Seeing spin direction is not too difficult, especially if you are catching. Detecting seam orientation on a moving, spinning ball is much harder. Just because you grip the ball a certain way and try to spin it a certain way doesn't mean that it is actually doing what you think it is. The spin axis and direction might be spot on but the seam orientation might be way off. The release can effect the ball in ways that are surprising..I am 100% sure it is my DD not doing something correct, but she has (what seems to me) more downward movement on a 2 seam drop. Granted she doesn't throw a perfect 12-6 and it gets some sideways movement as well. Am i seeing things? I guess i had assumed that the 4 seam gave an evenly distributed disruption vs the 2 seam which has more of a wobble aspect to it. Even when i try to throw an overhand curve i have more movement throwing in a 2 seam orientation. Thanks in advance for the comment. Maybe there is another thread out there for this question.
If you want to check seam orientation take a ball and draw two 2 inch black circles on opposite sides of the ball. I use the places where the two seams come closest to each other. Now, with a true 4 seam rotation (around the center axis of the ball) the black circles will be stationary or close to it. But here is where it gets tricky. With a 'perfect' drop or rise the black circles should be on the sides of the ball, at 90 degrees to the direction the ball is traveling. If the dots are stationary but one is a little forward and the other a little behind then the spin axis is tipped a little. If the dots are wobbling or can't be detected then the seams are not in true 4 seam rotation. A perfect curveball would have one dot on top and the other on the bottom. Perfect bulletspin would have one dot in front and one dot on the back. This is for 4 seam orientation, for 2 seam rotation/orientation the dots would be spinning in a circle like a ferris wheel (and be difficult to see).
I had a mind bending experience this week that has me questioning some assumptions that I have about how to throw the riseball. I have a pitcher who can reliably throw very good backspin, often 12-6 at least 11-5. We were using the ball with 2 dots and working on getting 4 seam orientation on her rise. With her fastball the dots are close to the sides, stationary and tipped about 20 degrees to the right., so mostly topspin. She uses a 4 finger across the seams grip. She has a unique riseball grip, 2 fingers but across the seams like her fastball. We switched her grip so her fingers were lined up with the long seams and not across them. This should give 4 seam rotation but we could not get the dots to line up on the sides of the ball, spin axis was good, seam orientation was not. Finally I asked her to go back to her regular grip, and surprise, the dots were on the sides, a little wobble to them but there they were. WTF! So she can use the same grip on both her rise and drop, one is 4 finger and one 2 finger but the fingers line up across the seams the same way. There can be only one answer, what is it?
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