By: Safi Madain BS, CSCS | Contributing Author
Creatine usage in sports, bodybuilding, and even rehabilitation has increased within the last 10 years. Does this mean that everyone that is using it is reaping the benefits? Most likely the answer is no. Creatine monohydrate, phosphocreatine, phosphagen (the names go on and on), are only beneficial to certain athletes and only for certain types of exercise. To better explain why this may be so, let’s answer some questions about creatine and energy sources.
What is Creatine?
As defined by Dorland’s Illustrated Medical Dictionary, “creatine is a crystallizable, nitrogenous compound synthesized in the body, with phosphorylated creatine being an important form of high-energy phosphate”. Creatine is a substance in the body that stores a phosphate molecule. This phosphate molecule has the ability to produce a high amount of energy.
How does the phosphate molecule produce energy?
The molecule that we ultimately use to produce energy is adenosine triphosphate or ATP. Whether it is glucose, fat, or protein, every energy mechanism ultimately produces ATP. An enzyme cleaves a phosphate off of ATP to produce ADP, and at the same time releases stored energy. This released energy allows for a muscle contraction. It does this by allowing one type of muscle filament (actin) to slide across another filament (myosin) by being pulled. This pulling action by the myosin filament is what needs the ATP work. It also requires another ATP molecule to release the myosin from the actin. During high intensity, anaerobic exercise, a creatine molecule with a phosphate attached (referred to as creatine-phosphate) will come in and restore the lost phosphate molecule on the newly formed ADP to transform it back into ATP. Thus replenishing some stored energy and making it ready to be utilized again. The key ingredients to this reaction are creatine phosphate, high intensity exercise, and creatine phosphokinase or CPK (the enzyme that transfers the phosphate molecule to ADP).
Why should someone take creatine supplements?
Our bodies do synthesize creatine phosphate, but our bodies do not synthesize the maximum amount that our muscles can hold. In theory, the more creatine phosphate we have in our muscles the greater the supply of potential energy. Ingesting 20 grams of creatine a day for 5 to 7 days can increase total muscle creatine content by 10-25% (Harris, 1992). But, there are several requirements that a person must have for creatine phosphate supplementation to be beneficial. First, a person must have enough creatine phosphokinase to be able to transfer the phosphate from the extra creatine phosphate molecules (we can induce the creation of CPK by stressing the body anaerobically). Second, the type of exercise must be high intensity, anaerobic exercise. It is during these types of activity that creatine phosphate is beneficial. Free floating ATP, and ATP that is generated from glycolysis (the energy system used during high intensity exercise) are the molecules that have a phosphate restored to them when they convert to ADP.
Who should take creatine supplements?
As discussed before, it is high intensity exercise that is affected by creatine phosphate. Examples of those who may benefit from creatine phosphate are athletes such as sprinters, power lifters, body builders, football players, and endurance athletes who incorporate resistance training. Studies have shown that repetitive sprint performance was enhanced by an increase of 5-15% in total work output. In addition, sets of multiple repetition strength tests were enhanced by 5-15% and that one repetition maximum and vertical jump performance also increased by about 5-10% (Casey, 1996). Studies on creatine supplementation for endurance sports or activities have not shown any improvement performance. The reason for this is that endurance sports use aerobic energy systems and that anaerobic systems are predominant for only the first one to two minutes of aerobic activity, which then the body starts to shift to aerobic mechanisms. Another reason may be the difference in dominant muscle fibers for each athlete. It has been shown that greater concentrations of creatine phosphate are stored in Type II muscle fibers (those used during high intense exercise) compared to Type I muscle fibers (those used during lower intensity, long duration exercise) (Casey, 1996). If you’re a long distance runner or swimmer, creatine supplementation won’t work for you as pertaining to your sport. But it may work for the endurance athlete that incorporates resistance training into his/her regimen. Since an increase in strength reduces the chance of injury, supplementing the body to push harder during resistance training sessions may be of benefit.
Recommended Dosage of creatine.
The most commonly recommended dosage for creatine involves a five to seven day loading period where four, five-gram doses are taken per day. Then after the loading phase is the maintenance phase where about five grams is taken each day. There are no long term studies that display any major side effects from taking creatine. It just has not been around long enough. Some people say that they have had muscle cramps, but drinking plenty of water should help prevent any cramps from happening. Just like any other supplement, creatine should not be abused and the recommended dosages should not be increased. Stick to these rules, and you should be fine.
- Creatine is a substance that is synthesized by the body
- Creatine supplementation increases the amount of creatine stored in muscle
- Creatine will give those involved in explosive or anaerobic activities a boost
- There is no benefit in using creatine to enhance performance in aerobic sports
- Endurance athletes who also resistance train may benefit from creatine, especially since increasing strength reduces the chance of injury
- There is a loading phase for creatine and each brand may differ slightly
- Just like any type of product, if it makes you feel ill, stop taking it
-Safi Madain BS, CSCS | Contributing Author
Casey, A., Constantin-Teodosiu, D., Howell, D., Hultman, E., Greenhaff, P. (1996). Creatine ingestion favorably affects performance and muscle metabolism during maximal exercise in humans. American Journal of Physiology. 271, E31-37.
Harris, R., Soderlund, K., Hultman, E. (1992). Elevation of creatine in resting and exercised muscle of normal subjects by creatine supplementation. Clinical Science, 83, 367-374.
Kreider, R.B. Creatine, the next ergogenic supplement? In: Sportscience Training and Technology. Internet Society for Sport Science. http://www.sportsci.org/traintech/creatine/rbk.html.
Richard B. Kreider, Ph.D. is affiliated with the Exercise and Sport Nutrition Laboratory, Human Movement Sciences and Education, University of Memphis, Memphis, Tennessee.