All parts of the torso can contribute to this twist— both right and left sides of the front and both right and left side of the back, at different layers of muscle. The spine will have the most balanced rotation when in neutral extension. Flexion in the lumbar spine will jeopardize the stability of the lumbar vertebrae and disks, and too much extension will tend to lock the thoracic spine into place, inhibiting axial rotation there.

The twisting action of this pose can be “faked” by over mobilizing the scapulae and allowing them to adduct (the back one) and abduct (the front one ) excessively. When this happens there is the appearance of rotation, but not much actual movement in the spine. Because the shoulder girdle has more range of motion in this direction than the thoracic structures have, it is frequently a more intense spine twist when the arms are placed in a simple, nonbound position. It is, therefore, preferable to enter this pose without using the arms, so the maximum safe action is found in the spine. The leverage of the arms comes in last, as a deepening, stabilizing (not mobilizing) action. Overuse of the arms can direct too much force into vulnerable parts of the spine — particularly T11-T12.

Another factor that contributes to the intensity of the spinal twisting action of this pose is the arrangement of the legs, which greatly limits rotational movements in the pelvis— and in fact, counter rotates the pelvis away from the rotation of the spine.