Fish - do I remember correctly that you have a background in physio? If so do you have any good cutaway anatomical diagrams showing how the muscles attach in and around the pelvic girdle? My anatomical understanding is very limited on how the pelvis works and how muscles with attachment points in/on the pelvis link the bottom half of the body to the top half. Until recently I have had a very crude model in my mid of the pelvis simply acting as a skeletal frame to provide a socket for the top of the leg bones to fit into. But recently (while reading a tie chi book) I had one of those moments where things click. And I realised that the mechanics of hung gar make use of the muscles within the pelvic girdle in different ways to moderate the linkage between the top half of the body with the bottom half. Or put another way rather than the skeleton of the pelvis holding the muscles up, it is the muscles within the pelvis and pelvic floor that hold the skeleton up. and that my understanding of the anatomy of the pelvis and how it works is virtually non existent.