Originally Posted by SystemicAnomaly
For the most part, this is an excellent perspective on the FH stroke -- it further clarifies what I was saying in posts #3 and #7. However, I must take exception to the parts that I've bolded above. The torso/body might very well slow down prior to contact, but it does not stop rotating until well after contact. Once the "arm" stage of the rocket fires, the body continues to rotate for the FH (or a 2-handed BH). However, much of the later rotation of the torso/body is because of the momentum of the racket, racket arm and racket shoulder. Because the back shoulder continues to come around for the contact and follow-thru, the torso/body are pulled around with it.
One of the things I've always found different about the Nadal fh, and especially his rodeo finish fhs is how quickly his shoulder rotation stops. He almost does stop his shoulder rotation at contact on many shots, much more like what you'd see on a ohbh. It provides that odd abrupt look to his fh strokes when watched in real time.
However, how much torso rotation slows really depends on the player and shot. I believe that the core comes into play by stiffening and slowing torso rotation just prior to contact.