Anaerobic glycolysis is the transformation of glucose to lactate when limited amounts of oxygen (O2) are available.
During this time it can augment the energy produced by aerobic metabolism but is limited by the buildup of lactate.
[2] The anaerobic glycolysis (lactic acid) system is dominant from about 10–30 seconds during a maximal effort.
[1] Anaerobic glycolysis is thought to have been the primary means of energy production in earlier organisms before oxygen was at high concentration in the atmosphere and thus would represent a more ancient form of energy production in cells.
In mammals, lactate can be transformed by the liver back into glucose using the Cori cycle.