What? Don't know what you are trying to say here. You should not be dinking balls for mini tennis. If you are decelerating your swing into the ball, you are doing it incorrectly.
Balls should be hit at moderate pace and, like any other groundstroke, you should
accelerating, not decelerating, into the ball. Deceleration happens later, just like all regular serves & ground strokes. A generous amount of topspin is often imparted to the ball for mini, so the racket head speed is actually fairly fast (even tho the ball speed is moderate)
A number of videos in this thread and other similar threads have been posted of pros engaging in many tennis. Where are they decelerating?
Here is a video of Justine Henin that was posted a while back. We can see that she had started hitting fairly close to the service line. (Eventually she moves back to the BL). Where do you see her to decelerating her racket? Take a close look at how fast she is actually swinging the racket.