The “corkscrew” punch where we rotate the fist at the end of the punch is unique to Oriental martial arts.
Twisting the fist is something that we all know about and take for granted. And why shouldn’t we, we’ve been doing it since our very first class in Karate/Tae Kwon Do/most styles of Kung Fu . The reason that I write about it here, is because I believe that it is something that though deeply ingrained into us, is still not done quite right by a good many people.
It may sound a bit strange to question something so basic, but bare with me. Although many will be doing what I describe below, a good many others will not be.
Why not? Because people will rotate the fist to get it into it’s correct finishing position, but not think about how the rest of the arm is moving to get it there!
It would be more correct to say that you should “twist your forearm”. The fist is actually incapable of rotating on its own, it is only capable of moving up and down in a waving/hinged motion when isolated from any other arm movement.
Try this little exercise. Perform any linear punch, then just freeze for a second with the arm in the extended punch position (no snap back). Now keep check if the crease of your elbow joint (where it folds) is pointing upwards or inwards. If you are not sure, then being very careful not to move the upper arm at all, bend the elbow. It the fist rises up then the crease of the elbow joint is facing up. If the fist moves inward (parallel to the floor) then the crease of the elbow is pointing inwards.
So why should you care about that?
Like the fist, the elbow is incapable of rotating itself, it is a hinge joint rather than a ball joint. From the starting position with the fist at the hip, the crease of the elbow joint points forward. As the arm is extended forward (without rotating), the elbow crease should end up pointing upwards.
For the elbow to rotate (so that the elbow crease points inward), you actually have to rotate the arm in the shoulder socket. To be a bit more technical, you rotate the humerus bone in the ball socket at the shoulder.
This is something that you shouldn’t be doing. Firstly it is an unnecessary movement of the shoulder joint and as we progress, we should be looking to take out all unnecessary movements. Secondly, it creates a small jarring feeling at the elbow, so it is not good for the long term health of either shoulder or elbow joint.
Furthermore, it’s a less efficient punching technique, so it is less effective if you really need it.
Try standing in front of a mirror with you arm and shoulders exposed. Now extend your arm in front of you and towards the mirror. Don’t worry about making a fist or any technique, just relax. Now rotate the whole arm several times at the shoulder joint. You will notice when you look closely that upper arm actually moves very slightly away from the body when you rotate the arm so that the elbow crease points inwards rather than upwards. Linear techniques are based on having the body weight behind them, so anything that takes the strike sideways away from the body will weaken that technique.
Granted, this is a very slight outward movement, but as you get more advanced, so it become more about fine detail.
It also effects your muscular alignments too. The shoulder and lateral muscles (underneath the arm pits) act as shock absorbers and maintain the body structure when you strike a target and receive a reaction force from the impact. Rotating the humerus outward in the shoulder socket slightly stretches those muscles making them less efficient at absorbing that reaction force.
Furthermore, when you punch, you use your triceps to extend your arm. The triceps work more efficiently with the crease of the elbow facing upwards. Don’t believe me? Ask anyone who does weight training, or look up “triceps curls” on Youtube.
The bones of the forearm (the ulna and radius) are much smaller and they can rotate around each other. There is not a big ball in socket rotation required as with rotating the humerus in the shoulder socket.
If you are not used to doing it this way, it may feel awkward at first and you may not be able to fully rotate the fist all the way over. Stick with it, your forearm muscles will become more flexible and it will become easier. You’ll find when you get used to it that the whole punch is much smoother than when you rotate the shoulder joint.
There is an argument that the bone alignment is weaker when the ulna and radius are rotated about each other. However, the idea when punching is that you actually make contact with the target before rotating the forearm (when the fist is still palm up). So the point of impact is when these bones are still in a strong alignment. You only rotate the forearm after contact has been made so that the rotational energy is added to forward impact to the punch, giving it a very penetrating “corkscrew effect”.
This forearm rotation comes into many other techniques too, such as at the very end of Soto Uke (Outside Block), Uchi Uke (Inside Block) and others. With these blocks, the rotation of the fist at the end of the technique cannot be supported by the rotation of the shoulder joint because of the arm being bent and the elbow joint being lower than the fist. Practicing for maximum forearm rotation in the punches will help maximise the forearm rotation in these other techniques too, making them more powerful, even with smaller movements. It helps to give a small “whip” on the the end of these other techniques.