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I was a college swimmer, qualified for Olympic Trials in 2012 and 2016. There are absolutely slow and fast pools. It basically comes down to two things:

1. The depth - which is only 7ft in Paris, unusually shallow for a competition pool.

2. The sides. Does the water spill over the sides into the gutters, or smash into a wall and bounce back, creating more chop.

A trained eye can see all the swimmers in Paris struggling in their last 10-20 meters (heck, an untrained eye can spot some of these). Bummer that it makes the meet feel slow but at least it generally affects all the swimmers equally

I actually did a fairly lengthy research project on pretty much exactly this as a physics undergraduate - I wasn’t looking at swimming specifically, but rather boundary separation and Reynolds number in an open channel of varying depth.

The setup was simple - a constant head vessel to provide a constant but adjustable flow of water in from one end, and a little plastic boat sat in the middle of the channel, attached to a force gauge at one end of the channel. The outflow of the channel had a gate with an adjustable height in order to vary the depth. Also, a couple of dye injectors at different heights in the channel in order to see turbulent vs laminar flow.

The key finding was that at shallower depths, turbulent flow began much more rapidly and resulted in erratic but overall higher resistive forces on the boat. Deep water remained laminar for much longer, and could flow much faster before turning turbulent near the surface. This was the expected result, but it was nice to experimentally prove it.

So in short, the pool depth almost certainly impacts the point at which turbulence kicks in, and therefore athletic performance. It’s probably the dive/entry that is being most impeded, as that’s when the swimmer will largely be experiencing laminar flow.

Is there a formula to calculate the ideal depth at which going any deeper results in diminishing returns? In other words, how deep should future competitive swimming pools be built to provide the most world record opportunities (and perhaps more excitement for spectators due to increased world records)?

Does it manifest directly? The water has had some time to settle when they start.

Yes. An object moving through water is more or less equivalent to water moving around an object, and the moment you cross a boundary condition, be it depth, velocity, viscosity, the phase transition is instantaneous to all intents and purposes.

I’d have entire days of experiments screwed up just by the water being slightly too warm or cold, or there being dust, or not enough dust, or sunshine, or… fluid dynamics are finicky.

Yes, but there will be no turbulence at the start of a swimming race.

At some (shallow) point, does a 'ground effect' kick in? Or any sort of constructive interference?

Yes, in a very shallow flow you retain laminar flow - but you wouldn’t be able to swim in it, as we’re talking 15mm or so.

My untrained eye has noticed. But I also think it's not really a big deal. There are so few events where the conditions are exactly the same every 4 years. Just kinda the luck of the draw if you happen to be competing in the most ideal conditions for WR setting in any event

Also, the important bit is fairness for all competitors. As the OP said, the same conditions affect everybody. I have little sympathy for the (few) swimmers complaining. They are not owed a world record and if they’re that good, they’re going to get one anyway.

Wouldn't the sides affect swimmers on the edge lanes next to them more? And is this one reason why the strongest swimmers are usually placed in the center lanes?

Swimmers on edge lanes get affected more, and they leave the outside lanes unoccupied except for the first stage of qualifying.

From the races I saw they specifically had the edge lanes (left most, right most) empty probably for this reason. I.e. 8 out of 10 lanes are used. I think one of them did have someone in one of those lanes because one of the qualifying heats was a dead heat.

Given the other comments I must be missing something, but wouldn't it be pretty much fair? The end swimmer gets one real neighbor and one simulated (reflection) neighbor from the wall. The middle folks have two real neighbors creating chop.

Correct.

> But I also think it's not really a big deal.

the difference of the resulting turbulence from the wave bounced back from the bottom surface at 2m here and from the more traditional 3m is a big deal. The water is pushed by the swimmer's hands with the speed of something on the scale of 2 meters per second, so, as the swimmer moves forward, that turbulent movement of the water reflected by the pool bottom may as well come behind the legs in the 3m depth case while in the 2m depth case it would catch the legs decreasing the efficiency of their movement.

It's not a big deal in terms of competition as long as all players are affected equally. People are just being whiny.

Additionally, anybody good enough to be prevented from setting a world record because of this pool will undoubtedly have multiple chances in other competitions with faster pools.

This isn't really the case. You need a fast pool and good competition.

The Titmus vs Sanders vs Ledecky 400m could have been a world record race in another pool, but there's a pretty good chance we'll never see the three of them race each other again.

Counterpoint: Ledecky has never had anybody even close to her level in the 1500 and she has broken her own WR half a dozen times. I think good competition can help, but that effect is likely far less than pool conditions.

Yes, this is absolutely true.

In Ledecky's case the clock is the only competition, and she's just so much better than anyone else it's currently impossible for someone to race her.

In Athletics at non-Championship meets they have pacemakers who provide a pace for the eventual winners to chase when they are going for fast times.

It'd be interesting to see what Ledecky could do if she swam (for example) with male pacemakers as competition.

Or maybe Summer Sanders will move up to the 1500m and we'll see a real race before Ledecky retires.

Wouldn't any of these people not try for a WR in other comps without strong competitors? WR seems more prestigious than just a win and going for it and getting it means you win that race too

> There are so few events where the conditions are exactly the same every 4 years.

The Olympics used to be held at Olympia. It's not difficult to make the conditions the same every four years.

On that note, I should mention the idea of having a permanent Olympic city. Perhaps a new one.

That way, there's no circus that goes around at great expense each time, and the Olympic city becomes a centre for sports science during the interim.

Perhaps have separate summer and winter cities.

Only drawback is the ioc doesn't get to choose a city every four years.

The circus is the point of the Olympic.

If there is no big event happening somewhere, the Olympic have no point. There are already permanent venues and international competitions happening for each of the sports of the Olympic.

> Only drawback is the ioc doesn't get to choose a city every four years.

That’s a massive drawback which is probably insurmountable.

They to love kickback.

Imagine the bribes they would get when choosing the permanent city though!

I'm no expert, buy there also seems to be loads more stuff lying on the bottom of the shallow floor than I remember from previous Olympics. Not even sure exactly what it is - large white panels and other equipment that the swimmers don't look that far off touching when underwater (not the robot cameras which are relatively unobtrusive).

digital lap counters to help the swimmers keep track

Thats pretty nice, when I swam the 500 I would have to lift my head to see the lap counter dropping the sign in the pool which messes with your head position

Wouldn’t the underwater camera on a track cause currents?

I could be fully enclosed for the full length and just have a glass top

Would the swimmers in the center lanes have any advantage by being furthest away from the wall-induced chop?

Yes, those on the outside will have choppier waters as the water bounces off the sides of the pools. The modern competition pools do a pretty good job of reducing this effect, but it is always there.

Plus, you'd have a big advantage later if you start fast and gain a few meters from your two neighbors. Their waves would slow you down. Gliding is much faster than fighting through rough waters.

Could probably increase fairness by doubling the width and throwing away the last few lanes (leaving them empty). But would that incentivize the edges? I don't know.

They could get almost perfect fairness in any kind of Olypmic-style race by just letting competitors all use exactly the same lane, one after another.

In earlier times, measuring equipment wasn't accurate enough, so races had to be done in parallel with people starting at the same time. Today, that's no longer necessary. In fact, people racing one after another is exactly how we hand out world records.

Of course, the Olympics and other events like them aren't there to find the best athletes in some absolute sense; these events are there to entertain spectators. Otherwise, swimmers could just do time trials at home and mail in times.

And spectators like people racing each other at the same time.

There's something to be said for racing _someone_ and not just the clock, for the swimmers/racers, not even thinking about the audience.

Additionally, it would make races take 8x to 10x amount of time.

> There's something to be said for racing _someone_ and not just the clock, for the swimmers/racers, not even thinking about the audience.

Yes, it's more fun.

> Additionally, it would make races take 8x to 10x amount of time.

Well, that's not a problem, they can run different events in parallel. Eg swimming and running shouldn't interfere at all with each other.

It's not just about the fun; having someone next to you can make you push a little harder.

They already run events in parallel.

It's not supposed to be fair (as in equal) though, lane assignment goes inside-to-out based on qualifying times. The easiest way to avoid the chop is to get out in front and stay there.

> The easiest way to avoid the chop is to get out in front and stay there.

While that's technically true, the drafting effect actually means that being a bit more than a body length behind the swimmer next to you is beneficial to you. That's another part of the philosophy why the fastest swimmers are assigned the center lanes, and the slowest the outermost lanes, to balance out the choppiness of being by the sides with creating a potential for drafting. Of course intentionally drafting is not a strategy that will win you the race, especially in short events, but in longer events it can be important to keep pace with the swimmer next to you while they need to expend more energy and you draft off of them either with the intention to eventually pass them or to stay ahead of the swimmers on your outside.

Makes sense.

They do throw away one lane on each side already, FYI (in addition to positioning competitors to minimize influence on results, as others discussed)

They put the most favoured (by entry times or heat results) swimmers in the center lanes, slower ones out from there. You've probably noticed that you usually see the race leaders in the middle, and you hardly ever see the edges winning.

In cases where there are less swimmers than lanes, they leave the edge lanes empty.

Alternately: a swimming pool on the interior of a cylinder - rotated to provide artificial gravity.

Supposedly, that's why the fastest qualifiers get the middle lanes.

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If you put them in the slow lanes then there would be an incentive to place poorly in qualifying rounds.

Don't the qualifying rounds determine whether you get to compete or not? So if someone intentionally slowed down, even a fraction of a second, there's a chance they wouldn't get to compete at all.

Yeah, but it would create weird incentives where e.g. if two people are way ahead of the pack, one of them wants to finish after the other. So do they just wait until the rest of the field catches up and then try to trick the other guy into hitting the wall first?

Better to just avoid it by keeping incentives aligned with winning your qualifying heat.

Or they could randomize the order?

Good point. Some events do in fact do that.

But then there is no incentive to try to win the qualifiers.

Randomize the lane assignments.

Why not give them a choice of Lane?

Everyone would choose the middle lanes anyway.

Tactically this may not be valid.

https://www.youtube.com/watch?v=kQNY5htc9_k

When the US 4x100m swim relay beat France about three olympics ago (the one where Phelps won all those medals), France was comprehensively faster man-for-man aside from Phelps in that relay.

The US won because Jason Lezak, the anchor, swam in the wake of the final French swimmer (a draft basically) and was able to save energy and pass him.

If the US and French had been separated by a lane, the US would have lost.

If you are slightly faster (and especially if you go out faster) than your #2 rival, you want to have a lap between you to deny them the draft.

Draw slips from a hat

Not sure if you are being satirical, but yes that's the point.

The entire point of qualifiers in most sports is to reward better participants - otherwise they would have incentive to sandbag their performance or perform other shenanigans for preferential matchups.

You get rewarded by qualifying. If you perform better in the heat that doesn't mean you should get an advantage in the race. Random allocation would be better.

> should

Why do you believe this should be the case? Keep in mind the majority opinion of most forms of racing and other competitions is to reward competitors for their qualifying or heat performances by assigning the most valuable starting positions to the top qualifiers. This is generally considered more fair than randomizing the final’s lane assignment (or grid order, etc) because it reduces the chance of BS in the finals itself and avoids perverse incentives in the qualification rounds.

I get it with motor racing like F1 because of the linear nature of the track, plus during the qualification laps they have a clear track and are not jockeying for position.

My reservation with swimming is that if you were randomly assigned to a middle or side lane in the qualification stages, your advantage or disadvantage is compounded as the competition proceeds. It's not clear to me how lane assignments are conducted for heats; perhaps they use a seeding system.

https://www.nbcolympics.com/news/swimming-101-olympic-compet...

The system isn't there to be fair, it's there to be entertaining.

If you wanted a fair system, there would be no qualifiers and no simultaneous racing. You would just have everyone compete at home and mail in times whenever they have a new record. Like eg speedrunning for computer games is done today, or like any world records for fastest time are done.

> I get it with motor racing like F1 because of the linear nature of the track, plus during the qualification laps they have a clear track and are not jockeying for position.

Track conditions can change throughout qualifying so that the later qualifiers might have a slightly faster or slower track.

You already get rewarded for better performance in the heat by being allowed to participate in the race!

Yes...that's what I'm saying.

And having a better view on the competition in the neighboring lanes (just like in track running). There's even some applied psychology here, that competing swimmers 'push' each other to higher speeds because they can see each other more clearly (and 'feel' the push from someone just lagging).

Putting the faster qualifiers in the middle lanes is also a better view for the spectators on both sides of the pool.

Interesting to see the 400m and 200m track and field athletes starting to favor outside lanes.

That's because of the drag in the inner curves. There the outer lanes are faster.

It would be interesting to see a comparison of lane effect, say for instance, re-running a race after let's say a weeks rest with the top finishers now nearest the side walls and the lowest finishers in the center lanes. Oh and for incentive, let's say the average of their two times determines the winners.

The human factor would make this very difficult. A more scientific test might be to use RC boats with tightly regulated power outputs, with a wave machine to ensure consistency.

The fact that swimming competitions are so very close, often down to 100ths of a second, doesn't much help.

Olympic and similar competitions are timed to the nearest 1,000th of a second, but any result within the same 100th is considered a tie as that last bit is just entirely arbitrary, in part because pool dimensions themselves are not accurate to this degree. (The FINA standards mentioned in my earlier comment addresses dimensions accuracy standards.) The Olympics did break ties at the 1/1,000s standard in 1972, but has since judged any result within 1/100th as a tie:

<https://olympstats.com/2014/02/12/timing-accuracy-at-the-oly...>

Random assignment should make it easy to detect, depending on the size of the effect

Supposedly, all the Paris 2024 new accommodation were designed with re-usability for the general public after the Olympics. Is it possible that had an impact the swimming pool on design choices ? Put differently, are performance design at odd with more general/accessible design in the case of a swimming pool ?

Given the pool was put on top of a rugby pitch, which resulted in the shallower depth because they didn't want to destroy the pitch (a full depth pool would have weighed too much) - unlikely. The pool isn't a permanent structure, it's not going to remain there after the olympics are done.

I would be very surprised if they re-use it at all - an "above ground" pool of that size seems like it would be more trouble than it's worth to maintain over the long run.

A timelapse of the pool being put together: https://www.youtube.com/watch?v=jTuFidqy0yI

I can't speak to the French ecosystem, but in the US these pools often (usually?) get resold to swim clubs who find some land and build buildings around them.

Sometimes they just move the pool to a new city and set it up in an arena for another championship.

Given the abandonment of olympic venues all the way round the world, I don't think this is a bad thing.

There's a lot in the book Soccernomics about how the economic value promised by politicians lobbying for hosting things like this rarely pan out.

There's definitely economic value but it really only goes to the companies building facilities, the suppliers, and the hospitality industry immediately surrounding the events. In an already well-developed city, they aren't going to be building many new permanent structures. Many will be temporary that will eventually be torn down or just converted back to what they were originally. The money is spent, distributed to the companies that directly participated in the build up and run of the Olympics but there's little gain made after.

A more interesting way of doing the Olympics would be to only allow for developing countries to participate in the selection process. Each country would be required to meet a certain level of funding to guarantee they can support the entire Olympics. Foreign investment would be encouraged. There would be a requirement for some aspects to be permanent construction, you couldn't just build a tent city for the athlete village. Then a name is picked randomly. The host country then receives major foreign investment, not just in sporting arenas, but in many areas of its economy. The Olympic committee could also collect dues from participating countries based on GDP that would go to the host country for economic development. It would basically create a lottery system for the economy of developing countries. The build up to the Olympics would create the infrastructure needed for future investment. This would likely require host cities to be selected much further out in advance. An oversight committee would observe the development and if milestones are not met, a host city from a developed country that does have the infrastructure necessary would instead be chosen.

In this case, the pool is temporary. La Défense Arena is usually used for rugby (Racing 92) and concerts.

Dumb question I never thought about: do the circulation/filtration pumps get turned off during races? And for what minimum time before hand to let things settle?

If so, I guess this would be a serious competition only thing because you wouldn’t want them off for hours.

FINA competition pool standards have recirculation minimum standards, and pumps run continuously. Further, "water distribution has to be such that no appreciable current or turbulence is created. 'Appreciable current' is defined as water movement that can move a floating basketball (filled with 6 litres of water to obtain the right buoyancy) in one direction for more than 1,25m in 60 seconds."

<https://resources.fina.org/fina/document/2022/02/08/77c3058d...> (PDF)

Most competitive swimming pools have a large number of inlets with diffusers on them, laid out every 2m or so across the pool floor.

Those are circular disks about 10cm in diameter, looking vaguely like this:

  __________
  \________/
   |      |

    ^^^^^^

Because the gutters are continuously removing water from the pool, circulation needs to be on to maintain a consistent fill level.

They do, but circulation cannot be totally stopped. This is a greater problem in outdoor pools but any pool will have some sort of temperature gradient that will inevitably result in circulation. Any water movement means slower times, at least in those events longer than 50m (1 length).

Surely that has far less effect than that of all the other swimmers? Naïvely I would think we should be running time trials of a single swimmer at a time before caring about any of this?

>A lot of this is perception vs. reality,” he said. “If you were to talk to many very accomplished coaches, they would say the pool has to be a minimum 3 meters deep. Most of our research shows that anything over 2 meters is frivolous. … Obviously, some depth is very important. But after a certain point, it's diminishing return.

Maybe it's just the swimmers and not the pool as such

But a lot of the swimmers themselves are not able to go anywhere near their personal bests: this is a sharp reversal from past Olympics, where many athletes reached new personal records.

Plus, they are the worldwide foremost experts on competitive swimming. Definitely I would be more interested in their evaluation of a swimming pool rather than trust "research results" from the company that built the pool in question.

> they are the worldwide foremost experts on competitive swimming

On swimming, sure. But not fluid dynamics. It's a bit like music listeners shouldn't be treated as experts on music quality, or you'll get the audiophile nuts who need gold connectors. Some combination of personal experience for comfort and objective measurements for performance would be much better.

It's strange that you would pick on gold connectors. Gold is an excellent conductor and does not corrode in air, so it makes a great plating material. In the quantities needed for plating, it's not too expensive, either.

Silver corrodes relatively quickly and is expensive; that's a bad tradeoff against copper, which is much cheaper and nearly as conductive. So: gold-plated connectors on copper wires are extremely common.

None of that makes an audible difference, as it turns out: humans can't tell the difference between silver, copper, gold, aluminum, or even iron wires at audio frequencies and realistic (sub-kilometer) lengths with comparable resistance. All the advantages are material costs vs longevity without maintenance.

Also, most music listeners are not experts on music quality or sound reproduction quality (two very different things). Many music listeners are experts on their own preferences. Everyone is entitled to their own preferences.

Picking on it exactly because there's no difference in sound, but the extreme audiophiles will claim they hear it anyway. https://ventiontech.com/products/toslink-to-mini-toslink-opt... - "gold-plated connectors resist corrosion for optimal signal transfer over time." - it's an optical cable!

There is an audible difference after being in a high temp high humidity environment for 5 years :)

Audible difference from an OPTICAL cable not corroding at ends? One where the gold plated parts are only the frame that holds it in the socket?

Well, there is always an ADC and amplifier stage involved, at some point you have to cross to the analog domain - and there's an absolutely wild difference between a central, decent and expensive ADC/amplifier and whatever crap ships in "active" loudspeakers that bring their own ADC/amplifier.

Ok. That's not what we're talking about here.

Have you tried not listening to music underwater??

Under boiling water. He did mention high temperatures as well as humidity, after all.

> It's strange that you would pick on gold connectors. Gold is an excellent conductor and does not corrode in air, so it makes a great plating material. In the quantities needed for plating, it's not too expensive, either.

It’s not strange at all. Gold plating improving quality sounds truthy but is absolutely false. I have yet to read a serious study, at least single blind, showing any meaningful difference. And I have yet to read a serious engineering study showing any meaningful difference in characteristics. Steel plated jacks are just fine, and optical connectors make the whole thing irrelevant. As you write yourself:

> None of that makes an audible difference, as it turns out

> Also, most music listeners are not experts on music quality or sound reproduction quality (two very different things). Many music listeners are experts on their own preferences. Everyone is entitled to their own preferences.

Indeed. But their preference have no effect on Physics. If they are happy to get gold-plated ruthenium cables with diamond coatings, more power to them. It does not make these cables any better.

Theo are entitled to their own preferences, not their own reality.

"I reject your reality and substitute my own!"

> Gold is an excellent conductor

Actually, gold is a worse conductor than both copper and silver, and only a little better than aluminum.

> and does not corrode in air

This is the real reason for plating contacts in gold. But gold wires would be a bad idea, since they would be worse than both copper and silver wires.

Parent didn’t say gold was a better conductor than silver or copper though. How does gold compare to copper- or silver oxide? Which was the point parent was making.

The text was unclear; perhaps they did not believe that gold is a superior conductor to copper and silver. But in my experience, many people do think that, and I thought it would be useful to point out that this is not true.

Parent did say gold was a good conductor which is arguable false.

Aluminum is also an excellent conductor.

But also corrodes more than copper, making it unsuitable for household wiring unless special precautions are taken.

Indeed. It has some practical issues that need properly mitigated, but it is still a very good conductor.

You're comparing the science of electronics and sound (well understood, rigorous) with sports science (cesspit of low-N, hard to study well). In sports, anecdata are valuable - putting guff in a journal doesn't make it any less guff.

> Plus, they are the worldwide foremost experts on competitive swimming. Definitely I would be more interested in their evaluation of a swimming pool rather than trust "research results" from the company that built the pool in question.

But they are very prone to psychological effects.

Professional athletes are MORE superstitious than other people, and are prone to serious amounts of bias in how they attribute outcomes.

Maybe they all change their behavior because they know the pool is less deep as they are used to.

Some kind of placebo effect or fear of coming to close to the ground.

Many athletes are superstitious.

There's Olympic gold medals on the line.

People are going absolutely as hard as they can.

There's no way an Olympic pool for the actual Olympics should be that shallow. If athletes prefer a deep pool, the pool should be deep.

Swimming is one of the premier sports at Olympics. It's also a facility that has one of the most reuse if built properly.

You don't think a Paris aquatic center wouldn't get tons of reuse in world championships and other types of top end level events if they'd built a fast pool

It's a mystifying decision. Especially since one of the standout athletes on the French Olympic team is a swimmer, and it appears that their decision now cheap out on the pool cost him a world record on the Olympic stage on his home soil

Placebo or fear can absolutely be a possibility regardless of how badly they want to do well because it's the Olympics.

Firstly, if a swimmer were to wrongly worry about hitting the floor even if there is 0% that any of their races ever saw them go as low as this floor, it could be in the back of their mind that going as low as they usually do might cause them problems and therefore seem logical to avoid.

Secondly, humans are not perfectly rational machines. Many a football (soccer for any Americans) player has come back from a nasty injury and found themselves unable to play as boldly as they used to, even though the odds of getting injured haven't changed just their perception of it.

I do agree that if the athletes feel it's needed then they should be listened to, just explaining that it's possible for both things to be true, that the depth doesn't create any physical problems yet still lead to changed behaviour from the swimmers.

> Placebo or fear can absolutely be a possibility regardless of how badly they want to do well because it's the Olympics.

But it seems unlikely all swimmers would be impacted equally by psychological effects. Some thrive some wither, lots of variation.

> It's also a facility that has one of the most reuse if built properly. You don't think a Paris aquatic center wouldn't get tons of reuse in world championships and other types of top end level events if they'd built a fast pool

They didn't build a dedicated aquatic center. "The pool here in suburban Paris — a temporary vessel plopped into a rugby stadium"

So you agree they cheaped out?

Paris allegedly spend 1.5 billion to clean up the Seine presumably for fringe events like open water swimming and triathlon.

Again: premier top-of-program sport in Olympics primetime. All they had to do was dig a hole in a rugby field.

> People are going absolutely as hard as they can.

Not necessarily. If they think the pool is slower, they’ll think they will have to swim for a bit longer, and may (possibly subconsciously) adjust their power output to allow for having something left when they have swum for as long as they think it would take them in a fast pool.

In fact a lot of the upcoming olympics specifically don’t have as much new construction because of the white elephant criticisms of the Olympics leading to most developed host candidates declining and/or having hosting referenda rejected.

The Athens 2004 and Rio 2016 venues in particular are not doing very well post-Games.

> There's Olympic gold medals on the line. People are going absolutely as hard as they can.

They don't have to outswim the bear. They just have to outswim the silver medalist.

As much as it's about winning the medals, this is about setting personal and world records, too.

Regardless, they have to make do with what they have. Nobody is moaning that the weather affects triathlon timings.

If the organizers controlled the weather and made it rain, people would absolutely be complaining.

People are complaining that the local g varies, though. https://www.xkcd.com/852/

Right, if you are swimming in multiple events then it doesn't necessarily make sense to swim as hard as you can in the early events if that is going to tire you out for the latter events.

The pool is a temporary structure, La Defence is a multi purpose venue. The pool is literally a tub on top of a rugby field.

Perhaps this is why its shallower than normal.

All major competitions will be in temporary pools from now on. It’s a major spectator sport with growing popularity, but as seen in 2008, 2012, 2016, etc purpose-built facilities for that crowd size are failures.

Paris is swimming in a rugby stadium. It is loud and exciting. The US trials this year were in a temporary pool at the NFL stadium in Indianapolis with 60,000 seats filled! LA 2028 has already announced that they will be using a temporary pool in an NFL stadium and will have 38,000 seats. Brisbane 2032 hasn’t said anything as far as I’ve heard, but you can bet that’s also what they will do.

Edit - I was wrong about LA swimming capacity. It is going to be at the NFL stadium in Inglewood, but as of now they are only aiming for 38,000 seats

> Brisbane 2032

The current plan is a temporary pool in a new inner-city arena (15k seats) for the major swimming events, with diving, artistic swim and water polo prelims at an existing (to be refurbished) sports centre.

Thanks - it makes perfect sense. There is nothing wrong with a temporary pool, and as we've seen in Paris there are records being set.

I had read in one of the other articles about this issue that you are correct, that is exactly why the pool is shallower than usual.

The building was going to need structural modifications to make the pool standard depth.

Experience shows that the pools don't get much reuse. Look at the abandoned venues in Beijing. After all, there's only one world championship each year and dozens of very nice pools already on the planet.

BTW, it's not clear the decision was purely monetary. Raising the water level means ruining the view of the closest seats. The spectators would be that much further away.

When you measure human performance, placebo matters.

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Considering touching the bottom results in disqualification it isn't a superstitious fear.

Being good at swimming doesn’t mean you can evaluate the pool performance better than everyone else. I trust someone running a CFD analysis of a pool more than a competitive Olympic swimmer when it comes to the effect of pool depth. It’s very hard to make accurate statistical assessments from intuition.

Edit: maybe I’m not making myself clear:

I don’t doubt they are slower in the current pool than they were before. But I doubt they can accurately tell you that it’s because of the pool depth. There are other factors that could also influence the performance, and I’m not sure the swimmers can accurately determine which factor is the primary difference.

Competitive Olympic swimmers in G20 countries aren't always rocket scientists and brain surgeons ... BUT .. thay are frequently coached by teams that include leading sports scientists with degrees in fluid dynamics | applied mathematics | etc.

Australia, as one example, took swimming (and a few other sports) next level with a plethora of studies on all things performance related.

Any theorectical results from, say, CFD, would be parallel tested in real conditions and|or modelled in a scale pool (like a wind tunnel for water).

Those who competed at that level in sport in the larger countries almost certainly heard first hand bleeding edge results from cutting edge sport science.

The powerhouse swimming nations (USA, China, Australia, Canada, UK, etc) are so far ahead of everyone else it isn't even close anymore.

My niece was not fast enough to be invited to the trials this year (missed by .03 seconds in her favorite event), but her time would have put her into the second heat in Paris. She's the ~150th fastest person in the USA, but would have come in ~25th place in the Olympics. It's the same situation in China, Australia, Canada, UK, etc.

Most countries only have a small handful of elite swimmers. The power nations can each provide 20-50 swimmers fast enough to get to the semi-finals in every single event. They're analyzing and optimizing for everything. This is why most of the elite swimmers not from these countries go and train in the powerhouse countries. And why the powerhouse countries don't care that they do. I'd bet that 90% of all the medal winners this year do their training in 5 countries.

If she's likely to continue to be fast again in 4 years, it might be time to venue shop her team? Have any connection to other countries not in the top? Even if not, 4 years might be enough time to develop a connection. Being 25th in the Olympics is way cooler than being 150th in the USA, even if they're objectively the same speed. Also, you may need to adjust her speed if the Olympics pool is slower than the trials speed; but still it's way cooler to be any place in the Olympics than 150th faster in the USA --- maybe unless you're in the know for swimming.

Venue shopping might feel ick, but I don't think it's too bad if you're in the competitive envelope, as opposed to what's perhaps a tradition of less then competitive entrants in some events.

Feels like you're missing a variable here. If your nieces time in a fast pool would be 25th in Paris, that means her time in Paris will be slower than that, because now she's in the slow pool, right?

You don't necessarily need to do an in depth study of the pool when every Olympic swimmer in it fails to meet their own personal records. A study may be useful to understand why depth still matters beyond the 2m point, but a study isn't needed to show that swimmer performance is impacted.

> You don't necessarily need to do an in depth study of the pool when every Olympic swimmer in it fails to meet their own personal records.

This is a weird standard. Out of 200 people doing anything, how many do you expect to set a personal record? Say you drive to the grocery store. Are you setting a time record for the trip more than 0.5% of the time?

These athletes plan their whole training and fitness regime for years so that they are at their absolute best at this particular day.

Tbh I don't do much of that sort of thing for my grocery store trips at all.

> These athletes plan their whole training and fitness regime for years so that they are at their absolute best at this particular day.

The only way this could actually happen is if they intentionally sandbag their performance starting several years in advance -- and continuing indefinitely -- which would prevent them from qualifying for the Olympics in the first place. It's not a possibility.

Or it could happen that the training, diet and injury-avoidance regime for long term success is different from that for short term optimisation. As it is for many, many sports.

All right. The 2020 Olympics were canceled and a replacement event was held in 2021. According to this theory, there should have been a shocking drop in personal records set at the 2021 event. Was there?

No, that's according to a theory to which you've added a strange caveat that a year is insufficient advance knowledge to know how to peak, despite annual world championships - and them often being the reason a competitor knows they're going to the Olympics at all.

Allow me to be equally facetious: according to your theory, Lamine Yamal is currently doing the same training he'd be doing deep into a season. Which is impressive, because his Instagram page currently suggests he's on holiday in another country.

> No, that's according to a theory to which you've added a strange caveat that a year is insufficient

I'm not the one who specified multiple years.

You're making my point. Scarblac claimed people set personal records at the Olympics because they plan to set that record years in advance, adopting a personal regimen with the goal that their performance before the Olympics won't be as good as their performance during the Olympics, because that would mean an embarrassing failure to set a personal record.

You're saying that (1) that can't happen, because people don't know they're going to be at the Olympics years in advance; and (2) the personal records result from short-term efforts, not long-term efforts.

And you're saying that, in particular, people don't know they'll be going to the Olympics at all until they see their own results from a recent high-stakes competition in the same event.

So... why aren't they devoting the same short-term efforts towards their performance in the Olympic qualifiers, or towards other annual competitions for their sport?

People who are capable of setting world records are capable of beating the competition, to allow them to qualify for a more prestigious competition, without 100% effort.

Those are people who do know that they're winning the qualifier before it happens.

Sure, there could be multiple peaks. That doesnt really subtract from my argument that this isn't a day like any other for these athletes, form and fitness wise.

The motivation of a commute is not comparable to the motivation of a swimmer in 4th place of a medal event, etc.

So what? Is the motivation of a swimmer in 2nd place in a non-Olympic event comparable? Is the motivation of a swimmer who wants to work toward the Olympics comparable? Is the motivation of a swimmer trying out for the Olympics comparable?

Every Olympic athlete, with the possible exception of the Jamaican bobsled team, has been equally motivated at dozens or hundreds of officially-measured points in the recent past. Why do we expect personal records at the Olympics?

Well, for one thing, world records don't get ratified in a local pool.

And athletes are competent enough to achieve the time needed for qualification without going all-out. Look at the finish times of the heats. Pan Zhanle was over a second slower.

Or maybe there’s something else going on? There are a lot of other variables in a pool except depth, no? Maybe water tension, density, viscosity? Someone else mentioned the walls of the pool also influencing the wave properties in the pool. Just noticing the pool being more shallow and people swimming slower doesn’t mean that’s the reason.

Explain to us how water "tension", density, and viscosity are variables that would change? It's just water, and temperature is set at ~25 C. The shape of the pool and gutter setup are the only major factors at play, assuming the filtration system isn't causing major currents.

It’s not demineralized water though, have you ever added a tiny bit of soap to water and it immediately reduced the surface tension? I’m not saying there’s soap in the water in France obviously, but there’s a lot of other additives that could theoretically affect water properties even with a fixed temperature.

Edit: for example, compare salt and fresh water properties here: https://ittc.info/media/4048/75-02-01-03.pdf#page2

At 25 degrees, fresh water has a Viscosity of 0.000890 Pa⋅s and sea water has 0.000959 Pa⋅s. That’s an 8% difference in viscosity by adding NaCl to water. Is it that strange that there could be a 1% difference in viscosity for example by having different additives in the pool water?

Yeah but it's not just "water", as in plain H2O. All water has different things dissolved or mixed into it. In pools there's commonly several chemicals added to that water: to correct the pH for humans, to sanitize, control corrosion of metal, avoid calcium deposits on other surfaces, etc. It's entirely possible that the additives in the water could be way off of normal and somehow affect things like viscosity or surface tension.

No, it isn't.

Rereading your last comment and I think I just misunderstood it, sorry! I first read it as saying a study would be needed to know if something about the pool was anything them down, but you were still specifically talking about whether the depth is the issue.

Yes, I think a lot of people misunderstood the point, I’m ESL so maybe i didn’t write it up properly. I was just talking about the effect of pool depth, not doubting that something is different this time.

For what it's worth, my misunderstanding wasn't actually due to your message at all. I simply focused on the first sentance and lost the next sentance that tied it back to pool depth.

Your English is actually very, very good! I wouldn't have guessed that it is a second language for you.

So to be clear, you have no idea, you just insist on discounting the experiences of the swimmers because you can?

I misread the earlier posts here when I started dow this comment path, but I actually agree with them. There seems great evidence, including the swimmers', experience to say that something about the pool slows them down. It seems less clear that the depth is the issue, it could be something else or a combination of factors related to the pool that cause it.

While part of it may be true. The athletes who spend 1000s of hours can probably intuit something being different.

The can maybe intuit being slower, but I doubt they can accurately tell you that it’s because of a different pools depth. There are a lot of other variables that could be the reason.

Do you have links available to any peer-reviewed scientific literature on which you base your theory that – just to make sure we’re on the same page — the theory that it is difficult to the point of impossibility for people to correctly ascertain that the depth and construction of the pool they swim in has no effect on their swimming dynamics, efficiency, and competitive performance?

Isn’t that the null hypothesis?

I have these data points:

1) The pool is shallower than normal in this Olympic

2) The pool seems to be slower this Olympic

3) swimmers seem to think it’s because the shallower depth

4) people responsible for building the pool say the effect of depth is negligible

5) there are other things that can be different about the pool except depth because the pools aren’t strictly standardized in their properties

My only claim was that point 3 doesn’t tell me a lot because I find it very plausible that you can’t really detect the reason for the slowness just from swimming. I don’t have positive proof of that though.

I was always told that CFD is not a substitute for “actually going and testing”.

It will get you a fair amount of the way there, but at some point you have to go and actually do the thing to validate your model.

I trust someone who's life is getting that 2/10 of a second to know when the 2/10 of a second is impeded.

The how can be argued

Even CFD analysis is a model though, with all that implies.

Would a large, blind empirical study be more trustworthy?

Yes and no. The empirical study could identify correlations and the strength of those correlations, but does nothing to say why they are correlated (maybe just spurious). But a CFD analysis may give you insight into what may be happening to cause the issue, which can then lead to a hypothesis that can then be tested further. All models are wrong, but some are useful.

Only if the depth is the only variable that’s changed. You can’t just use two entirely different pools at different times and locations and conclude that the depth is the reason for different performance.

Sure, it is not necessarily the pool depth. But that is almost surely the one factor that deviates the most from the "average". Paris is 50-100m above sea level which is pretty unremarkable gravity- and pressure- wise. Its water is unlikely to be macroscopically different from that of other French or Western European cities.

I am aware the above may be proportionality bias, but at the same time there is some kind of "reverse proportionality bias" at play here: the assumption that since the effect of a shallow pool are too small, they can't significantly affect the athletes. Human behaviours are very nonlinear, and even very small sensory inputs may very well "throw off" an experienced swimmer.

A CFD analysis is based on a model - an abstraction of reality. If the CFD analysis found everything is okay, yet reality shows it isn't, I wouldn't trust the competency of the person behind the analysis.

But CFD didn’t say that everything is ok, it said that pool depth has a very small effect. So either CFD is wrong or something else is wrong with the pool that’s not depth.

Intuition forms because it works. When it doesn't it's remarkable to the point of writing books and movies about it.

Intuition is a heuristic that lets you form decisions fast without a lot of effort. But I wouldn’t say having a wrong intuition is that uncommon that I would write a book every time I had a wrong intuition. I have intuitions all the time about stuff and when I check, it turns out I was wrong. That’s also why I wouldn’t make important decisions based purely on intuition. Intuitions form because sometimes, you need quick decisions and it’s better to do something wrong some of the time than take longer to make a better decision.

When it works we call it intuition. When it doesn't we call it superstition. There are all sorts of availability biases at work here; none of which really support the use of intuition as a valuable, predictive resource. After all, if your intuition fails to predict something, there must be some lurking variable somewhere that you failed to account for. Not that the intuition is wrong /s.

The thing is, depth discussions have been going on for decades and these swimmers literally live in the pool. When people spend literally 40+ hours a week in water I trust them well before I trust scientists because it takes scientists so much longer to catch up and measure what the practitioners are observing.

Like this reminds me of Beckham/Ronaldo doing free kicks. They had a deep understanding of controlling the ball well beyond what scientists knew how to measure and explain what they're doing.

I trust the swimmers’ intuition far more than an ad-hoc CFD analysis. Plus the shape of the pool itself isn’t necessarily the only variable that might be affecting the race times.

The gold standard would be an empirical randomized controlled trial to compare two pools, assuming you could hide “which pool” from the participants.

I don’t doubt that they are slower, I doubt that it’s the pool depth. To be more accurate, i have no idea if it the pool depth, but a swimmer saying that it is doesn’t tell me a lot. I’m not sure if the intuition of a swimmer can differentiate between the pool depth effect and other effects that could influence performance. I don’t doubt that something is making them slower, but i don’t believe it’s pool depth until there’s better evidence.

It's pretty amazing that people here are willing to wade into a field and contest what is accepted amongst practitioners. Olympians literally spend around 40 hours a week in the pool if not more. Places like team USA and other well funded teams have an army of coaches and scientists trying to eke out every basis point of performance as their full-time job.

As a swimmer, I remember everyone lauding over how cool the Beijing Water Cube was because it was a uniform 3m deep which made it excellent for racing in - this was 16 years ago in 2008.

Since the Paris Olympics were accepted the regulation recommendation for pool depth has been revised from 2m to 2.5m

So clearly people vested in the sport and live and breathe it have seen enough evidence (including the sleepy regulatory board) to advise deeper pools.

If you wanted another possible explanation for how depth may affect the swim - a crucial part of the swim is the dive and also the underwater kicking. Both of those may have separate dynamics to swimming on the surface.

Wouldn't they notice the extra turbulence affecting their legs?

Looks like they don’t if you look at the quotes in the article. Nobody said “I can feel the turbulence reflected from the bottom of the pool slowing me down”, they just said they notice they are slower and the article claims they think it might be depth-related.

At the end of the article it notes thqt quote is coming from the company who built the pool.

On some swimming forums competitors were complaining about the bidding process for the pool construction and giving a different opinion, noting that the depth is less than what was recommended by international standards bodies. There's also something about video equipment at the bottom of the pool?

I'm not sure what to think, as there are things to consider both ways, but there's a bit more out there than swimmers versus pool officials.

The Olympic swimming is held in temporary pools in an indoor arena. Temporary pools explain the shallow depth and high walls. It isn't construction problem but decision to not use permanent pool.

Temporary pools seem to be thing recently. The US trials were held in one.

You can set up a temporary pool in a huge venue such as a football stadium and get higher attendance, or stated differently, you can accomodate a one-time need for that much spectator capacity for an event like the Olympics when you will never need that again in the lifetime of the facility.

Maybe not the same level of attendance, but you can build a permanent pool with temporary stands for the Olympics, and use the larger than necessary deck in other ways after the Olympics.

Notice the “most of…” and “diminishing returns”. The vagueness is doing a lot of heavy lifting in that statement. Since world records are often broken by mere tenths or hundredths of a second, I would think that an Olympic games would err on the side of extra spending for exactly those diminishing returns. The excitement and extra viewership from having many new WRs would more than offset the added cost anyway.

I doubt that. What is P(set of slower times across swimmers | pool is not slower)? Seems like it wouldn’t be too hard to calculate if we make a few reasonable assumptions about observational data.

And if you don’t like inferring causation, one could just directly perform an experiment to test this pool vs another pool using swimmers who didn’t quite make the Olympics.

There are more things that influence if a pool is fast or slow than just the depth.

How the pool gutters neutralizes or doesn’t neutralize waves; water temperature; the design of the lane lines; design of the starting block; the electronic touch sensors(how hard are they - do you get a good solid feel for push off?); etc

Depth is probably only part of the reason the pool is slow. It would be very unlikely everyone happens to be slow at the Olympics this year.

Perception is everything. If the pool 'feels fast', you'll feel like you're on your way to your best, which is a huge boost to your motivation. The converse is also true.

I mean, "diminishing effects" - these folks are the absolute apex of swimming struggling for the absolute maximum speed in the water that any person has ever achieved (under the watchful eye of someone with a stopwatch, at least). Small effects don't matter unless you're going for a world record, and then they might.

The one aspect which isn't equal at least amongst Olympic and other competitions is that a slower (or faster) pool will generate fewer (or more) records overall. One measure of the current games' bias would be the number of new Olympic and world records set as compared with other events --- prior or subsequent Olympics, and other world-level competitions within the current year, say. I expect the quants at sites such as 538 would be looking at this.

Are records generally evenly distributed over time? Or do we see massive spikes due to single generational talents?

The more general tendency that I've seen and which has been noted in articles/studies I'm familiar with is generally technique and technology.

Two examples of technique I'm aware of are the Fosbury Flop (1968) in the high jump, in which the jumper goes backwards over the bar (previously jumpers had gone forwards and feet-first, by 1968 with a sissors step), and heads-down technique in Australian Crawl "freestyle" swimming. Both dramatically improved results.

The Fosbury Flop was enabled by the technological introduction of foam mats on the landing side of the high-jump. Without mats, landing on your back after clearing a 2m+ bar position was somewhat undesirable.

Heads-down stroke in freestyle was in conjunction with freshwater (rather than salt) in swimming pools. Swimming heads-down without goggles in a salt-water pool burns the eyes quite strongly. With freshwater, and acrylic plastic goggles (acrylic being invented in the Great Plastics Boom of the 1930s). I'm not entirely sure when plastic swim goggles became widespread, though it may not have been until the 1970s, and the Montreal Olympics (1976) were the first to permit goggles.

Track generally has also seen tremendous improvements in the track composition (loose cinders to rubberised surface). Swimming pools have hugely reduced wave action through wave-absorbing lane lines, deep gutters, inlet diffusers, and laser-guided construction ensuring accurate and consistent distance.

That's on top of vast improvements in training, other equipment, doping (which has a very long history), professionalisation of sport (including the Olympics), and other factors.

Talent is a component, but the overall phenomenon is highly multidimensional.

> Or do we see massive spikes due to single generational talents?

Various types of doping could cause this too. More positively, tech, diet and science changes could too in some sports too.

> Bummer that it makes the meet feel slow but at least it generally affects all the swimmers equally

Shouldn't the middle swimmer be worse off with "fast" pools? There would be less waves on the side lanes, compared to a "slow" pool where there are reflections.

> at least it generally affects all the swimmers equally

> 2. The sides. Does the water spill over the sides into the gutters, or smash into a wall and bounce back, creating more chop.

My only experience with competitive swimming is playing some water polo some 25 years ago, but wouldn't that effect disproportionately affect the swimmers on the outermost lanes?

To a lesser effect, there's also the surface tension of the water, which can be adjusted with salt and borates.

Density and viscosity must also play a role, or are those managed via temperature control?

Seems very plausible. I haven't noticed a speed difference in my own pool with temperature changes, but that might just be because the temperature itself can be so distracting. But I do feel like a salty pool makes me faster (maybe from buoyancy), and borates makes the water feel smoother and less "sticky" (something about surface tension changes with borates, it even makes the surface look different).

Oh and of course the cooling effect. That's a factor for long distances especially if the water is too warm.

This is yet another reason on the huge list of reasons to keep the Olympics in Athens and just use the same facilities each time.

Why aren't swimming lanes stadium shaped like running tracks or speed skating? Floor mounted LED indicators could advise competitors of the relative distance ahead and behind of nearest adversaries.

Shouldn't that be part of the standard "Olympic Pool" definition? Depth, water height on side and overflow etc. seem to be as important as the nittting of a football goal net.

Why doesn't it affect more the people closer to the sides?

It does. This is why the fastest qualifiers get to swim in the middle lanes.

this is the reason that the leftmost and rightmost lanes of the pool aren't used for competition.

For point 2, wouldn't the reflections off the sidewalls create more issue with chop on the outer lanes than the middle?

The outer lanes are where the slower swimmers are placed already anyways, so if they were having more chop, it wouldn't likely impact a medal contender and cause a big upset... Not saying that outer lanes haven't come out on top in the last, but less likely.

All swimmers are affected equally so I don't see a problem.

Off-topic but congratulations for qualifying for trials!

So now that two swimming worlds records have fallen, we can't blame the pools anymore, can we?

[dead]

Why does it matter how deep the pool is?

Edit: the article addresses this, so if anyone else is curious like I was, I suggest clicking.

Because it means waves bounce off the bottom faster (less distance travelled) and much more importantly, with far more energy (square cube law works against you). So the waters far more choppy far faster, since you have 50% less water volume to absorb all the energy.

If it's too shallow the swimmers arms hit the bottom ...

Slightly deeper and there's drag from the floor as their arms barely miss it. That effect persists until it doesn't .. now it's deep enough.

It needs to be deep enough that vortex's created by swimmers have disapated by the time they reach bottom and reflect back to the surface so as to not interfere with following swimmers or swimmers returning.

> If it's too shallow the swimmers arms hit the bottom

Is it’s deep enough, the gravitational mass of the water will form a black hole and squash the swimmer to death.

    Big whorls have little whorls
    Which feed on their velocity,
    And little whorls have lesser whorls
    And so on to viscosity.

    and then to an event horizon.

Well before that the hydrogen atoms would fuse into helium and release vast amounts of energy, killing all the swimmers, spectators, and many people in Paris.

Edge effects affecting the flow field around the swimmer. I suppose the floor might trap turbulence near the surface rather than dissipating into the depths.

The pool in Beijing was said to be fast (25 world records broken). But they were also using a now banned swimsuit. https://www.npr.org/2008/08/10/93478073/chinas-olympic-swimm...

But you don't need to compare these results to 2008. It's not the suit. There wasn't a banned swimsuit used by everyone in Tokyo three years ago. (The 2020 Olympics were postponed a year.) As the first sentence of the article says, the eight men in the men’s 100-meter breaststroke final would have finished no better than eighth in Tokyo. Mactinenghi won in 59.03 seconds, more than two seconds slower than the current world record (and slower than the then-world record set at the 2008 Olympics).

The water cube was such an epic pool - extremely deep and the level perfectly flat rather than elliptical. I still have dreams of swimming in it

What do you mean the level was perfectly flat vs elliptical? The surface of the pool? I'm confused

I had the memory that race pools were deeper in the middle but I think that may have changed especially as I haven't competed since 2008

Here is a source from 2012 which shows pool depths weren't always uniform but it seems more modern pools are

https://www.swimmingworldmagazine.com/news/olympic-pools-whe...

Slow pools absolutely exist, as wave drag is the major impediment to speed and contributes about 55% of total drag. A shallower pool has more reflected wave energy in all directions. 2m is very shallow for a competition pool.

This paper does a decent job of modelling how swimmers move through water: https://royalsocietypublishing.org/doi/epdf/10.1098/rsif.201...

from the washington post version of this article, the winners are slower but everybody else is faster...

>But the “slow pool” theory does not hold up as well when one looks beyond the winning times. In fact, it appears a bit, ahem, shallow.

>When you consider the times it has taken to earn a spot in the finals in Paris — which is to say, the eighth-place times from either preliminary heats (in events 400 meters or longer) or semifinals — those times have been faster than in Fukuoka in 10 of the 12 events and faster than in Tokyo in five of 12. In the women’s 400 free, for example, it took a time of 4 minutes 3.83 seconds to make it into the final, faster than in Fukuoka (4:04.98) or Tokyo (4:04.07).

https://www.washingtonpost.com/sports/olympics/2024/07/30/pa...

So it's more shallow, which is a problem. Like if you trained for track on pavement vs rubber vs sand, you're going to have different results, even if "everyone has the same environment" not everyone's body will have the same relative response. I don't like that assumption that just because it's the same for everyone means the difference will affect everyone the same.

Are France competition pools across the country just always that shallow? What are dimensions of the pools from the past 10-15 Olympics? Should this have been an established standard? (gonna say yes to that one)

"minimum standard of 2 meters that was still in place when Paris 2024 plans were approved; but below the new World Aquatics minimum of 2.5 meters."

Although the recommendation has been 3 meters for a while.

It's nowhere near the difference of a rubber all weather track vs pavement or sand, it's a difference of maybe 1-2%. In any sport different venues can have favourable vs unfavourable conditions that would exceed this

Considering that the Olympics are supposed to be a test of high caliber athletics, you could argue that the lack of a standard, and the resulting variation, means that the athletes who are most adaptable have an edge. Which doesn't seem bad to me.

Plenty of pro sports have variation in conditions. World Cup soccer is played outdoors with rain, heat, whatever. Rain matters even more in Le Mans, where time records are being set. It doesn't really matter as long as it's cool to watch.

We've just finished Copa America, where players and managers complained about the pitch and its dimensions.

In baseball too, you have things like playing in LA or NY vs playing in Denver with thin atmosphere that completely affects movement of pitches as well as how well they fly through the air.

I wonder if there is some kind of mesh that you could put on the bottom of the pool to absorb the interior waves. Sort of like soundproofing in a recording studio.

A lining of triangular foam blocks would make for an interesting pool. It might work, but practicality (installation, cleaning etc.) would likely rule it out

There was a pretty strong world record tonight in the men’s 100 m freestyle of 46.40. Actually more than a second faster than the second place and beating the previous wr by 0.4 seconds.

https://www.nytimes.com/2024/04/20/world/asia/chinese-swimme...

Worth noting that the WR was from a Chinese swimmer and there's a current controversy around whether or not a large contingent of swimmers from the Chinese team violated anti-doping rules after a banned substance was found in their test results several months prior.

Reports are self-policed because it would spread the IoC or other international bodies too thin (ahem... convenient), and the Chinese reporting body "Chinada" dismissed it after saying "trace amounts were found in the kitchen where the athletes were staying at a meet".

I attempted to track down the report to see if the 100m world record breaker was amongst those who tested positive, but wasn't able to find it posted online anywhere. So he may have NOT been incriminated there, or may have been, can't say either way.

I want to celebrate the increased emphasis on swimming internationally as a former college swimmer, but it's also hard to ignore some of the clouds of controversy that have formed surrounding Chinese athletes. I understand the Olympics are a focus point for the country, and again as a former D1 swimmer I can empathize with wanting to do well, but at the same time I hope they're not crossing any lines in effort to win, as that defeats the spirit of competition.

Also worth noting that Phelps and Alison Schmitt testified before Congress and spoke about the intrusive frequency and nature of how often they were drug tested.

The NYT/The Daily did some great reporting and follow-up podcast on the situation.

https://open.spotify.com/episode/4Rcc852dmPSPytDdRCKInU?si=2...

I haven't been watching but I presume its a 50m pool. So the 100M would just have one turn, and so the swimmers would only be going through the "wall of chop" they generate once. In other words I'd expect shorter distance events to be less affected by pool depth and whatever turbulence effect that has. Also free might be less affected vs something like breaststroke due to the angle of the body in the water. (Without good technique breaststroke is really draggy, even amateurs can notice)

>Could we have seen a sub-4 minute 400 IM by Marchand

Marchand beat the rest by more than 5 seconds in the end but basically "gave up" after 300 meters. Shoulda coulda woulda but he didn't need to push himself at all for the gold (his last split was the 2nd worst against everyone else).

We’ve just got a huge WR in the 100 men sprint by Pan Zhanle (just 19 years of age, the future is all his), I have no sympathy for those crying after WRs, maybe they’re not that good to begin with.

More generally, and talking about being good, it’s noticeable how the US, the biggest force in swimming, is going through a change of generations, as their only remaining star is Ledecky, who’s on her fourth Olympics. The Russians are also missing, they always used to have one or two super-stars ready to push the Americans to the limit (think Popov and Pankratov). The Aussies are doing a very fine job, and fair-play to them for that, but they’re also kind of not up to the highest levels in the men’s competition.

Years ago Johannesburg put in an Olympic bid. Because of the high altitude (1753m) they had issues affecting a number of disciplines when it came to records due to the thinner air...

If I recall correctly: - Javeline would go further (less air resistance) - High cardio events would go slower (less oxygen for athletes)

That would have been a "slow pool" factor all things being equal!

You might find it interesting to know that for track cycling the penalty due to lower oxygen uptake is less than the advantage due to less air resistance. In other words track cyclists, at least in some of the longer disciplines, will go faster at higher altitudes despite there being less air to breathe.

That's actually super cool. I ran cross country through high school and one year of college. I was fast. Very, very fast in Ohio.

We traveled to Colorado for an invitational.

I was so slow and so tired. 18 year old me didn't realize that air changes. Idiot.

I also realized that if those guys ever came to the Midwest, they would absolutely dominate.

Yeah. I’m an aged mountain biker. Very mediocre. But when I travel to low altitude, I feel like Superman when I ride.

I live at 5000 ft now, but in my 30s I lived and slept at 9000 but did all my rides near 5000. That was an amazing time for my fitness. I could go hard at “low” altitude but recover at high which is what my body adapted for.

As we're probably familiar, dealing with an under spec computer for doing your job is frustrating. Even marginal differences in speed can be perceivable and lead to a growing dissatisfaction over time. I imagine these competitors face the same sort of frustration when dealing with a 'slow' swimming pool like this.

How is there not a standard regulation design

One can ask the same about baseball diamonds and how it's remotely fair to compare home run records when the distance needed for one is different (though with a minimum) 30 times over.

Do they make anechoic swimming pools that would absorb waves like acoustic anechoic chambers?

Well, if this is the case, then wouldn't a person who gets out to an early start have a tremendous advantage over the rest of the group since she'd be swimming largely without interference for the first length of the race while the trailers would have more turbulance? Also, I've never understood why there aren't more standards for Olympic tracks / pools / gear. For example, everyone should be required to train in and wear identical apparel when in a timed event like swimming so that nobody gets a technological advantage.

Identical apparel is a non-starter unless the athletes have identical body shapes, or we're abandoning (US) broadcasting rights to go Olympic Style.

Devil's advocate, body shape's going to affect them while swimming even if they're not wearing anything, so the interaction between the "regulation apparel" and body shape could be considered just another form of that. (I can see how it might not be in the spirit of the sport, though.)

...would they all have to train the same, eat the same food, etc?

Let's not be intentionally obtuse.

I don't think it's obtuse when you're saying they should be required to wear the same thing while training.

If you want to regulate what they wear for the competition itself, fine. But I don't see how regulating what they wear while training is different than regulating what exercises they do while training, what their diet is while training, etc.

I didn't say anything about training, because training has nothing to directly do with competing.

I was talking about competing. I don't care how they train. The purpose of competing in the event is to win, and in those circumstances, gear should be normalized as much as possible. There are always going to be differences in size, strength, etc. The purpose of the competition is to find the best in the world, and gear prevents at the competition that if some teams have items that give them a huge advantage over others.

What I remember from the London Olympics is that records don’t fall from the sky, but venues can be planned/ optimised for them. Maybe this did not happen in Paris so much?

See this bit on the Velodrome in London: https://www.cyclingweekly.com/news/making-tracks-building-th...

In Paris they didn't want to build a white elephant swimming venue that will never get filled outside of the Olympics. So instead they converted an indoor stadium, the Paris La Défense Arena that is normally used for rugby and concerts.

You can see in the timelapse video here[1] the pool being built above the surface. They built it to a depth of 2.15m, the minimum required is 2m, but the recommended depth is 3m.

I can only assume that making it deeper would have cost more, and perhaps reduced the sightlines from the stands as the pool would have been higher in the arena?

[1] https://www.thesun.co.uk/sport/29555045/paris-2024-olympics-...

And similarly for Los Angeles, the current proposal is to have swimming events at SoFi, a ~70,000 seat NFL stadium.

Ummmm....

https://en.m.wikipedia.org/wiki/Paris_Aquatic_Centre

that has a seating capacity of 5000, which is a size that can have future uses.

la defense arena has a capacity of 40000.

Paris La Défense Arena -- Aquatics (swimming, water polo finals)

Paris Aquatic Centre -- Aquatics (water polo preliminaries, diving, artistic swimming)

> Paris Aquatic Centre -- Aquatics (water polo preliminaries, diving, artistic swimming)

Why not have those events at a different temporary facility? Feels like they did not avoid building a white elephant...

>Last Thursday, President Emmanuel Macron inaugurated the Olympic Aquatic Centre, but behind the flashes and smiles of the opening ceremony was a complex story that saw the budget increase by more than €115 million and the number of events reduced.

https://olympics.com/en/paris-2024/venues/aquatics-centre

> From swimming lessons to recreational use and high-level competitions, the Aquatics Centre will be multifunctional. From July 2025, the Aquatics Centre will become a vast multi-sports facility open to all, including two pools (50m and 25m), a fitness area, bouldering area, paddle tennis section and pitches for team sports. It will also have an adjustable floor to serve a variety of purposes (swimming lessons for babies and children, etc.). The Aquatics Centre will also be the state-of-the-art facility that the French swimming community has been looking forward to for decades. The French Swimming Federation will be able to host national and international competitions in its four indoor disciplines. The Centre will also provide a best-in-class federal training facility for leading French athletes and will notably be home to the country’s diving centre

You don't need a 150 million Euro facility to teach swim lessons and recreational uses. As far as high level competitions...

>This capacity, which may be overlooked by many, is not for World Aquatics, which requires a minimum of 15,000 for top-level swimming events, so France will not be able to host a World Championships

"it is hosting the diving, water polo, and artistic swimming competitions."

I hadn’t really considered the energy bouncing off and interfering swimmers. I was just imagining the plausibility given the limited science I know about water flow in a stream and cross sectionally how the furthest from edges (drag) will be fastest.

Which got me wondering if there’s any detectable correlation on record setting and what lane you’re in (closer to the side of the pool might be slower?)

Feel like we should probably be looking deeper into the lack of doping (be it Chinese or otherwise) as probably a bigger factor here.

I'm fairly certain I read a thorough analysis linked on here a few years ago, about how there was a kind of draft/current in the pool used in the championship at the time. Some analysis determining that certain lanes were favorable or not.

But unable to locate it. Fairly certain it was Barcelona.

As a counterpoint to the Parisian pool being slow, China beat the world record in 100m free 10 minutes ago.

That's not a counterpoint, it doesn't imply the pool is fast or even normal. In a faster pool his time could've been even lower.

It is if the only data is lack of world records, and mixed opinions from experts (per the article)

Nitpick: for individual sports, probably better to refer to participants as "Pan Zhanle from China" than "China".

Nitpick of the nitpick: in international sports, the preposition used is "of", as in "Pan Zhanle of China", as an elision of "of the Chinese team".

Now, I could make up reasons for this, like not every athlete is strictly "from" the place they compete for, but a just-so story isn't needed here, prepositions are what they are, often arbitrary but always specific.

Citation:

https://apnews.com/article/paris-olympics-china-swimming-pan...

If this is a "slow" pool, then should we toss world records from "fast" pools? There are a lot of other events where factors affecting performance aren't completely controlled. Perhaps comparing records across different times and places is meaningless.

No, in the same way that all Marathon records are set in only a few marathons which have very favorable conditions.

It's hard to control conditions for a Marathon, but what's to stop some future Olympic host from intentionally creating the fastest pool possible that wouldn't be objected to, just so they could watch "their" Olympics break all the records?

That is exactly what happens almost every time... Just not this time

Don’t we want Olympic hosts to create optimal conditions for athletes to demonstrate their skills?

We want Olympic host cities not to go into billions of debt that they'll never make back, as that will make it hard to find good hosts. Paris tried to be prudent tinancially.

>Perhaps comparing records across different times and places is meaningless.

This is a line of thought that leads to the consideration that sports as are whole are rationally meaningless. That leads to hobbies being meaningless. That leads to emotions and ethics being meaningless.

You can't apply rationality to explain why people care about things. But people do care about it, so it matters.

This is entirely just my own opinion...

I completely understand why you might not want a slow pool in a competition like this, but the emphasis on it being "not ideal for record setting" is weird to me. I guess I just don't understand the constant quest to set better and better records. Do we really always need to be hitting new world records? What's the point of that, why does that need to be a thing? If records like that are expected to be broken at every Olympics, what's the point of striving to break them if they're just going to be broken again?

Meh, I'll go back to yelling at clouds, I guess.

Setting a new world record is part of making history, and many are not broken at every Olympics. Consider this example - the men's 100m sprint world record was last broken by Usain Bolt 15 years ago! Now if you're not into that particular sport then maybe that doesn't mean much to you, fair enough. But wow, when someone comes along who is able to break that record it will really be something special.

Yeah, that's kinda what I was getting at. The way this talks about "impeding world records" makes it sound like they're expected to be broken frequently. If that's the case, to me, it kinda cheapens world records - that's to say, if they're broken so often, it doesn't seem as big of a deal. But when someone like Usain sets a record that lasts for a while, it does make sense to me that the breaking of that record is special.

It ain't special if it happens a lot, I guess is my thinking.

Sure, but I think you're missing the point.

The point is that many athletes are only at their peak for one or two Olympics. How rubbish for them that they're not able to get a fair shot at the record like others have had in the past.

I think it might be a motivation for competitors when they are already at the top, it is a way they can compare their performance with all past (and future) performances, and most importantly, with their own performance in other competitions.

The Olympic committee mandates that new facilities get built for every Olympics, which is partly why the games are so damn expensive everytime.

With that in mind though, what is the point of a world event like this if, given the time and resources, we're not going to try and optimize for peak performance for the participants given that for many of them it's the career peak?

I'd argue plenty of blame to go around though: for one, why is there not a standard pool design and dimension?

I guess, at least to me, there's a bit of a difference between "optimizing for peak performance in order to best your opponent(s)" and "expecting to break world records".

/shrug

I guess I just don't understand the constant quest to set better and better records.

Money. All else being equal, setting a new world record will lead to you earning more money, compared to 'just' winning gold. Both because there many cases are cash bonuses tied to world records, and from a sponsorship point of view it is easier to 'sell' a world record holder. Most people know that Usain Bolt holds the 100m world record and Olympic record, you have to be pretty into sprinting to know who won gold at the 100m last Olympics.

It's amusing that the day after this was published a monstrous world record beat occurred in the 100 m freestyle.

According to airparif.fr air quality is currently degraded in Paris, could air pollution be the culprit ?

It’s also not ideal to try setting a high jump record right after the Olympics in Mexico City. So what.

Honestly, my first reaction was "oh, they just stopped doping."

Good thing there's credible explanations about the differences in pools and how that effects swimming speed. Otherwise, I'd assume that no one wanted to "'fess up" to prior doping.

World records don’t matter in the Olympics. Medals go to those who show up and prevail.

World records matter on their own, as long as the measurement is trustworthy. The way we know this matters at the Olympics, is that world records are being tracked and discussed at the Olympics.

But you're right, they don't affect medals.

My point is that it’s not the spirit of the games. Ancient Greeks didn’t even keep a record of any metrics. Back then, there was no assumption that “modern” competitors should exceed the performance of those who competed decades or centuries before.

This type of focus leads to unhealthy expectations and doping in my opinion.

Indeed. I also don't find fractional seconds very exciting. I call a difference of .02 seconds a tie.

Could the percentage of deuterium in the water be affecting the speed too?

Why would we expect that to vary by any appreciable level?

In addition to physical issues raised (7ft depth, configuration of sides), I wonder if there might be any other reasons that aren't mentioned at all in the article…

Something causing these elite athletes to be a bit off their game? Whatever could it possibly be…

- https://www.usatoday.com/story/sports/olympics/2024/07/31/us...

- https://www.walesonline.co.uk/news/uk-news/team-gb-swimmer-m...

- https://www.theguardian.com/sport/article/2024/jul/30/paris-...

- https://svenska.yle.fi/a/7-10061397

Yup, no idea. ¯\_(ツ)_/¯

That's not a very satisfying explanation because everyone seems to be slow and it's pretty unlikely that everyone has COVID.

Covid is a highly contagious virus that spreads and lingers in the air, and we have athletes in close quarters without any virus control procedures [1] (other than the Olympic organizers providing hand sanitizer [2], which is an odd choice for airborne virus prevention).

Given lack of testing and that many countries (including European countries) are seeing Covid surges right now, I think it's highly likely that most competitors are competing with either current or recent Covid infections affecting their peak performance capacity.

Edit: I wouldn't suggest it's the sole cause of performance issues. But for an entire article on the topic of swim performance to completely ignore multiple reports of viral infection from top performers seems a glaring omission.

-----

1: "The 29-year-old does not have to isolate from other athletes and does not have to test negative before competing again": https://www.espn.com/olympics/story/_/id/40672610/olympics-2...

2: "For now, nothing has been put into place by the organizing committee … but hand sanitizer is available in its clinics and restaurants.": https://www.cbsnews.com/news/2024-paris-olympics-covid-cases...

To be clear, there is no scientific consensus on the term "surge". It is purely editorial, in my view. Iff you believe KFF.org, there trend lines show a sharp fall in the last six months here: https://www.kff.org/coronavirus-covid-19/issue-brief/global-...

Sidestepping nomenclature bikeshedding, healthcare organizations are seeing an increase in patient load which seems like a reasonably tactical datapoint that there's a meaningful increase over the last couple months.

Google is your friend; this [1] is but one France-specific example of coverage. You can find many similar articles in jurisdictions across Western Europe raising concern specifically in the last month or two.

Edit:

Many jurisdictions stopped collecting and/or sharing robust datasets in 2023 (KFF even calls attention to this). This often means digging through opaque reports to get useful data.

Here's an example [2] from the UK government, in PDF format, but bottom of Page 10 looks pretty "surge-y" to me over the last couple months and not yet at peak.

Edit:

Another example of good data horrible to access. Scotland wastewater monitoring [3] I can't provide a direct link; have to click on "Respiratory pathogens" and the first chart is wastewater monitoring; July 2024 shows the highest "surge" in levels since 2022.

--------

[1] https://www.connexionfrance.com/news/covid-19-advice-for-tes...

[2] https://assets.publishing.service.gov.uk/media/66337699cf3b5...

[3] https://scotland.shinyapps.io/phs-respiratory-covid-19/

The Olympic Villages are notorious for being germfests.

Now up to at least 11 known aquatic competitors [1]. And most teams aren't testing — for example, Australia brought their own PCR machine; nothing has been provided by the Olympic organizers.

[1]: https://swimswam.com/swimmers-pieroni-and-gatt-join-the-covi...

Let's also not forget doping. Chinese swimmers noticeably slower this year than last olympics in particular. Wonder why that is?

Has anything in the drug testing changed that can affect swimmers?

Russian imports/exports are much more restricted now than 4 years ago.

Did previously a lot of doping come russia? I am curious.

Russia is banned from the Olympics for, among other things, doping.

Chinese swimmer just broke the record, this article is nonsense.

a good tech talk about the venue & technology and it's impact on olympic scores. tl;dr the surfaces and shoes likely account for 95% of the record breaking

https://www.ted.com/talks/david_epstein_are_athletes_really_...

As with any tech talk, think critically. Athletes train more vigorously, and have much better nutrition. Earlier athletes in the Olympics and Tour de France drank alcohol and smoked during performance.

It's still helpful to pay attention to the venues, like the swimming pools, tracks , wrestling mats etc. My verdict is that venue plays a big part, and records are not comparable from different venues.

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You probably will dismiss it, based on your username, but people like https://en.m.wikipedia.org/wiki/Patrik_Baboumian completely demolish your argument.

Olympic athletes are not allowed to take steroids, while strongmen take as much as humanly possible.

Gorillas are vegan and they have a ton of muscle.

Only humans are vegan.

Few gorillas were seen distributing pamphlets and letting their local community know of their superior dietary philosophy.

Animals are classified as herbivores, omnivores, or carnivores.

Gorillas are omnivores with a predominantly plant-based diet.

Can gorillas become vegan?

Good question.

Gorillas are not vegan, they eat a significant amount insects. They also opportunistically eat small (vertibrate) animals. They also eat a whole lot more than humans.

Yeah, but gorillas have a different digestive system to humans.

FUD. Vegan food also has protein.

All protein derived from veggies are considered incomplete when compared to animal derived protein, which also require substantially more volume to obtain the same nutritional content.

You only need to look at the amount of waste (feces) between a veggie based diet and an animal based diet - the difference is staggeringly different.

I.e. far less waste is produced, because far less is required when eating animal based foods.

This argument isn't even anywhere close to making any sense. The amount of waste that's left after food is digested doesn't indicate anything about the nutritional values of the food you've consumed. The reason there's more waste after eating veggies is because veggies generally contain high levels of fiber and the human body cannot digest fiber.

(Aside: this doesn't mean fiber isn't good or useful for you, consuming fiber is a key component in keeping your gut fit and healthy because your gut has to do work to deal with the fiber, similar to lifting weights for your other muscles.)

It males sense if you consider the volume/weight/quantity values and compare them to the basic requirements for life - rather than what the psych wants, which is often overindulgent due to the other non-animal based type of nutrition(?) being consumed.

I wonder what the Inuit use as a natural source of fiber.

> All protein derived from veggies are considered incomplete when compared to animal protein

You’ be interested to have a look at amino acid in quinoa, tempeh and most of the mushrooms

Dunno man, I poop a lot more (and stinkier) when I eat more meat as compared to vegetarian dishes.

Considered incomplete by whom? References?

+1 for the stinkness. Also you very feel those fibers that helps everything slide as a soap. Or is it a the fence hydratation level, lower for animal proteins that stays longer in the belly?

> Considered incomplete by whom?

Probably means incomplete in that most plant based protein sources do not contain all essential amino acids.

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Finally an explanation for my hopelessness at childhood swimming lessons. It was a slow pool!

In perhaps the most Slate article ever, they attempt to blame the lack for record breaking Paris on (wait for it), Climate Change.

https://slate.com/technology/2024/07/paris-olympics-2024-bre...

I mean, if it's hotter, that will impact performance. Not for swimming necessarily, but track will suffer.

Of course it's slower. CFD simulations would also prove that.

But maybe they wanted not to be too many world records be broken, to damage control the apparent doping problem.

You can easily see on TV now, who is doped and who's not. All the dopers do have dark purple faces after the swim, usually the middle swimmers from the US, GB, AUS, Ireland, F, China, whilst the non-dopers keep their usual skin color. Italy, Hungary, Germany, ... Some hormone effect probably with these rushes.

So you’re claiming the American, British, Australian, Irish, French and Chinese swimmers are all on drugs? And that everyone apart from you is unaware of that fact?

Right.

Are you claiming that all swimming medal winners are not on drugs? That's highly ridiculous. They are just not caught.