Does this help you coordinate your core muscles around your diaphragm with the rest of your body?
(He also told us to not shout after the action stopped, as is common in a lot of fencing, but that didn't always work out so well)
Screaming does help with:
* Raw power (which is largely not a factor for fencing or aikido). Weight lifting, tennis, javelin throwing, etc. Shouting during the action gets really common.
* Coordinating with other people (not a thing for one on one, but team fights, yea. E.g. if you've ever watched player comms for high level eSports, it can get really spammy when coordinating attacks on a specific target)
* Mental intimidation. Either of the other competitor, or, as it looks like in fencing, the ref lol
Some notes:
* That's mostly national team people in the video
* All of the yelling is after the action stops
* As you'll see, the primary reasons stated are to mess with the opponent's head, and the ref. And then stress relief, yea. You'll do other things like, uh... stabbing your own foot... for that purpose as well. (Sounds bad to say out loud but it doesn't hurt)
Akido (and kendo too) are a lot more stylized. Some yelling in there is for the same reasons, but a lot of it has been passed down in some almost mystical level. It's not a hyper optimized/gamified sport that cares only about results, so you get a lot more style points type things happening in aikido/kendo/etc.
gamified - as an example, there was a period of time from like late 90s to early 00s where foil fencing became dominated by an offensive strategy that involved literally bending the blade and hitting your opponent's back. It got so ridiculous that they messed with the weight/timing on the electronic equipment so it didn't work as well. And in the later 00s people started using plastic chest protectors because with the new timing, you'd get some attacks literally bouncing off your chest protector and not registering. Just kinda a ridiculous results-only-everything-else-be-damned situation lol.
See my other comment here: https://news.ycombinator.com/item?id=35437249
The "Kiai" is a staple of Japanese Martial Arts and is not easy to Master; you have to get the Timing and Source right else it is just a shout from the throat instead of a energy inducing sharp exhale with sound from the belly. It is also the case that in Japanese Martial Arts it is more stylized and loud than is necessary; a simple grunt/shout (as is found in Chinese/Other Martial Arts) with the correct Timing and from the correct Source is more than enough.
1) https://en.wikipedia.org/wiki/Kiai
2) https://kojutsukan.blogspot.com/2018/03/the-science-behind-k...
https://youtu.be/510BzHX9qa4?t=17
in terms of "inspired by", "independent co-evolution", or "nothing in common"
(of course, the timing of the audio/video might be different)
I remember watching these games when i was young and the comments/controversy around "Grunting in Tennis". I was already doing martial arts then and hence knew the basis but apparently many thought it was just "Gamesmanship"; there is even a Wikipedia page on it : https://en.wikipedia.org/wiki/Grunting_in_tennis