Become a Movement Pitch Expert by Doing This

Why didn’t my curveball move? There’s an answer for that! It’s the offseason and many of you are adding to your pitch repertoire. Once you reach January you’ll pick one or two of those pitches to perfect so they are ready for your season. If you know why your pitch didn’t work, you have a chance to change. it.

The three factors that make a movement pitch break are 1) the number of rotations, 2) the axis of spin, and 3) body position. Once a pitcher can master all three of these elements the ball will move.

They physics of it are kind of cool, actually, so I’m going to attempt to explain it here. The “Magnus Effect” is the spin axis and the number of spins combined. Velocity plays a part, too. Velocity and number of rotations combined is measured in “Bauer Units.”

But before we get too far into talking about axis and spin, we can’t forget the third factor that makes a ball move, and that’s body position. The pitcher’s body should be in a position that allows the hand to deliver the ball on the correct axis. When developing a pitcher, as soon as she is able to get into the correct body position (which allows her to manipulate her hand in any way), you should begin teaching movement pitches.

For example, when throwing a riseball, a pitcher must deliver the ball on the “downswing” of her arm circle, meaning a little earlier. To make it easier to get her palm underneath the ball and cut underneath, she must lean her body back towards second base at delivery. The reverse is true for a dropball. She must lean forward to get her hand on top of the ball, palm facing downwards.

Once her body position and ball trajectory is correct, the Magnus Effect becomes relevant.

Magnus Effect is explained as, “As spinning ball moves through the air, it spins a boundary layer of air that clings to its surface as it travels along. On one side of the ball [front] the boundary layer of air collides with air passing by. The collision causes the air to decelerate, creating a high-pressure area. On the opposing side [rear], the boundary layer is moving in the same direction as the air passing by, so there is no collision and the air collectively moves faster. This sets up a low-pressure area. The pressure differential, high on one side and low on the other, creates a lift force that causes the ball to move in the direction of the pressure differential (i.e., from high to low). “ (1)

As you can see, the number of rotations the pitcher puts on the ball will increase the pressure of the ball against the air, causing it to move..

The seams will affect the Magnus Effect as well. They create a larger boundary layer on the surface than a ball without seams would. A four-seem fastball moves in a predictable way because the seams are evenly spaced. The two-seamed fastball is less predictable because the seams are uneven.

As far as speed goes, the types of pitchers who are able to throw faster are also able to put more rotations on the ball, simply because of their strength. if the same pitcher throws two pitches, one at 50 mph and one at 60 mph with the same mechanics, she will put more spin on the ball with the 60 mph pitch. (2)

The final factor is the axis of the spin. The ball will move in the direction of the axis. When practicing, a pitcher should put a piece of black tape around the middle of a ball. While pitching, if the line looks smooth and not “wobbly,” it has the perfect axis.

Practically speaking, when learning or improving your movement pitches, isolate each aspect: body position, axis, and spin. Use tools such as a ball on a stick or a tightspin trainer to work on forearm strength and finger dexterity.

(1) Human Kenetics, Magnus Effect, [internet] Available from: http://bit.ly/2QzdzoV
(2) Drive Line Baseball, Bauer Units and Pitch Comparison [internet] Available from: http://bit.ly/2NDmBPX