As the sun filtered through the towering trees of Mt. Lebanon's Bird Park, about 45 people gathered Saturday morning in a clearing to practice the slow, rhythmic exercise tai chi. Some were there for the physical benefits of the ancient discipline, while others sought a more spiritual level in the measured movements.

"It's relaxing," said Maxine Bickel, 77, of Mt. Lebanon, who brought her husband, Melvin Bickel, 77, for his first lesson and a low-key workout.

Bone and lung cancer survivor Ginny Nimpfer, 62, of Dormont, who has rods through her bone from the hips to knees, hoped to improve her health.

Mt. Lebanon High School students Kai Guo, 17; Xi Fu, 17; and Binbin Ye, 16, who grew up in China, came to observe and learn the American version of tai chi, one of the major soft martial arts.

The boys view the Chinese version in Chinese-language films.

Tricia Bendis, 44, of Mt. Lebanon, who suffers from a type of muscular dystrophy and who has taken tai chi classes at the Mt. Lebanon Recreation Center, said the exercises helped keep her muscles loose and stretched.

"It gives me balance and inner peace," said Ute Philipp, 67, of Mt. Lebanon, who practices daily at home.

"Right now, there's 5,000 of you doing this in Central Park," instructor David Clippinger said, referring to Saturday being World Tai Chi Day.

Tai chi, with its deep breathing and graceful dance-like movements, is an ancient Chinese form of exercise and meditation designed to boost energy, cultivate physical and emotional balance, and instill a sense of spiritual and physical well-being.

Mr. Clippinger, a Buddhist monk, said the exercise was especially beneficial for seniors because it does not put undue stress on the joints.

His Mt. Lebanon studio, Still Mountain Tai Chi and Chi Kung, the latter being the "umbrella" term under which all soft martial arts fall, hosted the 90-minute free local celebration for the third time.

"You'll be strong internal soldiers after this," he said during breathing exercises for the heart and lungs.

"You need to think of samurai movies," he said during the "bending the bow" exercise in which students cross hands and pull one elbow back as if drawing a bow.

Mr. Clippinger, 38, acquired an interest in martial arts as a teenager. That developed into an interest in the soft martial arts while he was a student at Penn State University.

The Mt. Lebanon man, who has a doctorate in American literature and culture, is a visiting professor of American literature at the University of Pittsburgh. He has written books on Buddhism and Taoism, and the reciprocal influence of Eastern and Western cultures.

He teaches medical chi kung, or stationary exercises, to improve the circulation of the entire body in the Dean Ornish program at Allegheny General Hospital.

He also conducts cancer chi kung workshops at Magee-Womens Hospital for women with breast and ovarian cancer.

After Saturday's session, Kyle Chizeck, 14, of Mt. Lebanon, who runs track and came to exercise his newly injured hip, deemed his first tai chi experience a success.

"I feel totally loosened up now," he said.

For more information, contact David Clippinger at 412-480-9177, or go to www.stillmountaintaichi.com.