This type of respiration happens when there is no Oxygen that can be used .This means that the Link, Krebs cycle and The Electron transport chain are unable to take place. The only reaction that can is Glycoysis and for this reason it is known as the common Ground.
In this reaction pyruvate is reduced by NADH2 (The NADH2 is oxidised which allows it to go and accept more hydrogen to continue the process this is one of the reasons why The ETC can not occur with out oxygen ) The reduced pyruvate is then converted into Lactate .The build up of this causes cramp. 2 ATP are produced by this process, so it is not as effeciate and Areobic respiration.
In Yeast and plants
Pyruvate is decarboxylated to produced ethanal which is reduced to form Ehtanol when reduced NADH2 passes on the H+ to ethanal.CO2 is also formed
As Alcohol is produced in this process it is unsuitable for Animals as it is a toxin , imagine running and becoming drunk it kind of defeats the object of running to be healthy