I broke smth in my ring finger bc I punched walls as a kid hoping to break it the way they did in spy kids. We make brick houses here. Was reminded of this after I saw a similar post on lemmy somewhere.
Some of my more intelligent friends were punching holes in drywall. Sure enough one poor guy found the stud and fucked up his wrist so badly he has a metal pin in it now.
You just need practice ; I, for one, just considered it a given that you have to gradually raise the strength of your punch at a fscking concrete wall painted over, and then it'll start slowly crumbling in the place you hit, like in those vids about Shaolin monks. Didn't work, but aside from pain, no problems with my fists.