In this study, I wanted to test the impact thumb position has on fastball movement. As we all know, there are various ways to hold a baseball, but is one more favorable then another? Let’s dive in.
Guidelines and Participants
For this study, 10 pitchers from various levels were used (high school, college, and pro). Each pitcher threw 10 consecutive pitches with three different thumb positions. The three positions were a traditional grip, tucked thumb, and directly on the side of the ball (pictured above). The metrics that were looked at included velocity, spin rate, Bauer Units (to normalize velocity and spin), spin axis, spin efficiency, and as a result of all of these things, movement.
Pre-Testing Hypothesis
Regular Grip – This grip will produce the highest velocity rank in the middle in every other category.
Tucked Thumb – This grip will result in the highest spin rate and the highest spin direction.
Thumb on Side – This grip will produce the lowest spin direction and the lowest spin rate.
Regular Grip – This grip resulted in the highest velocity, spin efficiency, and was in the middle for everything else.
Tucked Thumb – This grip resulted in the lowest Bauer Units, had the highest spin direction, and the lowest efficiency.
Thumb on Side – This grip resulted in the lowest velocity and spin direction, the highest Bauer Units, and tied for the highest spin efficiency.
The individual results of the 10 participants are listed below:
As you can see, there were a variety of results with each grip. This is why conclusions can’t be drawn solely on what the averages are. There is individualization that must occur if we are going to get the most out of our pitchers. In order to do that it will sometimes take trial and error to find what works right. Finding what does not work can be just as valuable as finding what does work.
As a result of this study, player 6 saw an improvement in every category by changing his grip to a tucked thumb position. If we would have gone off the averages, it would have been concluded that a tucked thumb does not improve efficiency, but in this player’s case, it did. I want to make it clear that understanding the averages and what the trend is, is important, but there will always be outliers. It might take more time and energy to find the right answer for each player, but it will be worth it in the end.
Making Sense of the Results
One thing I failed to account for was the unfamiliarity players would have with the different grips. Almost all of them noted that it became more comfortable the more they threw each grip. When you are uncomfortable, you are naturally going to do something different with your hand at release and will likely not be able to throw it as hard.
The high thumb position results were very interesting to me. The idea to use that grip came from seeing Cody Stashak’s grip. It really intrigued me that he throws a carry fastball like that. Nearly every pitcher in this study had a lower axis with this position then any other grip. When you think about a changeup, the thumb is usually more on the side of the ball, so it makes sense why it would create more side spin. What was also surprising was that the average Bauer Units was the highest with this grip. For guys we want to lower VB, raising the thumb slightly could show to get the sink we are looking for.
I predicted that the tucked thumb would create the most spin, when what actually happened was the opposite. A lot of the pitchers expressed that it felt like the ball was slipping out, as a result it made them feel like they had to grip the ball tighter. Hand and finger size would be something worth looking into to see if there is a correlation.
The regular grip created the highest velocity because it was the most familiar to them. There was no extra thinking involved in this, so they were able to move better and just throw. The other grips brought on more thinking and doubt, resulting in a less optimal throw. The psychological factor was underestimated on my part.
Further Study
This study provided insight and ideas going forward, but there are still many unanswered questions that will require further examination. Things that would be worth diving deeper into include:
Using more participants
Measuring hand and finger size prior to testing
Having players throw on multiple days with each grip and play catch with it
Using motion capture to see if sequence is impacted by different grips
Testing different degrees of thumb position
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