Does my fist have to be in line with my forearm when I use the vertical fist?

Question

I've heard of people saying that you might break your wrist if you punch hard when your fist is not in the same line as your forearm. So does my fist have to be in line with my forearm even if I am doing a vertical fist?

Answer 1

Yes, and vertical fist strikes with the lower three knuckles. With horizontal fist the first two knuckles strike in line with arm.  It will become obvious if you slow motion punch and push against a flat vertical surface like a wall, and watch how the wrist torques when not in the proper position relative to the arm.

Answer 2

Definetly. The same principle applies to the vertical fist as the horizontal fist. If your fist is cosked to one side, it can hurt or damage your wrist.

The style I train is Isshin-Ryu, and while our fist is not quite vertical(it is tilted maybe 20-30 degrees), proper body mechanics still apply. We also punch with the thumb on top of the fist which actually locks the wrist and helps keep it from buckling when striking a solid object.

Unlike Kung fu styles that punch with a verticak fist, the slight tilt inward allows us to make contact with the top two knuckles, noit that there is anything wrong with using the bottom 3, only that Okinawin karate always uses the first two knuckles on a punch. Just different phylosiphies.