But there is something valuable I can teach you with this one short slo-mo video. First, here it is:
Charlie has an out-to-in swing. Although many instructors use the term "out-to-in" synonymously with "over-the-top," the two are not the same. This down-the-line shot of Charlie shows the difference very clearly.
Charlie reaches the top of his backswing right at the :07 mark in this video. If you start at the :06 mark and watch his change of direction carefully, you'll notice that his hands reach the highest point of his backswing BEFORE they start moving forward over his backswing plane. After he hits the ball, the club goes very much to his left -- you can see on the video that, in the followthrough, his hands are moving to the left below his left shoulder. That's an out-to-in swing.
In an over-the top swing, the followthrough looks similar. However, the start of the downswing would look much different. The club would start moving forward before it ever reached the top of his backswing -- putting his hands much more toward the ball -- then start moving steeply downward.
The little diagrams below may help explain this more clearly. Note that the over-the-top swing goes higher, loops forward as it nears the top, then drops down more sharply:
over-the-top out-to-in * * * * * * * * * * * * * * * * * * * * * * * *The reason for this is two-fold. In the out-to-in swing (that's the good one!) the trailing knee stays bent and the trailing elbow stays closer to your side as you start down. That keeps the club much closer to your body -- lower and inside -- so the downswing plane is much shallower and you hit the ball solidly below its equator. That gives you the maximum use of the club's loft.
But in the over-the-top swing, the trailing knee straightens and the trailing elbow moves away from your side as you start down. That throws the club much farther away from your body -- higher and forward -- so the downswing plane is much steeper and you end up hitting more on top of the ball. That causes the ball to squirt out lower.
In other words, joints straighten too much in the over-the-top swing.
Just watch Charlie. See how his trailing knee and trailing elbow stay flexed during his change of direction. You can't suddenly grow to 6'4" but you can certainly keep your joints flexed during your swing! That will help keep you from coming over-the-top.