DANCE / And the earth moved . . .: When the LA earthquake deprived Twyla Tharp of a venue, the London Riverside stepped in. Smart move. Review by Judith Mackrell

It has taken an earthquake to get Twyla Tharp's company back in London again. Eleven years have passed since we last saw them here. And if it's good news that Riverside have had the wit to book them after their venue in LA was damaged, it's absurd that we owe their visit solely to a natural disaster. The Riverside's tiny Studio Two can barely contain the energy of these excellent dancers (one collided with a lighting rig as she streaked dangerously off the stage), and some of the time the dancers are obviously having to perform with the volume turned down. So when do we get to see them in a proper theatre?

Carping aside, this surprise season does provide wonderful views of Tharp's repertoire, dipping into work from the last 20 years. When she first started choreographing, Tharp used only women dancers, writing: 'For the longest time I could not understand duets between men and women. Why aren't they just in bed together?' Since then she's made up for lost time. Sextet, created in 1993, is entirely about dance as sex. Three couples spend 20 minutes locked in sensuous and witty duets where the dignified moves of classical pas de deux are invaded, mocked and enthralled by jive, rock and tango. Tharp juggles ballet and the demotic with dazzling sleights of hand - a pirouette ends in flashy Latin American knifing of legs or with the woman straddling her partner's waist. At the same time, she engages in an exploration of all the ways in which a body can turn, can change focus or spin on its own or on its partner's axis. The six wheeling dancers seem caught in a constant drama of advance and retreat until the end when they slump into a long and artless grope - the final reminder that this was only, ever, about sex.

In Baker's Dozen (1979) Tharp is less interested in twos than threes - couples just get started on some involved manoeuvre when another dancer joins in the fun, interfering with a balance, complicating a turn or making off with one of the bodies. The piece evolves into a delightful scramble of near-missed beats and surprises with bodies falling out of the wings or freezing halfway through an exit. In Nine Sinatra Songs (1982), which is one of Tharp's most popular works (but also one of her thinnest), life is refracted through the ballroom floor as the whole company meets in a series of romantic, hopeful and deliberately tacky duets.

At times, Tharp's seductive facility with couples dancing outdoes itself and becomes glib - the dancers can seem more involved with the ingenuity of the moves than with each other. Octet (1991) shows another Tharp completely - hard and disquieting, setting dancers in a frame of abstract sculptural groupings. The piece is set to Edgar Meyer's The Plumed Serpent and, of all the works this season, Tharp's movement digs deepest into the music here for its rhythms and atmosphere. (Though she is a profoundly rhythmic choreographer, Tharp is not always a particularly musical one.) The mood is dark and strange: the dancers' movements are either wildly, hungrily extravagant or nervily clipped. When two dancers meet, their relations are attenuated, ready to fly apart - a woman caught by one leg between a man's quivering knees fights free with her other leg in angry jabbing circles. When the men and women separate they form almost antagonistic ensembles - like the mesmeric but spooky close where the women criss-cross the stage in fast deadpan bourrees while the men revolve between them in slow, exhausted turns.

Octet is the season's masterpiece, but its undoubted hit is In the Upper Room (1986), combining a phenomenal explosion of energy with a structure of staggering cleverness. Steps are restated, turned inside out or upside down, and whole groups work in counterpoint, with different movements pitched against each other, different rhythms, even different styles. These opposing forces are all so neatly dovetailed, though, that even as your eye scurries to keep track, the overall logic feels natural, unflurried, sure.

When American Ballet Theater danced this work four years ago at the Coliseum I found it slightly overwrought, but at the Riverside, surprisingly, it came alive. Seeing the dancers close gives you a direct encounter with the beat and tug of the different movements, makes you feel the draw of each dancer caught up in this huge and complex movement machine.

Almost as soon as the piece opens it moves into top gear, Philip Glass's music pumping the dancers to a pitch of adrenalin and endeavour. In the middle sections it starts to cruise - the large groups are dismantled, the movements get woozier, slower, more quiet. But towards the close it winds back up to a level of tension and activity that keeps intensifying. The audience can barely contain its need to let rip and applaud, and though the Riverside does not not hold a big crowd, 400 people can still make an enormous amount of happy, grateful noise.

Runs to 11 March (Booking: 081-748 3354)

(Photograph omitted)