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

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

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]!

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

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