Experiment Idea for Coach Kreber


Coach Kreber,
There is some debate as to why a 2 seam fastball tends to be slower than a 4 seam fastball. Most believe that having more seams spinning reduces the drag. However, some studies have shown analytically that there shouldn’t be any significant change in the drag coefficient between a 2 seam and a 4 seam fastball.

In any case, velocity measurements are usually taken at a point very close to release where the aerodynamics haven’t had a chance to make much difference at all so there shouldn’t be any difference in the release velocity of a 2 seamer and a 4 seamer unless pitchers simply don’t try to throw 2 seamers as hard.

It would be interesting to gun a large group of pitchers throwing 2 seam and 4 seam fastballs, measuring velocities at release and at the plate to see if there’s a difference in how much a 2 seamer slows from release to the plate compared to how much a 4 seamer slows. At the same time the 2 seam vs. 4 seam release velocities could be compared. This should be enough to determine if the velocity difference exists, and if there is an aerodynamic effect.


If you do this experiment, I would expect to see two things…

  1. The 4-seamers should cross the plate faster than the 2-seamers.

  2. The 4-Seamers should cross the plate higher than the 2-seamers.



It sounds like an interesting experiment. What is your hypothesis? I can set it up and this is actually a good time. I have another long term experiment going using soft toss success as a predictor for batting success. The results should be out in May. Also, the long term effects of using weighted balls for training the throwing arm. We are now in year 2 of the 4 year study. Stay tuned.



Coach Kreber,
My hypothesis is that on average 4 seam and 2 seam fastballs thrown for maximum speed will have the same velocity as read on a radar gun picking up the speed at release. (This is consistent with my assertion that 2 seam fastballs measure slower because pitchers aren’t trying to throw 2 seam fastballs as hard as they are trying to throw 4 seam fastballs.)

The second part of the hypothesis is that the drop in speed, from release to the plate, for 2 seam and 4 seam fastballs will be roughly the same. Since 2 seam fastballs have a tendency to sink more there may be a slight difference due to the approach angle rather than the actual velocity. In other words, high fastballs will tend to have higher radar gun readings at the plate because they are traveling in more of a straight line at that point.