Why Optimizing Curveball Shape Matters

Push Performance - Increase pithing velocity

Building an arsenal is a large part of the pitching development process and something we focus on here at Push. 

Typically, pitch design is the final step in the process after an on-ramp/movement focus and velocity phase. Using technology such as Rapsodo gives us the information we can’t see with just our eyes such as velocity, spin rate, and spin efficiency. 

These metrics combine to produce the vertical and horizontal break numbers on Rapsodo.

When interpreting metrics of a curveball specifically, there are two broad areas to look at, movement and velocity. 

Usually one comes at the expense of the other; as velocity increases, movement decreases.

So which is better?

Graph showing data relevant to improve pitching velocity.

(Visual from Chris Langin- @langintots13 on Twitter)

The visual above shows the impact velocity and vertical break have on the whiff percentage of curveballs. There is a lot to unpack from this graph, but the general theme is that throwing your curveball harder generates more whiffs, no matter what the induced vertical break is. 

The impact is drastic when curveballs start getting thrown over 81 miles per hour. As we look at the graph, a 10% increase in whiff percentage from 81-85 mph (33-43%) is a massive jump to consider when building a curveball during pitch design sessions. 

Since we know that typically the lower the vertical break is (ex: -24”) the slower the velocity will be, we can put that into practice. 

For example, let’s say an athlete comes into the gym with a curveball that is 77 mph and -17” VB. That’s not a bad curveball profile by any means, but it’s definitely worth a shot to try and improve upon those numbers to generate more swing and miss. 

Once we determine we want to try to make a change with an athlete, a simple cue of “throw it harder” could be an easy fix. If the profile stays the same and velocity increases, it automatically becomes a better pitch.


What happens most of the time is that throwing the curveball harder decreases spin efficiency which leads to a vertical break number closer to 0 (-17” to -13”) and a smaller shape visually.

Increase Curveball velocity

When an increase in pitching velocity leads to a smaller shape, it’s almost always a positive. A smaller shape is typically a sharper break and pairs better with the rest of an athlete’s arsenal by holding the fastball tunnel longer. 

The strike zone is only so big. 

For this example let’s say the strike zone is 24” from top to bottom and you give yourself 4” on each end that the hitter will possibly chase. If your curveball has -20” of vertical break and your fastball has even just 16” VB, the curveball is going to have to “pop” out of the hand above the fastball tunnel, even if that line is 4 inches above the strike zone, giving the hitter an increased chance of recognizing it. 

If they do come out of the same tunnel, the curveball will drop below the zone to get a swing. That is at the absolute extreme top and bottom of a hitters “swing zone.” An advanced hitter’s swing zone is going to be even smaller, so there is even less room to work with.

We always try to optimize every athlete’s arsenal to generate the most swing and miss. 

Getting them to throw their breaking balls harder is paramount for us here at Push to achieve that goal, even if it comes at the expense of vertical break. Sometimes we even want a smaller, sharper curveball to more effectively tunnel with the heater. 

Velocity is the number one indicator of swing and miss stuff across all pitches, and curveballs are no different.

Learn more about how to increase pitching velocity and output by reading Director of Pitching, Simon Mathews’ latest article here.