What’s In the Splits? A Breakdown of 500 Frees from Carson, Rex, Leon, and More

2024 Texas Hall of Fame Invite

  • November 20-22, 2024
  • Where: Lee and Joe Jamail Swimming Center — Austin, TX
  • When: 10 am CT prelims/6 pm CT finals
  • Participating Teams: Pitt, Stanford, Texas (host), USC, Wisconsin, BYU, Cal Poly
  • Meet Info
  • Live Results
  • Results on Meet Mobile: “Texas Hall of Fame Swimming Invite”
  • Day 1 Prelims Live Recap | Day 1 Finals

There is only one coach in swimming history who has coached a man under 4:06 in the 500 free, and he happens to have done it with three different swimmers.

A pair of Texas Longhorns broke the American Record in the event on Wednesday evening at the Texas Hall of Fame Invite. First, in a time trial, post-grad Carson Foster  swam 4:05.81. A couple of hours later, current Texas sophomore Rex Maurer cleared that mark to go 4:04.45.

Those swimmers are both in their first season training with Bob Bowman and now are the #2 and #3 performers in history. The top performer in history is Frenchman Leon Marchand, who is currently training in France until an American return in January, and who has spent the last few years training under Bowman. That includes in the run-up to the 2024 NCAA Championships where he swam 4:02.31 to shatter his own all-time record by almost four seconds.

So how are they doing it? I laid out a whole bunch of splits next to each other to see what stood out.

Here’s the first thing that jumped out at me:

Rex vs. Carson

Carson Rex
50y 22.21 22.24
100y 46.93 (24.72) 47.06 (24.82)
150y 1:12.12 (25.19) 1:12.18 (25.12)
200y 1:37.00 (24.88) 1:37.22 (25.04)
250y 2:02.00 (25.00) 2:02.08 (24.86)
300y 2:26.91 (24.91) 2:27.04 (24.96)
350y 2:51.76 (24.85) 2:51.84 (24.80)
400y 3:16.61 (24.85) 3:16.59 (24.75)
450y 3:41.33 (24.72) 3:41.00 (24.41)
500y 4:05.81 (24.48) 4:04.45 (23.45)
4:05.81 4:04.45

Wednesday night’s pair Rex Maurer and Carson Foster were nearly identical on their splits for the first 400 yards before Maurer powered away at the end.

There has been so much talk and baited anticipation over the pending training battles between Foster and Marchand, but even without swimming the race together, Foster and Maurer were able to hit their splits almost perfectly before Maurer pulled away on the last 100 (and what a brilliant last 100 it was). With Foster still three weeks away from his big winter  meet at Short Course Worlds, that last 100 could be explained by simply being at a different spot in their training cycles and Rex maybe having a little more rest this week than Foster does.

Either way, it was impressive to see, and would have been a really fun race to watch head-to-head (though that’s not allowed anymore by new NCAA rules which precludes pros from racing in the same meets as the collegians, so they have to swim in “separate meets”).

Adding Kieran Smith

Carson Rex Kieran Smith
50y 22.21 22.24 22.45
100y 46.93 (24.72) 47.06 (24.82) 47.28 (24.83)
150y 1:12.12 (25.19) 1:12.18 (25.12) 1:12.07 (24.79)
200y 1:37.00 (24.88) 1:37.22 (25.04) 1:37.08 (25.01)
250y 2:02.00 (25.00) 2:02.08 (24.86) 2:02.25 (25.17)
300y 2:26.91 (24.91) 2:27.04 (24.96) 2:27.35 (25.10)
350y 2:51.76 (24.85) 2:51.84 (24.80) 2:52.40 (25.05)
400y 3:16.61 (24.85) 3:16.59 (24.75) 3:17.25 (24.85)
450y 3:41.33 (24.72) 3:41.00 (24.41) 3:42.19 (24.94)
500y 4:05.81 (24.48) 4:04.45 (23.45) 4:06.32 (24.13)
4:05.81 4:04.45 4:06.32

Kieran Smith was the record-holder before Leon came around, and while he never went sub-4:06, he was close.

Interestingly, he was right there with Carson and Rex through the first 200 yards and held on pretty well even through the 300. By the 350, though, he started to fall of the pace just a bit. That little regression from the 200 yard mark through the 350 yard mark allowed him to close well (not as well as Rex), but there doesn’t seem to be much room for ‘backing off’ in the middle section of the race to get under 4:06.

Getting under 4:06 seems to be more about controlling the first 200 (though those are very fast first 200s) and then descending rather than maintaining. Both Carson and Rex had their slowest splits from the 100 yard – 150 yard mark.

Rex vs. Rex/Carson vs. Carson

Note: Carson was 4:07.67 in another time trial last year, but we couldn’t find any splits. This comparison uses his prior best time from 2022. If you’ve got last year’s splits, please send them to [email protected]!

Rex
Rex Previous PB
50y 22.24 22.89 -0.65
100y 47.06 (24.82) 48.08 (25.19) -0.37
150y 1:12.18 (25.12) 1:13.58 (25.50) -0.38
200y 1:37.22 (25.04) 1:39.30 (25.72) -0.68
250y 2:02.08 (24.86) 2:05.02 (25.72) -0.86
300y 2:27.04 (24.96) 2:30.90 (25.88) -0.92
350y 2:51.84 (24.80) 2:56.77 (25.87) -1.07
400y 3:16.59 (24.75) 3:22.33 (25.56) -0.81
450y 3:41.00 (24.41) 3:47.65 (25.32) -0.91
500y 4:04.45 (23.45) 4:11.88 (24.23) -0.78
4:04.45 4:12.58
Carson
Carson from 2022 Minnesota Invite
Change
50y 22.21 22.37 -0.16
100y 46.93 (24.72) 46.90 (24.53) 0.19
150y 1:12.12 (25.19) 1:12.10 (25.20) -0.01
200y 1:37.00 (24.88) 1:37.55 (25.45) -0.57
250y 2:02.00 (25.00) 2:03.18 (25.63) -0.63
300y 2:26.91 (24.91) 2:28.94 (25.76) -0.85
350y 2:51.76 (24.85) 2:54.54 (25.60) -0.75
400y 3:16.61 (24.85) 3:19.85 (25.31) -0.46
450y 3:41.33 (24.72) 3:45.28 (25.43) -0.71
500y 4:05.81 (24.48) 3:45.28 (25.03) -0.55
4:05.81 4:10.31

Both swimmers’ personal bests came when they were training with other coaches. Foster’s was at the 2022 Minnesota Invite while training with Eddie Reese, as an undergrad at Texas, while Maurer’s came at the 2024 Pac-12 Championships while training at Stanford.

Carson’s shift wasn’t really in how fast her went out as much as it was in how well he pushed through the latter half of the race. Bowman, known as a higher volume coach generally, seems to be really good at doing volume better for 200-500 yard or meter events especially.

On Maurer’s deltas, it’s clear that his swim is just better, generally, but the gaps grew as the race got longer. Whatever the change is from Stanford to Texas, he’s thriving in it (we’ll try and get some podcasts with coaches and athletes in the next few weeks to talk about it).

Interestingly, there wasn’t really much of a comparison to make between what Carson and Rex are doing and what Leon did in his 4:02, even if we scale for Marchand being way faster. Marchand, in relative terms, was out blisteringly fast, and was white-knuckles holding on at the end. He didn’t show the same descend pattern as Foster and Maurer did, but the opening 1:33 is one of the craziest splitting patterns we’ve ever seen in swimming.

Carson vs. Rex vs. Leon

Carson Rex Leon
50y 22.21 22.24 21.09
100y 46.93 (24.72) 47.06 (24.82) 44.62 (23.53)
150y 1:12.12 (25.19) 1:12.18 (25.12) 1:08.61 (23.99)
200y 1:37.00 (24.88) 1:37.22 (25.04) 1:33.12 (24.51)
250y 2:02.00 (25.00) 2:02.08 (24.86) 1:57.94 (24.82)
300y 2:26.91 (24.91) 2:27.04 (24.96) 2:22.31 (24.37)
350y 2:51.76 (24.85) 2:51.84 (24.80) 2:47.18 (24.87)
400y 3:16.61 (24.85) 3:16.59 (24.75) 3:12.30 (25.12)
450y 3:41.33 (24.72) 3:41.00 (24.41) 3:37.76 (25.46)
500y 4:05.81 (24.48) 4:04.45 (23.45) 4:02.31 (24.55)
4:05.81 4:04.45 4:02.31

Here’s the full table of times I looked at (sorry for folks on mobile, it’s pretty wide).

Carson Rex Leon Leon Pac-12 Carson 2022 Minnesota Invite Carson 2022 PB Rex Previous PB Kieran Smith
50y 22.21 22.24 21.09 22.04 22.37 22.37 22.89 22.45
100y 46.93 (24.72) 47.06 (24.82) 44.62 (23.53) 46.32 (24.28) 46.90 (24.53) 46.90 (24.53) 48.08 (25.19) 47.28 (24.83)
150y 1:12.12 (25.19) 1:12.18 (25.12) 1:08.61 (23.99) 1:10.83 (24.51) 1:12.10 (25.20) 1:12.10 (25.20) 1:13.58 (25.50) 1:12.07 (24.79)
200y 1:37.00 (24.88) 1:37.22 (25.04) 1:33.12 (24.51) 1:35.85 (25.02) 1:37.55 (25.45) 1:37.55 (25.45) 1:39.30 (25.72) 1:37.08 (25.01)
250y 2:02.00 (25.00) 2:02.08 (24.86) 1:57.94 (24.82) 2:01.08 (25.23) 2:03.18 (25.63) 2:03.18 (25.63) 2:05.02 (25.72) 2:02.25 (25.17)
300y 2:26.91 (24.91) 2:27.04 (24.96) 2:22.31 (24.37) 2:25.81 (24.73) 2:28.94 (25.76) 2:28.94 (25.76) 2:30.90 (25.88) 2:27.35 (25.10)
350y 2:51.76 (24.85) 2:51.84 (24.80) 2:47.18 (24.87) 2:50.62 (24.81) 2:54.54 (25.60) 2:54.54 (25.60) 2:56.77 (25.87) 2:52.40 (25.05)
400y 3:16.61 (24.85) 3:16.59 (24.75) 3:12.30 (25.12) 3:15.66 (25.04) 3:19.85 (25.31) 3:19.85 (25.31) 3:22.33 (25.56) 3:17.25 (24.85)
450y 3:41.33 (24.72) 3:41.00 (24.41) 3:37.76 (25.46) 3:41.42 (25.76) 3:45.28 (25.43) 3:45.28 (25.43) 3:47.65 (25.32) 3:42.19 (24.94)
500y 4:05.81 (24.48) 4:04.45 (23.45) 4:02.31 (24.55) 4:06.18 (24.76) 3:45.28 (25.03) 3:45.28 (25.03) 4:11.88 (24.23) 4:06.32 (24.13)
4:05.81 4:04.45 4:02.31 4:06.18 4:10.31 4:10.31 4:12.58 4:06.32

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le chase
20 days ago

As a former 500 swimmer, I am always in awe of Leon’s splits – going out that hard is fearless. I wish I had the gumption to do the same back in my day. And I wish I had spent more time working on my underwaters.

After his 4:02 in March, I really didn’t think we’d see anyone coming anywhere close in the near future. But as usual, I am continually surprised and impressed by these young guys pushing the barrier.

I think later this season we’re going to see a few guys push into 4:05/4:04/4:03 which is exciting. After years of slower progression, the 500 is finally coming into its own.

HeGetsItDoneAgain
Reply to  le chase
20 days ago

Honestly thought we’d have to wait until Luka arrived at Texas to start approaching Leon’s mark. Maurer might be there by spring.

Kevin
20 days ago

First I love articles like this.

Second I think what Leon did was what Carson and Maurer are still training for and still getting a feel for. Even though Leon didn’t quite fully execute it correctly either.

It’s been a staple part of mid and long distance running to do some training where you descend your pace at intervals. Even with a mile which time wise is closest to a 500 free. I always knew them as progression runs. Did them once every two weeks to once a week for my marathon training. Did them a little more often for 10k and 5k because they were shorter. With the marathon training it was usually around 2 miles easy to get… Read more »

Wirotomo
Reply to  Braden Keith
20 days ago

Hahaha.
So why don’t you ask Kevin to submit articles to Swimswam. At least he can write that long.

Kevin
Reply to  Wirotomo
20 days ago

That actually happened to me a few times on the old Football Outsiders boards (RIP), they’d take stuff from my comments, polish it up, give me credit and post a new article. But huge comments like this were a bit more common there, from multiple posters not just me, than on SwimSwam. There were a surprising number of data analysts, statisticians, and data scientists who posted there. But yeah I doubt many will actually read what I wrote. That’s alright. 🙂

Kevin
Reply to  Braden Keith
20 days ago

Thanks, I needed the laugh and it was a true out loud laugh. I like data and I’m stuck in verbose mode after work sometimes. 🙂

Isaac
20 days ago

Is Rex’s last 50 the fastest last 50 in a 500 ever

PK Doesn't Like His Long Name
Reply to  Isaac
20 days ago

It might be, but it wouldn’t be the fastest last 50 in a mile, which is funny.

PFA
Reply to  PK Doesn't Like His Long Name
20 days ago

Nah Kieran Smith was 23.2 back in 2021 at NCAA’s when he lost to Jake.

Last edited 20 days ago by PFA
Swammer
Reply to  PK Doesn't Like His Long Name
20 days ago

Pretty sure Finke was 22.99 in a 500 at NCAAs as well

USA
Reply to  Isaac
20 days ago

Kieran went 23.27 in 2021 to nearly run down Magahey at NCAAs

Fake Gregg Troy
20 days ago

Carson doing 4 IM today?

bobthebuilderrocks
20 days ago

Not much of a difference, but Maurer’s PB was a 4:11.8 from Invite last year.

Braden, thanks for this article!

Mac daddy
20 days ago

So what you’re saying is with Marchands first 300 and Rex’s final 200 that under 4 minutes is possible……

Diehard
20 days ago

Even splitting is still the best race plan for most! It seems men do it more often than the women?!?

Togger
20 days ago

I know being the best male swimmer on the planet probably boosts your confidence, but to go out like Marchand did and have confidence you won’t totally die is insanely gutsy.

Unknown Swammer
Reply to  Togger
20 days ago

To be fair – that opening 200 is still like 4 seconds slower than his flat start 200…

About Braden Keith

Braden Keith

Braden Keith is the Editor-in-Chief and a co-founder/co-owner of SwimSwam.com. He first got his feet wet by building The Swimmers' Circle beginning in January 2010, and now comes to SwimSwam to use that experience and help build a new leader in the sport of swimming. Aside from his life on the InterWet, …

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