That's the beauty of backbends. Emotionally we can never be disturbed, for the emotional centre becomes an extrovert. When you do Viparita Dandasana, your head looks backwards, but your conscious mind stretches everywhere. Study by observing how the mind gets regulated. You not only know the freedom in the spine, but also the freedom in the spirit.
B.K.S. IyengarWhy should you practice Yoga? To kindle the divine fire within yourself. Everyone has a dormant spark of divinity in him which has to be fanned into flame.
B.K.S. IyengarNot all practitioners can jump to that highest level. They have to climb, step by step from the physical sphere to reach the spiritual sphere. If it is treated as exercise it is not the fault of yoga but of the practitioners.
B.K.S. Iyengar