Patanjali talks about the qualities that we would like to see in both our asana, and our pranayama. Our asana should be comfortable, and steady. Our breath should be long and subtle.
Sthira sukham asanam
Sthira-from Stha-to stand/stay. Means stable, firm, alert, steady
Sukha=light, pleasant, comfortable, soft, agreeable
‘Steady and comfortable should be the posture’ – Sw. Satyananda
‘Asana must have the dual qualities of alertness and relaxation’ – Desikachar
Sutra 1.50 tells us that there are three parts to the breath-inhalation, exhalation, and suspension of breath. There are various ways of changing the breath using different ratios of these three for periods of time. Patanjali describes the quality of the breath that we want as dirgha sukshma-long and subtle.
Further, he describes how to become masters in asana practice! We bring in awareness of the breath.
Prayatna shaithilya ananta samapattibhyam
Yatna – intelligent , complete, whole.
Shaithilya – looseness
Ananta – symbolically, the serpent from the Puranas that Lord Vishnu rests upon-also means endless-in this context means breath
Samapattibhyam – by meditation
‘By loosening of effort and by meditation on the serpent ananta, asana is mastered’ – Sw. Satyananda
‘These qualities can be achieved by recognising and observing the reactions of the body and the breath to the various postures that comprise asana practice. Once known, these reactions can be controlled step by step.’ – Desikachar
The serpent ananta is a symbol for the infinite-in this sutra, it refers to prana, or more specifically, the vehicle of prana, the breath. Patanjali is telling us that to master asana, one must be closely aware of the breath
So-in asana, the body should be steady and comfortable. The mind should maintain an awareness of the breath. And the breath should be long and subtle. One can see how these things are interdependent-if the body is not comfortable and steady (if we are straining, in other words) then the breath will not be long a subtle-and the mind will not be able to focus on the breath. So having a smooth and steady breath, and a mental awareness of the breath is also a guide to practice-if the breath becomes disturbed, or if our mind loses contact with the breath, we have lost the qualities that allow us to master asana.