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Can We Train Fastball Spin Rate?


This post is presented in a form mirroring that of a research paper, but written very colloquially. This was a conscious decision, and an attempt to bring awareness to the somewhat scrupulous nature in which we collected our data, as well as the complete lack of quality scienceing in the construction of the experiment or the analysis of the results. My hope is that this is both meaningful and fun to read.


Don’t count out the ability to train fastball spin rate just yet. A finger strengthening program undertaken concurrently with a throwing program may be able to increase fastball spin rate.


A decade ago, few believed that velocity could be trained. The consensus was that you either had it or you didn’t. Today, that viewpoint is laughable. The ability to train velocity is more or less a given. It’s wild that today’s norm was yesterday’s impossible. It’s also likely that today we’re making similar mistakes in other areas of pitcher development.

One of those areas is fastball spin rate. Current wisdom states that you can’t train it. Instead, we claim that it’s dictated by some amalgam of fingerprint orientation and natural oily secretions. You certainly can’t learn to improve it, at least without losing efficiency or adding a foreign substance.

So because we can’t train it, we’ve transitioned our focus as a player development community to improving fastballs via changes in efficiency and axis. And this works. Don’t get me wrong, improving the efficiency or axis on a pitch can have a much larger impact on pitch movement than adding some spin. We’re attacking the lowest hanging fruit, which is great. A few solid sessions can improve a pitcher’s movement profile tremendously.

But the problem is that we’re only attacking the lowest hanging fruits, and soon all of those fruits will be harvested. So we’ll be left with what? That’s right, the fruits at the top of the tree. The fruits that are hard to get to but oh so juicy.

I believe that fastball spin rate can be trained and that we should be training it. The tricky part is that we don’t know what trainable attributes (other than velocity) correlate to spin rate. Without this knowledge it becomes nearly impossible to train.

My contention is that improvement in finger strength (not standard grip strength) can increase spin rate within an individual. (I would be shocked if other bio-mechanical patterns don’t also correlate to spin rate, but that’s for another day.)

Let me lay out the thought process I used to come up with this hypothesis:

  1. More friction = more spin

  2. More friction = the ball remains on your fingers for more time

  3. By the transitive property, the ball remains on your fingers for more time = more spin

As the baseball is being accelerated forward, just before release, huge amounts of force are being exerted by the fingertips. The baseball is exerting an equal amount of force back on the fingers. Having sticky fingertips allows the ball to remain on the fingers for more time, leading to more spin. I believe having strong fingers that don’t get pushed into extension by the force of the ball will also lead to more spin.

This small pilot study tries to disprove this theory.


The original plan was to run this study on myself, which of course is perfect science. But a few friends liked the idea so a study of n=1 turned into a study of n=4. Unfortunately number 4 got sick during our re-testing period, so the final study was conducted on 3 people.

We tried our darndest to keep the scenarios of the pre-testing and post-testing as similar as possible. I tested all subjects but myself on the pinch grip measurements we’re about to get into. Nicky tested me. Nothing about this study had any real controls. Nothing was blind. There are certainly many issues with it.

We had two days of pre-testing and two-days of post-testing, with four days of rest between the first day of pre-testing and the second as well as four days of rest between the first day of post-testing and the second. We had a six week training block between the end of the pre-testing and the beginning of the post-testing.

Our independent variables were four versions of pinch grip. We used a Saehan SH5005 Pinch Gauge to measure pincer grip, tip to tip with pointer and thumb, tip to tip with middle finger and thumb, and three jaw chuck. (Definitions can be found here.)

We cycled three times through each measurement on each hand, taking full rest between sets of trials. We took two more sets of measurements after our throwing warm up, giving us five measurement trials per testing day.

Our independent variable was Bauer Units, which is RPM/MPH. (Learn more about this here, here, and here.) We used the Rapsodo 1.0 and Stalker Pro IIs concurrently, throwing out any pitch that gave us an insane and probably inaccurate reading. The RPM and MPH numbers we ultimately used were those from the Stalker. (See our validation here.) We tracked spin efficiency as well in an attempt to verify that any possible increase from pre to post test wasn’t the result of an increase in gyro spin.

Each pitcher warmed up however he wanted, being sure to closely mimic the warm up in every session. He then threw 15 fastballs. The sessions often went over 15 pitches, as technology isn’t perfect, especially when the subjects like to wildly miss the strike zone. Ultimately, each session went long enough for us to record data on 15 pitches. Each subject threw his pitches at a rate of perceived exertion that he felt comfortable with, knowing that he had to repeat the session in five days.

Between the pre-tests and the post-tests, the subjects each completed a specially designed pinch grip workout that I made up, and that you can find here. We all continued with whatever other training we were doing. I was the only one who was throwing consistently during this period.


This section is going to get a little bit crazy, because the results aren’t super clear. In some ways, there seems to be evidence pointing towards increased finger strength leading to increased spin. In other ways I’m not so sure the evidence supports this at all. I’ll try to present everything with as little bias as possible, but understand this study is inherently biased because I partly studied myself.

Let’s start with the group as a whole.

It turns out that training works. We saw increases on all four pinch grip measures, three of which were significant at the .01 level. Here’s the table for the throwing side:

The crazy thing is, according to this study, the contralateral effect is very real. Either that or we just got good at the test. Maybe the cause was a combination of both, but the result was that we got stronger on our non-throwing side, which we didn’t train! Again, the results were significant at the .01 level in three of the four tests. It might be interesting to note that the change in the Three Jaw Chuck test was minimal, but that the other three tests all showed extremely low p-values. Here is the table for the non-throwing side.

And here are the graphs showing the same information:

The group showed similarly significant increases in Bauer Units, going from an average of 21.9 Bauer Units before the training period to 22.6 Bauer Units after. This was significant at the .01 level.

So awesome. Super clean. We increased finger strength and it led to a jump in spin. Awesome. We figured it out.

...Not so fast. Let’s dive into this differently. Let’s look at this person by person. There were only three of us who completed this, so it’s doable. Here we go.

Nat Ballenberg

You will see that my results likely skewed this whole study, and I’m going to tell you why.

First, my arm felt like absolute garbage on the first day of pre-testing. I had done a few lessons either the day before or earlier that day, and my shoulder was really struggling. It was one of those days where you take the ball, but you know you’re going to have to figure out a different way to get guys out. That’s where I was on our first day of testing.

Also, I was the only subject who continued to throw throughout this trial. I worked on some things, mostly focusing on getting my shoulder external rotation to better sync into the line of my shoulders. This may have had an impact on my post-training results. (Which, if it did, still hints at the trainability of spin.)

Lastly, I ‘figured something out’ at some point with the pinch grip testing. Maybe the training led me to use a better neural pathway or something, but at some point I just found another gear. That could be the point of the training. Or I may not have understood how to take the test in the beginning.

Let’s look at the data.

To start, all of my throwing side finger strength metrics improved, but only one improved at the .01 level. I know I could say that 3 of the 4 metrics improved at the .05 level, because they did, but if I said that I’d have to say that they all improved at the .879 level. Still, the changes in my Three Jaw Chuck strength were essentially non-existent while the increases in the other three tests were fairly large.

The crazy part - the one I alluded to earlier - is in my non-throwing side Tip to Tip Middle test. I just figured something out. It was one of the crazier experiences of my life. I just wanted to let you know. It really has little to do with the study.

The most confusing part of this study starts with my spin data. I’ve thrown off a Rapsodo enough in the past to know that I’m usually a 23-24 Bauer Unit guy. On Day 1 of Pre-Testing though I averaged just 19.8. My arm felt terrible. I chalked it up to that. On Day 2 of Pre-Testing, after four days of rest, my Bauers were better. They were up to 22.9. It was still lower than normal, but to be fair I don’t have any actual averages from the past. For all I know I could just be remembering my best pitches. Either way, I felt really good that day, so the excuse of pain and altered ‘something’ goes out the window. My average Bauers for both pre-tests combined was 21.3.

My post test Bauers were way up. I averaged 24.8 across the two sessions, with session one averaging 24.6 and session two averaging 25 Bauer Units. This was beyond what I had done before. No matter how you slice it, these changes showed to be significant at the .01 level.

Nicky Miranda

I am not Nicky Miranda, so I can’t tell you about the specifics of his training outside of this study, but the results of his finger strength tests were interesting to say the least. On his throwing side he improved in three of the four tests. Of those, only one showed significance at the .01 level. He went down in one of the tests as well. Here is his chart:

Nicky actually did better on his non-throwing (untrained) side.

When we look at Nicky’s spin data, we again see little difference between our pre-test and post-test. His spin rate went down by .1 Bauer Units, which was not significant.

Jared Deveau

This is where it gets crazy again. Jared, who completed the training just like Nicky and I, also improved on all four of his finger strength tests on his throwing side. Three of those improvements were significant at the .01 level. He also improved across the board on his untrained, non-throwing side. Again, three of those improvements showed significance at the .01 level. I don’t know what to make of it.

But here’s the kicker. Remember how my Bauers improved significantly and Nicky’s stayed the same? Well, Jared’s got significantly worse. He went down one full Bauer Unit, which was significant well beyond the .01 level.


Having the tiny sample that we had, and including myself in the study, brings into question any conclusions that I attempt to make here, so I will keep them vague and use uncertain language. I’m not comfortable really concluding anything. But here are my thoughts.

The fact that we saw finger strength in the non-trained side increase at nearly the same rate as the trained side makes me skeptical of the validity of the measurements. If we are to assume the measurements were accurate however, this would be about as good a study as any to be able to identify the crossover effect (other than sample size of course). The muscles are small, untrained, and linked less to the strength of other body parts than something more dynamic like a pistol squat or one arm dumbbell bench press. Still, whether we successfully trained it or not, I am fairly confident in saying that finger strength can be trained.

Assuming that the results we saw with the increases in finger strength were real, it is safe to say...nothing. Not much seems to add up. The only conclusion I can draw that sufficiently brings the finger strength data together with the spin data is that maybe the only important aspect of finger strength is Tip to Tip Pointer. This is the one metric in which I improved drastically while Nicky and Jard remained about the same. Maybe this explains the significant increase in Bauers I saw that the others did not.

By best guess at the reason I improved has to do with the transfer aspect of this training. While we were all doing the finger strength exercises, I was the only one who continued to throw between trial periods. Is it possible that by continuing to throw while improving my finger strength, my body adapted and learned that it had new finger strength to utilize? Maybe it found that it had new degrees of freedom to exploit and learned to exploit them.

Meanwhile, Nicky and Jared had increased finger strength, but their bodies hadn’t figured out how to use it when throwing the baseball. I might even have some evidence to support this.

When you plot the Bauer Units of each successive pitch during the post training period, for each pitcher, you can get a general idea of the consistency of their Bauer Units. Looking at the graphs below it is clear that both Nicky and Jared’s trend lines stay almost perfectly flat (technically Nicky’s decreases slightly and Jared’s increases just a little bit), while mine has a discernible upward slope. You can also see a distinct point where my body seems to have ‘figured something out’ after the 8th pitch of the first post-training session.

This certainly isn’t enough evidence to say anything with confidence, but it does give hope that maybe, just maybe, with finger strength training implemented concurrently with throwing training, spin rate may be trainable.

Where to go next

I think this pre-trial of sorts provides enough hope that fastball spin rate might be able to be trained. By partaking in a finger strength training protocol concurrent with a throwing program, we may be able to impact a pitcher’s ability to spin the fastball.

The next step is to run a trial with a much larger group, this time of current players. Each group would test their finger strength and Bauer Units before and after a training cycle. During the training cycle one group would go through their usual training. The other group would go through their usual training, but they would also follow a finger strengthening program. The results of the two groups would then be compared. I hypothesize that some members of the finger strength group will see increases in their fastball Bauer Units, and that the group average change will be positive and significant. So I guess the null hypothesis for this study would have to be, “Finger strength training, concurrent with a throwing program, does not increase fastball Bauer Units.”

I hope someone tries it.


The data from this study can be found here.


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