Ardha navasana is a truly difficult pose because once you begin to lean backwards the psoas muscle no longer helps to support the extension of the spine. And the full version of ardha navasana isn’t really available if you don’t have latissimus dorsi that want to get in the game, as you can see at the end of the video above. Once I put my hands behind my head and try to lean backwards into ardha navasana I am basically done.
That said there is a lot of information to be gathered from the transition as I do it, keeping my arms forward, before I try putting my hands behind my head.
Navasana, where we try to maintain a long spine and extended rectus abdominis, allows us to maintain a natural curve in the lower back. When we move backwards towards ardha navasana the body is moving more towards a cow like position with a posterior pelvis. If we are in navasana with a curve in the lumbar spine the psoas major is toned, and the erector muscles of the spine engage tapping into the inherent power of an extended spine.
When we begin to lean backwards and lose the lumbar curve we also lose the engagement of the psoas and spinal extensors so the abdominal muscles need to truly kick in to support the pose. I don’t actually hear the change in my voice in the video in the way I perceive it in the moment but I hope that you can see how much more effort I have to put into maintaining stability when I go backwards into ardha navasana, and then how relatively effortless navasana becomes when I pull back up.
As much as I love the strength building aspect of my asana practice, the experiential piece of feeling what does and doesn’t work while I am at it, is equally important. Navasana and ardha navasana are very difficult poses that are worth the effort to learn for the value of both building strength and body learning.