Backfield in Motion
There is good reason to develop strong rotators. They are important for moving and positioning the hip joint in daily activities and in standing poses. The primary action of the deep rotators is external rotation, and, like all muscles that are deep and close to a joint, they help to stabilize that joint. However, the piriformis is probably best known as a troublemaker, as it contracts and even spasms in association with low-back pain and may press on the sciatic nerve. This pressure can cause painful leg symptoms, including the shooting pain, deep aching, or even hot or icy sensations commonly called sciatica.
The gluteus maximus and the deep hip rotators are also responsible for horizontal abduction. This is different from standard hip abduction, which is what you do when you stand with your back against a wall and lift your leg straight out to the side. To experience horizontal abduction, stand on your right leg with your left hip and knee flexed up to 90 degrees each, as they'd be if you were sitting in a chair. Open the left leg out to the side so the left knee points to the left. This is the action that you'd perform to align the left knee over the left foot in Virabhadrasana II (Warrior Pose II) and in Parsvakonasana (Side Angle Pose).
But when both layers of buttock muscles are short and tight, they will pull the hip into external rotation, horizontal abduction, and extension, which means that internal rotation, horizontal adduction, and flexion will be limited. And that, in a nutshell, is what causes problems in forward bends and twists.
When you're sitting on the floor, tight buttock muscles, often in partnership with tight hamstrings, tend to tilt the pelvis backward, causing a slumped spine and reversing the normal lumbar curve, which can contribute to low-back strain and even disk injuries. This tendency to tilt the pelvis backward affects all sitting poses, including twists, cross-legged poses, and forward bends. In all these floor poses, the struggle to sit up can be eased by sitting on one or more folded blankets until you've had time to stretch the buttocks and hamstrings.!--page-->