Unsupported (no-arm) Shoulderstand (Candle Pose)
In this pose, the scapulae are elevated, adducted, and slightly upwardly rotated; without the levering action of the arms, this calls on the muscles that move the scapulae on the rib cage to work strongly. It might feel like contradictory actions to perform adduction, elevation, and upward rotation simultaneously. It is indeed possible, and in fact necessary in this pose in order to protect the neck. 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 being alongside the body. 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 niralamba 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. Resisting this tendency toward lumbar flexion makes the spinal flexors work much harder eccentrically, against the body weight’s tendency to roll down to 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.