Energy Systems



Energy can be measured in Joules or Calories.

Work= Force (N) X Distance Moved (M).

This is also measured in Joules.

Power = (Force X Distance)/ Time (secs).

          = Work/ Time.


When ATP is broken down it is an exothermic reaction which means energy is released.

It can broken down quickly as it's a simple compound.

ATP/PC system

Phosphocreatine is broken down by creatine kinase into phosphate and creatine.

The energy from the breakdown of the phosphocreatine allows ADP to combine with the phosphate to form ATP. This is why it is a coupled reaction.

It takes place in the muscle sarcoplasm.

It produces ATP from 3-10 seconds.

It is triggered by an increase in ADP.

It has no fatiguing bi-products even though it is anaerobic.

During anaerobic training that takes uses the ATP/PC system can increase the bodies stores of ATP, delaying the threshold between the ATP/PC system and the lactic acid system by 1-2 seconds.

ADV: No oxygen required.

PC is readily available in the muscles.

Simple reaction so quick.

It is automatically stimulated when there is an increase in ADP.

PC is quickly resynthesised.

It provides energy for ballistic movements.

There are no fatiguing bi-products.

Disadv: They only produce energy for 8-10 seconds.

1 PC molecule only produces 1 molecule of ATP.

There is a limited store for PC and ATP in the muscles.

Lactic Acid system

One molecule of glucose is converted…


Sam Killoway


is this for AQA? it seems like it but it's hard to tell, thanks anyway