Energy systems

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.

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