Energy Systems – 1: Phosphagen (ATP-CP) System

Things are getting all sciencey in here, *cue music*.

Last week I posted about the different systems in the human body responsible for producing energy. Three to be specific.

I’m going to expand on those 3 a bit today, to show the different circumstances of how they trigger and how we can fuel to match going forward.

Today’s subject, class: The Phosphagen System (aka ATP-CP system)

This was my favourite system to study as for such a simple method to produce energy (using ATP) it produces impactful energy for the sole purpose of exercise less than 10 seconds long! 10 seconds!!! Our bodies can’t store ATP, the energy making molecule, we have to make it ourselves and these systems do this.

What’s more this energy system requires no nutritional fuel in carbs or fat, OR oxygen, it is ANaerobic, meaning requiring no oxygen.

Here’s how:

Creatine Phosphate (CP) is stored in our muscles. In it’s chemical structure, CP contains a phosphate group which is donated to a molecule called ADP (adenosine di-phosphate). When donated, ADP reacts to form ATP (adenosine TRI-phosphate).

Now the fun bit. Using water, ATP undergoes hydrolysis, a reaction involving water, and breaks down to from ADP and a spare phosphate (this phosphate is shuttled off elsewhere in the body for other bodily processes).

When ATP is broken down a proton, ‘free-energy’ and heat is produced. This free energy is utilized by the reacting muscle cell and used to fuel movement.

The cycle repeats itself over and over, with CP donating a phosphate group to ADP and starting back from ATP.


Image result for atoms


HOWEVER, due to a large amount of power required to do sprints or massively intense short bouts of energy less than 10 seconds long, our demand for ATP is high, therefore we fatigue very quickly, our body isn’t an infinite resource right? As demand is so high, it needs to be a fast process, and is the quickest way to resynthesise ATP to be broken down again.

So as we can see, no sugar was seen in this reaction, or even fat. Not much in nutritional value other than supplementary Creatine Phosphate. This is why Creatine supplements are quite paramount in exercise. Through taking Creatine we saturate our muscles allowing for more Creatine Phosphate being available for the above reaction, in theory, fatiguing slower. Creatine DOES NOT provide direct energy, only assists in the above reaction.

Supplements are a different subject on their own but it’s SO interesting to see how supplements can play a game in aiding exercise like this and bridging into nutrition.

But the verbal bridge here is that supplements will be discussed upon further at a later time, some are useful, some are not. All I’m aiming to show everyone is what our bodies do and how potentially we can get an nutritinal edge if we know.

After all, I studied Chemistry for 4 years and the scientist me is way too strapped to theory for my own good. You can’t argue the science though.

Tune in next time for more science, added banter and an energy system which requires some sort of nutritional assistance



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