistance training program, leading to greater improvements in strength than a conditioning program without creatine. Creatine has thus been shown to improve athletic performance in activities that involve short periods of intense exertion.
There have also been several additional studies showing creatine to be effective in increasing muscle mass during training. These tests usually show gains of 2-5 pounds more than control groups during 4-12 weeks of training.[4] This is most likely because of one of two reasons; a result of the athletes’ ability to train harder due to their enhanced capability to perform high intensity exercise which leads to greater gains, or it could be that supplementing with creatine frees up glycine, arginine, and methionine to be used for other anabolic functions.
So we now know that creatine benefits anaerobic athletes. But what about endurance athletes? Do the claims hold up? Let’s take a closer look.
In 1998 a unique study[5] was conducted in which creatine was tested in endurance athletes. In many endurance competitions, the athlete is required to exert short bursts of energy at times. For example, a 5K runner will often speed up at the end of the race. The study involved athletes ingesting 3 grams of creatine twice daily for 5 days. On day 6, the outcomes were evaluated. The results showed that the interval performance part of the activity was, in fact, enhanced by the creatine – performance was increased by18%; however, the endurance performance was not affected.
Several other studies have also been done strictly to test the creatine effect on endurance athletes, resulting in no improvement at all. In fact, some studies show decreased performance in endurance athletes who used creatine. This is suspected to be due in part to the weight gain associated with creatine use, which is not an asset for these athletes.[6]
These results make sense when you look at the differences between endurance athletes and anaerobic athletes. Anaerobic athletes rely on ATP and creatine for immediate energy in their sports, as discussed earlier. Endurance athletes, on the other hand, do not. They rely on oxidative metabolic pathways to produce the majority of energy they need. This could come from glucose, muscle glycogen (stored carbohydrates in the muscle), fat, or amino acids. Due to the nature of their sports, endurance athletes would benefit more from carbohydrate loading and carbohydrate drinks.
Since creatine use has become so attractive, research has been done to determine the safety of creatine. Studies show that the usual loading and maintenance doses (20 grams per day for one week, followed by up to 5 grams per day) are safe. Further inspection reveals that more is not better[7], and could possibly put unnecessary strain on the renal system[8], since creatine is excreted through the kidneys. Individuals who currently have renal disease should not use creatine, and elderly users should have their renal function checked regularly.
After hundreds of studies and years of research on creatine, it can be concluded that creatine supplementation is a safe and effective way to enhance athletic performance in anaerobic athletes when the recommended doses are used. Despite aggressive marketing, creatine has not been proven to be effective for endurance athletes.
Copyright © 2009 by A.M. Birmingham, ISSA CFT, SPN
Reference Websites:
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