Plank`n`push

Rannoch's recent post on his Surfers push up gave me the idea to post my plank`n`push up. See it here, http://simplestrength.blogspot.com/2009/05/surfers-push-ups.html

In my one below, the person underneath dynamically shifts from plank to pushup position as the person on top has to keep balance as he transitions, as well as to push ups. Core and skeletal stacking, different and dynamic!