Yoga asana is steady and confortable position
Patanjali's YogaSutras II, 46

Such posture should be attained by the relaxation 
of effort and by absorption in the infinite

P.Y.S. II, 47

From this, one is not afflicted by the dualities of the opposites

Yoga is one of the most extraordinary spiritual sciences that mankind has ever discovered. It's like a gem of great proportions, containing many facets whose light can illumine the whole of our lives with great meaning. Yogic methods include all the aspects of higher evolution in humanity: phisical postures, ethical disciplines, breath control, sensory methods, affirmations and visualisation, prayer and mantras, and complex meditative disciplines.
David Frawley

Gokarna yoga classes 2013