For example, if we consider the feet, the front foot focus is on the rooting of toes, whereas the focus on the rear foot is on the rooting of the heel.
Thus here we have an example of a Pratikriyā Bhāvana, or opposite action focus, where we need to hold our attention with a contrasting dynamic in two places simultaneously. In this example on both the front or rear foot at the same time, but with different points of attention.
This opposite action focus continues as we move onto the knees. Here the focus on the front knee is to bend or strongly flex it forward, whereas the focus on the back knee is to straighten it or strongly extend it backwards.
Moving up and arriving at the hips, we find here that the focus on the front leg forward hip is to pull the hip firmly backwards, whereas the focus on the rear leg hip is to pull the hip firmly forwards.
Now, this action involving opposite work on the same leg hip and knee, brings with it a kinesiological dilemma. In that as I push the front leg knee forward it drags with it the front leg hip forward. Equally when I pull the rear leg knee back it drags with it the rear leg hip backwards.
Thus we need to multitask, in that if we look at an example of Vīrabhadrāsana where we have the left leg bent forward and the right leg straightened back, we find that we need to push the left knee forward whilst simultaneously pulling the left hip back.
Equally, in this example, with regard to the right rear leg, we need to pull rear right knee back to straighten it whilst simultaneously pulling the right hip forward.
Thus the practitioner is faced with a complex structural dynamic that involves opposite tensions within a constant trade off, with over emphasis in one area diminishing the overall balance of structural tensions.
The skill is to be able to reach a common, yet opposite, point of attention in both hips and knees at the same time. Here, this means that I can hold an opposite tension in the same leg, in terms of both the hip and the knee working in opposing ways, and yet at the same time considering the impact on the opposite side leg in terms of the effect here on the hip and knee.
For example, over emphasising, say with pushing the front left knee forward, will drag the left hip forward and with it cause a buckling of the rear right knee. Or, equally over emphasising keeping the rear right knee straight will drag the right hip back and with it a tendency for the front left knee to straighten.
Thus, a kinesiological understanding of the mechanics of body movement, along with an understanding of how the structure works in terms of muscle groups and joint movement is helpful, to be able to skilfully combine the opposite tensions that create a postural dynamic that I was taught as part of the Rūpa or postural form that comprises Vīrabhadrāsana.
This is part of the performance dynamic around Vīrabhadrāsana and, in my studies I felt fortunate to be working with the viewpoint of a structural engineer, inherent within the early training of Desikachar, combined with the viewpoint of an energetic engineer inherent within the Āsana teachings of Krishnamacharya.
A further post will consider the question of Pratikriyā Bhāvana for Vīrabhadrāsana from the viewpoint of the trunk and upper part of the body. Though both of these posts will only look at Vīrabhadrāsana from the Annamaya or structural viewpoint.
Considering Vīrabhadrāsana from the viewpoint of Prāṇamaya or an energetic perspective is a topic for consideration within a different framework, such as the Lakṣana or the systemic characteristics inherent within each Āsana.