could it have something to do with how well a soccer field fits in the middle?
actually, i think that the distance of 1 mile had much to do with it. tracks were 440y before they were 400m. while 400m is a nice even number, 440 is not. but it is 1/4 of a mile. just as events like the 220 and 880 were portions of a mile. i think these distances were commonly raced before the introduction, or more appropriately the acceptance, of the metric system.
seeing as the majority of the world uses metric, i believe it was all converted for convenience.
why the 1500 became a distance race is still a mystery to me. same goes for 5k, and 10k. i assume it is because when tracks were switched to 400m, rather than yards, there would be confusion about where to start a mile, a 3 mile, and a 6 mile, which would all have different starting lines on a 400m track. so they switched them to simplistic metric distances. that's my guess.
a better question is:
we know a day's length by the the rotation of the earth. but who decided to split that into 24 pieces? and those 24 into 60, and those 60 into 60 more? seriously, where did time come from?