Many coaches seem to stress, keep the shoulder in their, and the elbows start the swing and move somewhat independently of the shoulders without any "connection" with each other during the swing, and during the drill with just the bottom hand on the bat it seems many stress to keep the shoulder in to be able to stay through the ball, but on the model swing thread most of the hitters shoulders at contact are perpendicular to the plate, they seem to stay somewhat connected and rotate naturally with the arms, not keeping the shoulder in at contact. Is it something we just dont want them thinking about during the swing, or do we really want them to try and keep their shoulder in.