Any pitcher I've ever seen has significantly higher velocity from the windup....but that may be partly because of the guys I've seen 99% of the time there is a runner on base when they were in the stretch and they aren't trying to overthrow a FB for fear of throwing it away and letting the runner advance. I can give you my son's velo from Sunday....first inning...first batter, 90, 92, 91, 92, 91.....nobody on base. He was 90 or over on every fastball that inning...3 batters....no baserunners. Next inning....gave up a lead off HR at 92. Got a ground out on a curveball to the next kid......then a single. With runner on 1st, he was 88-89. Was it because of the stretch, a runner on base, tiring a little, or a combination of all 3.... I don't know I guess. I'm not sure he's ever thrown from the stetch with a gun on him and no runners on base. Would be interesting to know. I will say that his command is usually better from the windup....but that could be because when he was younger (HS) he didn't allow many baserunners so he's got alot more experience throwing from the windup.