Yoga loosens up large muscles, so they aren't stressing smaller muscles and bones resulting in injuries. It also loosens up joints and improves circulation, which is good for health.
The procedure is to go through a contortion which stretches the large muscles causing them to loosen up. As the largest muscles loosen up, the force shifts to smaller muscles. If the position is held too long, a small muscle could get injured.
So when muscles are real stiff, a position shou...