# Almost powers of two

The Olympic running events are in the following distances: 100m, 200m, 400m, 800m, 1500m, 5000m, 10000m, marathon (42195m, although the original marathon in 1896 was 40km flat).

It’s clear that this sequence is trying to have each race be roughly twice the length of the one before… but there’s a bit of interference from the desire to make the races “round numbers” in base 10. And there are a couple omissions: why is there no 3km race, or 20km race?

In the winter, Speed skating contests a slightly harder to explain sequence: 500m, 1000m, 1500m, 3000m (women only), 5000m, 10000m (men only). This makes a bit more sense, I suppose, if you bear in mind that speed skating is done on a 500 meter track, so the first three are once, twice, and three times around the track. (But then why 1500 meter running — why not 1600, which is four times around the 400 meter track?)

Swimming actually does the best job of sticking to powers of two, racing distances of 50m, 100m, 200m, 400m, 800m (women only), and 1500m (men only). Again, though, it’s 1500 instead of 1600. It’s almost as if they’re trying to avoid 1600m because it’s too close to a mile.

It actually makes some sense that the basic principle is that each race should be twice the length of the one before; presumably the idea is that “twice as long” is long enough to be a different sort of race, but not so much longer that there are people who would be best at some distance that falls in the gaps.

I’m not going to pretend to understand how Olympic cycling races work, because I don’t.

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## 2 thoughts on “Almost powers of two”

1. Abigail says:

Actually, speed skating is done at a track of 400m, not 500m. Track length and distances were standardized back in late 19th century, and world championships have been held since 1893, using 500m, 1500m, 5000m and 10000m as the distances to race. The 1000m was a much later development; it has only been an Olympic distance since 1976. The distances picked were a compromise, between skaters favouring short distances, and skaters favouring larger ones.