This is an important series of poses for spinal health, increasing flexibility and strength in the back and spinal muscles.
During a twist, the spine is activated and the flow of nutrients carried to the inter-vertebral disks rise. This action accelerates circulation to the spinal nerves, blood vessels and tissues. Also, as the torso twists, one side of the back and abdomen stretches while the other side contracts. While holding the twist, by-products and toxins leave the organs. When the twist is released, fresh blood flows in, bringing with it oxygen and other building blocks for tissue healing.
Thus, we can say that twists have a strong influence not only on the spine but on total health and vitality.