It's a sunny Saturday afternoon in suburban Washington, D.C., and choreographer Troy Powell has found himself in a familiar seat: the second row of a darkened theater. Funky acid jazz is oozing from the speakers, and on the floor below, eight dancers are contorting their bodies provocatively to the music.

When the final trumpet riff fades, Powell is ready with a few requests.

"Try that last lift again," he instructs Dominque O. Rosales. She obliges and leaps into her partners' arms. He promptly flips her upside down.

Rosales is young, fearless and pliable. She will do anything Powell asks. But if he were to ask this dancer, a German immigrant, some simple questions about U.S. history, she might hesitate and plead ignorance of the American civil rights movement. This is the paradox Powell faces as associate artistic director of Ailey II, the junior ensemble of the famed Alvin Ailey American Dance Theatre.

"These dancers," Powell said, shaking his head slightly, "they don't have those blood memories."

Since its founding 50 years ago by Alvin Ailey, a black man who was born in rural Texas and grew up to be a choreographer, the company has gained global fame as America's premiere African-American dance ensemble. The Manhattan-based Ailey School attracts international dancers who admire the company's versatility, energy and athleticism. As a result, Ailey II can't rightly be described as African-American. Two dancers are white and one is Hispanic. Of the nine who are black, three grew up in foreign countries.

And so, Powell finds himself in the unenviable position of teaching a dancer like Rachael McLaren, who was born two decades after Martin Luther King Jr. won the Nobel Peace Prize, how to move like a Texas sharecropper sweating and singing in her Sunday best.

That's the scene set in the final movement of "Revelations," Ailey's signature work. When it premiered in 1960, "Revelations" was hailed not only as a milestone for modern dance, but as a sublime artistic expression of the African-American experience. In many cities, crowds go wild when the recorded chorus starts to sing the spirituals that serve as the "Revelations" score, songs like "Sinner Man," "Rocka My Soul in the Bosom of Abraham" and "Wade in the Water."

Critics have begun to worry "Revelations" is more than just a crowd favorite, it's a cash cow that may come at the expense of artistic growth. "Stepping lively but in a rut," was the headline in last week's Washington Post when the senior company performed at the Kennedy Center.

Powell was disappointed when he saw the headline, but he admitted that dancing "Revelations" repeatedly has its drawbacks.

"Doing it every night is a challenge," he said. "As an artist, you have to ask yourself, how are you going to keep it fresh? It's hard, dramatically speaking."

Powell, who danced in Alvin Ailey for many years himself, may be aided here by those young, diverse dancers who lack the "blood memories" Ailey used to talk about. Now when Ailey II dancers don the Sunday best costumes, their faces glow with innocence and hope, and they perform with an exuberant zeal that even the senior company sometimes lacks.

Dwight Horsey, a Millersville University administrator who advises the campus cultural affairs committee, is excited to see the dance Saturday. And he points out that while the average New York modern dance fan has seen "Revelations" six times, the average Lancaster County resident has not.

"I don't think people hear the name Alvin Ailey around here too often," he said.

Ailey II Dance Company, Sat., 7 p.m., Lye Auditorium in Alumni Hall, Millersville University, adults $15, seniors and children $5, 872-3811.