

Sunday, January 13, 2008

How Your Back Works

The Healthy Back is a Back in Balance

The human back is a marvelously evolved structure, the supportive center of every imaginable movement. We can see that in the way young children roll and tumble as they play, and in the way champion athletes and master practitioners of yoga, Pilates, tai chi, dance, and other movement disciplines have trained their bodies to perform.

The free and easy movement of childhood is everyone’s birthright, but most of us have lost it by the time we are adults. That doesn’t have to happen. And if we do lose the joy of movement, we can almost always regain it.

One of the most important things to know about the low back is that a high level of pain does not necessarily indicate severe damage. The pain of a low back injury can be worse than a root canal without an anesthetic, but even the most painful injuries seldom pose any serious threat to the spine or brain. The vital parts of the body are simply too well protected for that, except in the most extreme cases. So don’t lose hope or fear the worst because the pain is bad. If you follow the pain-relief guidelines on pages xvii–xx and do the exercises in this book for fifteen minutes, three times a week, the odds of a full and lasting recovery are overwhelmingly in your favor.

The human back is so robust because of the way its intricately interwoven parts reinforce each other. The back’s function is to support balanced movement and posture and to protect the nerve bundles within the spinal cord. These nerves, the body’s information superhighway, carry electrical impulses to and from the brain, where the impulses are translated into sensations, images, emotions, and thoughts.

The back does its job with a hardy structure of bones, muscles, tendons, and ligaments. Layers of muscle—thirty-one muscles tie into the pelvis alone—wrap protectively around the spine, which makes a gentle S-curve from the neck to the tailbone, or coccyx. The spine has twenty-four vertebrae separated and cushioned by the intervertebral discs, which are shock absorbing, doughnut-shaped pads made up of a soft inner portion, the nucleus pulposus, and a hard outer portion, the annulus.

There are seven cervical, or neck, vertebrae (commonly referred to as C1-C7, counting from top to bottom); twelve thoracic, or chest vertebrae (T1-T12); and five lumbar, or lower back, vertebrae (L1-L5). If a physician or other caregiver diagnoses a low back problem located at disc levels L4-L5, for example, this means that the focal point of the injury is in the area of the fourth and fifth lumbar vertebrae and the disc sandwiched between them.

All of the vertebrae have small projections called facet joints that stabilize the spine and allow it to move in different planes.

Below the fifth lumbar vertebra is the sacrum, a triangular-shaped bone with five segments (S1-S5) that attach to the pelvis (or ilium) to form the sacroiliac joints. Together with the body’s core muscles, the back’s S-curve can gently dissipate the energy of harsh impacts or sudden, wrenching movements like a giant spring, and the fluid that fills the soft inner portion of the discs can absorb shocks better than any other known substance. That is, as long as we maintain them in good shape.

At birth the discs are 80% water. As we age, they gradually lose water, stiffen, and turn brittle. Nothing can entirely stop this natural aging process. But as I’ll explain in Chapter 4, proper back exercises can be a great age-fighter, dramatically retarding the discs’ loss of water and keeping us flexible and resilient.

To stay out of pain, the back has to stay in balance. All of its interlocking parts have to work in harmony. For example, the neuromuscular system works through paired muscles and muscle groups, like the biceps and triceps. The biceps lets you bend your arm, the triceps lets you extend it. Similarly, in the low back, the abdominals let you bend forward, whereas the paraspinal muscles let you extend straight and arch backward. If one muscle or muscle group is disproportionately stronger or weaker than its opposite number, the whole system will suffer.

As I mentioned in the introduction, one muscle imbalance that tends to be especially significant for low back pain is the poor flexion and reduced range of motion in the hips, which results from too much sitting in chairs. In Chapter 2, we’ll look more closely at how chair-sitting upsets the body’s natural balances and how we can restore them.

The back’s need for balance includes a balance of the body and the mind. In terms of the neuromuscular system, a relaxed, balanced posture depends on a host of tiny cells, called proprioceptors, that feed data on position and movement from the muscles, tendons, joints, and inner ear to the brain. To test how proprioception works, try this experiment: Stand on one leg with your arms extended straight out to the sides at shoulder height. You’ll probably notice a little wobble, but nothing you can’t control. Now increase the difficulty by closing your eyes. The wobble gets worse and before long you’ll have to open your eyes and put your foot down to regain your balance. Proprioception is what enables you to hold the position even briefly, and the better your proprioception the longer you’ll be able to hold it.

Proprioception underlies all of our body awareness. With good proprioception, we sense intuitively when our bodies are in proper alignment and we instinctively walk and move with good posture and balance. This helps the back by enabling the discs to breathe. Like the rest of the body, the discs depend on the circulatory system to bring them essential, nourishing oxygen. Blood vessels at their periphery are the final stage of this delivery system, so far as the discs are concerned.

Walking in balanced alignment with good posture pumps a steady, ample flow of oxygen to the discs with the rhythmic muscular contraction and expansion of every step. By contrast, our modern chair-bound lifestyles cramp the discs into a stressed position and starve them of oxygen for hours at a stretch. This not only weakens abdominal and back muscles and reduces hip flexion and range of motion, it also inevitably degrades our proprioception and body awareness. With this degraded proprioception—a condition that being overweight, out of shape, or a smoker can worsen—we walk and sit hunched over, straining our discs and back muscles with every movement without realizing it. As proprioception weakens, our brains lose the all-important ability to “see” ourselves accurately in space.

The mind’s role in low back pain naturally extends to other levels of awareness. Stressful life experiences that agitate our minds and burden us with excessive anxiety, guilt, and other difficult feelings have long been known to be linked with low back pain. And a low back injury can easily trigger a pain-depression cycle that blocks recovery. Over time, an unbalanced state of mind can contribute to low back pain as much as, or more than, any other factor. The bottom line is that if we go too far off-kilter in any area where we need balance—physically, mentally, and/or emotionally—we face an increased risk of low back pain.

All things considered, there is no doubt that balance is the hallmark of a healthy back. When your back is truly in balance, all sorts of tasks become easier to do and life becomes physically, mentally, and emotionally less stressful. Our stress doesn’t disappear by any means, but we become energetic and resilient enough to handle it and thrive. With that in mind, let’s look at the mechanisms of low back pain and the specific ways in which the Back Rx program counteracts them, especially the healing power of doing the Back Rx exercises with proper breath control.

Excerpted from

by Vijay Vad
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