ENCINITAS, Calif. — Public school yoga instructor Katie Campbell proudly looks out at 23 first-graders as they contain their squirming in a child-friendly version of the lotus position.
In a voice barely above a whisper, she says into her microphone: "Why, look at everyone showing me they're ready for yoga. A-plus, plus, plus!"
Then the lesson begins with deep breathing and stretches common to many yoga classes. But there is no chanting of "om," no words spoken in the Indian language of Sanskrit or talk of "mindfulness" or clasping hands in the prayer position.
Ms. Campbell avoids those potential pitfalls for the Encinitas Union School District, which is facing the threat of a lawsuit as it launches what is believed to be the country's most comprehensive yoga program for a public school system.
Parents opposed to the program say the classes will indoctrinate their children in Eastern religion and are not just for exercise.
It's a debate public schools across the country are increasingly facing with the rising popularity of the practice and the recent dispute over school prayer.
Yoga is now taught at public schools from the rural mountains of West Virginia to the bustling streets of Brooklyn, N.Y., as a way to ease stress in today's pressure-packed world, where even kindergartners say they feel tense about keeping up with their busy schedules. But most classes are part of an after-school program, or are offered only at a few schools or by some teachers in a district.
Encinitas is believed to be the only public school system that will have yoga instructors teach full time at its nine schools as part of an overall wellness curriculum that includes nutrition and a school garden program, among other things.
"This is 21st-century P.E. for our schools," said Encinitas Superintendent Timothy B. Baird. "It's physical. It's strength building. It increases flexibility but it also deals with stress reduction and focusing, which kickball doesn't do."
The program is expected to teach a 30-minute yoga lesson to roughly 5,000 students twice a week at the district's schools, which extend from kindergarten through sixth grade. It is funded with a $533,000 grant from the Jois Foundation, a nonprofit whose board of directors includes the son of the late Indian instructor Krishna Pattabhi. Researchers at the University of Virginia and University of San Diego will study the program, including analyzing data on students' resting heart rates.
They want to know if public schools can affect not only children's learning, but also instill in them good eating habits and skills to help their well-being.
The program started in several schools in September but will go district-wide in January after months of protests by a group of parents.
Mary Eady pulled her first-grade son out of the classes.
Ms. Eady said she observed a kindergarten class in which the children did the motions referred to in yoga practices as a sun salutation. The folded over children, stood upright, sweeping up their arms toward the sky.
She said while the teacher called it an "opening sequence," the connotation was the same in her mind: Students were learning to worship the sun, which went against her Christian beliefs that only God should be worshipped.
"It will change the way you think," she said. "What they are teaching is inherently spiritual, it's just inappropriate, therefore, in our public schools."