Understanding How Breaking Balls Work
Breaking balls in baseball move in many different directions.
Even a so-called “straight” fastball can be seen as a pitch that uses backspin to resist gravity.
So why do breaking balls actually move?
To throw effective breaking pitches, it is important to first understand how they work.
Some parts may be a bit technical, but understanding the mechanics will help you identify why your pitches don’t break and what you may be missing.
It may also help you discover the grip and release that best suit you.
Even a so-called “straight” fastball can be seen as a pitch that uses backspin to resist gravity.
So why do breaking balls actually move?
To throw effective breaking pitches, it is important to first understand how they work.
Some parts may be a bit technical, but understanding the mechanics will help you identify why your pitches don’t break and what you may be missing.
It may also help you discover the grip and release that best suit you.
The Essence of Breaking Balls: Spin
When learning a breaking pitch, many people first think about the grip.
However, simply changing your grip does not guarantee that the ball will break as intended.
What actually makes the ball move is spin and gravity.
The first thing to consider is: “What kind of spin is needed to make the ball break in the desired direction?”
The grip is only a tool to help generate that spin.
Therefore, you should first understand the necessary spin, and then consider which grip allows you to produce that spin effectively at release.
However, simply changing your grip does not guarantee that the ball will break as intended.
What actually makes the ball move is spin and gravity.
The first thing to consider is: “What kind of spin is needed to make the ball break in the desired direction?”
The grip is only a tool to help generate that spin.
Therefore, you should first understand the necessary spin, and then consider which grip allows you to produce that spin effectively at release.
Two Types of Breaking Balls: Spin vs Reduced Spin
Breaking balls can generally be divided into two categories:
Spin-based breaking pitches
Curveballs, sliders, cutters, sinkers
Reduced-spin breaking pitches
Forkballs, changeups, knuckleballs
For spin-based pitches, the direction and rate of spin are key factors.
For reduced-spin pitches, spin rate (the lower the better) and air resistance play the most important roles.
Spin-based breaking pitches
Curveballs, sliders, cutters, sinkers
Reduced-spin breaking pitches
Forkballs, changeups, knuckleballs
For spin-based pitches, the direction and rate of spin are key factors.
For reduced-spin pitches, spin rate (the lower the better) and air resistance play the most important roles.
Magnus Effect, Air Resistance, and Gravity
Even pitches not designed to break still experience some degree of the Magnus effect if they have spin.
For example, a fastball with backspin generates an upward force (as shown in Figure 1), which partially counteracts gravity and reduces the amount of drop.
Air resistance is exactly what it sounds like—the resistance of air against the ball.
Normally, a thrown ball slows down due to air resistance, and the faster the pitch, the greater the deceleration.
Spin helps reduce this resistance by allowing the ball to cut through the air more efficiently.
(The force redirected from this interaction contributes to the Magnus effect.)
Seam orientation also plays an important role, as seams increase interaction with the air.
Finally, gravity—something we often take for granted—is a key factor.
Most downward movement is caused by gravity.
Forkballs, changeups, vertical sliders—all rely heavily on gravity.
A topspin curveball combines gravity with the Magnus effect, making it one of the pitches with the greatest downward break.
It is important to note that pitches like forkballs and vertical sliders (unless they include topspin) do not inherently generate downward force through spin.
Their drop comes from gravity acting over a longer time due to reduced velocity caused by air resistance.
How Spin-Based Breaking Pitches Work
The key elements are:
• Spin direction
• Spin rate
Spin direction determines the direction of movement.
From the catcher’s perspective, the ball moves in the same direction as its rotation.
(Remember that gravity is always acting downward.)
Spin rate determines the amount of break.
Higher spin rates create sharper movement, while lower spin rates result in less break.
Velocity is also an important factor.
Faster pitches require more spin to achieve noticeable movement.
This is because higher velocity reduces the time the ball has to move before reaching the catcher.
For example, with the same spin rate, a pitch might start breaking noticeably at 100 km/h, but at 150 km/h it may reach the catcher before the movement becomes visible.
If your pitch is not breaking enough, it may not only be due to insufficient spin—it could also be that the balance between velocity and spin is not optimal.
• Spin direction
• Spin rate
Spin direction determines the direction of movement.
From the catcher’s perspective, the ball moves in the same direction as its rotation.
(Remember that gravity is always acting downward.)
Spin rate determines the amount of break.
Higher spin rates create sharper movement, while lower spin rates result in less break.
Velocity is also an important factor.
Faster pitches require more spin to achieve noticeable movement.
This is because higher velocity reduces the time the ball has to move before reaching the catcher.
For example, with the same spin rate, a pitch might start breaking noticeably at 100 km/h, but at 150 km/h it may reach the catcher before the movement becomes visible.
If your pitch is not breaking enough, it may not only be due to insufficient spin—it could also be that the balance between velocity and spin is not optimal.
How Reduced-Spin Breaking Pitches Work
The key factor is:
• Spin rate
These pitches rely primarily on gravity for downward movement.
With less spin, the ball becomes more susceptible to external forces such as seams and air currents, which can also cause horizontal movement.
The goal is to minimize spin as much as possible until the ball reaches the catcher.
Lower spin increases air resistance, causing greater deceleration.
As the ball slows down, it spends more time in the air, allowing gravity to pull it down further.
If air resistance is lower, deceleration is smaller and the drop becomes more gradual.
As with spin-based pitches, velocity also plays a role.
Higher velocity increases air resistance, which can lead to sharper deceleration and a steeper drop.
• Spin rate
These pitches rely primarily on gravity for downward movement.
With less spin, the ball becomes more susceptible to external forces such as seams and air currents, which can also cause horizontal movement.
The goal is to minimize spin as much as possible until the ball reaches the catcher.
Lower spin increases air resistance, causing greater deceleration.
As the ball slows down, it spends more time in the air, allowing gravity to pull it down further.
If air resistance is lower, deceleration is smaller and the drop becomes more gradual.
As with spin-based pitches, velocity also plays a role.
Higher velocity increases air resistance, which can lead to sharper deceleration and a steeper drop.
There Are Many Ways to Develop Breaking Pitches
We have explained the basic principles of breaking pitches, but there are many ways to apply and refine these concepts.
Some pitches, like the cutter, intentionally reduce movement by prioritizing forward force.
Others, like the two-seam fastball, rely on subtle differences in spin axis.
By understanding these principles and experimenting with your own adjustments, you can develop a breaking pitch that fits your style.
Some pitches, like the cutter, intentionally reduce movement by prioritizing forward force.
Others, like the two-seam fastball, rely on subtle differences in spin axis.
By understanding these principles and experimenting with your own adjustments, you can develop a breaking pitch that fits your style.