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. IyengarYou have to create love and affection for your body, for what it can do for you. Love must be incarnated in the smallest pore of the skin, the smallest cell of the body to make them intelligent so they can collaborate with all the other ones, in the big republic of the body. This love must radiate from you to others.
B.K.S. Iyengar