Seconding or thirding martial arts (MA). I do Kung Fu, but I'd bet all the internet cookies there's at least one Brazilian Jujutsu practitioner on HN.
On the point of tech in MA, I recall seeing a documentary where some people got a Xing Yi Quan master to perform a form in mocap gear so they could analyse his movements. I think there's still a lot that kinesiology could learn from the way different people move (especially from Inclusive Karate practitioners).
I've had pretty good luck finding bands on 7Digital when they don't have a Bandcamp. I'm sure they aren't perfect, but they seem better than Apple at least.
Imagine being on hacker news and having an iPhone instead of a Pinephone /jk.
I'm always annoyed when some real-world good or service is only available to people with a smartphone, especially when it wasn't always so. Blue Bikes (rentable bicycles) were in the past usable with a membership card, but it got phased out in favour of an app.
It's weird how some sports have it figured out and others don't.
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