Is the Olympic swimming pool too shallow? Why depth matters in race for world records

La Defense Arena in Paris has undergone an extraordinary transformation to host the Olympics swimming events at Paris 2024 .

Usually a rugby stadium and the home of Racing 92, as well as a concert hall,  organisers had just 36 days to build a pool and turn La Defense Arena into the home of swimming at the Olympics and host a crowd of 15,000 people per night.

That’s because the newly constructed Olympic Aquatics Centre was unable to meet capacity requirements for the swimming events, so the venue there will only host the diving competitions.

The results, though, are spectacular - with La Defense Arena with its enclosed roof and towering stands on three sides of the pool set to create an electric atmosphere over the next weeks as the world’s top swimmers do battle for Olympic gold.

The swimming events are set to be one of the highlights of Paris 2024, with superstar athletes such as Katie Ledecky, Ariarne Titmus, Calaeb Dressel and Adam Peaty all capable of smashing world records on the biggest stage in the sport.

One question remains, however. In a non-swimming venue, will a temporary pool be a fast one?

So what does a fast pool mean?

Simply, a fast pool would give swimmers the optimal conditions to produce their best performance.

But there are concerns that the pool at La Defense Arena is not deep enough to create such conditions. The pool is 2.15m deep, which is considerably below the 3m depth recommended by Fina, the sport’s governing body.

Why does that matter?

Well, depth is said to be one of the most important factors in creating a ‘fast’ pool. That’s because the deeper the pool, the less turbulence in the water, as waves bounce off the bottom.

Having a pool that is too deep creates a negative psychological effect, however, as being able to see the bottom of the pool helps swimmers track their progress over the coloured tiles and “feel” fast. A depth of 3m, therefore, has been identified as optimum for a fast pool but the Italian company, Myrtha, who have constructed the pools at the last six Olympics have unveiled a shallower one than usual at Paris, and one that is also below the requirements of 2.5m for major international  swimming competitions.

Could that make a difference?

Well, in the sprint events over 50m and 100m, the difference between gold and silver can come down to tenths of a second. There are other factors that come into making a pool ‘fast’ - such as the height of the gutters, which can further reduce wave splashes, and the temperature of the water - too cold and swimmers won’t warm up properly, too hot and swimmers will overheat and lose sweat in the pool.

The first finals at Paris 2024 will reveal if any of these concerns have been overblown.