Mark is asked the following, by Ken Adams.
"Is putting meant to be a rocking shoulder movement with nothing from the hands?
The reason I ask is that in an interview they did with Ben Crenshaw on a putting green… he said it was all about the forearms and hands and to keep the tension out of both and keep the grip nice and light so the putter head feels heavy.. and to "roll the rock" (the ball) with long stroke with the hands" Mark discusses how Ben Crenshaw being one of the best putters in history probably knew what he was doing and other should take note!