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.
Willpower is concrete, not ethereal. When you do something, you demonstrate your willpower, and it becomes all the easier to have the same power of will the next time.
While doing the postures, your mind should be in half-consciousn ess, which does not mean sleep. It means silence, emptiness, space, which can then be filled with an acute awareness of the sensations given by the posture. You watch yourself from inside. It is a full silence.
