[purehitter]

The reason A Hammer thrower moves his hands up and behind his head before his pivot starts ( a little different then the Power Rover Hammer drill) is to get momentum. With your Hammer swing, do you gather momentum of the clubhead before the back swing?

Look up the example of Momentum Transfer in the glossary of TGM book and you will find the connection for The Hammer Swing. I teach from the yellow book. The Hammer Swing is in it.