BOB ABERNETHY, anchor: This week, an amazing demonstration of what a disciplined practitioner of yoga can do. The yoga tradition goes back thousands of years, to ancient Indian philosophy and the Hindu religion. In this country, many Americans find the beginning exercises of yoga good ways to reduce stress. But lifelong practitioners also find it very much a spiritual discipline, using the most severe postures to help quiet the mind and achieve a sense of union with the transcendent. One yoga master and teacher is John Schumacher of Bethesda, Maryland. He has practiced two to four hours a day for 30 years.

JOHN SCHUMACHER (Founder and Director, Unity Woods Yoga Center): Yoga is a spiritual practice for me. I was 25, and at that stage of my life I had been questioning a lot of things about what was important and not important, what were my values.

I found that what yoga said about the way things are was very much in line with what I had begun to discover on my own. Up to that point, it had been very difficult for me to find much in my western philosophical and spiritual studies that really addressed that.

Yoga is, according to Patanjali, who is the author of THE YOGA SUTRA, the cessation of the fluctuations of the mind, so that when the mind becomes quiet -- that's yoga.

There are several major schools of yoga. The kind I do is Iyengar-style hatha yoga, named for B.K.S. Iyengar. He just celebrated his 85th birthday and still practices daily.

His way of doing the yoga postures is very exacting, precise, detailed. What comes about is an increasingly deeper and deeper state of focus, of meditation. This meditative quality rises out of this tremendous intention to work precisely and with alignment in the body.

There's always a correlation between mind and body. Anything that happens in the body has a direct effect on what goes on in the mind, and vice versa. It's a two-way street. Quieting the body down is a way to bring some quietness to the mind. There is a relationship between keeping the body still or rhythmic that brings about a steadiness and quietness of mind.

The idea of balance is really an important part of the practice. There's a physical balance, mental balance, psychological and an emotional balance. And the practice really is on some level designed to create that feeling of balance in the body, mind, and spirit.

In the practice of yoga, we observe that the mind is very, very busy. It's sometimes referred to as "monkey mind." It's all over the place like a monkey in a tree. And through the variety of the practices of yoga, we eventually come to a place of slowing down, of becoming quieter, a little more focused, a little steadier.