Backbends are to be felt more than expressed. The other postures can be expressed and then felt. Like in meditation each person has to feel backbends.
B.K.S. IyengarThe physical body is not only a temple for our soul, but the means by which we embark on the inward journey toward the core.
B.K.S. IyengarWhenever asana is done mechanically from the front brain, the action is felt only on the peripheral body, and there is no inner sensation, there is no luminous inner light. If the asana is done with continual reference to the back of the brain, there is a reaction to each action, and there is sensitivity. Then life is not only dynamic, but it is also electrified with life force.
B.K.S. Iyengar