Yup, that's the frog pose- with the "PNF" stretching..
I was with ya on this one when I first saw it, so I did a little research, and though that whole hip track is a toughie it really makes a lot of sense. PNF stretching (which I believe stands for Proprioceptive Neuromuscular Facilitation) is a method used often in PT and rehabilitation, and is" a more advanced form of flexibility training that involves both the stretching and contraction of the muscle group being targeted."
(ok, snagged that from http://www.thestretchinghandbook.com/archives/pnf-stretching.php)
I had to figure this one out to help explain to the members why this odd-looking pose was really advantageous! :)