If taking a yoga class conjures up images of weird hippies twisted into pretzel-like positions with psychedelic sitars playing in the background, it's time you took another look. One of the fastest-growing activities in the fitness field, yoga is an incredible way to improve flexibility, increase strength, improve cardiovascular capacity, reduce stress and develop a mind-body connection.

Yoga is essentially about the basic, fundamental movement of the spine. The idea is to keep the spine healthy and mobile throughout life. In the East, it was originally a spiritual practice, the purpose of which was to get one in touch with the divine or "greater consciousness" that lives inside all of us.

Today, at least in our country, yoga is a popular method of training the body for everything from fitness to relaxation to flexibility to stress management. It is not necessary to give up your religion to do yoga, and you can enjoy the many physical benefits of this fascinating, challenging activity without ever being exposed to its religious or devotional sides.

There are many types of yoga, each with a different emphasis. Yoga can be restorative and therapeutic, or it can be as physically demanding as any sport on the planet. Let's look at three of the main styles practiced in the United States.

Hatha yoga means, literally, all of the physical aspects of yoga. Under the heading of Hatha yoga there are three basic "lineages," or styles of practice. Like different types of martial arts, each style has a different emphasis and may appeal to a different kind of person.