Thanks Scrap. I've been looking for way to train that incorporates my shoulders more. My trainer Joe Byrd says that he'll get us in the ring some time and swing a towel at us to help work on upper body movement as you see for yourself at the end of this video: http://www.youtube.com/watch?v=pM5dXhUTvvg
Anyways I tried what you're saying about shadowboxing in knee pads. It feels a little awkward moving around like that. I'm not yet sure if it changes my upperbody movement at all. Is there something more that I need to do when I'm shadowboxing like that?