[HN Gopher] Is a 'slow' swimming pool impeding world records?
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Is a 'slow' swimming pool impeding world records?
Author : phkx
Score : 88 points
Date : 2024-07-30 10:49 UTC (1 days ago)
(HTM) web link (sports.yahoo.com)
(TXT) w3m dump (sports.yahoo.com)
| samldev wrote:
| 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
| davidmurdoch wrote:
| To a lesser effect, there's also the surface tension of the
| water, which can be adjusted with salt and borates.
| HPsquared wrote:
| Density and viscosity must also play a role, or are those
| managed via temperature control?
| davidmurdoch wrote:
| 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).
| HPsquared wrote:
| Oh and of course the cooling effect. That's a factor for
| long distances especially if the water is too warm.
| mysterydip wrote:
| Would the swimmers in the center lanes have any advantage by
| being furthest away from the wall-induced chop?
| hgomersall wrote:
| Supposedly, that's why the fastest qualifiers get the middle
| lanes.
| jschulenklopper wrote:
| 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.
| iknowSFR wrote:
| Interesting to see the 400m and 200m track and field
| athletes starting to favor outside lanes.
| johnp314 wrote:
| 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.
| sandworm101 wrote:
| 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.
| dr_dshiv wrote:
| Random assignment should make it easy to detect,
| depending on the size of the effect
| etempleton wrote:
| 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.
| renewiltord wrote:
| 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.
| elevaet wrote:
| 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.
| skeeter2020 wrote:
| 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.
| renewiltord wrote:
| Makes sense.
| SECProto wrote:
| They do throw away one lane on each side already, FYI (in
| addition to positioning competitors to minimize influence
| on results, as others discussed)
| umanwizard wrote:
| 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.
| creshal wrote:
| 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.
| HPsquared wrote:
| 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.
| defrost wrote:
| 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.
| sshine wrote:
| > _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.
| defrost wrote:
| Big whorls have little whorls Which feed on their
| velocity, And little whorls have lesser whorls
| And so on to viscosity.
|
| ~ Lewis Fry Richardson and then to an
| event horizon.
|
| ~ sshine
| croes wrote:
| >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
| lou1306 wrote:
| 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.
| echoangle wrote:
| 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.
| CoastalCoder wrote:
| Even CFD analysis is a _model_ though, with all that
| implies.
|
| Would a large, blind empirical study be more trustworthy?
| echoangle wrote:
| 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.
| Eddy_Viscosity2 wrote:
| 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.
| _heimdall wrote:
| 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.
| echoangle wrote:
| 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.
| _heimdall wrote:
| 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.
| echoangle wrote:
| 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.
| _heimdall wrote:
| 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.
| freejazz wrote:
| So to be clear, you have no idea, you just insist on
| discounting the experiences of the swimmers because you
| can?
| _heimdall wrote:
| 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.
| mmmrtl wrote:
| 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.
| ff317 wrote:
| 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.
| throwaheyy wrote:
| No, it isn't.
| boringg wrote:
| While part of it may be true. The athletes who spend
| 1000s of hours can probably intuit something being
| different.
| echoangle wrote:
| 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.
| AnthonBerg wrote:
| 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?
| Xcelerate wrote:
| 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.
| echoangle wrote:
| 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.
| fullspectrumdev wrote:
| 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.
| defrost wrote:
| 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.
| Kon-Peki wrote:
| 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.
| toast0 wrote:
| 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.
| TylerE wrote:
| 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?
| MrPatan wrote:
| Intuition forms because it works. When it doesn't it's
| remarkable to the point of writing books and movies about
| it.
| echoangle wrote:
| 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.
| Rayhem wrote:
| 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.
| lou1306 wrote:
| 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.
| sdwr wrote:
| 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
| tanewishly wrote:
| 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.
| echoangle wrote:
| 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.
| viraptor wrote:
| > 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.
| dsr_ wrote:
| 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.
| teddyh wrote:
| > _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.
| Gud wrote:
| 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.
| teddyh wrote:
| 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.
| viraptor wrote:
| 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!
| mensetmanusman wrote:
| There is an audible difference after being in a high temp
| high humidity environment for 5 years :)
| warkdarrior wrote:
| Have you tried not listening to music underwater??
| lelanthran wrote:
| Under _boiling_ water. He did mention high temperatures
| as well as humidity, after all.
| viraptor wrote:
| 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?
| kergonath wrote:
| > 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.
| croes wrote:
| 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.
| AtlasBarfed wrote:
| 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
| Someone wrote:
| > 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.
| bobthepanda wrote:
| 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.
| swores wrote:
| 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.
| RaftPeople wrote:
| > _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.
| stingrae wrote:
| > 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"
| AtlasBarfed wrote:
| 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.
| beAbU wrote:
| 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.
| ben7799 wrote:
| 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.
| Kon-Peki wrote:
| 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
| bregma wrote:
| > 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.
| duggan wrote:
| As much as it's about winning the medals, this is about
| setting personal and world records, too.
| kergonath wrote:
| Regardless, they have to make do with what they have.
| Nobody is moaning that the weather affects triathlon
| timings.
| s1artibartfast wrote:
| When you measure human performance, placebo matters.
| stonemetal12 wrote:
| Considering touching the bottom results in
| disqualification it isn't a superstitious fear.
| aleph_minus_one wrote:
| > 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.
| Xcelerate wrote:
| 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.
| qzw wrote:
| 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.
| derbOac wrote:
| 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.
| ianburrell wrote:
| 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.
| SoftTalker wrote:
| 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.
| toast0 wrote:
| 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.
| etempleton wrote:
| 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.
| rscho wrote:
| 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.
| tweetle_beetle wrote:
| 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).
| ranie93 wrote:
| digital lap counters to help the swimmers keep track
| creaghpatr wrote:
| 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
| Scoundreller wrote:
| 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.
| sandworm101 wrote:
| 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).
| madaxe_again wrote:
| 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.
| bjoli wrote:
| Does it manifest directly? The water has had some time to
| settle when they start.
| madaxe_again wrote:
| 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.
| manojlds wrote:
| Why doesn't it affect more the people closer to the sides?
| notatoad wrote:
| this is the reason that the leftmost and rightmost lanes of
| the pool aren't used for competition.
| mb7733 wrote:
| It does. This is why the fastest qualifiers get to swim in
| the middle lanes.
| conductr wrote:
| 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
| kergonath wrote:
| 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.
| teractiveodular wrote:
| 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?
| killingtime74 wrote:
| 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.
| trhway wrote:
| > 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 that turbulent movement of the water
| reflected by the pool bottom may as well come behind legs in
| the 3m depth case while in the 2m depth case it would
| envelope the legs decreasing the efficiency of their
| movement.
| candlemas wrote:
| 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...
| 5555624 wrote:
| 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).
| haunter wrote:
| >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).
| raspasov wrote:
| Has anything in the drug testing changed that can affect
| swimmers?
| callalex wrote:
| Russian imports/exports are much more restricted now than 4
| years ago.
| Cupprum wrote:
| Did previously a lot of doping come russia? I am curious.
| Waterluvian wrote:
| 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?)
| lacoolj wrote:
| 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)
| p0ckets wrote:
| "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.
| morepork wrote:
| 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
| tonymet wrote:
| 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.
| MisterBastahrd wrote:
| 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.
| Ylpertnodi wrote:
| ...would they all have to train the same, eat the same food,
| etc?
| MisterBastahrd wrote:
| Let's not be intentionally obtuse.
| toast0 wrote:
| Identical apparel is a non-starter unless the athletes have
| identical body shapes, or we're abandoning (US) broadcasting
| rights to go Olympic Style.
| f_allwein wrote:
| 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...
| morepork wrote:
| 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 Defense
| 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-...
| hnburnsy wrote:
| Ummmm....
|
| https://en.m.wikipedia.org/wiki/Paris_Aquatic_Centre
| morepork wrote:
| "it is hosting the diving, water polo, and artistic
| swimming competitions."
| phatfish wrote:
| Paris La Defense Arena -- Aquatics (swimming, water polo
| finals)
|
| Paris Aquatic Centre -- Aquatics (water polo preliminaries,
| diving, artistic swimming)
| notatoad wrote:
| that has a seating capacity of 5000, which is a size that
| can have future uses.
|
| la defense arena has a capacity of 40000.
| well_actulily wrote:
| And similarly for Los Angeles, the current proposal is to
| have swimming events at SoFi, a ~70,000 seat NFL stadium.
| mlsu wrote:
| 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.
| beloch wrote:
| 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.
| BobAliceInATree wrote:
| No, in the same way that all Marathon records are set in only a
| few marathons which have very favorable conditions.
| beloch wrote:
| 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?
| bitmasher9 wrote:
| Don't we want Olympic hosts to create optimal conditions
| for athletes to demonstrate their skills?
| mb7733 wrote:
| That is exactly what happens almost every time... Just not
| this time
| MichaelBurjack wrote:
| 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. -\\_(tsu)_/-
| khuey wrote:
| That's not a very satisfying explanation because everyone seems
| to be slow and it's pretty unlikely that everyone has COVID.
| MichaelBurjack wrote:
| 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/oly
| mpics-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...
| outside1234 wrote:
| Let's also not forget doping. Chinese swimmers noticeably
| slower this year than last olympics in particular. Wonder why
| that is?
| outside1234 wrote:
| Feel like we should probably be looking deeper into the lack of
| doping (be it Chinese or otherwise) as probably a bigger factor
| here.
| gwbas1c wrote:
| 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.
| jeppebemad wrote:
| As a counterpoint to the Parisian pool being slow, China beat the
| world record in 100m free 10 minutes ago.
| elliottkember wrote:
| 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.
| matsemann wrote:
| 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.
| jlarcombe wrote:
| Finally an explanation for my hopelessness at childhood swimming
| lessons. It was a slow pool!
| notatoad wrote:
| 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...
| jjulius wrote:
| 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.
| EternalFury wrote:
| World records don't matter in the Olympics. Medals go to those
| who show up and prevail.
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