The marathon distance is an accident nobody corrected

Twenty six miles and three hundred and eighty five yards was a scheduling convenience, and the sport froze it into scripture.

Nothing in physiology, geometry or history requires a marathon to be that long. The early Olympic marathons were run over varying distances, all of them roughly forty kilometres, because the organisers measured out a plausible course between two places and ran it.

The number we use now comes from London in 1908, where the course was laid from Windsor to the stadium and then extended around the track to finish in front of the royal box. That produced twenty six miles and three hundred and eighty five yards. It was adopted as standard in the 1920s largely because it had been used a few times and somebody had to pick one.

An arbitrary origin does not make a bad standard. Standards mostly are arbitrary; what they need is stability, and this one has been stable for a century, which is why marathon times form the longest continuous comparable series in endurance sport.

But the arbitrariness has consequences people rarely notice. The distance sits at a very particular point in human metabolism: long enough that a trained runner cannot store sufficient glycogen to complete it at race pace, short enough that the deficit only becomes decisive in the final quarter. That is why the wall exists at roughly thirty kilometres, why fuelling strategy is a discipline of its own, and why the event rewards a specific kind of athlete who is neither a pure aerobic monster nor a fast finisher.

Move the standard five kilometres either way and you get a meaningfully different sport with different winners. At forty kilometres the fuelling crisis softens and it becomes more of a pure speed test. At forty-five it becomes an ultra in character, dominated by resilience and gut tolerance.

So a course laid out to suit a royal viewing position in Edwardian London decides which physiology wins the most famous race on earth.

I find that more interesting than embarrassing. Sport is full of frozen accidents: the height of a tennis net, the distance between cricket stumps, the length of a football pitch, all of them chosen by somebody with a tape measure and a deadline.

The mistake is not the accident. The mistake is treating the number as though it were discovered rather than picked.