It was hot and humid Wednesday night at Wolf Trap, but that didn't deter the sizable crowd that came to savor the Alvin Ailey American Dance Theater's fervor, elegance and physical daring. For this third and final performance of its run, the troupe offered two contrasting distractions from the weather -- one a company premiere, one an Ailey classic -- plus a choreographic dud that made one long for the comforts of an air-conditioned room.

The premiere, Jennifer Muller's "Speeds," is a wonderful romp of a group dance, light as a piece of melba toast, cool and clever as can be. Created in l974 for the choreographer's own company, The Works, the piece is built around the notion that variations in rhythm and pulse can wreak startling changes on the same movement sequence -- hence the dance's title. But Muller -- aided immeasurably by Burt Alcantara's electronically burbling, stop-and-start score -- adds another layer to these experiments, setting up mini-comedies and dramas that grow naturally out of a slowed-down or speeded-up phrase. Then there's the quality of the movement itself: easy and languorous, full of looping arms, fluid running patterns and balances that dissolve into plush lunges.

The Ailey dancers captured all of this to perfection. A line of five men and six women in sleek white outfits snaked regally forth from stage right, curved about the stage and departed double-time. Two women swirled lazily around a bounding man. A man and woman went through stages of an intense love relationship while the others sprung about like human pogo sticks. And when any of these individuals called out "Change!" the ensemble did just that.

If "Speeds" made for delightfully lightweight viewing, Ailey's signature work "Revelations" allowed the audience a genuinely spiritual experience. Though several of the solo passages were not quite as precise or affecting as they should have been, this gospel-infused suite of wrenching and ebullient dances sent the audience into rapture.

Louis Johnson's tacky and amateurish "Lament" completed the program.