6 Things I Learned from Watching One of the World’s Best Underwater Kickers

As a collegiate swimmer at Texas A&M University, Beryl Gastaldello proved herself to be one of the fastest short course sprint butterfliers ever. That includes posting the fastest women’s 50 yard fly split in history. She later verified that with a French Record in the 50 fly in short course meters.

In 2019 she cashed in her underwater kicking ability to the tune of $35,250 in prize money in the inaugural season of the International Swimming League, in addition to an individual European Championship silver in the 50 fly.

Now the Frenchwoman, who still trains at Texas A&M under men’s team assistant Jason Calanog (who was the teenage club coach of Caeleb Dressel) has posted a video of her underwater dolphin kicking 25 yards.

This offers a unique glimpse into the underwater technique of one of the world’s best.

Here are 5 things we can learn from watching Beryl Gastaldello kick underwater:

1) Tempo –  Beryl does approximately 27 full dolphin kick cycles (up kick, down kick) in about 9 seconds at peak rate. That’s about 3-per second.

For those who are musically inclined, this comes out to about 180 BPM on a metronome, per cycle. That’s 360 BPM per hit. For comparison, when Usain Bolt ran the World Record in the 100 meter dash, he hit a rate of 257 steps per minute – without water resistance.

You can play around with the Google Metronome here at 180 BPM to see how fast that is. Below is a video of 360 BPM. That’s a much, much higher tempo than the average age grouper kicks underwater with.

Want a playlist of songs that are around 180 BPM? There are lots of them available on Spotify, just search 180 BPM. If you’re not quite at that level yet, start lower – people have made playlists for all kind of tempos, mostly designed for runners or cyclists. Here’s some of our favorites.

  1.  Rock Lobster – The B-52s
  2. “Curbside Prophet” – Jason Mraz
  3. “Santeria” – Sublime
  4. Gangsta’s Paradise – Coolio
  5. They Don’t Care About Us – Michael Jackson
  6. “Hey Ya!” OutKast
  7. “Jesus Walks” – Kanye West
  8. “Back in Black” – AC/DC

2. Body Motion – Notice how her whole body gets involved in the streamline. Of course, you all knew this by now, but to see it from this angle really highlights it. When her feet push backward, her hips press forward (toward the surface in this video), and so too do her shoulders. There’s a connection in her body. Hips are connected to shoulders, and chest is connected to feet. This 2nd “break” in the bodyline is where real underwater kicking mastery comes into play. Lots of young swimmers can visualize the break in body line at the hips, but getting that 2nd break between chest and shoulders can be a lot harder.

3. The whip-like motion – Especially in the last few frames, as Beryl gets closer to the camera, you can really see how much of a whip she has with her lower legs. With younger swimmers, you can work on this feel at a slower tempo, and then as they get older (or with better athletes) begin to increase the tempo without losing the whip. This takes real effort – there is a lot of focus from a lot of coaches about “stay under until at least halfway” in workouts. But that’s not the key. The intensity of the tempo + whip is far, far more important than the distance that your athletes stay under. I can go 12 yards underwater dolphin kicking without putting out too much effort, but that’s not going to do me much guild in building the core muscles needed to get this intense whip-like motion in a race.

4. Hand placement – Maybe this is common knowledge to some coaches, but it’s something I’ve never seen before. She’s got the thumb hooked, that’s good, but watch in the last few frames the angle of her hand. The knuckles on her top hand are sticking up, almost making a little spearhead, with a gap between her hands. That’s as compared to the flat hand-to-hand contact that I learned growing up. Is this just a tick of her technique, or has she figured something out? It’s worth more investigation.

5. She does all of the above with very little motion in her head – This is crucial to keeping drag low. I’m not sure I could match that, but it’s something to shoot for. Keeping your neck loose allows your head to roll through the shoulder motion rather than with it.

6. Feet placement – Her legs and feet very rarely touch during the entirety of the video (very briefly at the end as she’s surfacing). While the imagery of a “dolphin kicking” makes us believe that we should make our legs as tail-like as is possible, that doesn’t mean that the best technique actually has the feet touching. There’s some principles of water tension probably in play for why this works, but it also gives more freedom to the feet to get that “whiplike” motion when there is some separation.

In This Story

Leave a Reply

6 Comment threads
28 Thread replies
Most reacted comment
Hottest comment thread
23 Comment authors
newest oldest most voted

Just an idea, what if the ISL added an event to the lineup like a 50 meter underwater? Might be something new for the athletes and they wouldn’t have to get DQ’ed for it anymore.

Swammer from Wakanda

Underwater skins. Whoever survives wins.

Swammer from Wakanda

While on the subject of new events, this isn’t the first time I’ve seen skins. I was at a meet in Australia 10 years ago and that was a high school duel meet event. It was cool to see. They also had an “All Team Relay”. Now that would be legit to see in the ISL.

Old Man Chalmers

someone sign david berkoff

David Koch

The original backstroke underwater was actually Jesse Vassaio from Miami. He won the gold in olympics whole doing it in the early 80’s

Anthony Preda

Makes you wonder what the unofficial underwater world records would be from the DQ and exhibitions swims over time

Ol' Longhorn

Yozhik would have a stroke.


100 corkscrew followed by pounding a beer.

Chaitha D.

Just wondering. Who do u guys think the best underwater kicker ever is? I know Phelps and Lochte are the obvious picks but tbh Shields might have them beat in a straight 50 underwater race.






Phelps wasn’t the fastest as far as having pure speed. He was one of the best at maintaining his kicks during his 200 and 400 events. When everyone else started swimming off the walls, he stayed UW which was faster. Lochte was similar to Phelps in this regard but Lochte probably has a little more pure UW speed.

Shields was probably faster than both of them. Although it wasn’t Phelps 2008, I remember seeing Phelps/Shields race in a 100 fly around 2012 and Shields destroyed Phelps off the turn wall.

Dressel definitely has the most pure speed out of all of them. 17.6 in the 50 means you have the most pure speed.

Ol’ Longhorn

Re Dressel, Braden’s point about his vertical jump is a good one. He doesn’t pull away from anyone on his dolphins alone, He hits his dolphins at greater speed/distance off the start and wall. Schooling was apparently legendary doing dolphins with a kickboard. It would be interesting analytics to subtract start/turn distance and entry speed and see who is the actual fastest underwater kicker. It might be Dressel, but I don’t think it’s as clear cut as time to 15 meters.


I would put Stravius and Kawecki in this mix.


For me it’s definitely between Dressel (17.6), Le Clos (200 free final Rio 2016), and Amuary Leveaux (100 free SCM WR, nearly 15m every wall). Honourable mentions are Shields and Lochte who edge Phelps for pure speed except maybe for Phelps in his ’08 prime.


I’m going with either Austin Staab or Albert Subirats. Watch them in old race footage at NCAAs. Staab was faster than Shields underwater and you can see it head to head. Albert kicked a full bucket in 13 seconds and he was the first to go 44 in both fly and back.
Honorable mention is Nate Dusing. National high school record in fly and went one stroke per lap 47.1 back in the day.


Natalie C.!

Ol' Longhorn

I’d also point out depth. Again, somewhat common knowledge, but useful as a reminder. She’s a good meter (at least) under the surface of the water. She’s basically equidistant between the surface and the bottom of the pool. Give her a huge wall of water for the upkick and downkick.

About Braden Keith

Braden Keith

Braden Keith is the Editor-in-Chief and a co-founder 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, …

Read More »