Is there a difference in velocity when pitching from the Windup or Stretch?
I ran across this interesting article that answers the question.
It's often said that the stretch costs a pitcher 2-3 miles an hour off his fastball, and (considering how easy that is to check) I'll assume that's roughly accurate. (Rob Neyer)It is very easy to check, and it turns out that it's not accurate at all. A pitcher's fastball speed turns out to be almost identical with runners on base as compared to his average fastball speed with the bases empty. If anything, the average starting pitcher throws about 0.1 mph harder with runners on base.