By Barbara A. Brehm, Ed.D.

Most of us probably received our first posture advice at a very young age, perhaps when a well-meaning relative like Aunt Betty poked us in the back and admonished us to “stand up straight.” Since children don't think grown-ups “know anything,” many of us straightened up momentarily, and then ignored the irrelevant remark.

But now some of us have found out for ourselves how much better we look and feel when we pay attention to how we sit, stand and move. And others of us are in rehabilitation programs for back, neck and shoulder problems that have resulted at least partly from our accumulated years of slouching over desks, computers, children and steering wheels. Good back health, as well as a confident appearance, come with good posture. Aunt Betty was right after all.

What is good posture?

Our primary opponent in the good posture game is gravity. Gravity is always our partner, as we sit, stand or move about. The muscles of our neck. For example, must exert enough force to lift and balance the head, which, in an adult, weighs about 10 to 12 pounds. Good posture results when our muscles maintain our skeletal frame in the best possible balance, a balance that places the least possible amount of stress on our joints. A person with good posture seems to make light of gravity.

In general, our posture goal, whether sitting, standing, lifting or dancing, is to maintain the normal shape of the spine. The spine has a slight forward curve in the lower back, and a slight backward curve in the upper back. Injury is more likely to result when these curves are exaggerated or removed. For example when lifting a heavy object like a barbell from the floor, the lifter should try to lift “with the legs” by keeping the back long , and never lift with a rounded back.

For good standing posture, the center of the head, shoulders and hips should fall in a line when viewed from the side. The most common posture problems are rounded shoulders, a forward head (chin jutting forward), a protruding abdomen and swayback (an exaggerated lower back curve). It's not uncommon for all four to occur together.

When sitting, your back should have the same gentle curves as it does when standing. Slouching places pressure on the lower back that is 10 to I5 times greater than that placed on the joints when you're lying down.

Ideally, good posture results from a “natural” skeletal balance maintained with a minimal amount of muscular contraction. But if you have practiced slouching for many years, good posture will feel anything but natural, and it will take some getting used to.

Posture and fitness

Physical fitness is essential for good posture. Those antigravity muscles must be strong and flexible to maintain skeletal balance. The most important posture muscles include the following:

Abdominal muscles

Inadequate abdominal-muscle strength allows the pelvis to tilt forward, creating an exaggerated lower-back curve. Thle large, strong muscle group can be strengthened with weight training and calisthenics.

Back muscles

These muscles need to be strong and flexible, so both strengthening and stretching exercises are important. Upper-back muscles involve the shoulder and neck, which are especially vulnerable to tension produced by poor daily posture. Lower-back muscles may also become tight unless regularly stretched. Over time, some types of exercise (such as jogging) can decrease flexibility in this critical area unless stretching exercises are performed regularly.

Leg muscles

Both the hip flexors (which pull the leg up toward your chest) and the hamstrings (back of the thigh) are important for a balanced posture. Inflexibility in these groups can pull the pelvis out of alignment. Strength in these groups is important for good antigravity support when standing.

Fitness is also vital for weight control. Excess weight around the middle can put additional stress on the posture muscles of the lower back. Osteoporosis, a loss of bone mineral, may cause a rounded back posture in later life. Exercise may help slow this loss of bone mass. (Many other factors influence this disease as well.)

While posture-muscle fitness is essential for good posture, most people find that good posture requires more than physical fitness. It also requires knowledge of body mechanics and daily practice. Sitting in chairs that reinforce good alignment, car seats that support the lower back, and a little extra effort to lengthen the back while standing and walking help prevent habitual slouching that can lead to future orthopedic problems.