This week's asana is Eka Pada Bakasana (One-Legged Crane Pose variation 1).
In the past, from Bakasana, I have played with lifting one knee and then the other from my upper arms, thinking about Eka Pada Bakasana, but not understanding how to shift the weight and extend the leg back from there. I tried the full pose for the first time during a teacher training session a couple of weeks ago. We were discussing the difference between Crow pose and Crane pose. Who knew there was a difference?
Apparently, Crane pose is with the knees in or near the armpits done with straight, or nearly straight arms (this is what I understand to be bakasana). Crow pose, on the other hand, is the modified version, with the knees wide, squeezing into the outer triceps, and keeping the elbows well bent. My teachers argued that the actions of the two postures are so different that they should be specifically instructed, one way or the other to achieve a desired result (by that I mean working specific muscle groups versus others or being in a position to move to the next asana, not necessarily whether or not the pose is achieved by anyone).
Anyway, bringing this all back to the Asana of the Week, Crow pose, not Crane pose, is where you want to begin to come into Eka Pada Bakasana. This had been my mistake in the past. Since I always practice a tight Bakasana, with the arms straight, it's no wonder I couldn't figure out the transition to the asymmetrical version. The knee or shin must be further down on the upper arm and the elbows need to be bent in order to lower the center of gravity, or you'll just tip over.
There is a tendency in Eka Pada Bakasana to try to leverage the hips up by pressing the knee or shin of the bent leg into the tricep. I'm finding, in my limited experience with this asana, that rounding the back and lifting the hips from the core -- bandha action -- is the better way to go. I actually prefer to take almost all of the weight out of the knee and squeeze in with the inner thigh instead of pressing down. It takes a little more core strength, but it's much easier on that upper arm.
One of the fun things about this week's asana is that there are a few ways to enter Eka Pada Bakasana. First, of course, from Bakasana (but remember to keep the knees a little lower on the arms -- no armpit action). One may enter from plank, by drawing one knee to the outside of the same-side upper arm, then bending the elbows and shifting the weight well forward of the hands, lifting the back leg (almost exactly like the prep for Eka Pada Koundinyasana II, knee just a hair higher up the arm). BKS Iyengar in Light on Yoga prescribes finding Eka Pada Bakasana from Sirsasana, but the loveliest transition I've seen is entering Eka Pada Bakasana from Marichyasana A or C. I use this vinyasa in my practice of the Primary series exiting Mari A and C. It's a beautiful moment and a welcome break from the regular seated jump back.