Pitch Development and Design… What is Relative Movement? And Why is it Important?

By Robbie Aviles (RHP Cleveland Indians, Pitching Lab Coach)
By Bahram Shirazi (BSEE, MBA, Co-Owner RPP)

How often have we heard so and so throws hard but his ball is flat? They are talking about movement. Velocity is a pre-requisite but movement and relative movement is the other half of the equation.

Let’s quickly review where movement comes from. The diagram further below provides a summary of how velocity, true spin and spin axis determine not only the amount of movement/break but also the direction of movement.  According to Dr. Alan Nathan (University of Illinois: The Physics of Baseball) some of this relationship is linear and some is non-linear.  Nonetheless, putting earthly topics aside these three attributes… 1) velocity, 2) true spin and 3) spin axis… pretty much determine ball movement.  It’s hard to argue with Sir Isaac Newton.  For one, he is dead and two, he was dead-on.

The following post was recently posted on Twitter by a relatively well “Followed” baseball enthusiast:

“I have gotten into many arguments re: the value of knowing total spin versus useful spin. I’ve run into many people who very firmly believe movement is the only thing worth knowing. Which I disagree with but can’t prove wrong.”

It certainly sounds like those “people” the baseball enthusiast is referring to are all old school guys.  So, let’s take this head on.

Yes. Movement is the only thing worth noting; if (a very big IF) your pitches already move well and are well differentiated in their movement and velocities.  Keep in mind movement is the result of everything that comes before it, as in velo, true spin and spin axis.  So, you can’t simply ignore it all.  Those are the ingredients that create your movement.  It’s like saying the cake I baked recently tastes great, but I don’t know what I put in it.  That’s ok, but what if you don’t like the taste.  Then you better find out what you put in it if you want to make some changes.

Here is some movement data on Rapsodo from a typical pitcher who says he has 5 different types of pitches: 4-seam, 2-seam, Change-up, Slider and a Curveball with the following movement patterns:

One quick look at this movement pattern and you can say that this young man only has two pitches, perhaps three at most, depending on the velo of his various pitches.  His 4-seam, 2-seam and change-up move similarly and his curveball and slider are almost identical in terms of movement. You would be surprised how many pitchers fall into this category.  So, yes movement is everything because the above movement pattern is NOT good.  Without good movement, it won’t long before hitters figure you out.

But here is the big question.  How SHOULD these pitches be moving in relation to one another?

The following is a summary of 2017 velocities and movements (courtesy of Brooks Baseball and Pitch/Fx) from over a dozen reputable MLB pitchers we selected.

These pitchers include Kluber, Tomlin, Stroman, Verlander, Allen, Sanchez, Bauer, Ohtani, Tanaka, Kimbrel, Porcello, Syndergaard, Degrom and Archer.  The chart below is the graphical rendition of the same data.

As you can see these guys definitely move the ball around pretty well.  The best pitchers actually have very distinct movement patterns from pitch to pitch.  We call this “Relative Movement” and if you want to go far in this craft you should work towards creating similarly distinct movement patterns from pitch to pitch.  Here are a couple examples of MLB-level “Relative Movement” data from the above pitchers list (2-seams relative to 4-seams… and… Change-ups relative to 4-seams).  You can see how they are well differentiated.

So, with that let’s get back to the Twitter quote from earlier:

“I have gotten into many arguments re: the value of knowing total spin versus useful spin. I’ve run into many people who very firmly believe movement is the only thing worth knowing. Which I disagree with but can’t prove wrong.”

Here is our response…

    • Movement is the result of everything that comes before it (i.e., velo, true spin and spin axes).
    • If you don’t know how your various pitches are moving then you might want to find out.
    • And, finally, if you aren’t happy with your movement pattern then you better start making some adjustments.  College coaches and scouts will be asking for this type of data in the not too distant future (click here for that topic).

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