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.

Things a Wise Zebra Once Taught Me Part:1

It’s been a while since my last post, and for that I apologize, but I’ve been devoting most of my spare time these past weeks to reading rather than writing. I’ve been reading Robert M. Sapolsky’s “Why Zebras Don’t Get Ulcers,” and would highly recommend it to anyone who is interested in biology and/or the human body. The aim of the book is to explain how, “prolonged stress causes, and or intensifies a range of physical and mental afflictions.” So you may be wondering, how does stress apply to human performance? My answer is, anything that causes your body to leave its homeostatic state is a stressor, and there for any type of athletic endeavor is a “stressor.”


With this post I am beginning a series of post’s entitled “Things a Wise Zebra Once Taught Me.” The series is an attempt to look deeply at the bodies physiological response to stress caused by physical exertion, and to better understand how this knowledge can help athletes to train smarter. I hope my summary of Sapolsky’s work is of help to you.

Any public school educated second grader has learned that as they begin to run, there heart beat begins to race. Any second grade PE teacher could tell you that the reason this occurs is to allow the heart to pump more blood, through the lungs, faster, so the blood can be delivered to the working musculature to keep up the good work. While this answer is enough to suffice the inquisitive mind of the average second grader, it doesn’t explain the physiological reaction that occurs, and how it is remarkably similar to what’s going on in the body of a zebra being chased by a hungry lion. While these two stressors are definitely different types of stressors, your body’s response is not.

When your body senses a stressor (physical or psychological) the message is immediately sent to your brain (hypothalamus to be exact). Once your brain understands what is going on it makes a quick call over to the pituitary gland which initiates the Sympathetic Nervous System which is responsible for getting the body ready for one of four functions: fight, flight, fright, or sex. First, the body increases the stimulation rate of the accelerator nerve, which is responsible for regulating heart rate. Next, the body triggers hormonal secretions to prepare the body for one of the four previously stated functions. Most of the hormones secreted are the same no matter which stress response function you chose, there are however minute differences depending on the function chosen. Epinephrine (adrenaline), norepinephrine, and later glucocorticoid’s are allways released into your blood stream to allow your body to kick into ready mode.

So this stuff is already pretty cool, but it gets better. Your body is actually capable of instantly prioritizing which functions are necessary and which ones can wait. Do you think the zebra is spending massive amounts of energy on digesting that yummy grass it just ate? Or taking brakes to stop, and hide behind a tree so it can use the restroom? No the zebra is sending as much nutrient rich blood as it can to the working musculature, and turning as many functions off as it can, digestion included. One can easily see how if this stress was to become prolonged how big of a toll it would take on the body. Fortunately for the zebra, it lacks the cognitive ability to realize that in reality there are probably always lions within a few miles. To the zebra, the lion is out of sight, out of mind. To the human it is easy to stay up at night wondering if that minor headache you’re having could be the beginning of an onset of chronic migraines, or maybe a brain tumor? Because of humans increased cognitive ability we are prone to initiating our sympathetic nervous system (stress response) and being unable to turn it off.

This last paragraph is something we will continue to explore in the upcoming posts. When your stressed your body does turn of functions, some of these are extremely important for healthy living (i.e. immune system). I hope this post has at least peaked your curiosity and will lead you to come back and learn a few more “Things A Wise Zebra Once Taught Me.”

- Will Hawkins

Sapolsky, Robert M.. Why Zebras Don't Get Ulcers, Third Edition. 3rd ed. New York: Holt Paperbacks, 2004. Print.