You ever watch mma ?

Check this out
Warning, this is nsfw and a bit gruesome as well
https://youtu.be/ddWOhKWhsXk

The camp.of the guy that won, Chris weidman, said they specifically trained that defence for checking kicks, you get the knee cap with the right timing and position, you could break a baseball bat over it, at times you think the lower leg seems to be kinda fragile, like you say, an innocuous collision

You ever watch mma ?

Check this out
Warning, this is nsfw and a bit gruesome as well
https://youtu.be/ddWOhKWhsXk

The camp.of the guy that won, Chris weidman, said they specifically trained that defence for checking kicks, you get the knee cap with the right timing and position, you could break a baseball bat over it, at times you think the lower leg seems to be kinda fragile, like you say, an innocuous collision

"jog it off lad"

"jog it off lad"