LOS ANGELES — The dance flick "Stomp the Yard" was a step ahead of the competition at the box office, debuting as the No. 1 weekend movie with $22 million.

Starring Columbus Short as a raw but talented dancer at the center of a step competition between rival college fraternities, the Sony Screen Gems movie knocked off 20th Century Fox's "Night at the Museum," which had been the top film for three straight weekends.

"Night at the Museum" slipped to second place with $17.1 million, raising its total to $185.8 million, according to studio estimates Sunday.

The weekend's other new movies had ho-hum debuts. Universal's youth drama "Alpha Dog," featuring Emile Hirsch, Ben Foster and Justin Timberlake in a tale of drugs, kidnapping and murder, opened at No. 7 with $6.1 million.

Disney's "Primeval," a thriller with Dominic Purcell and Orlando Jones as part of a news crew pursuing a prolific serial killer, premiered at No. 8 with $6 million.

Expanding to nationwide release after a limited run in December to qualify for the Academy Awards, "Arthur and the Invisibles," a live-action and animated family film from the Weinstein Co. and MGM, was No. 9 with $4.3 million.

Strong turnout by black moviegoers — who accounted for nearly two-thirds of the audience, according to Sony — pushed "Stomp the Yard" over the top. The movie followed in the footsteps of other black-themed films that debuted at No. 1 over previous Martin Luther King Jr. Day weekends, including "Glory Road" last year and "Coach Carter" in 2005.

1. "Stomp the Yard," $22 million.

2. "Night at the Museum," $17.1 million.

3. "The Pursuit of Happyness," $9.1 million.

4. "Dreamgirls," $8.1 million.

5. "Freedom Writers," $7.1 million.

6. "Children of Men," $6.4 million.

7. "Alpha Dog," $6.1 million.

8. "Primeval," $6 million.