A different way to consecrate birthday runs

Running X miles, or even X kilometers, on my Xth birthday became a "Y bother?" option years ago. There are literally many ways around this obstacle to natal-locomotive novelty

I didn’t race in 2022 (or haven’t yet), and although I have missed only four or five days of running at most, all of that running has been gloriously mundane. Perhaps for this reason, I was determined to imbue my birthday run this morning with added significance.

The idea of running 53 miles or 53 kilometers was off the table. 53 furlongs (6.625 miles) would have been entirely typical. I decided instead to run about 12.1769 miles. Achieving accuracy to the one-ten thousandth of a mile (about the length of a useful human penis) is difficult (as is achieving an erection during a run when it’s 20 degrees American outside). So I cheated, and ran for 18 minutes with Rosie and 80 by myself. I’ve little doubt that the first bout exceeded 2.1769 miles and the second 10.0 miles; if I’m right about both guesses, the chances I ran at least 12.1769 miles are astronomical.

Most of you didn’t read the second half of the preceding paragraph, because you’re lost in whether you can apply this scheme to your own running and date of birth. You’ve probably noticed that moving the decimal point leftward may be required, especially if you were born between February and September inclusive. But remember, this is pretty clearly all about you, so don’t be afraid to carve out your own path here provided you adhere to the spirit of the game.

On both the precursor of this site and the existing one, I’ve bragged about sharing a birthday (and in one case, a date of birth) with a seemingly unusual number of distance runners who qualify by any reasonable standard as notable. At least one person has challenged this idea, I believe the same reader both times.

And he’s probably right. If you do some research, you’ll probably find that you share a birthday with at least four runners who qualify as world-class, including long-retired and in many cases long-dead athletes whose times today might make them at best edge cases. (You’ll probably also discover in the course of this research that you cannot justifiably add yourself to this club.)

The math behind this is simple. If you assume that at least 1,500 male and female runners throughout history qualify as world-class, that number is greater than 4 x 365.25 = 1,431. If 1,500 rolling marbles were allowed to sort themselves randomly into containers in an array of 365 such containers, probability theory dictates that each container will wind up containing an average of four-plus marbles.

It’s also true that if you are standing in a room with only 23 people, the chances that two people in the room share a birthday are just over 50 percent. This relies on basic combinatorics, which entails computing the number of possible interactions in a set (explanation). Note that the odds that you are among the birthday-sharers in this scenario are a lot lower: (2/23) x 0.5 = less than 5 percent, or less than 1 in 20. That we* tend to personalize our probability estimates is among the reasons you may find this result surprising, i.e., you likely expected a higher number of people would be needed to push the odds of any shared birthday over 50 percent.

The claim that 1,500 distance runners have ever reached the world-class level is of course open to debate. I’ll lead by stating that over 1,000 men have broken 28:00 for 10,000 meters, with the total standing at zero until 1965, and over 500 women have cracked 15:15 for 5,000 meters outdoors. with that number standing at a similarly low zero until 1981, which is when I think the below photo was taken. That no one is lamenting the loss of the blatant bowl haircut among male tweens represents another cultural mystery.

This is a crude way to attack the question, and although I necessarily have to “penalize” women in this analysis for already being penalized by being radically excluded from the sport until I was in my twenties myself, it’s unclear to what extent this should be done.

Another way to look at this: In the past one hundred years, have an average of fifteen runners newly attained world-class status each year? Well, twenty-nine women have broken 2:20 in the marathon this year, and while I didn’t count the number who ran personal bests in 2022, it’s a good bet that virtually all of them were already world-class before this year. While the sport’s globalization and worldwide population growth ensure that this number creeps up each year, this kind of snapshot is enough to convince me that 1,500 runners throughout history can make a solid case for having recorded world-class performances, in appropriate context.