Beside the 'spinning' mechanics. Maybe, the mind set is swing down. I'm thinking that on this swing like any other swing it's 50/50 percent chance If the ball is slightly struck on the lower side of the bat it's a ground ball. If the ball is slightly struck upper side it's a fly ball possible HR. Struck square its's a line drive(Yogi Berra). I'm sure it's been said before 'keep bat/barrel above the ball as long as possible'.