by Dennis Zacharkow, PT
For optimal standing and seated postures, acupuncturist Gokhale (2008) advocates contracting the upper abdominal muscles "to pull the front of the rib cage downward and inward." She considers this maneuver difficult to learn.
According to this author (Dennis Zacharkow, originator of sacral-lower thoracic support and YogaBack™ inventor), anchoring the rib cage is difficult to learn because it is not only unnatural; the concept lacks any scientific basis from the functional anatomy of the respiratory and abdominal muscles.
Activation of the upper abdominals (upper rectus abdominis and medial fibers of the obliques) inhibits the elongation reflex of the trunk. It is the lower abdominals that are intimately connected with the elongation reflex (Rathbone, 1934). The lower abdominals include the lower fibers of the transversus abdominis, the lower anterior fibers of the internal obliques, and the lower (lateral) fibers of the external obliques. The upper abdominal muscles, primarily the upper rectus abdominis, are grouped with the flexors of the body (Rathbone, 1934).
For example, in the slumped, fatigue standing posture (sway back posture) with a leaning backwards of the upper trunk, activity in the erector spinae is significantly reduced, and is replaced by much greater activity in the upper rectus abdominis, as the head and upper back are brought forward to retain balance (Klausen and Rasmussen, 1968; O'Sullivan et al., 2002). (See Figure 1.) In this posture, the angulation of the ribs is more nearly vertical, with less depth and fullness in the lower rib region.
In elongated standing, the lower abdominal wall is flat, but the upper abdominal wall is rounded (Goldthwait, 1915; Rathbone, 1944). However, the upper abdomen is often constricted by overdevelopment of the upper rectus abdominis (Drew, 1945). The forced flattening of the upper abdomen restricts the free functioning of the diaphragm (Frost, 1938). When the diaphragm contracts and descends with inspiration, the upper abdominal wall must relax (Rathbone, 1944).
Pulling the front of the rib cage downward and inward as advocated by Gokhale (2008) obstructs the healthy dynamics of respiration, speech, and singing.
This normal movement of the diaphragm and ribs on inspiration is interfered with by actively pulling the front of the rib cage downward and inward. As a result, the increase in the vertical and transverse diameters of the thoracic cavity are restricted, thereby reducing inspiratory airflow (DeTroyer and Estenne, 1988).
In a study of opera singers by Watson and Hixon (1985), during singing the rib cage was always found to be maintained in a more expanded state. When inspiration was called for during speaking activities, the diaphragm descended against the resistance from the lower abdominals to expand the rib cage (Watson and Hixon, 1985).
In conclusion, pulling the front of the rib cage downward and inward as advocated by Gokhale (2008) obstructs the healthy dynamics of respiration, speech, singing, and an elongated posture.
In direction opposition to anchoring the rib cage is the YogaBack Concept of Sacral and Lower Thoracic Support. YogaBack's elongated posture promotes proper activation of the deep lower abdominals, and a high diaphragmatic position at the start of inspiration. This improves the diaphragm's ability to lift the lower ribs and rotate them outward, thereby expanding the lower rib cage for optimal inspiratory air flow.
The YogaBack Posture also results in a relaxation and lengthening of the upper rectus abdominis, a muscle that plays no part in either inspiration or the elongation reflex of the trunk (Austin and Ausubel, 1992).
The more time spent driving or sitting in YogaBack's elongated posture, the greater the carry-over of YogaBack's healthier respiratory dynamics into standing posture and activities.
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