"Think of the blacksmith. If he wants to hammer a hunk of metal into a beautiful sword, the first thing he has to do is put it in the fire. When the iron is glowing red and completely soft, he brings it out and slowly starts hammering it and shaping it into a strong, resilient, razor-sharp blade.... It's the same with yoga. Yoga changes the construction of the body from the inside out.... so before you change it, you have to heat it up to soften it, because a warm body is a flexible body."