energy for exercise

• Energy systems


  • ATP-PC
  • Glycolytic
  • Aerobic
• ATP


  Adenosine triphosphate
• ATP


  • Made up of one adenine and three phosphate groups held together by bonds of chemical energy
  • The only usable form of energy stored in our bodies
  • Readily available as it is stored in the muscle cells
• ATP breakdown


  1. ATP-ADP (adenosine diphosphate) + phosphate

  2. Releases energy that can be used to make the muscle cell contract and shorten
• ATP resynthesis


  ADP + phosphate + energy -> ATP
• The body can only store a small amount of ATP, enough for around 2 seconds
• To maintain exercise beyond 2 seconds, ATP has to be resynthesised
• ATP resynthesis


  • Depends on the intensity of the exercise
  • Can be achieved by the ATP-PC, glycolytic or aerobic energy systems
  • The energy systems do not work in isolation, they can work together
• ATP-PC system


  • Coupled reaction where the products of one reaction are used in another reaction
  • Occurs in the sarcoplasm
  • Controlled by the enzyme creatine kinase
  • Provides a rapid but short-lived source of energy (1 mole of ATP)
• Glycolytic system


  • Anaerobic
  • Occurs in the sarcoplasm
  • Controlled by enzymes like phosphofructokinase
  • Provides a moderate but longer-lasting source of energy (2 moles of ATP)
• Aerobic system


  • Occurs in the mitochondria
  • Involves the Krebs cycle and electron transport chain
  • Provides a large but slower source of energy (up to 36-38 moles of ATP)