Stretched Out Butterfly: Another Look At Yajima’s Elongated Stroke

With the Pan Pacific Championships roster announced for Japan, you may want to take a closer look at one of the nation’s 200 flyers who may potentially take on the likes of Jack Conger, Chase Kalisz or Tom Shields on his home turf of Tokyo. Waseda University’s Yuya Yajima fired off a super quick time of 1:54.72 to take gold at this year’s Japan Open, notching his spot ahead of Olympian Masato Sakai on Japan’s Pan Pac line-up. Splitting 54.94/1:00.78, Yajima’s time of 1:54.72 ranks as the 6th-fastest swimmer in the world this season.

In the case of Yajima, however, his stroke technique warrants a second glance more so than his times, even as fast as they are. We’ve analyzed his ‘dolphin dive-esque’ mechanics previously, as on-lookers can’t help but take note of Yajima’s heavily elongated glide at the front end of his stroke. In 2015, his paused butterfly helped win him a silver medal at that year’s World University Games.

Even before that, however, Yajima was perfecting his stretched-out stroke, challenging America’s Andrew Seliskar for Junior Pan Pacific gold back in 2014. In the video below, watch how Yajima (lane 5) extends his glide prior to initiating his pull and contrast that to next-door Seliskar’s immediate pull upon entry (lane 4). As a result, Yajima’s stroke count follows 14-15-15-16 pattern, while Seliskar’s race followed a 17-19-19-21 pattern. Seliskar wound up winning by a hefty margin, beating Yajima 1:55.92 to 1:58.30.

Studying Yajima’s stroke as it appears underwater gives us insight into how the kicking works with a paused stroke. As opposed to the more traditional two fly kicks that are performed as the hands enter, as well as when the hands exit, Yajima’s kicks are timed quite differently.

In the video below from the 2016 Japan Swim, Yajima is seen kicking his hands in at entry, but he completes his 2nd kick while his arms are still out front.  As his arms pass his hips, the bottom half of his body acts as one unit, with no additional kick undulation until his arms re-enter the water. This action produces the true ‘dolphin-dive’ look, with Yajima winding up deeper in the water than those swimmers next to him. His stroke counts again were in the 14-15 range per 50, while his competitors were nearer to 19-20 per 50.

For Yajima, his stroke appears to fall within the FINA rulebook for butterfly, but he teeters on the edge specifically for FINA rule SW8.5. The rule reads:

At the start and at turns, a swimmer is permitted one or more leg kicks and one arm pull
under the water, which must bring him to the surface. It shall be permissible for a swimmer to be
completely submerged for a distance of not more than 15 metres after the start and after each turn.
By that point, the head must have broken the surface. The swimmer must remain on the surface until
the next turn or finish.

There may be a point in his stroke which renders Yajima completely underwater, which goes against the ‘must remain on the surface’ note of the fly stroke description. He was DQd in 2016 for this offense, but has since been able to compete successfully without penalty.

Additionally, this elongated fly works for Yajima in the 200m distance, however, he’s yet to crack the 53-second barrier in the 100m fly using this same technique.

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The thing that I think is worth noting is that although this would seem to be a more efficient, sustainable form of butterfly, he tends to fade at the end. In the Junior Pan Pacs video, he’s out ahead of Seliskar but dies the last 50, and in his most recent time he had a five second spread between 100s (or six.. 54.94 and 1:00.78 add up to 1:55.72 so I’m assuming he went 59.7 on the last 100 or, worse, 53.9 and 1:00.7… ouch). It certainly looks efficient on the front half, but the big, powerful strokes are probably hard to sustain for a whole 200 in the same way that small, fast strokes would be. My guess is… Read more »


I think the reason that he fades on the end is less due to “big, powerful strokes [being] probably hard to sustain for a whole 200,” as you say, and more to the oxygen deficit created from longer strokes. If he is taking 15 strokes a lap and his competitors are taking 20 (and if we assume they are breathing on every stroke, which seems to be the norm for elite 200 flyers), that’s 25% less oxygen each lap. That could be significant. Of course, what you said about super powerful strokes being hard to sustain is also certainly part of the equation.


That’s a good point, too. I can definitely see that being a factor. I think 7 of the 8 finalists in the men’s 200 fly in London breathed every stroke, and a majority of the Rio final as well, so I think it’s fair to say he’s getting less air than most of his competitors. Interestingly, though, not Seliskar. In that Junior Pan Pacs video, he breathes every other stroke and still finished stronger. Kenderesi also does not breathe every stroke, and he’s probably the best in the world right now (and most likely to break the supersuit record). It will be interesting to see how 200 fly breathing trends in the next few years as we transition into the… Read more »


Forgot about Milak??


errr.. right, that’s who I meant. Thanks for the correction. Too many Hungarian flyers!

Coach Kyle Tek

The other thing to look at that validates what you’re saying is how much vertical movement he has in that stroke. This is exhausting to sustain. You can see it by the MASSIVE vertical splash as his arms come down. Contrast that with a flat, low recovery exhibited by Phelps (or really any other top flyer). Could also be oxygen deficit as pointed out. I would hypothesize, however, that he is able to go this fast based on actually using the fly kick in a propulsive manner in streamline throughout the swim. Despite what they believe, most flyers do not kick propulsively in the surface swimming portion of the stroke. Yajima is borderline illegal (which is why he makes a… Read more »


I agree his stroke seems set up to take advantage of a powerful kick, which makes it odd that his underwaters aren’t that great.

You would expect a fly swimmer with a really strong in stroke kick to have monster turns, but he doesn’t seem to have that.


COACH KYLE TEK – doesn’t look like he’s taking any underwater kicks in addition to the two kicks he takes with his arms outstretched. and pretty sure that would be a definite DQ every time as it would count as a return to uw kicking?


1:57.9 also isn’t REALLY an impressive time anymore


1:54.72 as per the article above


watching the stroke underwater it looks illegal to me. He clearly goes fully submerged at times during the stroke, albeit for a just a moment.


Definitely high risk for dq.

About Retta Race

Retta Race

After 16 years at a Fortune 1000 financial company, long-time swimmer Retta Race decided to change lanes and pursue her sporting passion. She currently is Coach for the Northern KY Swordfish Masters, a team she started up in December 2013, while also offering private coaching. Retta is also an MBA …

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