The benefits of improving posture are well-known and studied. For example, according to A.I. Kapandji in the Physiology of the Joints, for every inch your head moves forward, it gains 10 pounds in weight, as far the muscles in your upper back and neck are concerned, because they have to work that much harder to keep the head from dropping. Additionally, Rene Cailliet, MD, a medical author and former director of the Department of Physical Medicine and Rehabilitation at the University of Southern California stated that head forward posture can add up to 30 pounds of abnormal leverage on the cervical spine, which can pull the entire spine out of alignment. This same head forward posture may result in the loss of 30% of vital lung capacity.