For every inch the head moves forward, it effectively gains ten pounds in weight because of the increased strain on the muscles of the neck and upper back. The suboccipital muscles, just below the base of the skull, must contract even further to lift the head up to face forward instead of looking down at the ground. Pain can result simply from all of these muscles being chronically contracted, and in addition, disc problems and nerve pain may develop from the increased compression of the cervical spine.
Hyperkyphosis can also cause back pain. When the abdominals contract and the weight of the head and ribcage are pulled in front of our center of gravity, we quite literally will fall forward if we don’t do something to balance ourselves out. So as the abdominals gradually become habitually contracted, the back muscles must work harder and harder to keep us upright in gravity. A person with hyperkyphosis may complain only of a sore back, but all attempts to treat the back muscles directly will have little effect until the underlying cause—the habitual abdominal contraction—is addressed.
In addition to causing pain and cervical disc degeneration, chronically contracted abdominals have negative effects on many other functions of the body. Tight abdominals limit the ability to take a full breath, which demands that the diaphragm be able to contract downward and push the contents of the abdomen forward. If the abdominals are tight, this action cannot occur and breathing becomes shallow and strained. Chronic tightness and compression in the front of the body also puts pressure on all the internal organs, contributing to high blood pressure, digestive problems, frequent urination, constipation and impotence.
The abdominal muscles are the strongest and most central muscles acting in the withdrawal response. However, habitual contraction of the internal rotators and flexor muscles of the extremities can cause health problems as well. The withdrawal response contracts the inner thigh muscles, rotating the thighs inward; this places stress on the knees and ankles and makes the arches of the feet collapse. Hip flexors, quadriceps and hamstring muscles become tight and sore from holding the body in a flexed position. Headaches, teeth grinding, TMJ disorders, and bruxism (ringing in the ears) can develop due to constant contraction of the neck and jaw muscles.
How and Why We Habituate the Withdrawal Response
The effects of the withdrawal response tend to be more obvious in the elderly, simply because they have been alive longer and have had more exposure to stress. But there are two important things to note here.
One, it is not inevitable that we will develop rounded posture as we age. The way that we perceive and cope with stress throughout our lives determines how the systems of our body react. Learning how to deal with stress in a constructive way can prevent you from automatically triggering your withdrawal response and suffering the negative physical effects.