>>> By square I mean the hips and shoulders start out square or facing the plate until the last minute just before contact. The lead foot remains closed and facing the plate.
A lot of hitters release the lead foot after contact but it happens so fast it is hard to see.
I'm thinking the closed front foot shortens the distance of rotation of the hips. This seems to make for a faster rotation of the bat where it really matters and that is across and just out in front of the plate.
It seems as if the rear hip acts as a gate and the lead hip acts as the gate hinges. If you slam a gate hard and it has a long rotation the velocity slows down whereas if you can shorten the gates distance it will have greater velocity when the hinge is pressed as far as it can open. A closed front foot seems to shorten the gates rotation and lead to more aggresive rear hip rotation.
I communicate with my son on hitting and am always looking for better ways to communicate. I've been travelling a lot and have been letting him go to a pretty good hitting instructor once a week but hit with him on a field this weekend and his power was down. He had lost some focus on using top hand torque and a circular hand path. We fixed this after a few rounds and he added 30 feet in distance instantly by refocusing on THT and Circular Hand Path. He is using some new vocabulary with his hitting and a lot of it is causing him to lose focus. My question is really one of simple communication to a young hitter. I'm sure you have established preferred simple communication with the hitters you work with and am wondering what that communication is. <<<
My first objective with a new student is to communicate the point that the hands should stay back at the launch position and allow the rotation of their shoulders to bring the hands around to contact. The more their arms get involved in advancing the hands, the more the swing becomes disconnected from the major muscle groups of the legs and torso. -- Note: The arms aid in apply THT but should got be used to advance the hands.
In other words, it is the initiation of shoulder rotation that should start the hands around the swing plane. Therefore, the shoulders rotate from the initiation of the swing to contact. If I interpret your post correctly, you may hold a different view. Take a look at the video below. I would be interested in your thoughts.
Rose - Bat & Shoulder Rotation
It appears we may also have different views on what constitutes the most productive hip rotation. Some of my new students exhibit the lower-body mechanics you advocate where their back-hip rotates about a posted front-hip -- like a gate swinging on a hinge. I advise them that this mechanic lend itself more to a linear type of transfer mechanics. Rotational transfer mechanics is better served when the lead-hip rotates rearward at the same rate the back-hip rotates forward -- like a revolving door.
I outline the difference in the Giambi clip below. I would also like your thoughts on this clip.
Giambi - Momentum & the Lead-Leg