Energy Systems
The ability to do work.
Primary energy source is ATP.
3 energy pathways – Aerobic, Lactic Acid and ATP/PC

1. Alactic/ATP/PC/Phosphate system (1st Anaerobic system)
Supplies of ATP limited, only enough supply for one muscular contraction.
The explosive muscular contraction causes ATP (adenosine triphosphate) to split to ADP (adenosine diphosphate)
Source of fuel: CP (Cretin Phosphate) stored in cells
Duration: 10‐12 seconds
Intensity of effort: Explosive activity, high intensity (85‐100% max effort)
Rate of recovery: 2 minutes to fully replenish
Cause of Fatigue: Results from inability to continually supply cretin phosphate
By‐products: Heat and energy Efficiency: Rapid but limited (not very efficient but acts instantly)

2. Lactic Acid System (2nd Anaerobic system)
Following 10‐12 seconds of ATP/PC system, body begins to use lactic acid system.
Produces energy without oxygen.
Source of fuel: Carbohydrates – Glucose (in blood) and Glycogen (in storage form)
Duration: 30 sec at 85% max effort. Can last 3‐4 minutes at 70‐80% and up to 30mins at 60% or less. This system is used from approx. 30sec into exercise to 3 min. Cause of fatigue: The build up of lactic acid in muscles
Rate of recovery: Takes approx. 30 mins to 1 hour to break down the lactic acid
Efficiency: Rapid but limited. Has adverse product.
Intensity of effort: Up to 85% max. effort.
By‐products: Lactic acid and heat.

3. Aerobic System
Activity lasting longer than a few minutes requires oxygen to maintain muscular contractions.
Source of fuel: Glucose, fat and in extreme cases protein are used to produce ATP in the presence of oxygen.
By‐products: Hydrogen and carbon dioxide
Efficiency: Extremely efficient in its metabolism of fuel, can continue for long periods of time at lower intensities. Is not rapid in beginning like other systems.
Cause of Fatigue: Glycogen stores depletion.
Duration: From Approx. 3min to many hours.
Rate of recovery: Up to 48 hours depending on length and intensity

Note: The three systems do not work independently of each other, but at times one will be more dominant than the others. All three combine to make the human body an efficient user of energy.

	Creado por katriina_b hace casi 11 años

(Factors affecting performance) PDHPE Apunte sobre Energy systems, creado por katriina_b el 10/02/2014.