Why Is a Marathon 26.2 Miles?

How long is a marathon, and who sets the distance?

World Athletics gives the marathon distance as 26 miles and 385 yards, or 42.195 km.^[1] Its Technical Rules list the marathon, at 42.195 km, among the standard distances for road races.^[2] The familiar "26.2 miles" is that figure rounded off.^[5]

The number was fixed in 1921 by the International Amateur Athletic Federation (IAAF), the body now known as World Athletics.^[4][5] Before then the race had no set length: the Olympic Museum says marathons were run over an undefined distance of about 40 kilometres.^[4]

Did a messenger really run from Marathon to Athens?

The race is named after a legend.^[1] In the story, a Greek soldier called Philippides, also known as Pheidippides, ran from the battlefield at Marathon to Athens to announce the defeat of the invading Persians, then died of exhaustion.^[1] The International Olympic Committee (IOC) dates that victory to 490 BC.^[3]

The ancient record is less tidy.^[6] The historian Herodotus wrote about a courier of that name, but in his account the runner was sent from Athens to Sparta to ask for help before the battle.^[5][6] National Geographic reports that Pheidippides is not recorded as delivering news of the victory or dying afterwards, and that sources conflict on whether the messenger who did so was called Thersippos or Eukles.^[6] The version in which Pheidippides announces the victory and dies seems to date from the 19th century, when Robert Browning wrote a popular poem about it.^[6]

No such race was held at the ancient Olympics, where the longest footrace covered 24 stades, or about 2.85 miles.^[6]

How long was the first Olympic marathon in 1896?

The modern race was the idea of Michel Bréal, a French linguist and classicist.^[6] He suggested a footrace from Marathon to the Pnyx, a meeting place in ancient Athens, a distance of 40 kilometers, or 24.85 miles.^[6] Planning papers shown by the Olympic Museum give different figures: 48 kilometres in an 1894 letter by Pierre de Coubertin, 42 kilometres in programmes printed on 24 November 1894, and a 40-kilometre course in a detailed programme dated 15 February 1896.^[4]

The first marathon was run at the Athens Games of 1896, on a 25-mile (40-kilometre) route from Marathon Bridge to the Panathenaic Stadium.^[3] The Greek runner Spyridon Louis won in 2 hours 58 minutes 50 seconds.^[3][5]

The distance then varied from race to race for the next two decades.^[5] The 1904 Olympic marathon in St. Louis was 40 km, the 1912 race in Stockholm was 40.2 kilometres, and the 1920 race in Antwerp, at 42.750 km, was the longest in Olympic history.^[4][5] The chart shows the distances the Olympic Museum gives for four early Games.^[4]

• Athens 189640 km
• London 190842.2 km
• Stockholm 191240.2 km
• Antwerp 192042.75 km

Source: The Olympic Museum (via Google Arts & Culture) [4]

Why was the 1908 London marathon 26 miles 385 yards?

The odd number comes from the London Olympics of 1908.^[3] According to the Olympic Museum, the organisers insisted that the race start on the lawn of Windsor Castle and finish inside the White City Stadium, right in front of the Royal Box, and that set the distance at 26 miles and 385 yards.^[4] The IOC calls the reason "rather arbitrary": the route gave the British royal family a full view of the start from the East Terrace of Windsor Castle and a clear view of the finish from the royal box.^[3]

Accounts differ on the details.^[1][6] World Athletics says the race was first extended to 26 miles, and that another 385 yards were added when the start line was pulled back so the children in the Royal Nursery at Windsor could see it, while the finish stayed in front of Queen Alexandra.^[1] National Geographic says the course was lengthened so that King Edward VII and Queen Alexandra could easily see the finish line from the royal box.^[6]

When did 26.2 miles become the official distance?

The London distance did not become the rule straight away: the Olympic marathons of 1912 and 1920 were run over other lengths.^[4] In 1921 the distance of 42.195 kilometres was officially accepted as the standard for all future marathons.^[4] World Athletics gives the same year.^[1] The Olympic Museum adds that IAAF records have not explained why this particular distance from 1908 was chosen.^[4]

The museum describes Paris 1924 as the Games for which the distance was set, and says it has stayed the same ever since.^[4] The Boston Marathon made the same change: first run on April 19, 1897, over 24.5 miles, it was lengthened in 1924 to 26 miles 385 yards to conform to the Olympic standard.^[8]

Not every source tells it this way: National Geographic says the race has been 26.2 miles ever since 1908, which does not match the Olympic Museum's record of different distances in 1912 and 1920.^[4][6]

How is a marathon course measured today?

World Athletics rules say a road course must be measured along the shortest possible route an athlete could follow within the part of the road open to the race.^[2] The course may not be shorter than the official distance.^[2]

The rules require the "Calibrated Bicycle Method".^[2] A guide published by the IAAF and the Association of International Marathons and Distance Races explains how it works.^[7] A device called a Jones Counter is mounted at the hub of a bicycle's front wheel and counts the wheel's revolutions.^[7] The measurer compares the number of counts needed to ride the race course with the number needed to ride a calibration course of known length.^[7]

The rules also build in a safety margin: they recommend a "short course prevention factor" of 0.1%, so that each kilometre is laid out as 1,001 m.^[2] At World Rankings Competitions the uncertainty in the measurement must not exceed 0.1%, which is 42 m for a marathon, and the course must be certified in advance by an International Road Course Measurer.^[2] The guide notes that defining a course by its shortest possible route ensures that all runners cover at least the declared distance.^[7]