Shaine Casas Waves the Warning Flag With Fast Back-Half Split


American swimmer Shaine Casas was the top qualifier in the men’s 100 fly field on Thursday morning at the US National Championships. The swimmer, who has had most of his international success as a backstroke, clocked a 51.04 to place himself more than a second ahead of the rest of the field in the heats.

Two weeks after swimming a personal best of 50.56 at the Austin Sectional Championships, Casas looked comfortable in prelims to come within half-a-second of that mark.

So comfortable, in fact, that his back-half split was almost too good.

Casas split his race: 24.48/26.56. 

For a few comparisons:

  • In his PB swim a few weeks back, he split 23.42/27.14
  • At the World Championships, Hungary’s Kristof Milak split 23.42/26.72
  • In his World Record swim, Caeleb Dressel split 23.00/26.45

In short: a 26.56 back-half swim is elite fast, and not normally how we see Casas pace this race. Whenever we see splitting like this at a championship meet in prelims, it gives hope that one of two things is happening: a swimmer surprises themself with how good they felt, or they’re trying something new that they hope will lead to a big breakthrough.

It could, of course, be none of the above, but there’s enough reason to watch in finals to see what happens.

The fastest back-half split in history that we know of is actually Kristof Milak’s runner-up time behind Dressel’s World Record at the Tokyo 2020 Olympics. He split that race 23.65/26.03 for a European Record of 49.68. A notoriously-fast closer in the 100 fly, Milak surpassed Michael Phelps on that list. Previously, Phelps had the seven fastest back-half splits in history.

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Gregg Troy 2024🇺🇸🇺🇸
1 year ago

Lol the A&M tattoo

Michael Schwartz
1 year ago

Lolz! A timing error invalidates this entire article.

1 year ago

Imagine how fast he’ll be if he doesn’t wave any kind of flag!?!

Negative Nora (they/them)
1 year ago

The splits are wrong as he was out in around 23high. There was a timing issue during the heat as his 24.48 registered after he had pushed off the wall based on the livestream.

Reply to  Negative Nora (they/them)
1 year ago

I agree, he touched at 23 something. The touch pads appeared to be wrong.

1 year ago

Five of the seven top back half swims by MP were in 08-09, with assistance from the super suits.

Reply to  OldNotDead
1 year ago

Yeah but he was know for freight training people on the second 50 for years before that point. I think if you remove all the super suit times Phelps still dominates the list.

1 year ago

I thought he would break 48 in his 100fr the other day and it didn’t go so well

Reply to  Taa
1 year ago

What did you swim this meet?

Reply to  hahhahahaha
1 year ago


Reply to  hahhahahaha
1 year ago

I only swim 1000yd pentathlons and ocean swim with great whites

Reply to  Taa
1 year ago

If it isn’t a pentathlon, how do you know the Great Whites are there? Do you have to bring them in first with bait or something and then start swimming? I’m not just sure I can trust this information.

Reply to  R&R
1 year ago

The only sure fire way to know they are there is to locate a dead whale carcass floating in the open ocean. The stench is horrible but thats when your nose clip serves its purpose. Other than that you just have to swim in their known locations: Farallons, Guadalupe, Catalina, Channel Island and also Central Coast near any marine mammal congregations; in late spring/early summer San Onofre has lots of juveniles if you are just starting out and want to get your feet wet swimming with the smaller ones. You can use a drone to site them from above.

About Braden Keith

Braden Keith

Braden Keith is the Editor-in-Chief and a co-founder/co-owner of 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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