Day 9 into the Void revisited – hands
Have you ever noticed where a major leaguer’s hands are when they’ve made good contact?
I’ve heard coaches advocate rolling the wrists to create wrist snap and they feel that will increase bat speed, but again, as I’ve challenged you from the beginning, let’s see what they actually do.
Notice this picture where is the top (the one up the bat) hand’s palm facing?
It’s pointing to the sky or top hand – palm up. In other words the ball is struck and you drive through the ball before the wrists "break" or roll.
Try to find another picture any other way.
For another discussion, is the bat barrel above or below the hands? Maybe we’ll need a larger sampling to determine this one.
How to Hit Like a Major Leaguer 
Part of it could have to do with where the pitch is located. The pitch Derrek Lee is hitting is just below his waist, and so the barrel should be below the hands here. Clearly he is taking a swing intended to blast one, but if there was a situation that called for the ball to be hit on the ground it might be easier to pull this off by rolling the wrists over (sort of like a swinging bunt). The wrists might also be rolled on a high pitch in order to hit a line drive, otherwise a pitch up there would be popped up.
I also want to point out here that at the point of contact, Lee’s weight is shifted back. This goes back to the argument on whether the weight at the point of contact should be on the back foot for a power swing. This picture here is my common perception of a typical power swing, which is why I think Aaron’s swing was an oddity.
It will be interesting to find lots of pictures, because according to Tony Gwynn, 100% of the pictures he’s seen of major league hitters, they all have their top palm “pointing to the sky”.