Re: inward turn
I know Jack will respond but I wanted to add my 2 cents. There are a two possibilities IMO:
Number 1. You have an inward turn but your hands/arms are also acting on their own a little too much (are you thrusting them back as part of the turn?) By coincidence I just discovered my son who just a couple weeks ago had a good turn--lately started trying to get more power by adding this thrusting motion which has started to affect his swing in a negative way. I think it's important that the hands and arms feel connected to the shoulders in a one-piece takeaway. A little additional movement might be OK but not a major disconnection. If the hands start far enough back by the shoulder in your basic stance (as opposed to being more in front of the chest) you will be less inclined to start those hands moving too much on their own.
Number 2. You have a good inward turn that doesn't need to be changed and those guys have their own definition of a good swing. I have heard from many who don't like an inward turn and just teach kids to step away from the hands. I've heard comments that it's difficult to teach. There are many players that use an inward turn but sometimes it's timed so well that it flows smoothly into the stride and swing that it appears as one move. I'm sure you've seen players the lift the front foot all the way--in a cocking move too. Ted Williams was a big advocate too.
The turn can be overdone. Too much rotation and the rear eye may lose sight of the ball. That is a limiting factor. My definition includes turning in with shoulders, hips, and a slight inward knee cock that may include lifting the front heel some. But don't pivot the heel to the front. It comes up naturally. This pre-movement comes before the stride IMO (not with it) unless you count the lifting heel as part of the stride which some do. I think players using the inward turn should time this move to the pitcher rather than the stride.
The inward turn may be difficult to master (as I'm finding out) but I think it's well worth it and I also think it's a cornerstone of rotational technique.
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