Bioenergetics Part 1: Creatine Phosphate

Bioenergetics is a field of biochemistry that explains how the body converts energy into a usable form to accomplish mechanical work. Notice I didn’t say that the body creates energy for mechanical work. According to the First Law of Thermodynamics, no energy is ever created or destroyed. All of the energy that we are able to convert to usable energy forms comes from the sun and enters our body through eating, drinking and breathing. The body has four primary ways of producing ATP (fuel for mechanical work), and over the next month or so I will be writing a post about each. First up is the ATP-Pc energy system.

So right off the bat we need to get some vocabulary straight. Adenosine Triphosphate (ATP) is to the human body what gasoline is to the car. ATP interacts with myosin which attaches to the actin filament causing contraction. Once this contraction occurs the ATP becomes ADP, because it loses a phosphate in the contraction process. So this ADP can’t be used for contraction again until phosphorylation occurs (the addition of a phosphate). This is where the energy systems come into play.

The Creatine Phosphate energy system is an anaerobic energy system and is the first energy system used during maximal work. It is the fastest energy system because it requires only one chemical reaction to produce an ATP. A molecule of Phosphocreatine (Pc) meets up with a molecule of ADP and the enzyme Creatine Kinase causes the phosphate group bonded to creatine to join the ADP molecule. This makes ATP and leaves a creatine molecule.  Pretty simple, right? Your body can use the ATP-Pc energy system to produce roughly ten seconds of maximal work, and in about 2 minutes, it’s ready to yield another ten seconds of maximal work. Think of this energy system as a toilet. Once you pull the lever it takes about 10 seconds to flush all the water, and then it takes about two minutes for the tank to refill to allow for another flush. If you were to flush before the tank was entirely full, you would empty the tank, but it wouldn’t take 10 seconds to empty this time. The same is true for the phosphor creatine system. Fortunately, after the initial ten seconds of work, anaerobic glycolysis is ready to kick in and pick up the slack. We will talk about anaerobic glycolysis next time.

So now that the Creatine Phosphate energy system has been explained (hopefully), I would now like to talk about creatine supplementation. Anyone who has ever flipped through the pages of a Muscle and Fitness/Fiction magazine has heard boisterous claims of the unregulated supplement industry concerning creatine. For your pleasure/laughter (mostly the latter), I have compiled some of the more humorous product claims that I was able to come across on a recent trip to the GNC and have posted them at the bottom of this article. While there is a lot of ridiculous hype that comes with creatine supplementation, there is no denying that the stuff works. By boosting the amount of creatine stored in the body, the proverbial toilet tank begins to hold more water (produce more ATP) before it needs to be refilled. Wichita State University has been on the cutting edge in researching the effects of creatine supplementation in the elderly, and in a recent study they found that old people who were taking creatine and working out averaged 15% more strength gains than groups using the same workout protocol but not supplementing with creatine. This same study has been done on athletes and other people and has been substantiated over and over. 

So some of you might be thinking, “Why should I care about energy systems?” I reply with an equally thoughtful question (like Socrates). How do you feel about rigor mortis? Not only do your muscles need ATP to contract a muscle, but ATP is also needed to return the muscle to its resting length. This, coupled with the fact that at any given moment your body has only enough ATP to keep you alive for 2-3 seconds, should be enough to convince you that knowledge of energy systems is important. Thank you for your readership, and please comment if you have any questions, comments, concerns or rebukes.

“947% increase in lean mass” – Gaspari Nutrition, Super Pump 250

“234% increase in muscle performance” –Gaspari Nutrition, Super Pump 250

“26 times more lean muscle mass than those who use creatine monohydrate alone”- Cell Tech Hardcore

“148.65% increase in muscle DNA”- NO Shotgun

- Will Hawkins 

Rogers, Michael E., and Ruth M. Bohlken. "EFFECTS OF CREATINE, GINSENG, AND ASTRAGALUS SUPPLEMENTATION ON STRENGTH, BODY COMPOSITION, MOOD, AND BLOOD LIPIDS DURING STRENGTH-TRAINING IN OLDER ADULTS." Journal of Sports Science and Medacine 5.1 (2006): 60-69. Print.

Howley, Edward T., and Scott K. Powers. Exercise Physiology: Theory and Application to Fitness and Performance. 7 ed. New York: McGraw-Hill, 2008. Print.