Asana is a steady, comfortable posture.
Asana are the postures associated with yoga, such as downward facing dog, warrior I, and child’s pose. While most people think of these postures when they think of yoga, Patanjali only refers to asana in three of the yoga sutras.
Asana is defined by Patanjali in Yoga Sutra 2.46 as “a steady comfortable posture.” This sutra refers to the ability to hold a posture for meditation without discomfort. Patanjali goes on to direct that to master such a posture, one must focus on the infinite and lessen the tendency for restlessness. Yoga Sutra 2.47. This suggests that the purpose of asana is not just a physical one, but also a mental one.
While asana can provide physical benefits, the primary purpose of asana under yoga traditions is to prepare the body and mind for meditation. The asana calms the restless body, and prepares the practitioner to focus the mind. When practiced in conjunction with the other limbs of yoga, asana allows a practitioner to open himself and his body to enlightenment.
But that’s not the only reason to practice asana.
This is not to say that enlightenment and the yogic path are the only reasons to practice asana. The health benefits such as strength, flexibility, balance, and stamina are important to feeling good and moving energetically throughout our lives. Further, many practitioners simply enjoy how they feel performing the postures, which is possibly the most important aspect of any physical or mental practice.
So, enjoy your asana practice, practice it consistently, and practice with enthusiasm. As you do, the physical and mental benefits will make themselves known to you.