AMU, Sadler's Wells, London

The piece is certainly ambitious. Commissioned by Sadler's Wells and the Wellcome Trust, it has a score written for seven singers and an orchestra of 50, the Southbank Sinfonia.

McGregor, whose Random Dance has been resident company at Sadler's Wells since 2002, arranges stage action that looks like a rite. The nine dancers are used as soloists and corps - moving and standing in patterns, breaking into individual dances. McGregor pays attention to stage space, dancers carefully grouped and placed.

This sense of pattern is a departure for the choreographer. McGregor's aggressive, wriggling style has often lacked rhythmic shape. The rhythms of Amu don't feel subtle or complex, but they are sustained.

Other aspects of McGregor's style are unchanged. The hectic, splaying limbs are still there, with quick twists and squirms. A soloist will kick a leg high, grab the ankle and pull, forcing the leg still higher. The dancers perform full out, pushing the exaggerations for all they're worth.

The dancing is framed by gauzes and computer images. There is no heart imaging on stage in Amu, though Houshiary's pictures, animated by Mark Hatchard, pulse and shift on backcloth and drop-curtain. Fuzzy, swirling patches settle into hard squares, then swirl again. Dust falls on stage.

In Amu, McGregor includes long periods of stillness, dancers standing or lying quietly. For the finale, they are gradually lifted into the air. This is a simple image of transcendence. After so many false endings, it comes as an anti-climax. Behind gauze, half-lit and surrounded by projected shadows, the dancers look not quite human: I wasn't sure if people or puppets were being lifted off the ground.