On Wednesday night, the Bolshoi presented its new "Romeo and Juliet," a bold venture into contemporary dance theater by a company best known for its classical repertoire. This new production fails as a ballet, however, because director Declan Donnellan and choreographer Radu Poklitaru do not at heart seem to believe in the power of dance as an idiom.

At the highest moments of emotion, they choose to have the dancers run around laughing or screaming as if they thought the voice a more expressive instrument than the body. Many of the by-now-tired conventions of contemporary and experimental dance were offered — vocalization, spasmodic trembling, shadow-puppet gestures with the fingers, semaphoric side-to-side waving of arms and body, crotchy crouches and buttocks-up crab-crawls — but all with stolid predictability of pacing and little sense of joyous inventiveness.

Still, the committed and passionate dancers of the Bolshoi, their pointe shoes put away for this experiment, were thrilling to watch as they gave each wag and grimace the clarity and care of their superb classical training.

Donnellan, a highly regarded British theater director, working with designer and longtime collaborator Nick Ormerod and lighting designer Judith Greenwood, created an effective theatrical structure for a contemporary, urban "Romeo and Juliet." If only the design had framed either Shakespeare's language or credible choreography.

Working with Moldavian choreographer Poklitaru, Donnellan's primary device and metaphor is to keep the corps of dancers onstage during the love scenes. These groupings of men and women hoist Juliet up to form a human balcony and forcibly keep the lovers from touching each other, reminding us, throughout the ballet, that it is the lovers' society that is keeping them apart. (There are times when drama and choreography briefly work together. One is the high leaping knife fight between Mercutio, Tybalt and Romeo. Another is Romeo and Juliet's necromantic death scene — until repetition blunts the effect.)

Romeo, danced by the impressive corps dancer Denis Savin, is all urge. He stabs Tybalt repeatedly and drags the dead body of Juliet around the stage by the ankle. Juliet, danced by principal Maria Alexandrova is a confident teenager who knows what she wants when she sees it.

Yuri Klevtsov's Mercutio was compelling, sneaking into the ball in drag, toying with the homo-erotically confused Tybalt (Denis Medvedev). The Bolshoi orchestra, conducted by Pavel Klinichev, played the cut and rearranged Prokofiev score exquisitely. It provided a kind of antidote to the brutal doings on stage. Though this famous score is often bombastic, there are themes of sweetness between the lovers that were not picked up on by Donnellan and Poklitaru.

Strangely, when Prokofiev's sometimes florid music, experimental in the 1930s, is matched up with the choppy, thrusty choreography of Poklitaru, the combination suggests expressionist dance of that period, such as the 1932 "Green Table" by Kurt Jooss. It is as if a director unversed in modern dance and a choreographer working outside the contemporary dance mainstream have accidentally stumbled across a modern dance style of an earlier age and mistaken it for innovation.

It is certainly time that the Bolshoi expanded its repertoire to include modern and contemporary ballet, and it is moving to see these fabulous dancers challenged in new ways. Let's hope that the flaws of this attempt don't discourage this great company from adding new works.

Starting tonight the Bolshoi will present its more traditional side, "Don Quixote" with choreography by Marius Petipa.