Anaerobic glycolysis. – this is the partial breakdown of glycogen. As no oxygen is present, the system stops with the production of lactic acid.
Glycogen to (GPP)
Glucose to (PFK)
Pyruvic acid to (LDH)
Lactic acid.
Aerobic/anaerobic - anaerobic
Intensity - high
Duration – 10 – 180 secs
Number ofATP resynthesised - 2
Where reaction takes place -sarcoplasm
Fuel used – glycogen/glucose
Enzyme(S) – GPP/PFK/LDH
By-product(s) – lactic acid/low pH
Sporting example – 400m sprint
Advantages of system
Large stores of glycogen in muscles and liver
2 ATP resynthesised (more than PC system – 1ATP)

Relatively quick energy provision – quicker than aerobic system
Provides energy for high intensity activity for up to 3 mins
GPP/PFK kick start system automatically, having detected decrease in PC
Disadvantages of system
Not as quick as the ATP/PC system
Causes pain and muscle fatigue
Produces lactic acid (fatiguing by-product)
Lowers pH (acidity) which inhibits enzyme action
Causes pain (stimulates pain receptors)
Training adaptations
Increases tolerance of lactic acid – lactate buffering
Increases stores of glycogen