ATP-PC Energy System Notes

The ATP-PC energy system provides energy for muscular work.
Its use is limited due to the small supply of creatine phosphate (PC) in the muscle.
It primarily supplies ATP for muscle contraction during high-intensity, short-duration activities.
Activities typically last up to 15 seconds.
Once muscle PC supplies are exhausted, muscles cannot maintain high-intensity work without rest.
It takes about two minutes of complete rest to almost fully replenish muscle PC stores.

After about 15 seconds, once creatine phosphate stores are depleted, the body utilizes other energy systems to produce Adenosine Triphosphate (ATP).
The choice of subsequent energy system depends on the intensity of the activity.
If the activity remains high-intensity, the lactic acid energy system becomes predominant.
If the intensity decreases, the aerobic energy system becomes predominant.

The ATP-PC system is used for short, maximum-intensity activities lasting 5-15 seconds.
Examples include:
- 50 or 100m sprints
- Long jump
- Shot put
- Specialized movement sequences in 'Invasion' and 'Net and court' physical activities.
  - Examples in these activities are making a jump shot in basketball, diving to save a goal in soccer, or scooping from dummy-half in Touch Football.