Energy Systems

• What is HIIT?

  High intensity exercises with short rest intervals, usually in a 2:1 ratio.
• What are the controlling enzymes of of the Aerobic System?

  PFK and Acetyl CoA
• Aerobic System

  • Aerobic reaction
  • By-products: CO2 and H2O
  • Low/moderate intensity activity
  • Lasts from 3 mins to hours
  • Stages: Aerobic Glycolysis, Kreb’s Cycle, Electron Transport Chain
• What is Aerobic Glycolysis?

  Glucose is broken down into two molecules of pyruvate, releasing 2 molecules of ATP to be resynthesised.
• What is Maximal Oxygen Deficit?

  The difference between estimated O2 cost of exercise and accumulated O2 uptake
• ATP-PC System:

  • Uses phosphocreatine stores (limited) found in the muscles
  • Breaks down to release creatine and phosphate
  • Enough energy is released to resynthesise 1 molecule of ATP
• Where does the ATP-PC System take place?

  The sarcoplasm
• ATP-PC System:

  • Very high intensity exercise
  • No by-products
• Hypobaric Conditions:

  • Used to improve performance of endurance athletes
  • Train above 2000m for several weeks
  • Body produces RBC / Haemoglobin
  • Gives improved O2 transport on return to sea level
• What is EPOC?

  Excess Post-Exercise Oxygen Consumption
• Define EPOC


  The amount of O2 consumed during recovery above that which would have been consumed at rest
• What is Sub-Maximal Oxygen Deficit?

  When the body’s consumption of O2 exceeds its intake
• Kreb’s Cycle:

  • Pyruvate is converted into Acetyl CoA
  • Acetyl CoA diffuses into the mitochondrial matrix and combines with oxaloacetic acid to form citric acid
  • During a series of chemical reactions , hydrogen acceptors pick up H atoms
  • H atoms are taken to the Electron Transport Chain
• Glycolytic System:

  • Anaerobic system
  • By-products: Lactic acid