The 400m has achieved notoriety as a "man killer" because it is physiologically impossible to run at close to top speed for longer than 30 to 35 seconds before oxygen debt sets in and muscles "fill" with lactic acid. 400m runners must have good basic speed, they must be able to judge pace and they must learn to ignore pain!

The 400m has been run in lanes from start to finish, like the shorter sprints, at the Olympic Games since 1912.The great improvements in this event, although partly explained by the introduction of synthetic tracks in the late sixties, is mostly due to the development of highly intensive training programmes which successfully build both speed and strength. Although 400m runners were traditionally divided into 200m/400m and 400m/800m types, it is the "pure" sprinters like Michael Johnson who now dominate the event.