The myth of the wrist
Emphasis on the wrist snap has been part of the process of coaching fastpitch pitchers since Eddie Feigner soiled his first diaper. Generally it is interpreted to mean that you have to have a strong, powerful wrist snap driven by the muscles in the wrist in order to throw hard.
But how true is that, really? Let’s try an experiment. Have someone grab your forearm with both hands so you can use the wrist muscles — and only the wrist muscles — to throw the ball. Now snap the wrist as hard as you can. No matter how strong your wrist is, and how many fireman rolls you do, the ball is not going to come out that hard, or go that far. It’s because the wrist muscles are relatively weak compared to the rest of the body. Because of this, on their own they don’t really add anything to the pitch, no matter what all those expensive pitching videos might tell you.
It’s not the strength of the wrist, but its flexibility, that is the key to its contribution. Have you ever snapped somebody with a towel? First of all, shame on you. But if you have, you know that if you get the end of the towel to flick fast enough, you can make your teammate, spouse, dog, etc. jump. There is no muscle in the end of the towel. It’s the speed at which it accelerates, and the fact that the previous section stopped moving in the same direction, that creates the snap.
Your wrist is like the end of the towel. As long as it moves quickly it will impart the speed. And the faster it moves over a short distance, the faster the ball will come out. It’s also the most flexible joint in your body, capable of moving 180 degrees back to front, and in a variety of directions. Try that with your knee! Wait, maybe you shouldn’t.
Still not convinced? Try another experiment. Stand with your elbow at your side and your forearm pointing straight up. Now snap your wrist down as fast as you can using the wrist muscles. Doesn’t work too well, does it? Now relax the wrist so the hand is just sort of hanging there, and then abruptly move your arm back and forth slightly. If I’ve described how to do it correctly you’ll see the wrist move much faster. (If I haven’t no telling what you’ll see!) A loose, flexible wrist can move much faster than a tight wrist can be muscled.
So does that mean the wrist can be weak and you’ll throw hard? No. It still has to have enough strength to accept all the power and stress being driven into it by the other, larger muscles in the body. A weak wrist won’t be able to transfer the power. But just as a car needs both a powerful engine and a strong transmission to go fast, so do your pitches. You should strengthen the wrist so it can do its job effectively.
The point, though, is that you don’t need to practice endless strong wrist snaps or concern yourself with muscling the wrist at the end of the pitch. Instead, make sure you’re getting good whip of the forearm (the forearm going quickly from behind the elbow to in front of it at the bottom of the circle) and keep that wrist loose. Done correctly your wrist will snap all on its own, and at the right time, to help you achieve your goals.