Or Rodney Yee on Oprah, puffing his pecs while saluting the sun.

Or the nude midnight yoga class in Amy Tan's latest novel, where the guy on the next mat has exquisitely buff, umm, toes.

For me, yoga is all about sagging knees.

Decades of long-distance running had left me with a stiff back, shooting pains down my right leg, a $400 bill for custom orthotics and a month-long wait to see a physical therapist. When I finally got an appointment, the PT stood me in front of a mirror and pointed to my knees, which drooped like double chins on their day off. "There's your problem," she said.

The knee bone is connected to the thigh ... connected to the hip ... connected to the abdominals ... connected to the spine.

I needed to stretch and strengthen all those muscles. So, reluctantly, I unlaced my Brooks Addiction III running shoes and stepped, barefoot, onto a yoga mat.

For awhile I'd been intrigued by but resistant to yoga because it seemed so, well, extreme. Since I have a tendency to plunge into endeavors big time (couldn't just jog, had to run marathons; couldn't just paddle, had to build a kayak; couldn't merely take aerobics, had to lead classes in a refugee camp), I was afraid of winding up as a vegan Dharma bum wearing drawstring tie-dyed pants, ankles laced behind my neck.

But I couldn't sit without pain, let alone touch my toes, so I figured with yoga, I'd be safe.

The first class met in a tiny second-floor studio across from a used-car lot at 7:30 on Saturday mornings. It was deemed "Gentle" and designed for the elderly, infirm, injured and uncoordinated. I had expected fellow novices to be accident victims recovering from motorcycle spills and spunky old ladies fighting osteoporosis. Usually, given the early hour, I was the only one to show.

"Pull up your knees!" my instructor urged, gently, of course.

Yoga instructors, like librarians, are among the most accepting, sensitive and helpful bunch of people you'll ever meet. The best teachers support and adjust your poses, or asanas, in a way that allows you to maintain balance on your own. They sometimes scold, but only nicely, and never push you so far that you strain muscles or fall over. (Think Mary Poppins with incense.)

Most instructors avoid asking about work or family during class because the idea is to leave your worldly cares outside the yoga studio so you can focus your breath on the moment.

Wow. Did I just write, "focus your breath on the moment"?

The yoga asanas are part of a 5,000-year-old Indian tradition that branches into meditation, philosophy, mantras, prayer and awareness of the sacred and sensual. Breathing is practiced at many levels. The school of yoga best known in America is Hatha yoga, or the yoga of activity.

In physical yoga, even seemingly simple poses take mighty amounts of concentration and strength. Take Tree Pose, which is basically standing straight with lifted arms. You root your feet into the floor, align your toes, balance your weight evenly side-to-side, hands reaching for the sky, navel toward spine, shoulders dropped, knee caps, of course, pulled up. Remember to breathe! If your mind lingers on the parking ticket you need to pay - you'll topple over.

On the other hand, it's not good to throw yourself too hard at a pose. This was a new, and revelatory, concept for me. "When your body is ready, it will let you know," one instructor told me as I struggled.

Don't force your hamstrings to stretch in Downward Dog, she said. Instead, exhale deeply and ask them to open. Gradually, they will release, without searing pain. She was right. My muscles tingled warmly, like a massage from the inside out. Ahhh. The joy of living in the moment.

In "Yoga: The Iyengar Way," the authors write, One of the principles of Yoga is not to seek the fruit of actions. This practice should be for its own sake, without regard to success or failure. This is the way to gain equanimity.

That philosophy swirls through all types of yoga, but the poses themselves are interpreted and taught in as many ways as a Shakespeare play.

Ashtanga yoga focuses on jumping and breath control to create power. (Popular in Greenwich Village and with Gwyneth Paltrow.) Bikram yoga is a set routine of poses practiced in a steamy 100-degree room, the better to stretch and open muscles. Viniyoga, a flowing yoga, integrates breathing into poses, much like dance. Iyengar yoga uses props such as blocks, straps and blankets to help the unflexible reach the floor. (My instructor teaches a flowing form of Iyengar yoga.)

Slowly, I've progressed from the class of walking wounded to one in which we stand on our heads, bend like bamboo and twist like bean vines around a summer pole. I still need help to do handstands, but I know someday it will come on its own. Meanwhile, I let my legs flail - with equanimity.

During the five years I've been practicing, the number of Americans to join the barefoot yoga ranks has doubled to an estimated 15 million. The Seattle Metro phone book now lists 43 yoga studios. "One on every corner," jokes my current instructor at the Yoga Tree in Fremont, Emily Navar.

"People are getting the totality of it," she says. "It is a really complete system. It doesn't just build strength. There's stretch, flexibility, stamina and balance, and those spill over into mental strength, stamina, balance and calmness."

My favorite part of yoga class is at the end, savasana or corpse pose, when you lie on your mat, eyes closed, something like a kindergartner resting during naptime. If you breath deeply enough, everything falls away, everyone is the same, supermodel celebrities, yoga putzes, all.

Paula Bock is a Pacific Northwest staff writer. Paul Schmid is a Seattle Times news artist.