In this pose, the scapulae are adducted and slightly upwardly rotated; without the levering action of the arms, this calls on the muscles that move the scapulae action. If the scapulae are not maintained in adduction, the weight of the body falls into the spine; if the scapulae do not upwardly rotate, the arms are challenged in reaching to the knees. The scapulae are positioned in neutral rotation as they extend to the knees, but the action that gets them there is upward rotation, as they come from the downward rotation of Sarvangasana.

The upper fibers of the psoas major and abdominal muscles are very strongly engaged here to maintain the spinal flexion in the thoracic spine. In addition, more lumbar flexion occurs to bring the legs farther overhead and counterbalance the pull of gravity. Reducing the tendency toward lumbar flexion makes the spinal flexors work much harder eccentrically—against the body weight’s tendency to roll down the floor.

In this balancing act between spinal flexors and extensors, imbalances that are usually imperceptible show-up, because the arms aren’t available to leverage symmetry. When these torques appear, they make this pose that much more challenging to balance.