image for yoga article Jane E. says her daily practice of yoga makes her more flexible, improves her concentration, and gives her an aerobic workout as well.

"It's a really comprehensive kind of exercise that not only affects my physical well-being, but creates an important connection between my body and my mind. I feel more energized and also refreshed mentally after practicing yoga."

Apparently many people agree. Close to 10 million Americans report they do yoga, an exercise made up of a series of poses based on an ancient Indian spiritual discipline. If you're interested in starting yoga, you might want to try an introductory drop-in session—an option at many studios and establishments—before committing to weekly classes.

Since yoga first gained visibility in the 1960s, numerous teachers, styles, and organizations have emerged, but finding one that's right for you can sometimes be a challenge. A good teacher and the right practice can significantly contribute to your enjoyment, growth, and understanding. Moreover, a good teacher can ultimately determine whether you continue to gain the benefits from a constant and continuing practice.

How Yoga Practices Developed in the US

Yoga is rooted in India, where many of the historical religious texts refer to practices that help one attain liberation. Yoga means to "unite" or "yoke" and Indian texts describe four paths to this yoking of the individual to universal spirit—devotion (bhakti yoga), discernment (jnana yoga), the renunciation of the fruits of one's labor (karma yoga), and astanga yoga—the eight-limbed path. Within this eight-limbed path, postures or "asanas," what we usually define as yoga, are only one aspect; the others are restraint (yama), observances (niyama), breath control (pranayama), withdrawal of the senses (pratyahara), concentration (dharana), meditation (dhyana), and super consciousness (samadhi).

When yoga was first introduced in the US, the physical exercises were separated from the spiritual and mental disciplines and the latter were de-emphasized. As a result, the physical postures or asanas were presented as a relaxing form of exercise and many early practitioners were women. Over the last few years, however, the West has become more accepting of a well-rounded yoga practice.

The increased interest in yoga has also come at a time when traditional Western medicine is engaged in understanding more about the mind-body relationship. Many studies have explored the benefits of yoga, and although none were rigorously designed, they do suggest benefit for such conditions as carpal tunnel syndrome, depression, anxiety, osteoarthritis, and improving balance in seniors. Studies of yoga as a treatment for asthma have produced inconsistent results suggesting at most a minor benefit.

Different Kinds of Yoga

Perhaps your physician has recommended yoga to you as a way to relax, or you've talked to a friend who swears by her annual yoga retreat. Don't be fooled by the seeming passiveness of the idea of a "pose." While yoga is not a sport and is never competitive, it can be as rigorous as an aerobics class.

There are many different schools and styles taught in the US. Some teachers have been certified in particular traditions, others offer a synthesis based on their own practice with Indian masters. The various major traditions include the following:

Astanga yoga was developed by K. Pattabhi Jois, and is a very demanding form of the practice. This yoga uses a concept of "flow" that has participants moving continuously and jumping from one posture to another, building strength, flexibility, and stamina. This is a real workout and not for those looking for leisurely stretching exercises.

Integral yoga was developed by Swami Satchidananda relies on breathing exercises (pranayama) and meditation as much as on postures for the practice.

Iyengar yoga is a style of yoga developed by BKS Iyengar, who has systemized his training and certifies teachers who have completed an extensive 2-5 year training program. Iyengar practitioners use props such as blocks and belts to aid them in performing many of the more difficult postures, and great attention is paid to a precise alignment of postures.

Kripalu yoga places emphasis on "honoring the wisdom of the body" and allowing each student to develop an awareness of mind, body, emotion, and spirit. The practice is delineated into three stages: learning the postures and exploring the bodies ability; holding the postures for an extended time and developing an inner awareness; and moving from one posture to another in a spontaneous movement.

Kundalini yoga involves postures, meditation, and the coordination of breath. The practice is said to create a controlled release of kundalini energy, a creative force thought to sit at the base of the spine.

Viniyoga was was developed by Krishnamacharya, a teacher whose disciples have created numerous other yoga forms. Viniyoga is a gentle form of flow yoga (continuous movement) which focuses on a student's ability rather than on idealized form.

Bikram yoga , founded by Bikram Choudhury, utilizes yoga postures practiced in a heated environment.

Sivananda yoga involves a set structure that includes relaxation, pranayama (breathing), and classic asana postures.

For a description of other traditions see http://www.yogasite.com/yogastyles.html .

Finding a Teacher

There are many excellent yoga books that explain the postures and have beautiful photographs and illustrations. Yet a teacher can impart an understanding of the poses and the practice of yoga in a way that a book cannot. A teacher can also help you develop correct alignment in the various poses so that you get the greatest benefit and an internal stretching and healing begins.

While there is still an emphasis on yoga as a physical exercise, many teachers now address the more spiritual aspects of practice as well.

"My teacher includes a meditation practice and sprinkles our class with aphorisms about letting go and being in the moment," says Dale.

Other teachers take a holistic or even therapeutic approach with their students, reading their yoga practice as an open book on their personality and behavior.

"My yoga teacher would tell me 'stay in the pose' when I thought I was just too tired and needed to rest," says Anna, "but she was usually right. She seemed to know more about my endurance and capabilities than I did, and as a result I gained a new sense of self and discovered a reserve of strength and power that I didn't know I had."

This kind of encouragement, however, seemed like too much intervention to her friend Elisa who opted to attend a more structured class with a more reserved teacher.

"I just want a teacher who corrects my postures if they are sloppy, "she says. "Not someone who seems to have some advice for other aspects of my life."

What kind of relationship you develop with your yoga teacher depends on their philosophy and also on you and what kind of response you want. However, there are certain basic rules that you should follow in assessing a yoga teacher's capabilities.

When you first attend a new class, most teachers will acknowledge that you are new to their class and will come over personally and have a short chat with you. They also might ask you if you have any injuries and recommend alternative poses if they think some things are too difficult for you. You will also see good teachers watching carefully and both making adjustments to students postures and pushing them beyond their seeming limits.

The word "yoga" as we use it in the US, refers to a broad category of some very different kinds of mental, physical, and spiritual practices. If you have a desire to learn, you should take some time to get acquainted with the different schools and styles to appreciate what various teachers have to offer. This is, in fact, a most personal kind of exercise, and the benefits accrue slowly and subtly over time.