it's talked about in the dvd series on Hogan and it's also talked about in two other books I have about him. I don't know if this was part of his "secret" or not. Some believe so, but only part of it with the right knee being another part and now a turning of the lead elbow even yet another part. At any rate, the reason given for the cupping in his right hand was so that he could go at the ball as hard as he wanted with no fear of hooking it. With his weak grip to start with and opening the clubface on the backswing it made it all but impossible to hook. Good for Hogan, not so good for most imo.