I was asked to expound on this... so here goes!
This comes directly from my study and experience of Yoga.
Yoga = yoke, union.
What are we uniting, what are we yoking together?
In my experience, we are yoking every layer from which we can experience this human existence.
What are those?
In yoga, those layers are explained as Koshas, or illusory layers of existence:
Annamaya - the physical
Pranamaya - the energetic, often shown through our breath
Manomaya - the mind at the level of emotions
Vijnanomaya - the mind at the level of wisdom, thoughts
Anandamaya - the layer of bliss (without reason or cause)
Atman - true self, essence, universal
Because we are embodied, we experience existence in all of these ways. In the Yoga practice, we are taught to deepen awareness. Awareness of what? Awareness of existence. Awareness of the here and now. Awareness of what shows up in each moment.
When we can yoke together each layer as it shows up in each moment: mind, energy, emotion, though, bliss, spirit, THEN we are fully living this human existence.
But how often can we actually hold, truly hold, all of that? And for how long? That is the practice.
So when we practice Asana, it is only as a means from which to practice. To deepen. To become aware. To even become aware of what we are aware of. Moment to moment. That is the practice.
That means, the "advanced" asana, or the deepest expression of the pose, is not necessarily the outward, or physical, expression. To see only that is to miss the deeper meaning. The advanced asana is the one where within the shape of the pose is held awareness of every layer of experience: physical, energy, emotion, thought, bliss, spirit.
How are YOU doing with that? And, has the outward shape of your pose gone so far that you've lost sensation of the deeper layers? Has it not gone far enough to tap into them?
In the Yoga Sutras of Patanjali, 2.46 teaches, "sthira sukham asanam." Or, the posture should be a balance between effort, "sthira," and ease, "sukha." To me that means, if we achieve that balance, we are then best able to heighten awareness on all the layers of experience while holding the pose.
Mr. Iyengar says, "the pose begins when you want to get out of it." I believe he is correct, because only when you find that edge of wanting, does something else happen.
The interesting thing is, this ties in precisely with what I am practicing in Phoenix Rising Yoga Therapy. I am facilitating your deeper connection to every layer through which you experience this existence, in order to allow your inner wisdom to arise, and true healing to happen. If you are interested in a session with me, get in touch! firstname.lastname@example.org
Enjoy your practice! <3