David Epstein, a writer for ProPublica and the author of the book The Sports Gene, told a version of this story on Thursday’s edition of Slate’s Hang Up and Listen Olympics Extra.* An adapted transcript of the audio recording is below, and you can listen to Epstein’s essay by clicking on the player beneath this paragraph and fast-forwarding to the 17:37 mark.
When American cyclist Kristin Armstrong won the Olympic time trial on Wednesday, she became the first cyclist, male or female, to win three straight gold medals in the same discipline. But much of the talk around Armstrong’s win has centered around her age. She won the gold, and then turned 43 the next day.
Needless to say, we’re not used to people in their 40s winning Olympic gold medals. But while it’s an amazing feat, I would argue that we shouldn’t be so astounded purely by Armstrong’s age. Granted, we know that athletes become less explosive as they age. In fact, your so-called fast-twitch muscle fibers shrink more rapidly as you age than do your slow-twitch muscle fibers—the ones you use for endurance events. That’s one of the reasons why sprinters seem to age very quickly: They’re losing their fast-twitch muscle fibers. And yet, elite sprinters can be older than you think. Kim Collins, a sprinter from St. Kitts and Nevis, recently became the first 40-year-old to run under 10 seconds flat in the 100 meters. And this year, the top two contenders in the men’s 100-meter dash, Jamaica’s Usain Bolt and United States’ Justin Gatlin, will be nearly 30 and 34 years old, respectively.* And that’s in an event that really requires those explosive fast-twitch muscle fibers that are disappearing as you age.
The fact is, we don’t really know how long athletes can go. For most of history, athletes have retired from their sports long before they had to for physiological reasons. Maybe they wanted to get on with other careers, or maybe they had injuries, but it wasn’t because they couldn’t maintain their skills.
To get back to Kristin Armstrong, sports like cycling and rowing are far more ideal for aging athletes than something like the 100-meter dash. Explosiveness isn’t as important and aerobic capacity—the ability to move oxygen through your bloodstream when you’re working hard—doesn’t deteriorate that much as you age.
One fascinating study of a rower, Denmark’s Eskild Ebbesen, who won medals at five consecutive Olympics between the ages of 19 and 40, found that even as traits like his maximum heart rate decreased as he aged, he was able to compensate for it by improving the amount of blood, and therefore oxygen, that his heart could move each time it beat. Essentially, the athlete’s training was able to compensate for a decline in other physical parameters. Eventually, time caught up with him of course, but in sports like swimming and rowing, it takes quite a while. As we learn more about how athletes can compensate for age-related declines with certain types of training, we should expect more Kristin Armstrongs, not for her to be a one-off anomaly.
*Correction, Aug. 12, 2016: This post originally misstated that Usian Bolt is 30 years old. He will be 30 on August 21.
*Correction, Aug. 13, 2016: This post also misstated the date when the audio version of this story aired. It was Thursday, August 11.