Using the latissimus dorsi to help internally rotate and extend the arms will interfere with the flexion of the spine because the latissimus dorsi are also spinal extensors.

This pose has the potential of directing too much force into the spine, sacroiliac joint, and, with the arms bound in this position, the front of the shoulder joint. The subscapularis is working both internally to rotate the humerus and protect the joint from protraction.

The more freedom there is in the scapulae gliding on the rib cage, the less force will be directed into the glenomumerial joint and its capsule.

The bound position of the legs behind the skull and cervical spine creates potential stress in this area, too— either overstretching the back of the neck or overworking the muscles against the push of the legs.

If there isn’t enough mobility in the rest of the spine, the cervical spine can be overflexed to get legs in position. This should be avoided.