Eka Pada Sirsasana (Foot-behind-the-Head Pose)
Joel Kramer, a well-known yoga teacher from Bolinas, California, once described in Yoga Journal an aspect of his approach to yoga he called "playing the edge." Kramer's ideas have influenced my practice ever since. "Playing the edge," as I understand it, means taking yourself to your limit and, through subtle awareness and refined adjustments, continuing to practice without stepping back from or going over that edge.
To illustrate this concept, let's consider the first stage of Supta Padangusthasana. In this pose, you lie on your back with your legs stretched straight out on the floor. Then you raise your right leg and catch your right foot by either grasping your big toe with your right hand or by holding a strap around your foot. Keeping your right leg straight, you pull your foot back toward your head. As you move your leg, you are going to feel the stretch in the back of your leg intensify. At some point, the increasingly intense sensation of stretch will begin to turn into pain. Lilias Folan used to refer to the point just before pain as a place of "sweet discomfort." The art of playing the edge is to find and work at that exact point of transition, without losing either the sweetness or the discomfort.
A challenging aspect of practicing this way is that these edges are not at all static. They are in constant flux. Thus, playing the edge skillfully requires unwavering concentration and calm awareness. It transforms your practice into a meditation, and to my mind, is one of the primary differences between practicing yoga asanas and "exercising."
One possible result of playing your edge is that you might find yourself practicing increasingly difficult poses. For example, you may have become flexible in your forward bends to the point where you can rest your torso on your straight legs with ease in Paschimottanasana (Seated Forward Bend). In terms of flexibility, Paschimottanasana no longer
brings you to your edge. To find your flexibility edge, you might need to practice Kurmasana (Tortoise Pose).
Seen in this light, the practice of more advanced poses is not some ego-gratifying game of one-upmanship or a spiritually materialistic approach to acquiring more and more difficult asanas. (Bumper stickers notwithstanding, I suspect that when we die, the person with the most poses doesn't win anything in particular.) Instead, if you're committed to playing the edge in your practice, doing advanced poses may simply be a natural and appropriate progression.
When you say "advanced yoga pose," one of the poses that may come to mind for many folks is Eka Pada Sirsasana (Foot-behind-the-Head Poseónot to be confused with the Headstand variation that has the same Sanskrit name). It is difficult for almost everyone and is a real eye-catcher of a pose. I recall that the first time I thumbed through a book of yoga postures, the ones that jumped off the page were Eka Pada Sirsasana and
its more advanced cousin, Yoganidrasana (Yogic Sleep Pose). My reaction was not unlike that of a couple who, some years later, happened to observe me practicing Eka Pada Sirsasana on a remote beach. I was unaware of their attention until I heard the woman exclaim incredulously to her partner, "Oh, m'God, Harry! Look at that!"