A muscle-bound blond surf boy is standing in the kitchen, one leg bizarrely stuck up on the steel table top while he mixes the morning's pastry. After a couple of minutes' chat, he announces that I'll have to sit in the other room. 'I am supposed to be focused,' he announces, without a glimmer of humour. 'I've already burnt the porridge.'

My heart sinks. I have been up all night, on a charter flight to Iraklion airport, where lots of swarthy men emanate olive oil from their armpits and laughter from their moustaches; and then on an arduous two-and-a-half-hour taxi drive. I have finally arrived, at 6.30am, at the remote bay of Ayios Pavlos in southern Crete, for a health and fitness holiday. This is obviously going to be a very serious health and fitness holiday.

It gets worse. By 9.30am the organisers, Derek and Radha, both sporting all-over tans, extremely long legs and waist-length blond hair, are contorting themselves into all manner of highly improbable yogic positions and breathing heavily. Bronzed bottoms go up, feet go round ears, handstands, back-flips - they are all there. We, the future students, mostly women, look on with a mixture of awe and horror. Frankly, this looks like torture.

Vinyasa yoga - 'a dynamic form of yoga based on energetic breathing' - is hard. It is definitely not for the faint at heart. Fortunately the Practice Place, which overlooks the little blue bay, seems to be full of highly motivated career women who are sick of aerobics and the step, and want a new challenge. Take Sara, who has recently taken a law degree at Cambridge University after working as a nurse for 17 years: she has become hooked on Vinyasa yoga in the past two years. 'I like the discipline. It has improved my posture, redistributed my weight and reduced my stomach,' she says brightly. Stefan, a Finnish businessman - a rare male participant - who is another Vinyasa veteran, says: 'I was ecstatic after the first time. I also cried for half an hour afterwards.'

Talk over breakfast - fresh bread pudding, greek yoghurt, porridge, water-melon, honeydew melon, home-baked scones, feta, olives, nutritionally balanced and wonderful - is all anticipation and competitive fear. 'How long does it take to wrap your leg around your head?' asks Mia, a paper and printing rep from Wales.

By the next morning, all the novice Vinyasa yoga students are quaking. Radha, the Greek goddess who is our teacher (who is also Lesley Warrell from Brighton), is calm, collected and deadly serious. For two hours we throw ourselves at our rag mats in the relentless pursuit of exhaustion - sorry, perfect asanas (yogic positions).

The most frequent movement is the Vinyasa, which consists of a push-up combined with a very silly upside-down position known as the downward dog. During this 'holiday' we become extra-well acquainted with the downward dog. In fact, dog talk becomes a sort of Practice Place idiolect.

We are free from midday to 5pm every day, to swim, sunbathe, talk and (in my case) eat chocolate ice-cream. A constant subject of discussion in the local taverna, Nico's, is the lack of men. Why? Is it because yoga in Britain, while it has evolved from its gentle 'ladies over 50' image to a younger, more trendy holistic image, is still seen as a female pursuit? 'Most men come through their partners,' says John, the New Zealander cook/teacher who has transformed himself from skin and bones into a hunkish, three-hours'-Vinyasa-a-day man. 'Only very occasionally do they dare to come on their own. I think they would be attracted to it if they were exposed to it.'

Late afternoons see us play-acting at being hot drunken monkeys, massaging each other and saying goodbye to that red, red sun with Lydia Wong's Qi-netics classes, which are fun and free-flowing. Lydia has a down-to-earth, cheerful, spontaneous approach which is a complete and much needed counterbalance to the morning's disciplined yoga. There is a lot of shaking hips, jumping up and down, interacting creatively and, during the second hour, beautiful, slow-moving t'ai chi. One afternoon I find myself waving my hands in the air, grunting joyous squeaking sounds, while Huguette, a rather large lady from Luxemburg who oozes charisma and speaks mainly French, copies me with eccentric gusto. This is my kind of class . . .

By dinner time we are knackered. There is super-healthy bortsch, wild Cretan spinach, stuffed aubergines (only vegan food is served in the evenings), lots of salad, chickpeas and tahini; and only water and tea to drink. Discussion ranges from Koo Stark to taverna wars, from UFOs to Ian, the yoga nut who apparently dropped a couple of amphetamines before his class.

Koo Stark stayed for a month, she was so keen. The Koo story goes like this: 'I like your outfit,' comments a fellow student. 'Thanks, it's Kenzo,' replies Koo. The next day Koo decides to repay the compliment. 'Thanks, it's British Home Stores,' is the answer.

Only the real stalwarts make it to Nico's taverna for wine, desperately hoping Derek and Radha will not spot us. It is just like being back at school.

A typical Vinyasa yoga tale involves Pattabi Jois (the grandmaster, who is about 80 and teaches it in his house in Mysore, India). In his younger days, he was stepped on by his teacher and then sat up to find a rusty metal spike through his arm. I knew this yoga was based on pain, but that's going a bit far, isn't it? Discipline, pain, focus, rhythmic breathing, then contentment - that is the Pattabi Jois method.

On Wednesday morning I feel I am going to collapse. My body aches horribly and my aspirations for nirvana are severely tempered by thoughts of giving up instead. When it comes to remembering the warrior series, my mind goes cloudy and weak. Radha, strict as ever, exhorts us to breathe well and get those downward dogs properly positioned. I escape to a shiatsu massage from Lydia, which is painful but effective. By the next day my pain is over.

Derek and Radha run the Practice Place, which has been open for two years, according to their own philosophy. They are friendly but removed. 'Vinyasa yoga is all about self-practice and self-discipline,' says Derek. 'Our relationship with our students reflects that. We let them have their own space.'

Despite their appearances and their healthy regime, Derek and Radha turn out to be surprisingly funny. Especially Derek. A former Brighton football player, punk band promoter and a bit of a lad, Derek embraces the dynamic fitness aspect of yoga rather than its devotional side. 'Punk had the same prana, the same raw energy as Vinyasa yoga,' he says in his mischievous way.

His account of how he and Radha met differs from hers (she says she pursued him, he says he rescued her from drunkenness). But he did not attend one of her gentle yoga classes until a few years later. Vinyasa yoga, visits to Pattabi Jois and teaching followed. 'Vinyasa yoga is hard externally,' concedes Derek, 'but it's soft inside. In California, triathletes use this as a form of training.'

Controversial in his advocacy of the non-devotional approach, Derek upset a few TV-am viewers last year by referring to it as 'no-bullshit yoga'. 'We do Western yoga here,' he says. 'We are trying to provide modern yoga for working people who are interested in their physical wellbeing and peace of mind.'

Vinyasa yoga is no easy option; one of the claims made for it is that it opens up past pain stored in the muscles. 'There's one German guy who comes here. He smashed up both his legs in a car crash. He comes to yoga and often cries as he opens up the pain of the crash. Then, he smiles,' says Derek.

It is a revelation to hear that Radha likes a glass of wine and an ice-cream occasionally, and that Derek used to be into drugs, sex and rock'n'roll. No longer. 'Yoga is very wide, there is no moral code. It's just that you can't practise this type of yoga with a hangover,' he says. We don't. Not more than one glass of wine a night. I have never stayed so sociable and sober.

Thursday's class is almost enjoyable. I am getting worried. The downward dog is becoming a welcome companion. Balancing on one leg and bending over in the half lotus is still out of the question, but that is to be expected. I have nearly forced myself into full splits when I glance over to see Lou, the yoga teacher from Washington DC, on the ground in perfectly formed splits with her hands in the air in full sun salutation. It is sickening. At least Pam, an adventurous publisher in her sixties, is having a bit of difficulty.

'You were getting right into some of those positions this morning,' says Ian, a systems analyst, who has been taking photographs. 'It was the camera,' I joke.

'Haven't you heard of the camera drusty which gives you that little bit of extra stretch?' adds Derek, on cue. 'Drusty' is a yogic term for the gaze point when achieving an uncomfortable asana. Derek is, as usual, the jester.

Afternoon pleasures include watching the delightfully rubber-limbed Hamish, Vinyasa student and Practice Place odd-job man, drink a cup of tea while one of his feet nudges an ear; boat trips to nearby Ayia Galini to visit shops, or to Preveli, where there are waterfalls and impromptu discos hosted by Yanni, the boat captain; plus naked sizzling in the sun in a nearby secluded cove and long hikes into surrounding olive groves. On my last day I get lost amid the stark Cretan hills and searing midday sun, then return to a reflexology session with Huguette.

Relaxing on her balcony, she manipulates my feet and talks about channelling the blockages out of my body. But I do not realise exactly how much she will release them. One minute she is massaging my lymph glands, the next she (not me) is burping those blockages out. It is an original method and I feel deeply grateful for her efforts.

Huguette and her friend Patricia, both in their sixties (the latter's profession consists of going to remote areas, often in Africa, to find tribal art), provide the best night's entertainment. A sort of female Laurel and Hardy, they have had some unusual African adventures together. Huguette, raconteuse supreme, narrates (with incredible mobility of expression) stories of getting stuck in rivers, bartering her evening clothes - and, to maximum hilarity, her experiences in a hotel laundry basket with a self-proclaimed prince in Chad (he was in fact the hotel manager). She has us crying with laughter.

By the last day, the unthinkable has happened: I do not want to go. I can even contemplate more yoga. I have to confess that I have been doing it at home. Derek and Radha will be shocked.

Getting there Charter flights from London to Iraklion in Crete cost about pounds 200. Taxi from the airport to the Practice Place is about 13,500 drachmas ( pounds 36).

Courses run from May to the end of October. Yoga courses cost pounds 435 for two weeks. Other holidays available range from straightforward vegetarian breaks to t'ai chi or shiatsu massage.

More information from Derek and Radha, 17 De Montfort Road, Wimborne, Dorset BH21 1TG (0202 842853).

(Photograph omitted)