After the classes prompted discussion in local evangelical churches, parents said they were concerned that the exercises might nudge their children closer to ancient Hindu beliefs.

Mary Eady, the parent of a first grader, said the classes were rooted in the deeply religious practice of Ashtanga yoga, in which physical actions are inextricable from the spiritual beliefs underlying them.

“They’re not just teaching physical poses, they’re teaching children how to think and how to make decisions,” Ms. Eady said. “They’re teaching children how to meditate and how to look within for peace and for comfort. They’re using this as a tool for many things beyond just stretching.”

Ms. Eady and a few dozen other parents say a public school system should not be leading students down any particular religious path. Teaching children how to engage in spiritual exercises like meditation familiarizes young minds with certain religious viewpoints and practices, they say, and a public classroom is no place for that.