from Amazon
Tuesday, September 09, 2008
Movement v Break
I’m going to have to continue to be a d-ck on the matter of break and movement. The basic difference between a fastball and changeup is speed. The spin direction and spin rotation speed remains pretty much the same, though I will defer to those who study this issue more than I do. Let’s take a look at Josh’s chart on CC:
When you look at this chart, we see “movement”. That movement is the difference between how much movement the ball actually had, compared to how much movement that same pitch “would have” had with no spin, but thrown at the same speed.
What does CC care about? How much rpm and spin angle to impart on the pitch, and how much actual break the ball had in the physical world of Earth (gravity, time). This “movement” chart is an in-between data that shows implied movement, without actually telling the viewer what really happened. And it doesn’t tell CC exactly how much rpm and spin angle he’s got on the ball. These movement charts are great for analysts like us in order to classify pitches, but I don’t think it tells the viewer anything.
Just looking at the chart, and it looks like the fastball and changeup “moves” the same, except in the physical world, the actual break will show a difference for the batter and viewer.
I respectfully think that any movement chart be accompanied with a break chart. If someone like me, who thinks about this stuff too much, is confused, imagine those readers--who don’t give much thought to this--how little he actually appreciates what the chart is and is not telling him.
Flight paths, whether they are from batter’s angle (a la Mike Fast) or overhead/side-view like I tend to use, it is the key to the non-geek (and geek) accessibility to the information. I love me some movement charts, but, when I actually show someone them in person, they don’t get it unless there’s a flight path with it.
Another approach, used by Mike Fast and others, includes gravity in the movement graphs. I also find it useful to discuss or even quantify “movement” relative to other pitches (that slider moved a full foot relative to his fastball)