It is important to find the deeper intrinsic back muscles to do the action of spinal extension in this pose. Using the latissimus dorsi and other more superficial muscles will affect the scapulae and rib cage and interfere with breathing by inhibiting the movement of the ribs.

In cobra, the serratus anterior is active to maintain a neutral position of the scapulae against the push of the arms. When the arms push, the shoulder doesn’t elevate, but the spine is lifted.

The latissimus dorsi are not helpful as extensors of the spine, because they create flexion of the upper back and internal rotation in the arms.

Weakness in the pronators of the forearm, or tightness in the supinators (or interosseous membrane), will make the elbows flare out to the side and will affect both the elbow and shoulder joints. The forearms should stay parallel to each other for the best alignment of action through the arms into the spine.