This morning I reviewed my "To do" list of e-mail replies. Many of them were from dads with video of their son's swings asking what I would recommend to improve their batting performance. In reviewing the videos, I noted that my recommendations would probably be at odds with what many of their son's coaches were teaching.
While contemplating my recommendations, I had to keep in mind that most coaches feel "casting" is a major problem. Even a good number of coaches that promote rotational mechanics believe that 'the tighter the hand-path,' the more productive the swing. To train their students to acquire a tighter (or straighter) hand-path, they could use cues like "Keep your hands inside the ball" and use the "Fence Drill" to reinforce the cues. -- Below, are a few clips I found on the Web that might represent what the batters I was reviewing were taught.
Hands Inside the Ball
Knob to the Ball
Note that in the above clips, all the batters drive their top-hand across their body (inside the ball) while their lead-elbows start boxed (about 90 degrees) and straighten out approaching contact. Obviously, these mechanics would reduce casting. Therefore, with these principles being taught, I can understand the questions that would arise if I suggest acquiring mechanics that would take the hands in a wider (or a more "casting") path.
However, with many of the clips sent to me for analysis, that would be my recommendation. The mechanics they exhibit produce a hand-path to similar to the clips above. This is not the hand-path exhibited in the game's best hitters. The best hitters keep their hands back (including the top-hand) and while keeping their lead-elbow at a constant angle, allow the rotation of their shoulders to swing their hands into a more circular path.
Note: For a giving angular displacement rate of the hands, the wider the hand-path, the greater the bat speed generated. This is why many of the top hitters are farther from the plate than the clips sent to me. It allows them to take their hands in a wider path. Which brings up one of my concerns regarding the "Fence drill" shown below.
Fence Drill + Game Swing
The mechanics exhibited in the 'fence drill' batter closely resembles some of the clips I reviewed. First, notice how much farther from the plate the batter in the 'game swing' is to the batter in the fence drill. Secondly, note the position of the back-forearms as the bat approaches contact. In the 'game swing,' the forearm is pointing in the direction of the pitcher whereas the forearm in the fence drill is pointing over toward third base. This indicates the bat was dragging behind the hands through much of the swing. -- But then, wouldn't that be required to miss the fence?