"It's rubbish," said Neil Schapera, an expert in body positioning and movement. "That might be someone's idea of good posture, but it's a dysfunctional way to hold one's body."

For starters, relax. Tightening unnecessary muscles only makes tension habitual.

According to Schapera, posture that's truly good for you will: Free your neck, so that it isn't pulling your head down or backwards; loosen your belly for better breathing; enable you to stand with feet far enough apart to distribute weight equally between them -- knees at ease.

You're there when your back is long, your body is ready for movement and that achy, cramped feeling has disappeared. It's easier to describe than accomplish.

Back pain is one of the most common maladies of modern life. According to the "Oxford Medical Companion," four out of five adults suffer from it at some time, many experiencing considerable discomfort.

Good posture won't cure everything. But it can prompt improvements that ripple through the body.

"Posture isn't just about appearance," Schapera said. "It's an expression of an underlying functional quality."

Schapera and his wife, Vivien, are instructors of the Alexander Technique, a program aimed at correcting posture and maximizing physical function. They help people reverse years of misuse, which may be compressing the spine or squeezing organs, causing dysfunction and pain.

But for women, especially, attaining good posture means defying at least two cultural ideals. The first has to do with the feet. It's considered coarse -- "unladylike" -- for females to stand with feet about shoulder-width apart. But with feet held close balance is often impaired.

Another cultural ideal champions a flat stomach. But the belly needs to be released in order to breathe easily and deeply, Schapera said. "People say to me, 'But if I let go, my stomach will stick out.' Well, too bad, that's the reality of it. If your stomach sticks out, maybe you should address it with exercise or diet. But sucking in the gut is a whitewashing job. All it does is make you tense."

Schapera, who holds degrees in food science and psychology, retrained to become an instructor of the Alexander Technique. He works privately and with theater majors at the University of Cincinnati's College Conservatory of Music.

Teala Church of Cincinnati came for lessons at her doctor's suggestion. A car accident had left her with a protruding disk and chronic neck pain. Her health insurance for physical therapy was running out.

Although insurance coverage for the Alexander Technique also disappeared, she opted to return for weekly lessons because it involved her entire body. She realized just how many muscles she was using unnecessarily, which intensified her pain.

Six years later she's still getting lessons. The pain persists, though it is greatly diminished, she said, and her life is flourishing.

When people ask her how she can afford to take lessons, she fires back, "How can I not afford it? I wouldn't give it up for anything."

The Alexander Technique takes its name from Matthias Alexander, a Shakespearian stage actor from Australia. At mid-career in the late 19th century he began losing his voice. Various doctors and consultants were unable to help him.

So Alexander set to work on himself. He noticed, while watching himself in mirrors, that in certain postures his voice faded. Some stances caused him to silence his larynx. When he developed new postures his voice came back.

He then analyzed other people and developed a system of sitting, standing and moving that involves smooth, efficient muscle use.

Many of the people who sought assistance from Alexander were performers. That's still true, since proficiency on a musical instrument or on a stage often forces the body into challenging positions that cause long-term pain.

Schapera began his three-year training to become a teacher in the mid-'80s in South Africa. "It's clearly the best thing I've ever done," he said.

For the past decade he's been teaching people things as simple as how to sit in a chair, how to hold the head, how to use as few muscles as possible to complete any task.

These mundane accomplishments are not as simple as they sound. The problem, he explained, is that humans tend to forget good posture and natural patterns of movement. We acquire habits of misuse as early as the age of 8.

"These habits typically manifest as a stiffness, a loss of buoyancy or poor coordination in the use of the joints," he said.

The two most common problems are slumping or stiffness. When people sit with a slumped -- or collapsed spine -- it is curled under, compressing the vertebrae. But a person who is stiff (and often arched) has held on to tension, year after year. This too puts undue pressure on the vertebrae.

Poor posture is almost at epidemic proportions. Schapera sees it everywhere. "Going to the mall is a nightmarish experience," he said. "I see people using themselves so poorly, so inefficiently. It's just a question of time before they experience symptoms like back ache. It saddens me to see that when it's something they could learn fairly easily to change."