I've heard bodybuilders warning of this. How much do you need to exercise for this to happen? How come David Goggins hasn't become a victim of this?
No one can tell, I'm sure lots of people have gotten it, just not to the hospitalization point. It's one of those things that can range from "I feel crappy, let me take some days off" to "Help, my piss looks like clamato juice". Goggins has gotten it a ton of times, he just hasn't had it bad enough to kill him.
Years ago, when Crossfit was new, you weren't considered a true Crossfitter unless you had some sort of Rhabdo. One of the big culprits was aggresive sit ups on the Glute Ham Raise without having a base in them.
Rhabdo was so common, "Getting Visited By Uncle Rhabdo" became a meme in that circle -

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RIP to this young girl, rhabdo is a sneaky thing.