What are the predominant energy systems used by a 400m runner?

A 400m race is a high intensity event which typically last less than one minute, therefore the main energy system used is anaerobic glycolysis. In anaerobic glycolysis glucose is broken down into pyruvate and two adenosine triphosphate (ATP) molecules are resynthesised which are used to provided energy for muscular contraction. The key controlling enzyme in this reaction is phosphofructokinase (PFK). Pyruvate is then broken down by lactate dehydrogenase (LDH) into the by product lactic acid. The events of anaerobic glycolysis take place in the cell sarcoplasm.