The challenge of yoga is to go beyond our limits - within reason. We continually expand the frame of the mind by using the canvas of the body. It is as if you were to stretch a canvas more and create a larger surface for a painting. But we must respect the present form of our body. If you pull too much at once, we will rip the canvas. If the practice of today damages the practice of tomorrow, it is not correct practice.
B.K.S. IyengarPeople say that steadiness of mind is an end; no, it is a beginning. I am there; I can explain everything up to that point. Then I struggle to discover what comes after, so this steadiness is not an end, it is the beginning and the instrument.
B.K.S. Iyengar