A curveball is a type of pitch in baseball where the ball does not follow the standard trajectory, but instead, takes a downward curve on its path to the batter. Usually, when you pitch a baseball, the batter has to estimate the height at which the ball will reach him, and swing his bat accordingly. The curveball, due to the spin generated, dips down as it reaches the batter. It is one of the most popular pitches in baseball, and is one of the first advanced pitches taught to youngsters.
The secret to throwing a curveball well is not letting the batter anticipate that you are going to throw one. Batting in baseball works a lot on anticipation, seeing as the batter has to predict the way the ball is going to come to him before hitting it. So, if the batter works out that you're going to throw one, then he'll be able to predict the trajectory, and will smack the ball, rendering the otherwise effective curveball useless.
Grip is an important part of throwing a curveball. There are many grips used to throw it. The most basic grip is where you hold the ball like you would hold a glass, with your middle and index fingers close together, and your thumb completing the 'C' shape. The middle and the index fingers can straddle the seam, or go above it, while the thumb goes below its seam. The basic fundamental is to get a good grip on the ball, so that the necessary spin is generated for the ball to curve during the pitch. Try out different grips, and find the one most suitable for generating a good curve.
There are various factors that you can customize in your throw to get a good downswing. One of them is the elbow angle. Many recommend that the elbow angle should be perpendicular during the pitch, whereas, some pitchers prefer a wider angle known as a three-quarters arm slot, in baseball parlance. Another factor is, how far away from the body you release the ball. The rule of the thumb says that the closer the release is from the body, the higher is the spin generated. Then comes the wrist snap, one of the most important factors in a curveball pitch. The more sudden the snap, the more is the spin is generated. Here, the wrist snaps in a downward motion just before the release, generating the forward spin that is responsible for the downward curve in the trajectory.
The Follow Through
The follow through is another crucial part of throwing a curveball. Because it in part, influences where the ball is going to go. Once you release the ball, bring your arm down towards your left leg (right leg for left-handed pitchers), with the back of your hand facing towards the batter.
The curveball is one of the advanced pitches in baseball, and requires a lot of practice to perfect. But remember, the key to a good and effective curveball is the element of surprise which it brings. It is an important weapon in the pitcher's arsenal, but should not be overused!