Do You Know Creatine?

What Is Creatine?
A French scientist discovered creatine in 1835. Creatine is a natural constituent of meat, mainly found in red meat. Creatine is manufactured naturally in the body from the amino acids glycine, arginine, and methionine. This process takes place in the kidneys, liver, and pancreas.
Approximately 40% of the body's creatine stores are free creatine (Cr), while the remaining 60% is stored in form of creatine phosphate (CP). The typical male adult processes 2 grams of creatine per day, and replaces that amount through dietary intake and fabrication within the body.
Creatine is used for the resynthesis of ATP. ATP, or adenosine triphosphate, is the "power" that drives muscular energetics. When a muscle is required to contract, the bonds in the ATP molecule are split, yielding ADP (adenosine-diphosphate). The energy released by breaking this bond powers the contraction of the muscle.
When ATP is depleted within the cell, the cell can no longer contract. There are several methods by which the body rebuilds ATP. The fastest method, without oxygen, is through CP. Creatine phosphate is "split" to yield the phosphate portion of the molecule.
This phosphate portion bonds to the ADP, turning it back to ATP. Once CP stores within the cell are depleted, the body must use other methods to replenish ATP.
Supplementation with creatine increases Cr and CP within the muscle, allowing further capacity to regenerate ATP. In other words, the creatine enhances the ability of the muscle to maintain power output during brief periods of high-intensity exercise. The periods are brief because the ability of a cell to store CP is limited, therefore the body will quickly move to other methods of replenishing ATP.
The majority of studies regarding creatine supplementation have used creatine monohydrate, the form of creatine bound to a water molecule. Some studies suggest that the combination of creatine and carbohydrate will enhance absorption or "uptake" of creatine. Science shows that creatine is unstable in liquid form, meaning that serum or liquid delivery systems are currently not supported by scientific literature.
The creatine rapidly degrades to creatinine, which is not useable by the body. There is very little support for the notion that creatine in any type of mixture, including an effervescent mixture, is absorbed more efficiently by the body. A company known as Albion Laboratories, Inc. claims to have found an effective delivery mechanism by chelating creatine to magnesium (a chelate is an organic compound that is typically absorbed more readily by the body than individual elements).
What Does Creatine Supplementation Do?

The common mechanism for creatine supplementation is known to be the increase of intramuscular creatine stores. It is known that CP is used to replenish ATP, and that the amount of CP naturally present is well below the maximum amount of CP that the body can store. Increasing dietary creatine allows the maximum amount of CP storage to be reached, which in turn provides more capacity to regenerate ATP.
An interesting effect of creatine supplementation appears to be enhanced ability for the muscle to store glycogen.
Glycogen is a form of carbohydrate stored inside the muscle that is used to fuel anaerobic activity (i.e. activity that is too intense to allow the cardiopulmonary system to deliver adequate oxygen).
The ATP-CP pathway is used during the initial few seconds that work is performed. The next dominant system uses glycolysis, which requires glycogen to fuel activity. After several seconds to a few minutes, the dominant system becomes the oxidative or cardiovascular system - in other words, aerobic exercise.
Many studies have shown that replenishing glycogen stores may aid recovery and hypertrophy (muscle growth). Bodybuilders use a protocol known as "carb-loading" to supersaturate their muscles with glycogen. Glycogen requires water to enter the muscle cell, therefore having higher glycogen levels means more fat-free mass and larger, fuller muscles.
If creatine does indeed increase the amount of glycogen storage achievable through super compensation or "loading", it stands to reason that a well-timed creatine cycle in conjunction with carb-loading will not only create incredible muscle fullness, but also potentially create an environment suited to optimal muscle growth. It should be noted that the super compensation was most pronounced when performed following a period of creatine supplementation, not during the initial period of supplementation itself.
An interesting effect of creatine supplementation is possible interaction with satellite cells. There are several different fiber types used to classify muscle tissue. In general, muscle tissue can be considered "endurance" fiber - able to perform multiple repetitions and highly resistant to injury - or "explosive" fiber - able to perform maximal workload for a short duration of time and highly susceptible to injury. There is a special type of muscle fiber known as "transitional fiber".
This fiber can be considered the "fight or flight" fiber - despite an individual's lack of overall fitness, when faced with a potentially dangerous situation, these fibers can "activate" to provide enormous bouts of strength. These fibers are easily damaged, but it has been shown that if cortisol levels are blocked subsequent to this damage occurring, instead of being "swept" away by the body, these cells fuse with "satellite" cells.
Satellite cells are special structures that are not true muscle cells until they fuse with transitional cells. The resulting cell is much larger and stronger. If these transitional fibers are appropriately activated and subsequent cortisol levels appropriately managed, creatine supplementation may help induce a significant hypertrophy effect.