Breaking Down the Relay: Women’s 4×100 Medley

2025 U.S. NATIONAL CHAMPIONSHIPS

After the conclusion of the 100 backstroke on Friday, all four stroke 100’s have been and gone in Indianapolis. The World Record holders in the 100 backstroke and butterfly won their respective events, while on breaststroke Lilly King was dethroned by Kate Douglass in her final race in the US. Torri Huske backed up her breakout freestyle performances in Paris with a new American Record of 52.43 to round out the quartet.

All of the swimmers from the World Record-setting relay last year will be in Singapore and available for this relay. Kate Douglass and Lilly King will battle it out in the individual 100 breaststroke to decide who the coaches put on the breaststroke leg, but the other three are locked down.

So, what does all this mean for Team USA’s 4×100 medley relay this summer? We now know who will be on the team – and what a team it is.

Stroke-By-Stroke

Three of last year’s 100m champions won one of the 100s this year, with new champions in the 100 breaststroke and 100 freestyle. The math works out there because Douglass showcased her unparalleled versatility by sliding across to win the 100 breaststroke after placing 1st in the 100 freestyle in 2024.

The four winners from this year along with Lilly King give Team USA head coach Braden Holloway an almost ludicrous number of lineup options. Walsh and Huske took the top two spots between them in both the freestyle and butterfly, and Kate Douglass, 1:05.79 in the breaststroke, holds the fastest-ever 100 freestyle split from an American woman (51.79, 2023).

In fact, all four of the stroke 100 champions are 56.4 or better on the 100 fly. If you know of any other relay in history with that level of switchability, let us know.

Walsh and Huske will almost certainly swim fly-free after doing so on two relays (women’s and mixed) in Paris, but of the two it is likely Walsh’s spot that is safest. Kate Douglass could slide across to freestyle if needed, or drop out entirely if Lilly King caps off her final Worlds with some vintage breaststroke performances.

For all four women, as well as the second place finishers (King and Katharine Berkoff, this will be at least their third World or Olympic Championships. All four have swum on at least one World Record-setting relay in the past. That kind of experience cannot be understated.

First off, Regan Smith seems to save her best for relays. She has swum her best time of the meet on the relay at the last three international championships (2023 LC Worlds, 2024 Olympics, 2024 SC Worlds) and gives the US a reliable 57-mid or better split.

Katharine Berkoff is a stunningly overqualified replacement for prelims – the fifth-fastest swimmer of all time. She also has a relay World Record on her resume; the 4×100 free for the 2024 SC World Championships that Douglass and Walsh were on.

However, despite that there isn’t a debate on who will be in the final. Smith is the World record holder and has been the top American in this event since 2019. Barring injury or illness, she will swim the backstroke leg.

Breaststroke is the one leg where there is some debate. Lilly King has been a mainstay on the medley relay over the last few years, but her second place finish in the 100 does cast some doubt over that.

Douglass does have only one swim under 1:06, but like at the Tokyo Olympics the decision will come down to the individual event.

With Australia in transition this year China may be the strongest competitors, but cannot live with America’s pace on the backstroke and butterfly legs. Wan Letian, Tang Qiangting, Zhang Yufei and Yang Junxuan are their best team, although Yang recently opted out of Chinese nationals. Regardless, they have the most complete team even if someone like Wu Qingfeng replaces her.

The US should run away with this relay in Singapore. They set the World record of 3:49.63 in Paris to win by 3.5 seconds, and the add-up this year is only 0.31 slower than in 2024.

Once again, we’ll have a brief look back at the drops that the medley relay team has had from their Trials add-up, and a very rough prediction for what they may do in Singapore.

Here was what the gaps look like between the add-up from the top four at Nationals and the relay times swum later that summer since 2000.

The Numbers

Fastest three flat-start times of the four stroke 100 champions:

Fastest international three relay splits of the four stroke 100 champions:

Flat-start add-up (last 24 months):

Flat start + relay split add-up (last 24 months):

There are a lot of other ways to put this relay together, ranging from the ‘What are you doing?’

(All times are from the past 24 months)

To the covering an off/injured swimmer

To the two which are most likely

The only real question is whether it will be Kate Douglass or Lilly King on the breaststroke leg, and the answer to that will come in the individual event. Douglass’ 100 freestyle also does not appear to quite be at the level it was in 2023, so expecting another sub-52 split may be overzealous.

Due to the overlap between Huske and Walsh for the top two spots in free and fly, Claire Curzan and Simone Manuel may be pulled onto the relay for prelims. Curzan qualified in the 200 backstroke, but has a best of 56.2 in the 100 fly and was 57.24 at Olympic Trials last year.

The US has not necessarily been faster on the relay than their add-up, especially in the last few years. That is what happens when you have three world record holders all on one relay – they tend to be very fast when not swimming on relays as well.

And then just for fun, here are the U.S. Nationals/Trials to summer relay drops since 2000 based on location. The circles get darker as the year gets later, and any hollow circles indicate a negative drop – that is, an increase.