Pointe break: Siobhan Norton is put through her paces / Teri Pengilley

Ballet – which most girls abandon at school – is the latest fitness craze, says Siobhan Norton

I still remember the moment when I reached the pinnacle of my ballet career. Standing in perfect first position, trophy held aloft, proud tears pricking at the backs of my eyes. It was to be, aged four, my first and last ballet accolade. My parents insist it was bestowed out of relief that I'd finally stopped running around for long enough to master a few steps. Still, I spent my formative years poring over ballet books and turning out my toes, dreaming of my first standing ovation. But as the years went by, the trappings of life took over and my dreams of prima ballerina stardom dwindled.

It was probably for the best. I like cake too much, have a tendency to fall over walking in a straight line and never fancied the notion of bleeding toes. So why the hell have I found myself back in pumps, clutching a barre and trying to channel my inner swan?

For me, it's part vanity – who wouldn't want to look like as lithe and toned as a ballerina? But mostly it's the nostalgia. If, as a child, you ever sat agape in front of The Nutcracker, you'll recognise the wistful shiver. Perhaps this is why, now, ballet studios across the country are filled with thirtysomething women hoping that, although their dance career prospects are limited, they can still recapture some of this wonder.

Indeed, in my first adult class, I find myself shoulder to shoulder with quite a few women my age, with mercifully few sylphs present. I had assumed a ballet class would be a bit of a jolly – a bit of leaping around, a plié here or there. But, no, this is serious business.

We work diligently through our battement tendus, with a subtle tap here and there from the teacher to correct our posture. I am surprised to find that, although most of the movements are precise and isometric (where the muscle is tensed without moving), I am sweating with the exertion, and my muscles are quivering. That "muscle shake" is the holy grail of barre training, it seems, meaning the muscles are exerting themselves to their limit.

Pointe break: Siobhan Norton is put through her paces (Teri Pengilley)

The nostalgia is undeniable, but what really rocketed ballet back into the mainstream was the release of the film Black Swan in 2010. This psychological thriller may have been a commentary on the destructive, obsessive world of ballet, but what really fired our imagination was the powder-pink and grey marl wardrobe and the slender frames of stars Natalie Portman and Mila Kunis. Sports brands raced to release ballet-inspired looks and we all reasoned with ourselves that it was once more acceptable to don legwarmers. The health club perennial, Zumba, was overtaken by ballet-inspired classes.

The professional ballerina and fitness guru Mary Helen Bowers trained Portman for the role and pioneered the trend for ballet-based fitness. Her New York studio Ballet Beautiful attracts supermodels and actresses, as well as thousands of women logging on to her online classes from all over the world. And as with most trends, where New York blazes a trail, the UK soon follows.

Niki Rein founded the Barrecore chain of studios in London in 2009. "I didn't have a dance background – I was a football player," she laughs. "I loved lifting weights in university, but I put on muscle easily and never felt as feminine as I would have liked. I was introduced to dance-based fitness and it transformed my body."

If tights and tinkling ivories bring back more bad memories than good, there are plenty of other options. Frame offers classes ranging from ballet to jazz, and if you feel that you are perhaps more Beyoncé than Bolshoi, you can channel your inner rock star at a music video class. I tried a Frame Signature class, which incorporates barre technique with light weights, yoga straps and an upbeat soundtrack. My muscles screamed as I moved my leg in almost imperceptible circles and held squats for far longer than I ever thought possible. Poise was not at the forefront of my mind. The one relief here, though, was that I felt slightly more co-ordinated than in a full-on ballet class.

Joan Murphy, the founder of Frame, agrees that dance classes need not be exclusive – and that the biggest motivator for keeping fit should be fun. "There are people out there who don't want to go for a run or spinning – but a ballet class on a Sunday afternoon with friends is much more fun and sociable. We get everyone from beginners to experienced dancers."

There have even been a few men at the barre at Frame, although they are still vastly outnumbered. But ballet's image is evolving beyond tights and tutus. A recent advert for the fashion brand Rag and Bone featured the 67-year-old classical legend, Mikhail Baryshnikov, dancing with hip-hop impresario Charles "Lil Buck" Riley, while a reworked video for Hozier's "Take Me To Church" stars Sergei Polunin, the bad boy of ballet, flaunting ripped tights and tattoos for a head-clutching medley of classical and contemporary ballet. Pop singer Sia's "Elastic Heart" video, a contemporary ballet battle between the 12-year-old dancer Maddie Ziegler and 29-year-old actor Shia LaBeouf, courted controversy and plaudits in equal measure.

"We do have a couple of men, but not many," says Rein. "They can find our classes quite a challenge – men tend to have more upper body strength and we do a lot of lower body work in our classes. But we'd love to have more guys."

Ballet has not traditionally been regarded as the most healthy of pursuits; it's an open secret among professionals that having a dancer's body means a restrictive diet on top of the hours of training. Injuries are also common among professionals – bleeding and fractured toes, sprains, and lumbar problems. Classical ballet steps are stylised, involving turned-out feet and limbs and a tucked tailbone, so unless you've been training from an early age, the moves can feel difficult or awkward. But a good teacher will insist you remain within your limits, maintaining proper form to minimise injury chances.

"Professional dancers tend to get injuries because they are undergoing hours and hours of very repetitive moves," says Murphy. "People here aren't training long or hard enough to get those kind of injuries. One of the best preventions of injury is to cross train. Here, we have lots of different genres under one roof, so you can chop and change."

Rein maintains that you don't have to be swan-like to see the benefits of barre. "We have people that can barely touch the tops of their own shins and others that can bend over and put their hands flat on the floor. There are modifications for every exercise, so you are still working the same muscle group but to your anatomy's ability. There is really no plateau, you can always bring it to a deeper level because you're working with your own body weight. It leaves you strong and toned."

And skeletal? "We're not all 14, long and lean," laughs Murphy. "Ballet is definitely aspirational, but we simply want to give people a fitness option that feels like a fun couple of hours rather than a chore."