How important is spin?

My boy used this gadget a couple of years ago during a workout. It works!

It measures velocity and revolutions per second(spin).

How important is spin?

Here’s a link for further information on the gadget:


Conventional wisdom says, spin=movement, and tight spin=late movement. If this is true then spin is extremely important. That’s a cool little device my pitching coach told me about them but I’ve never actually used one.

I’m sure someone will suggest a pro-or-con to the device that you’re asking about, but I’d like to take this opportunity to cover another aspect of using this and other devices.

Spin, as you call it, means rotation. And with just about every pitch in your son’s inventory - rotation IS survival.

With using devices such as this, I do want to caution you on the environments that surround armature baseball - especially the field conditions and the influences these conditions place on a youngster.

First of all, let me make a short comment on spin … rotation.

But first – a very brief introduction to what exactly spin - rotation is suppose to do:
A four seam fastball gets its accuracy and deliberate effect about 60 feet down range across the batter’s swipe zone*, by having the seams rotate as tightly as they can, without that rotating seams orbiting too far left or right during their backward rotation after release. On the other hand, a two seam sinker, do in part to the pitcher’s grip, has the rotating seams doing exactly the same thing, only the two seam rotation has different physics of combined atmosphere and ball design dynamics imprinting the ball’s characteristics 60 feet down range. And as would be expected, the slider, curve ball, cutter, screwball, off-speed/change-up all follow suit - again, all using their particular spin - rotation, influenced by the pitcher’s grip and release phase.

Now, to address your question directly with respect to my statement in the first paragraph above —

Amateur ball players live in a feast or famine world as far as field conditions are concerned. This especially the case for pitchers. Either their pitching surface is letter perfect, or it’s a nightmare. More often than not, varying surface conditions with uneven angles of decent, holes and other imperfections plauge a youngster from day one. Hence, the leaning curve can be as haphazard as predicting the weather in New England.
These conditions are so wide spread that the imprint on a youngster learning this craft is a give-and-take proposition with the coaching experience - which can test the metal of even the best of them … player, parent, and coach. Hence, what works one day, can be a pot-luck adventure into success and frustration the next day.

As important as spin - rotation, is, this and other phases of the learning curve has to be forged and annealed with a bit of reality to the environments that any youngster is traveling in. So if you notice a rotation reading that’s right on target for the coaching level that your son is participating in, the very next day … on a different field, can lead to a totally disappointing experience.

I must be totally up front and honest here in my assessment of today’s advancement with training aids. They absolutely amaze me. What I spent years … no make that a better part of my life acquiring, now a device out of a carry case can display across a plastic screen with a precise digital readout. Talk about insecurity!! On the other hand, during the last two years of my work, I did depend on some of these gadgets to help … and help they did. Now today, a coach has to interpret and digest this output and use them properly - not as an end, of and by, themselves.

If you and your son’s coaching thinks this will reinforce your son’s experience, I would encourage you to rationalize with your son’s coach(s) the cost benefit relationship in time - money - and your son’s learning curve of competency using said output.

Coach B.

  • batter’s swipe path for this explanation pertains to the incoming flight path of the ball that the batter seems most susceptible to “swipe” at the pitch. Strike or not, it’s the deliberate location that the pitcher elects to deliver to.

I’ll tell you now I’d love to have one of those so that I know how close to 0 I am each pitch.

Studying the knuckleball has taught me that the rotation is everything, the way the ball is spinning or not spinning causes all the different movements that people create when throwing a pitch.

I will go ahead an explain the lack of spin and it’s importance to a knuckleball assuming someone out there will take in this information.

When there is no spin on a ball it simply won’t do anything but drop, but when there’s no spin on a ball with seams all sorts of things can happen in mid flight.

The seams are the key to movement on any pitch. With fastball spin the wake of air behind the ball is small and proportional to the ball, keeping it’s flight pattern controlled, the same is true of any other pitch, with a curveball the wake is slightly larger and directs the ball in a curving manner.

With a knuckleball the wake becomes much larger than the ball creating an unstable air current for the ball to be directed with. This is what causes the unpredictable fluttering motions that are traditional of a good knuckleball.

However sometimes very slight spin is desired because as the orientation of the seams changes so does the wake of air behind the ball thus creating even different movements.

This explains things like the corkscrew, camel hump and surge that some knuckleball catchers report.

Really movement on pitches is all about manipulating the air currents around the ball by spinning it in a desired manner so the seams can take hold and direct the ball.

Put short, spin is extremely important.

Bretzke - how does the tool work exactly?

Here’s a link to Marinelli’s RevFire system patent:

Basically, the ball has some circuitry embedded in it that measures angular acceleration and radio-transmits the info back to a receiver, so I’m sure it measures spin rates accurately.

Unfortunately, the system seems to require the operator to make an accurate determination of the exact distance the ball travels in order to derive velocity data…if the distance estimates are wrong by 1 or 2 feet, the velocity measurements won’t be nearly as good as radar, so that is not the RevFire’s main strength as far as I can tell.

Down in the fine print of the patent you will also come to realize that each ball also contains a non-removable battery whose lifetime determines the overall lifetime of the ball.

This was conceived in the 90’s and patented in 1998, so the advent of high-speed cameras like Casio EX-F1 and it’s little brothers makes spin-rate determination by video methods just as reliable as RevFire–if you really, really need to know how fast the ball is spinning.

Another good way to judge the spin is by results.


laflippin did a better job of explaining the technical stuff than I could.

When my boy used it, he was an 8th grader working out with several juco pitchers. The college guys were from a team that lost in the juco World Series Championship game. The college kids all tried the device and were eagerly comparing their spin rates. Competitive juices were flowing. Their top pitcher registered the best rate…

They finally let my boy try it. The 8th grader whipped them all on spin rate. The kids could all see how spin rate and ball movement were related with this gadget.


If I understand the technology, even with accurate distance, the velocity is being measured as an “average” speed. Sort of like a stop watch method. Most of the radar guns measure velocity shortly after release. The ball slows down by the time it reaches the plate. I agree that velocity measurement is not the gadget’s strong suit.

I think the balls have an estimated two year shelf life and 25,000 pitch life.

Can these newer cameras provide instant spin feedback on each pitch? The college pitchers I saw using this gadget made some minor grip changes and pressure point adjustments and then were able to measure the results right away.



No, the video solution can’t give instant feedback about spin rates…you really need to take the raw video back to a desktop computer for careful analysis to get that kind of information, so… I think I was too glib about inferring that high-speed video is a practical alternative to RevFire. High-speed video does work and it is very accurate; however, it is not a simple turn-key solution that kids/coaches could use in real-time during a bullpen.

If you’re into video, however, there are two other things that high-speed video can reveal, if it’s done carefully: The orientation of the spin axis of the ball for each type of pitch, and the orientation of the ball’s spinning seam pattern with respect to the spin axis for each type of pitch. Pretty interesting stuff…but probably far from what most pitchers want to know.

Well stated coach!

Have you followed Perry Husband’s work on “effective velocity”?

I’m really intrigued that the same velocity pitch can have an 8 mph variance to a batter simply by changing the location of the pitch.