What induced vertical break means
Once a pitch leaves the hand, gravity pulls it down the whole way to the plate. Spin adds a second force. Backspin pushes the ball up against gravity, and topspin pushes it down along with gravity. Induced vertical break isolates that spin effect. It compares the real flight of the pitch with the path a spinless ball would take from the same release, speed, and direction. The gap between those two paths, in inches, is the IVB.
IVB is different from total vertical break, which includes gravity. Every pitch drops on its way to the plate, even a fastball with elite ride. A high-IVB fastball drops much less than hitters expect, so they swing under it. That is why people say a good fastball rises, even though it never goes up. Coaches compare pitches by IVB because gravity acts on every pitch, and spin is the part a pitcher can change.
IVB depends mostly on spin rate, spin efficiency, and spin axis. The closer a fastball's spin is to pure, efficient backspin, the more it rides. For a four-seam fastball, higher IVB usually means more swings and misses at the top of the zone. For sinkers, changeups, and curveballs, lower IVB is the goal because you want the pitch to drop. The best number always depends on the pitch type and how it pairs with your other pitches.
Video explanation
Jake Fishman, PitchLab’s co-founder and CEO, pitched in the major leagues for the Miami Marlins. Here he explains induced vertical break and what it means for your pitching.
What affects induced vertical break
Spin rate
More spin means more force on the ball. A four-seamer with higher spin can ride more, as long as that spin is efficient.
Spin efficiency
Only active spin creates movement. A 2,400 rpm fastball at 70% efficiency can show less IVB than a 2,200 rpm fastball at 95%.
Spin axis
A fastball with pure backspin puts all of its movement into ride. As the axis tilts, some of that movement shifts sideways into run.
Arm slot
Higher arm slots make pure backspin easier, which helps IVB. Lower slots usually produce more run and less ride.
Velocity
Faster pitches reach the plate sooner, so spin has less time to act. Compare IVB between pitchers who throw at similar speeds.
Seam orientation
How the seams sit in the airflow can add or subtract a few inches of movement. This shows up most on sinkers and changeups.
What’s a good induced vertical break?
| Pitch type | Average | Good | Great | Excellent |
|---|---|---|---|---|
| Four-seam fastball | 16 | 17.5 | 18.5 | 20+ |
| SinkerLower is better | 8 | 6 | 4 | <3 |
| ChangeupLower is better | 6 | 4 | 2 | <1 |
| CurveballLower is better | -10 | -12 | -14 | -16 or less |
Higher is better for four-seamers, and lower is better for sinkers, changeups, and curveballs. Curveball IVB is negative because topspin adds to gravity, and amateur pitchers usually show a few inches less movement in both directions.
How PitchLab measures it
PitchLab measures induced vertical break on every pitch. For baseball, it shows IVB next to spin rate, spin efficiency, and spin axis, so you can see why a pitch rides or sinks. Trends across sessions show whether your IVB is changing.
Induced vertical break FAQs
How do you measure induced vertical break with your phone?
Set an iPhone 12 or newer on a tripod about 2 ft behind the pitcher, facing home plate, and start a session in PitchLab. PitchLab measures induced vertical break on every pitch and shows it with horizontal break, spin rate, and spin axis.
Is there an app that measures IVB?
Yes. PitchLab measures IVB with just an iPhone on a tripod, along with horizontal break and spin on every pitch. PitchLab is free to start.
What’s the best app for increasing IVB?
The best app for IVB shows it on every throw next to the spin numbers that drive it, so you can see why a pitch rides or sinks. PitchLab does this with an iPhone and tracks your IVB across sessions.
What is a good IVB for a high school pitcher?
Most high school four-seam fastballs land around 12 to 16 inches of IVB. Anything above 16 inches stands out at that level, and 18 or more is rare. Compare with pitchers at a similar velocity, since slower fastballs can show a bit more movement from the same spin.
What is the difference between IVB and vertical break?
IVB removes gravity and shows only the movement caused by spin. Total vertical break includes gravity, so every pitch shows a large drop. IVB is better for comparing pitch shapes. Some devices label IVB as just "vertical break," so check which one you are reading.
Why is high IVB on a fastball hard to hit?
Hitters learn to expect a certain amount of drop on a fastball. A pitch with high IVB drops less than that, so it crosses the plate above the hitter's swing path. The result is more swings under the ball, more pop-ups, and more whiffs at the top of the zone.
How can I increase my fastball IVB?
Work on cleaner backspin. Raise spin efficiency, keep the fingers behind the ball, and find an arm slot that produces mostly backspin. More spin rate helps too, but only when the spin is efficient. Track changes pitch by pitch so you know what worked.
