Typically, those signing up commit to long periods of meticulous planning, a careful diet and a regimented programme of progressively longer runs.
And yet those limbering up for the London Marathon on 22 April can be forgiven for feeling galled by Irish pop singers Jedward - aka John and Edward Grimes - who claim to have completed the Los Angeles marathon on a whim, straight off a flight and with no training.
Such an accomplishment flies in the face of all the advice offered by the medical world and the running community alike.
If you had to run a marathon tomorrow, could you do it?
Link -via Kottke | Photo: Flickr user steffenz