Iyengar says that the only type of tension one should have in yoga is “extension.” Ultimately, we become calm in all the asanas. We learn to settle our nerves in the practice of stillness amongst intensity (be it psychical, mental or emotional, or most likely a combination of everything). Stress is stress, and in the asana we learn to adapt to otherwise stressful positions. The end result is that the nervous system begins to heal.
In class, through the stillness, I hear the distant voice of an instructor talk about quieting the mind, relaxing, and focusing on the breath. Breath is key to yoga. It is a path that leads to a doorway, of which behind lies complete balance of mind, body, and heart. Along the way, we practice balance within each asana. Starting with the breath, we still our mind. Then, extend into a posture.
Ultimately, what do we benefit from doing the asanas? Many of my instructors say strength, balance, and flexibility…yes, those are benefits. But, these are just icing on the cake. The end-game of a great yoga practice is a nervous system in homeostasis. Meaning that everything is working properly, like a finely tuned automobile or jet airplane.