To throw a knuckle curve ball, put your middle finger against the outside seam of the ball, and hold your first knuckle against the inside seam. Hold your thumb snug against the lower seam, and throw the ball with the same delivery necessary to throw a curve ball.Continue Reading
Tuck your index finger into the inside seam on the baseball. Line up your middle finger just inside the outside seam, and hold your thumb snug against the closest seam on the bottom. Practice holding the baseball this way until it feels comfortable; tucking the finger is often the most challenging part.
Use the same motions that work for all of your pitches as you go into your windup or come out of the stretch. Snap your wrist as you release the ball, turning the hand toward the outside or straight down, depending on how you throw your normal curve ball. Bring your throwing wrist to the opposite hip.
Keep your fingernails short and cleanly manicured to throw this pitch effectively, as your index fingernail on your throwing hand impacts the movement of the ball. Put on a coat of clear nail polish or fingernail strengthener on the nail to toughen the fingernail so that it does not crack or wear as easily while you are pitching.