Designing a Curveball
A curveball is usually a pitch with the highest overall movement. It can have a wide variation of horizontal and vertical movement, while still being an effective curveball. On our chart you can see the average movement was around 6 inches horizontal and 6 inches vertical. However, there are curveballs with more horizontal motion, called sweeping curves, and curveballs with more vertical, called 12/6 curveballs.
A 12/6 curveball generates more swings and misses, on average, than sweeping curves; although, one may work better for you than the other. For example, if you throw a fastball with high vertical movement, then a 12/6 curve may work better for you. If you have more run on your fastball, a sweeping curve could be a better option.
The three most common grips used for an effective curveball are straight, knuckle or spike. Finding which one works best for you will take a trial and error approach on the mound.
Use Rapsodo to test each grip to see which one you can most effectively reach your spin rate, spin axis, movement, and control goals.
A straight grip is the most comfortable one to start with. Unlike a knuckle or spike grip, there is no extra pressure on the tip of your pointer finger. Sometimes the straight grip will be easier to control, but have a lower spin rate.
Experimenting with a knuckle or spike grip is effective in generating a spin axis closer to 6:00.
Find which grip is most comfortable for you to throw. It is important to be able to grip and throw this pitch while not changing anything about your mechanics.
If you look uncomfortable throwing it, the hitter will know you are throwing a curveball too early.
The way the ball rolls off the side of your finger has a direct impact on the spin axis of your pitch. If you struggle with wrist positioning to change the spin axis, utilizing a shifted grip could help you reach your goals.
This picture here shows a grip where the middle finger is shifted up the round horse shoe of the baseballs seams.
Spin Axis Goals:
For a 12/6 curveball, the spin axis must be at 6:00 generating perfect topspin. The magnus force works in opposite to a perfect backspin fastball and forces the ball downward. This creates the most amount of vertical movement. A sweeping curve needs more horizontal movement, so from a RHP the tilt may be more towards 7:00-8:00, or 4:00-5:00 from a lefty.
Just like with a fastball, the higher the spin efficiency, the more the pitch will move. This will also allow you to have better control, giving you the ability to throw your curveball for a strike.
In 2018, the Tampa Bay Rays drafted Matthew Liberatore 16th overall. His Rapsodo data showed his elite curveball spinning at just above 2800rpm with a 99% spin efficiency. That means his true spin affecting the balls movement was also around 2800rpm. His curveball is sharp, with near 2ft of vertical movement. You can even describe it as a sweeping curve with a tilt closer to 4:30.
Seth Lugo has one of the best curveballs in baseball. At 3360rpm, it is one of the highest spin rates ever recorded and he has an above average ground ball rate. Additionally, the higher spin rate makes it harder for hitters to pick up the seams, and that little delay in their reaction makes it harder for them to hit.
The chart on the left shows the measurements from Rockland Peak Performance Program. There are 7 different curveballs with different axis and efficiencies showing how both can affect the horizontal and vertical movement. According to the data, the pitches closer to a 6:00 tilt had the most vertical movement, and the pitches with the highest efficiency moved the most.
The curveball has so many different variations, I would love to hear from you on ones you found most effective. As long as it fits in your repertoire and you can confidently repeat it, there is no wrong answer.
Next week we will discuss designing a slider!