A.T.P-PC
As the name suggests the ATP-PC system consists of adenosine triphosphate (ATP) and phosphocreatine (PC).
This energy system provides immediate energy through the breakdown of these stored high energy phosphates.
If this energy system is 'fully stocked' it will provide energy for maximal intensity, short duration exercise
for between10-15 seconds before it fatigues.
Think of the ATP-PC system as the V8 of your energy systems – it provides you with the most 'power' because it produces ATP more quickly than any other system and because of this it fuels all very high intensity activities. It's downfall however is that it burns out very quickly.
How does the ATP-PC system work?
There are only a few steps involved in the ATP-PC which is why it provides energy so quickly.
Steps of the ATP-PC system:
1. Initially ATP stored in the myosin cross-bridges (microscopic contractile parts of muscle) is
broken down to release energy for muscle contraction. This leaves the by-products of ATP breakdown:
adenosine diphosphate (ADP) and one single phosphate (Pi) all on its own.
2. Phosphocreatine (PC) is then broken down by the enzyme creatine kinase into Creatine and Pi
3. The energy released in the breakdown of PC allows ADP and Pi to rejoin forming more ATP. This
newly formed ATP can now be broken down to release energy to fuel activity.
ATPase in this case assists the synthesis of new ATP rather than the breakdown. We see how this works in the diagram below.
During the first few seconds of exercise regardless of intensity, the ATP-PC
system is relied on almost exclusively, with energy coming from the breakdown of the ATP
stores within the muscles.
These ATP stores last only a few seconds after which the breakdown of PC provides energy for another 5-8 seconds
of activity.
Combined, the ATP-PC system can sustain all-out exercise for up to 10-15 seconds and it is during this time
that the potential rate for power output is at its greatest.
If activity continues beyond this immediate period, the body must rely on other energy systems to produce ATP as the limited stores of both ATP and PC will be exhausted and will need time to replenish.
This energy system provides immediate energy through the breakdown of these stored high energy phosphates.
If this energy system is 'fully stocked' it will provide energy for maximal intensity, short duration exercise
for between10-15 seconds before it fatigues.
Think of the ATP-PC system as the V8 of your energy systems – it provides you with the most 'power' because it produces ATP more quickly than any other system and because of this it fuels all very high intensity activities. It's downfall however is that it burns out very quickly.
How does the ATP-PC system work?
There are only a few steps involved in the ATP-PC which is why it provides energy so quickly.
Steps of the ATP-PC system:
1. Initially ATP stored in the myosin cross-bridges (microscopic contractile parts of muscle) is
broken down to release energy for muscle contraction. This leaves the by-products of ATP breakdown:
adenosine diphosphate (ADP) and one single phosphate (Pi) all on its own.
2. Phosphocreatine (PC) is then broken down by the enzyme creatine kinase into Creatine and Pi
3. The energy released in the breakdown of PC allows ADP and Pi to rejoin forming more ATP. This
newly formed ATP can now be broken down to release energy to fuel activity.
ATPase in this case assists the synthesis of new ATP rather than the breakdown. We see how this works in the diagram below.
During the first few seconds of exercise regardless of intensity, the ATP-PC
system is relied on almost exclusively, with energy coming from the breakdown of the ATP
stores within the muscles.
These ATP stores last only a few seconds after which the breakdown of PC provides energy for another 5-8 seconds
of activity.
Combined, the ATP-PC system can sustain all-out exercise for up to 10-15 seconds and it is during this time
that the potential rate for power output is at its greatest.
If activity continues beyond this immediate period, the body must rely on other energy systems to produce ATP as the limited stores of both ATP and PC will be exhausted and will need time to replenish.