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Articles The Basics of Creatine Supplementation - Part I Heather Pettingill, BSc, BPHE, BEd What is Creatine and what does it do? In order one to fully understand the role of Creatine, you need to familiar with the basics of exercise energy metabolism. When we exercise, the body needs energy to fuel its efforts. The body uses three main energy systems to power itself. For moderate intensity, long duration (i.e. greater than 3 min-- up to ultra marathons), the body uses a combination of carbohydrate and fat stores for fuel. The ability of your cardiovascular system to deliver oxygen to your working muscles determines your performance limits during this type of long duration activity. For shorter bursts of more intense effort lasting anywhere from about 30sec-3 min , the body relies only on glycogen --which is the body's storage form of carbohydrate. This energy system is called the anaerobic-lactic system because the processing of glycogen to create energy doesn't require oxygen ( anaerobic ), but, it does produce the nasty by-product lactic acid. The ability for an athlete to perform with all out effort over 30sec-3min is dependent on the athlete's ability to tolerate lactic acid build-up . Lactic acid is that "burning" feeling in your muscles you may have experienced during anaerobic intervals or during high repetition strength training. For maximal efforts of strength or power produced in 0-10 sec (i.e. a single maximal lift or a 5 sec sprint, or an explosive throw, or golf swing) the body relies on its quickest energy source -- the ATP/Creatine Phosphate system. As you could likely guess, the ATP/CP system uses creatine as its energy source. In her book Eat Smart, Play Hard, Liz Applegate, PHD, compares creatine to the "cylinders in your car's engine, helping fire up your muscles during high-intensity exercise such as weight lifting, jumping or sprinting. " The performance limiting factor during an athlete's efforts over 0-10sec is his or her available muscle stores of creatine.
Creatine is produced naturally within your liver or can be ingested in meats such as beef and fish. The body stores CPR (Creatine) within skeletal muscle and the average 70kg individual has a CPR pool of 120-140g (Bembem and La mont). The amount of "natural" Cr stored within your muscles is likely dependant on what you eat and what type of exercise you regularly engage in. Cr supplementation is potentially advantageous to those individuals who don't absorb or produce enough creatine "naturally."
Why might you want to supplement Creatine? According to manufacturers of Creatine supplements, active individuals who go through a loading phase of Cr over several days experience " incredible gains in strength, speed and training intensity." (Interactive Nutrition website). Some individuals suggest that when taken for a few weeks, creatine may even pump up muscle size. Of course supplement manufacturers are going to assert that their product produces amazing results, but what does the scientific community say about creatine supplementation? A search on PubMed* provided me with a link to hundreds of articles on creatine published in scientific journals. A recent review of Cr supplementation literature from 2005 dating back to 1999 concluded that regardless of sport, gender, or age, Cr ingestion did significantly and positively effect dynamic maximal force or strength contractions (Bembem and Lamont). In simpler terms, this comprehensive review of the scientific literature found that Cr supplementation did indeed make athletes of all types stronger, and more explosive.
Could every Active Individual benefit from creatine supplementation? This scientific review referred to above seems to suggest that if you are serious about your athletic performance that you will become stronger, more explosive, and develop more muscle if you supplement Cr. However, while science supports that the odds suggest that you should experience performance benefits if you supplement Cr, as Syrotuik and Bell found in their study, you still have a chance to fall into the category of Cr supplementers classified as "Non-Responders." Unfortunately, certain individuals find little benefit to supplementing Cr. The profiles of the "Non-Responders" include those individuals that already have a high percentage of "natural" intramuscular Cr stores or those individuals who possess a lower percentage of fast twitch (type 2) muscle fibres as well as less overall fat-free mass. The limitations of the study by Syrotuik and Bell was that it only assessed effects of Cr supplementation following a 5-day loading phase, and did not determine if "Non-Responders" would have experienced more favourable results if they had supplemented Cr over a longer period. Unfortunately, unless you have access to a Physiology lab, there is no way to pre-determine if you could potentially be classified as a "Non-Responder." Of interesting note from this study was that "Responders" (i.e. those that experienced performance improvements) experienced relatively fast results (i.e. within 5 days). Therefore, If you are considering supplementing Cr, keep in mind that if you don't feel positive results in a relatively short period, you might be a "Non-Responder" and would better off to save your money.
Other individuals who would likely NOT benefit from creatine supplementation include endurance athletes. Keep in mind that unless you are involved in activity that mainly relies on short bursts of 0-10 sec of all-out effort, creatine is probably not ideal for you. As will be discussed in the next section, one of the side effects of creatine supplementation is weight gain associated with water retention and muscle growth. While endurance athletes do rely on their ATP/CP energy systems for hill climbs or sprints to the finish line, they have to consider whether the weight gain associated with creatine is worth discrete increases in power. Over the long haul, the less weight you have to carry as an Endurance athlete, likely the more successful you'll be.
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Part II
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