Spin Rate: The Basics

What is Spin Rate?

Spin rate is one of the most underutilized and misunderstood metrics in amateur baseball and softball. With more being understood about this metric every year at the professional level, it is essential that we begin to apply that knowledge at lower levels.

First, lets take a look at the basics.

Spin Rate: The rate of spin on a baseball/softball after it is released, measured in revolutions per minute (RPM).

Combining different spin rates on different axes can causes the ball to move differently by utilizing the “Magnus Effect”.

Magnus Effect: the force exerted on a rapidly spinning cylinder or sphere moving through air or another fluid in a direction at an angle to the axis of spin.

A great example of this can be seen below: Note - that if this ball is moving to the left with backspin, it is actually pushing down air behind it, creating an an equal and opposite reaction pushing the ball back in a upwards direction. The faster the ball is spun backwards, the more force is created upward.

Credit : Driveline Baseball - “Spin Rate: What We Know Now”

Image Credit: Varitasium - “What is Magnus Force?”

This concept can be directly applied to a thrown or hit baseball. “topspin” or forward spin will cause the ball to drop, while “backspin” will cause the ball to stay flatter longer, or give it the appearance of “rising”.

How is spin rate measured?

As baseball continues to progress forward, deeper and more detailed analytics are becoming more popular and also more available to the general public. As Statcast continues to dominate today’s game, every single pitch of the MLB season is tracked and it starts to paint a picture of averages.

At 92mph the average spin rate seen on a fastball in 2016 was right around 2,200 RPM. This would be set as the baseline, and anything over 2,400 RPM would be considered a “high” spin rate and below 2,000 would be considered “low”. (Driveline Baseball)

For amateur baseball and softball, luckily there are a few options that allow the measurement of spin rate. These include Trackman, FlightScope and Rapsodo.

At Delta Sports Performance we utilize a Rapsodo to gather data on all of our baseball/softball pitchers, and it is the only one we know of in the state of Wisconsin.

What does this mean for pitchers?

Now that we have gathered the raw data and numbers, it can be used to develop a detailed plan or scouting reports of how to get hitters out. The chart below shows a drastic difference between two of the hardest throwers currently in the MLB.

Baseballsavant.com

Based solely on the spin rates, one can expect a very different approach from each pitcher. Hicks has a characteristically lower spin rate, even at his ridiculously high velocity fastball while Chapman’s spin rate is well above league average.

Based on these numbers one can assume that Hicks would have much more success throwing his fastball down in the zone and getting a lot of ground balls, while Chapman would tend to have much more success up in the zone getting swings and misses.

This occurs because based on each hitters slight upswing, the higher spin rate fastball tends to stay flatter longer, often making last second adjustments impossible as hitters continue to swing underneath the pitch. Hitters often say the pitch has the appearance of “jumping up” or “rising” on its way to the plate (although no pitch has even actually been proven to have risen).

Off-Speed Pitches

Breaking balls or off speed pitches work in the same manner. If a curve ball has a true “12 - 6” spin (based on the face of a clock), that ball will move downward in a vertical plane, while a “3 - 9” spin or “9 - 3” spin will cause the ball to move on the horizontal plane. As we continue to learn more about the way different pitches spin and move, pitchers can develop an arsenal of pitches that move in different directions out of the same arm slot known as “tunneling”.

Conclusion

As we continue to learn more about spin rate, and dive into metrics such as “Bauer Units” and “Spin Effeciency” an even clearer picture will begin to be painted on how each individual pitcher can find success.