- The marathon is a road race over 26 miles and 385 yards – or 42.195 kilometres.
- The course must be quite flat, with a maximum or one metre up or down per kilometre.
- Before the Olympics, there are many "Trials" qualifying events, where runners must meet standards before they can enter the Olympic Marathon.
- After a five-minute warning, the race starts.
- Runners have a transponder or "chip" in their shoe which means that the exact time between the runner crossing the starting and finishing lines is measured electronically.
- The race normally finishes in the Olympic stadium, but often starts outside.
- On the route there are signs telling the runners how far they have run.
- Every five kilometres there are official refreshment stations where the runners can eat or drink. In between the refreshment stations there are drinking or sponging stations, where they can get water or a wet sponge.
- If somebody helps a runner, or if a runner leaves the course without permission, the runner is out of the race. They must also leave the race if one of the official medical team tells them to.
Isn't there an ancient Greek legend about Pheidippides and the marathon? Was he a Greek god of speed or victory?
No, that was Nike. The legend says Pheidippides was the Greek messenger who ran all the way from Marathon to Athens to tell people that Athens had defeated the great Persian army.
Did he get a reward?
No, actually he dropped dead as soon as he delivered the news. It was a distance of 26 miles (41 km), after all…
… so that's the distance of the modern marathon!
Err, no. No, it's 42.195 kilometres or 26 miles and 385 yards.
Why the difference?
Well, one story is that, in the 1908 London Olympics, the Royal Box – where the King sat – couldn't be opposite the finishing line. So they extended the race a bit.
That’s not fair – it's already long enough!
Exactly. The winner, Dorando Pietri from Italy, was so exhausted that people helped him across the finishing line. Johnny Hayes (USA) was made the winner.
Isn't that illegal?
It is, and he was disqualified but you can see why some people might want some help.
Yes, in 1900, American Fred Lorz used a car for part of the race, ran for the last part and crossed the winning line first. The organisers found out and made another American, Thomas Hicks, the winner.
Who is the best Olympic marathoner, then?
Difficult to say, but perhaps the most amazing was Emil Zatopek from Czechoslovakia. In 1952 he won the 10,000 gold in a new Olympic record time, then won the 5000 in another Olympic record time. Then he ran his first ever marathon…
… and he won that too, in a new Olympic record time.
Yes! How did you know?