ATP-PC System

• Phosphocreatine: an energy-rich phosphate compound found in the sarcoplasm of the muscles
• Characteristics of the ATP-PC System:

  • used PC as its fuel
  • anaerobic process
  • used to resynthesise ATP
  • can be broken down quickly + easily to release energy
• How ATP-PC provides energy:

  • resynthesises ATP (adenosine triphosphate) when the enzyme creatine kinase detects high ADP (adenosine diphosphate)
  • PC --> Phosphate (Pi) + creatine (C) + energy
  • energy + phosphate + ADP --> ATP
  • for every PC molecule broken down, enough energy is released to create 1 ATP molecule (1:1)
  • this system delays the onset of the anaerobic glycolytic system
• Advantages of the ATP-PC System:

  • Atp can be resynthesised rapidly
  • PC stores can be resynthesised quickly (after 30s+ 50% replenished + after 3mins = 100% replenished)
  • no fatiguing by-products e.g. lactic acid
  • taking creatine supplements can extend the time the ATP-PC system can be used
• Disadvantages of the ATP-PC System:

  • stores are limiltlimiteded
  • only enough PC to last 5-8secs
  • can only be replenished during low intensity work when O2 is available
  • only one mole of ATP can be resynthesised for every mole of PC
  • once PC had been used up it takes 2-3mins to recover PC