Is the depth of the Olympic pool damaging swimmers? As world records stand, the mystery persists

NANTERRE, France — We are taught early in life that correlation does not equal causation.

But something prevents the world’s best swimmers from reaching their normal speed during the Summer Games.

Five days into the competition at La Défense Arena, not a single world record has been set in the pool here, a temporary facility built in what is normally a rugby and concert venue. And with swimmers as talented and dominant as Australia’s Ariarne Titmus, France’s Léon Marchand or the GOAT, Katie Ledecky, someone should have grabbed a heater and smoked an existing stand by now. This is what swimming (and track) is all about, right? Faster, and faster, and faster. Records are broken every year, it seems, and sometimes multiple times a year.

But for now, the best the best can do is set a handful of Olympic records — a substantial achievement, to be sure. But not a world record. None of the three favorites in Saturday’s “Race of the Century,” the women’s 400-meter freestyle, came close to breaking their own individual records.

Likewise, the four fastest women in the 100-meter backstroke in history competed in the final on Tuesday. Australia’s Kaylee McKeown won, setting another Olympic record with a time of 57.33. But she was two-tenths short of the world record of 57.13, set last month at the U.S. Trials by Regan Smith, who took home silver on Tuesday. With all that talent in the water, you’d think someone would swim the race of her life and break Smith’s record. (U.S. swimmer Katharine Berkoff won the bronze, marking the 3,000th medal won by an American athlete in modern Olympic history, including both the Summer and Winter Games, and the 600th medal won by an American swimmer, according to USA Swimming.)

Nicolò Martinenghi won the men’s 100-meter breaststroke in 59.03 seconds on Sunday, which would have been good for eighth place in the same event in Tokyo. (Lintao Zhang/Getty Images)

But in the swimming world, where hundredths of a second make the difference between reaching the podium or going home empty-handed, they didn’t come close.

Not that McKeown minded much later.

“I think it just is what it is, to be honest,” she said. “Whether it’s the trip to the pool or not — the buses have been quite a ride. But everyone’s in the same boat. So I think it’s just a matter of putting that aside for a moment and just knowing that you’ve put in the work to get up and swim. Seeing that the times weren’t, obviously, the best, some disappointments, some great swims. They were pretty average. (But) I knew tonight it was just a matter of getting my hand on the wall. That’s all I can really ask for.”

It’s certainly not something a swimmer thinks about when he or she is going for a gold medal. And most fans don’t care; those here on Tuesday were thrilled again when their national hero, Marchand, easily qualified for Wednesday’s 200m butterfly final, trying to win double gold after winning the 400m individual medley the other night. Ley-on, Ley-onthey chanted after he emerged from the water. No one cared that the world record of 1:50.34, set by Hungary’s Kristóf Milák in 2022, remained unchallenged.

The focus here was on the pool itself — and, more specifically, its depth. Olympic swimming pools are typically 10 feet (3 meters) deep. The venue here is just 7.3 feet (2.2 meters) deep — a far cry from the “Water Cube” at the 2008 Beijing Olympics, which was 33 feet deep and was the site of 25 individual and team world records and 65 Olympic records. That has led to some speculation that the relative lack of depth of this Games’ pool will create more turbulence in the water, slowing down swimmers. World Aquatics, swimming’s governing body, recommends that pools be 10 feet (3 meters) deep, with a minimum of 8 feet (2.5 meters). France was awarded the Games in 2017 and was allowed to build the pool to that depth.

“Three meters deep is much better,” says Amandine Aftalion, a senior scientist at the French National Research Center.

“When you swim, you create a wave, and the wave goes behind and under,” she said. “And if the pool is too shallow, the wave bounces off the bottom, and it makes the water turbulent, and therefore it slows down the swimmers. … Since 2008, it was advised to have a three-meter deep pool. The minimum (is) two meters. But it is advised to have three meters because it is much better for records and because it limits the waves that bounce off the bottom and create drag.

“It’s crazy that they built this pool. That’s obvious, because a lot of the swimmers are really good. They’re in top form. They could have broken their records. In the 100m breaststroke they should have done much better. And that’s really because of the waves that are created on the bottom.”

The deeper the pool, the theory goes, the more room there is for the waves to dissipate and not wash back onto the swimmers.

“It’s clear, even at my (swimming) level, that it’s very low,” Aftalion said. “Waves are really something you can feel. If you’re swimming in the lane that’s closest to the edge, you feel that it creates waves that bounce off the edge and go back to you. Or if you’re swimming behind someone, there’s an attractive wave that will pull you. If you’re swimming right into someone’s wave, you’re accelerating while you’re not doing anything. The wave is something you feel when you’re swimming. If you’re in the ocean and you’re trying to swim to the beach, at some point you feel like you can’t swim anymore. It’s not because your body is hitting the sand. It’s just because when it’s very shallow, the drag, the resistance of the water, is very strong. Because the water can’t circulate around you.”

But the pool is just made for world records, not for good swimming. Many of the winning times here so far have been better than those from similar races at last year’s world championships in Fukuoka, Japan, or better than those from similar races at the 2020 Games in Tokyo. It’s just that they’re not bending the curve any further than it already is. Maybe everyone is just a little off, or the pool isn’t deep enough, or… who knows, really?

The Olympic motto is Citius Altius Fortius: “Higher, faster, stronger.” Not “fairly high, fast, and strong for, you know, most people.”

GO DEEPER

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(Top photo of Regan Smith and Kaylee McKeown in Tuesday’s women’s 100m backstroke: Oli Scarff/AFP via Getty Images)