Asana (Steady Posture — Yoga Sutras)
Asana in Patanjali's original definition is the mastery of a steady, pleasant seated posture for meditation — far more about the quality of presence in the posture than its physical form.
Patanjali's three sutras on asana (2.46-2.48) are deceptively simple. The entire physical yoga tradition rests on these twelve words: 'sthira sukham asanam' (a posture is that which is steady and pleasant), 'prayatna shaithilya ananta samapattibhyam' (through relaxation of effort and absorption in the infinite), and 'tatah dvandva anabhighatah' (from this, disturbance by the pairs of opposites ceases). No specific postures are named; no alignment cues are given; no sequences are prescribed. Patanjali's asana is an internal quality — the capacity to sit with complete stability and complete ease simultaneously — that can potentially be cultivated in any stable seated position. The explosion of physical asana traditions (Hatha Yoga) that developed after Patanjali's time represents a legitimate elaboration of this single principle.
Posture is that which is steady and pleasant.
Physical therapist and yoga researcher Matthew Taylor documents that the most therapeutically effective yoga posture practice consistently reflects Patanjali's sthira/sukha balance — the dual cultivation of stability and ease — rather than the extreme range of motion prioritized in performance-oriented yoga.
Yoga Sutras of Patanjali