The Indianapolis 500 took place a couple of weekends ago, and I have no idea what happened. I simply don’t care about motor sports, even though they have distances and speeds, same as in running. Internal combustion engines are not people, and I guess I’m selective when it comes to spreading my admiration.

Horses are not people either, but their race efforts intrigue me. They have heart, muscles and blood; they have skinny legs; they train for their races; and they enjoy cooling showers after a hard, hot effort. I think I just described myself.

I only wish I could have run like Secretariat. Saturday’s Belmont Stakes will mark the 40th anniversary of Secretariat’s astonishing 1973 victory. He beat the field by 30 lengths, and established a time, 2:24.00, more than two seconds faster than any horse has run since. Last year the winning time was 2:30.42.

If you have any admiration for a race well run, you should watch the video of that 1973 Belmont Race.

Secretariat’s success also gives me another chance to cite my favorite physiology-statistics paper of all time. In it, marine biologist Mark Denny compares the improvement curve of thoroughbred racing horses, greyhound racing dogs, and world-record racing humans. He finds, essentially, that the horses and dogs came close to their biological limit about 40 to 50 years ago.

They have reached this limit despite the best efforts of money and breeding to engineer faster animals. As Denny suggests: “Breeding of horses is incapable of producing a substantially faster horse,” and current attempts may instead be “producing horses that are more fragile.”

Because we running humans are also animals, Denny predicts that we will reach our biological limits at a certain point, though we are currently still improving (perhaps through better nutrition, better equipment, more rewards, etc). In the men’s marathon, for example, he’s not in the crowd expecting a sub-2-hour race any time soon. Rather, he posits that there is a biological limit at about 2:00:44.

The below table summarizes Denny’s figures for likely percent improvement in horse, dog, and male marathon performances. The results show that marathoners are much more likely to improve going forward than horses and dogs. (I’ve rounded his “ranges” for improvement to produce a single number in the middle of the range.)

Future Improvement of Horses, Dogs, and Male Marathoners

FUTURE IMPROVEMENT Horses .7% Dogs .6 % Men’s Marathon 2.3 %

I often mention Denny’s work when I argue against those predicting a sub-2:00 marathon sometime in the next 10, 25, or even 50 years.

That said, this is a good weekend to simply watch and enjoy the Belmont Stakes, while also marveling over what Secretariat achieved 40 years ago.

My friend Michael Joyner, M.D., has also written about Secretariat's run. He adds that he considers Jim Ryun's 3:51.5 mile on a cinder track in 1967 to be an analogous event, in that subsequent improvements are likely due to faster tracks.

This content is created and maintained by a third party, and imported onto this page to help users provide their email addresses. You may be able to find more information about this and similar content at piano.io