Every dance company has doctors and physiotherapists at the ready, but Les Ballets Trockadero de Monte Carlo's orthopaedic consultant gets shared billing in the programme notes. Ballet is a beautiful but painful business. When a prima ballerina descends from her pointes to acknowledge her public's applause, her partner may envy her the spotlight but he's usually grateful to be spared the lifelong blisters and tendonitis that come with the shoes. Unless, of course, he decides to buy a pair of his own. The Trocks (as they are usefully known) are a hilarious New York dance troupe founded in 1974 whose 14 performers all dance in tutus on the tips of their toes - a source of concern (and revenue) for a certain Dr Weiss and his New York clinic specialising in dance and sports injuries.
Dr Weiss admits that there is a big difference between a female ballet dancer's feet - systematically strengthened from girlhood to take the punishment - and a young man who decides in his late teens that his talents lie in parodying the grandes dames of the ballet stage. The Trocks' Ida Nevasayneva and Helen Highwaters can zip through classic solos with more style and technique than many women - but at a price. "They have some of the same kinds of problems as women, the same kind of tendonitis, the same body alignment difficulties, but the big problem is that if they haven't done pointe work as youngsters they can be doing it for the first time at 18 or 19, and the older you are the harder it is for the body to respond."
Pointe shoes make your most uncomfortable pair of pumps feel like carpet slippers. The sheath of pretty pink satin traditionally conceals an unyielding interior of canvas, steel and glue. The Trocks favour an ultra-modern design whose plastic shell can be remoulded and tailored to the foot with the heat from a hairdryer, but no amount of made-to-measure technology can alter the fact that the human body wasn't really designed to support its weight on a few square centimetres of bone. Dr Weiss has seen the effect that toe-dancing has on human tissues: "If you look at an X-ray of a pointe dancer's foot, their metatarsal bones are actually thicker. The Trocks are heavier than women and this can be compensated for if they have a bigger and heavier foot than a woman but even if they're skinny - and they are skinny - they still have 10 or 20 per cent more body weight."
You might imagine small, dainty feet to be an advantage. Think again. Ideally a dancer should have what used to be called a "peasant's foot", rather than the "Grecian foot" (what Weiss calls the "too-good foot") with the long, slender shape and the longer second toe. "It may look pretty in a sandal but it isn't suitable for toe-dancing." Square feet spread the weight more evenly.
Overuse is always a danger and hard-working dancers risk tendonitis and stress fractures, but the very drudgery of the Trocks' 35-week tour schedule can protect them from more traumatic injury. Dr Weiss cites many examples of male dancers who wear pointe shoes once in a while and get hurt: "The advantage for the Trocks is that they are doing it all year round. It may put more wear and tear on the tissues, and they often end up with ugly-looking feet, but they're not usually maimed by it."
From tonight to 31 Jan at the Peacock Theatre, London WC2 (booking: 0171-314 8800)