I took a bit of karate in college. Our main instructor was this 6'4" American black belt who was pretty built etc. There was an Asian guy, maybe 5'5" 120 pounds, who usually just walked around looking occasionally he'd correct someone's form a bit. One day he walked by this force meter we'd hit at times and casually popped it, short punch, it maxed.
The big guy told us he would stand no chance against the Asian guy in a contest. One thing I learned is karate is good exercise, but you really need to warm up before using it against another person, it's more akin to dancing. I did get a pretty good callous on my knuckles when I was doing lessons but I was young. Heaven forbit you hit something the wrong way --> broken hand, "boxer's break".
