Keeping the upper half of your body back is key when attempting to hit the ball hard.  It keeps your head still allowing for better eye hand coordination on contact.  It also allows your hands to get out quicker in to the palm up / palm down power position.  Moving your upper half forward will give the ball approximately a 5 mph increase towards the hitter and cause many balls to be topped and hit towards the ground.  Don’t get me wrong, weight does transfer on to the front foot on contact but not the way most people think. The head should finish over top of the rear knee on contact.  If you are in the most powerful and correct position on contact, it should be very hard to hold that position for more than a second without hurting or stressing out your rear knee or foot.

The upper half coming forward is the old way which was used more in teaching methods in the 1980’s.  Since slow motion video analysis has become a big part with swing analysis in the 90’s, the upper half back has proved out to be for the better.  Bat speeds are at a much higher speed and players with rotational mechanics are quickly becoming the best hitters of all time.  Hitters with rotational mechanics can be seen in pictures included in this article.  Notice how all of them have their upper half back on contact. Players pictured are: Barry Bonds, Kash Beauchamp, Mark McGwire, Joe Mauer, Jim Thome, Manny Ramirez, Cody Ross, Chris Cresenzi and Al Roach.

Now I am not saying a player can’t still hit a home run or a line drive double with their upper half coming forward, but chances are a lot less.  Look at the mechanics of a player who hits a home run in to the 5th deck and then look at the mechanics of that very same player who got fooled on a pitch and hits a home run that goes out by a row or two.  Chances are that when he got fooled, he was out in front and reaching for the ball or shall we say upper half forward. These results show that his bat speed was much slower in the upper half forward swing resulting in the ball not going as far. Who would want to have a slower bat?  Hopefully no one.  The goal is not try and hit the ball out of the park every time but rather maximize bat speed so the hitter can hit the ball harder.  If a hitter mazimizes bat speed, chances are he will have a lot more base hits and be more successful at the plate.