Re: wrists at impact
If your palms are "flat" then your wrists will most likely be in the right position, with little to no roll of the bat at contact. By "flat" I mean, parallel to the ground when swinging at a pitch belt high. The top hand palm is facing up, while the bottom hand plam is facing down. Obviously, depending on the pitch height, your palms may not be perfectly parallel to the ground. To your point, for palms to be flat at contact, the top hand must be able to "slide" or rotate around the bat handle during the swing. I have found with my son, that it also helps relax the back side, which keeps him from pushing with the back side.
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