3. Elbow: The throwing elbow must be equal to or slightly above the throwing shoulder. As soon as the pitcher lowers the elbow below the shoulder, they put additional stress on that arm. The angle of the elbow joint should be no more than 90 degrees. Pitchers who throw curveballs at angles greater than 90 degrees may put additional stress on their throwing shoulder.
As a curveball flies through the air, the spin creates an imbalance of air pressure on either side of the ball. According to Bernoulli's principle, this imbalance of air pressure creates lift. When applied to a spinning object, the Magnus Effect holds that the force of lift generated will cause the spinning ball to move in the direction of lower pressure.
Asking if a kid can see that slider spin is occurring is a common question I will bring up in lessons. Having a thought process and feeling with what they are doing is something that he or she can control and fix from throw to throw but it is not often taught. We like to have kids visualize and react to what is being said and into what is being felt. When trying to recognize the slider spin, the catcher should be able to see where the thrower is missing with his fastball. Seeing the ball out of the thrower’s hand and knowing that a slider has clockwise spin on the baseball you will be able to clearly tell that they released the ball wrong.
Any baseball pitch begins with how the pitcher grips the ball. To throw a curveball, a pitcher must hold the baseball between his thumb and his index and middle fingers, with the middle finger resting on the baseball seam. When the pitcher comes through his motion to throw the ball, he snaps his wrist downward as he releases the ball, which gives the ball topspin. If the pitcher throws properly, the back of the his hand will be facing the batter at the end of the motion. The ball will break down and away from a right-handed batter if thrown by a right-handed pitcher.
For this pitching drill you don’t necessarily need a net. You can use a wall or another person. But the idea is to have something behind the pitcher that will let the pitcher know if he has broken his hands too early or is not gaining enough ground going forward. This is a great pitching drill if done correctly and will promote torque as well as linear momentum. Check the vid for more of an explanation!