AND then there were four, as an injury suffered earlier in the day forced Sean Marcs out of last Friday's performance of 5 Soldiers: The Body Is The Frontline.

While he was being taken to York Hospital for a check-up, choreographer Rosie Kay was re-choreographing the remaining 4 Soldiers for a speedily revised version of the Birmingham company's remarkable dance piece in the Imphal Barracks gymnasium.

Not wishing injury on any dancer, nevertheless Sean Marcs's misfortune was a reminder of the implications of the dance drama's title. The body is indeed the frontline for dancers, the butterflies of the arts world, who stretch their limbs to the limit in a notoriously short career.

The show's title refers not to dancers, but the young men and women of the British Army who put their bodies, their lives, on the line in Iraq and Afghanistan. "The human body is still essential to all [military] conflict, even in the 21st century," noted Rosie Kay, whose field research took her on full battle exercises on Dartmoor and Salisbury Plain and to a military rehabilitation centre.

Conflict is at the core of 5 Soldiers, as much a battle in the mind as in the body, as dancers Duncan Anderson, Chester Hayes, Oliver Russell and the outstanding Shelley Eva Haden undertake the training that leads to the battlefield. Repetitive parade-ground drill takes on a balletic quality, but fear, intimidation, initiation ceremonies and rivalries, as well as camaraderie, pierce the surface.

So too does sexual longing and frustration, the pecking order of men and women; the need for discipline and self-control; all this as the frontline awaits, with its uncertainties, its complexities, the risk to life and limb.

Kay's burning, bruising, breathtaking choreography makes for the most intensely physical contemporary dance theatre your reviewer has ever seen, an unbroken hour that is both physically and mentally shattering. Admiration for soldiers and dancers alike is sure to rise when encountering 5 Soldiers.