I actually did go back and forth on the Karate chop thing…many edits later.
I decided to leave it because 1) as you say more common and 2) Tom was a bit of a slacker in terms of discipline which is one reason he had stopped doing Tae Kwon do so I figured it might actually be in better character.
I say this, having also made this decision after work on another book where the main character is much more serious about his Tae Kwon Do and still actively practices it.
Of course it now sounds like I have a martial arts addiction for characters, but it’s really on 2 characters in two “worlds” out of about 6 book universes I’ve got in process…