I have been reading some threads on other discussion boards. There seems to be a consensus that for body rotation to be most productive, the back-side must rotate around a posted (or blocked) lead-side "like a gate swinging." This would make the lead-side the axis of rotation.
They maintain that when the batter rotates around the center of the body (the spine), they are just "spinning" (like a revolving door) which produces inferior results. If this were true it would raise some interesting questions.
I think we can all agree that the head should remain as still as possible from launch to contact. But for the head to remain still, the neck (top of the spine) must also remain stationary. Therefore, the shoulders must rotate about the neck (like a revolving door). If the back-shoulder were to rotate around a blocked lead-shoulder (like a gate swinging), then the spine, neck and head must also arc around and forward.
I did not develop the clip below to discuss the axis of rotation. However, this over head view of Rose’s axis clearly shows his body is rotating about the middle of his body – the spine.
Rose hip/shoulder comparison
My question to those that support the "blocked lead-side" theory is -- Why would you find it more productive for the hips to "swing like a gate" while the shoulders rotate like a "revolving door?" In other words, what advantage do you see in having the hips rotate about a different axis than the shoulders?