In this subtle movement, the abdominal muscles contract, rolling the pelvis toward the shoulders and flattening the back against the floor.

The Pelvic Tilt
Are we talking posture, exercise or something for Valentine's Day?

CONSIDER the pelvic tilt.

Rarely has so small a movement that might do so much for so many been so underused - and so misunderstood.

"Pelvic tilt," for starters, can refer to two things: an exercise and an aspect of posture. In both cases it often comes up as an essential element in back health, with repercussions throughout the body, for everyone from golfers to weight lifters to dancers to nurses.

As it's often described, the most common pelvic-tilt exercise seems simple and straightforward enough, something along these lines:

• Lie on your back with your knees bent and feet flat on the floor and hip-width apart.

• Contract your abdominal muscles, pressing your lower back against the floor. Feel your pelvis tilt or rock toward your shoulders. Your pelvis and the bottom of your buttocks should come slightly off the floor.

This movement also can be done while on hands and knees (the common recommendation in pregnancy), sitting in a chair or standing, always tightening the abdomen, rocking the pelvis and pressing the back flat. The sitting and standing versions can be integrated into everyday posture.

From what I can tell, the usual thinking behind the need for pelvic tilts is that the muscles of the abdomen, low back, hip and/or buttocks have become weak, causing us to slip into stressful positions, such as standing with a swayed back.

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But it's not a given that everyone would benefit from doing pelvic tilts, said Lori Coleman-Brown, a physical therapist, Pilates trainer and co-director of The Pilates Studio in Seattle. Since the Pilates exercise system emphasizes stretching, strengthening and stabilizing the "core" or trunk muscles, she's seen more than her share of pelvic tilts.

"Genetically, some people have, for example, bigger thighs, or a bigger stomach, but those muscles and soft tissue are all on top of bones," she said, and it takes an experienced eye to see the underlying alignments. So someone who has been helped by pelvic tilts isn't necessarily doing a friend a favor by recommending them. "They don't know if it fits on them."

There was a trend a while back, Coleman-Brown said, holding that everyone should do a pelvic tilt before lifting something heavy. "I think some people got into trouble because they already were 'tucked.' " The debate to tuck or not to tuck continues in weight-lifting circles.

"Tuck" is one way to describe a posterior pelvic tilt, in which the abdominal muscles contract and the back flattens. A neutral pelvis, then, would be a stance with the low back's natural curve, and an anterior tilt one in the direction of a swayed back. There's also lateral tilt (from side to side), often seen when one leg is shorter than the other.

However, "The average person I don't think knows what those mean," said Coleman-Brown. Even if they do, the movement is subtle enough that it's easy to use the feet, legs or buttocks to flatten the back instead of the abdominals.

So Coleman-Brown keeps in her head dozens of ways of describing each movement: " 'Pull your stomach in to a tiny waist,' 'Navel to spine,' 'Tuck back,' 'Pretend you're Frankenstein' - it goes on and on."

After all, she said, "All postures are good, as long as you don't use one posture over and over again. But you have to use one that suits you, if you want to use it over and over."

Sometimes, when images and technical terms aren't helping, an old standby even works.

"I've found that that 'lift tall' helps to organize people," Coleman-Brown said, meaning it lets their bodies kind of fall into their own efficient shape. "Some misinterpret that and arch their back like a military posture. But the most basic thing is to just stand tall, the ol' book-on-your-head thing.

"And if it bugs you, don't do it."

Molly Martin is assistant editor of Pacific Northwest magazine.