Choosing a hatha yoga class is far from easy. Names like Iyengar, Ashtanga, and Anusara can baffle even the brightest and most savvy of health-oriented consumers. And if you assume that yoga is all about meditation and relaxation, you're in for a big surprise. Chances are good you'll quickly work up a sweat in many yoga classes offered nationwide.

Know Your Yoga
Still confused? Check out this chart of hatha yoga styles.
yoga chart
The confusion begins with the use of the word "hatha," the most popular type of yoga in America. Simply put, hatha is the umbrella term for physical yoga. Styles such as Iyengar, Ashtanga, and Anusara fall under that umbrella, with each school incorporating several basics: breathing, holding a posture, stretching, and meditating.

"Some teachers emphasize the spirituality aspect of yoga; others may not bring it into play," says John Schumacher, the founder of the Bethesda, Md.-based Unity Woods Yoga Center, the country's largest Iyengar school.

What differentiates a yoga style is not necessarily that new positions have been created but how the mostly traditional postures are taught or sequenced, says David Ingalls, founder of Washington, D.C.'s Ashtanga Yoga Center. "One style may use postures slowly, another one quickly. One style might emphasize alignment; another the way you move from posture to posture," he says.

According to Larry Payne, author of "Yoga for Dummies" (IDG Books Worldwide Inc., 1999), "Some styles are safer for beginners, particularly older beginners. Ashtanga is the physical top of the line and is definitely for those under 35--max 40--unless they are professional athletes or dancers." Be careful to find the correct yoga style for your physical level, because choosing the wrong type can lead to injuries, he says.

To find a style that fits you, try a class and interview the teacher. Be candid about your physical problems, such as back pain or chronic injuries. Also verify a teacher's training. The Yoga Alliance in West Reading, Penn., sponsors a website with a state-by-state breakdown of its members, all of whom are required to have at least 200 hours of practice. In general, yoga classes run 90 minutes at studios, an hour at health clubs. Studios are the better bets to find teachers trained in a particular technique.

Here is a description of some popular yoga styles taught around the country:

Iyengar Iyengar is, so to speak, Jesuit yoga: precise and disciplined. Iyengar utilizes props such as straps and blocks to help practitioners hold a pose. A strap helps you slowly and safely stretch your leg if you lack flexibility. Say you can't sit comfortably cross-legged on the floor: A block placed under one or both thighs can help prop you up.

Precision rules in this yoga style. "Iyengar appeals to Type A people," says Schumacher. "Teachers provide detailed instructions so that people are clear about what to do as they move into a pose."

Anusara means “flowing with Grace,” “going with the flow,” or “following your heart" in Sanskrit. John Friend created this hatha yoga technique in the mid-1990s by unifying a Tantric philosophy of intrinsic goodness and a method of physical alignment he calls "Universal Principles of Alignment." The highest intention of Anusara is to align with the Divine and step into the flow of grace. On the mat, students are encouraged to be playful and light and to offer prayers for more beauty, love, and goodness in the world.