The Central Role of Head Balance in Upright Posture
In our last post, we announced the launch of The Zentralapparat Project—a research initiative aimed at studying the relationship of the head and trunk and its central role in organizing movement and action.
Anyone who has studied the subject of posture and balance is aware that the balance of the head on the spine is critical to upright posture. To maintain upright posture, muscles of the neck and back must act upon the skull and spine, maintaining the support of the head and the length of the spine. If this relationship is disturbed, as when we pull the head back or go into a postural slump, these muscles cannot discharge their normal function, and posture becomes disturbed.
Though one might assume that the skull is evenly centered on top of the spine, this is not the case. In fact, the skull has more weight in front than in back, so that its natural tendency is to nod forward at the atlanto-occipital joint, the point where the skull articulates with the top vertebra of the spine, or atlas. (See the illustration to the left)
This forward weight exerts stretch on the extensor muscles at the back of the neck, which counteracts the tendency of these muscles to shorten or contract, reduces downward pressure of the skull on the spine, and has the effect of actually lengthening the spine. (See the illustration to the right)
In this, our first study, we will examine head balance and its relationship to the spine, and the central role this relationship plays in upright posture. In describing this system, it is not our intention to advance a particular method for correcting or assessing posture but, more fundamentally, to understand how posture works. Studies on the Alexander Technique have focused primarily on the effects of receiving lessons or practicing elements of Alexander’s method. Such an approach might demonstrate that the method is effective in improving posture or movement patterns, but it cannot demonstrate the principles underlying how posture works, or address the fundamental question of whether and why the head/trunk relationship plays a central role in posture. Our goal is to understand the principles underlying posture and, in this first study, to make sense of the central role of head balance in organizing upright posture.