I also say with backbends, you have to be cautiously bold. Not carelessly bold. You have to descend to the dictation of the spine. You cannot command from the brain to do the poses. As you play with a child, guarding the child from injuries, similarly you have to play in backbends, guarding your spine.
B.K.S. IyengarThe conjunction of effort, concentration and balance in asana forces us to live intensely in the present moment, a rare experience in modern life.
B.K.S. Iyengar