Look into the games room at Mulberry House primary school in north London on a Wednesday evening and you’ll find a class of would-be atheletes. Nothing unusual about that, you might think. Except this group of “students” are not pupils - they teach the school’s 215 children.

Driving them through the pain barrier to fitness is their own personal trainer, Emma Newham. Since last September she has taken seven “pupils” per session, devising fitness regimes to meet their individual requirements: three want to lose weight, the others just want to get fit.

The school’s headteacher, 46-year-old Bethan Lewis-Powell, began training last year with Emma, a qualified personal trainer who boasts a sprinkling of celebrities among her clients. Ms Lewis-Powell was so delighted with the results that she decided her staff would also benefit. The class took off, and is now in its second term.

“It was partly an attempt to de-stress the staff,” she explains. “But also a way to bring everyone together outside school hours. The real advantage is that it’s on the premises. Lots of working people don’t get to the gym, even if it’s 10 minutes away. This makes it really easy.”

Mulberry House, which is fee paying in London’s West Hampstead, believes it is unique in having its own personal trainer, and while some may say this is just another perk only a private school staff could afford, it is the headteacher who foots the pound;40 bill for the hour-long session. The cook also attends, and caretaker Norman Slater is expected to join this term.

The hourly rate is fairly typical for a personal trainer in London, although nationwide the cost can very from pound;15 to pound;50 per hour.

In its purest form, personal training means a one-to-one session with a fitness professional who draws up a personal exercise programme for you. At least, that’s the closest governing bodies such as the Exercise Association have got to a definition. The organisation is still trying to hammer out something more concrete, as well as firming up qualification requirements.

The class at Mulberry House doesn’t allow for concentrated one-to-one training, but members are coached individually when they perform their circuit training exercises and as they work towards their fitness targets. One teacher, Julie Kirwan, says: “It’s very motivating when someone is beside you, watching and correcting you. You do work harder, and we’ve got our own goals, which helps. I’ve improved a lot. I can do high impact now, whereas I couldn’t when I started.”

Injury prevention is another advantage of having a professional watching. It’s all too easy to put stress on joints and muscles if exercises are done incorrectly, for example with an arched back. In classes at gyms, with a typical size of around 25 people, close observation of each person is impossible.

At Mulberry House, Emma puts up posters to illustrate the perfect bicep curl, press-up, high knee kick, star jump and squat, and Mulberry’s teachers do the best impressions their ages, sizes, muscle flexibility and fitness will allow. The equipment is minimal - a mat or two, a plank and a chest expander.

“Is it relaxing time yet?” asks one teacher, red-faced and clearly exhausted. Soon, it is, and “Disco Inferno” is replaced by a soothing classical piece as the students lie down and imagine they are “sinking in wet sand, getting heavier and heavier”. Their trainer has worked the women, aged between 21 and late forties, hard, and it shows. But they still manage to look pleased with themselves.

Emma wants to expand her personal training service into more schools following the success of teachers at Mulberry, and is advertising in magazines and newspapers. A spokeswoman for the Exercise Association, which has just opened a register of personal trainers, says: “Personal trainers are becoming more business-oriented, as there are so many new markets, like schools, for them to explore. The sector has mushroomed since the Eighties when only celebrities had their own personal trainer. It has significant appeal to the baby boomers aged 35-50 who want to age well but have left behind the Lycra, mirrors and loud music.”

The association says the exercise industry is growing in Britain more rapidly than anywhere else, and many people, particularly women, who are intimidated by gyms are opting for the personal touch.

Bethan Lewis-Powell believes that by helping her staff keep fit she will see a reduction in the number of sick days, and will also reduce the chance of their developing osteoporosis in later life.

Another member of the group, Marie Gold, says: “You’ve got to be hands-on and active to teach young kids, and this workout is helping me improve my overall fitness. It’s not just a perk. It’s in the school’s interest.”

The headteacher recognises the stresses of looking after young children, and hopes that the class helps staff unwind. But according to Emma Newham, schools are calmer, more pleasant places to teach than the average workplaces of her corporate clients. “Business clients are always worrying about where they have to be next, but here the day’s over when the kids go home, and it’s a nicer atmosphere when I arrive.”

Another advantage is that no room hire is required, thus keeping costs down. Emma says: “All schools have a hall, so you have a ready-made workout room, often with the equipment already there.”

For most one-to-one personal training sessions Emma takes a new client’s cholesterol reading and blood pressure, measures lung capacity and body fat and tests fitness levels before comparing everything to set norms. For the Mulberry group she did not have time for all that but did screen every class member to ensure they were fit to exercise.

There are other practical benefits to using a personal trainer, as the school’s head recently discovered when she had a medical for insurance purposes and found her insurers were impressed that she was going to such lengths to stay fit and healthy. She is also vegetarian, as is Mulberry House.

A company called Get Motivated estimates that of its 4,000 clients who use the services of 450 personal trainer members nationwide, just under five per cent are teachers. The Association of Personal Trainers, which represents 300 members’ interests, is also looking to expand into schools and is encouraging members to approach headteachers - although it does not approve of members running groups with more than two people in them.

Marilyn Luscombe, a spokeswoman, says “A personal trainer operates one- or two-to-one - no more, otherwise it’s just a small fitness group. But there is enormous potential within schools, and fit teachers will mean that pupils might be made more aware of fitness and health issues.

“Kids are getting blocked arteries by age eight because they exercise so little and spend so much time on computers and eat unhealthy food. Educating teachers on fitness must go some way towards redressing the problem.”

HOW TO FIND YOUR OWN TRAINER

* Get Motivated is a national organisation which has 450 personal trainer members across the country who charge a competitive pound;15 an hour. Tel: 0171 736 0401 for more details.

* The Association of Personal Trainers is a national membership body which represents trainers’ interests and offers education and training programmes. It was set up in 1992 and currently has around 300 members who charge varying rates. Tel: 0171 836 1102.

* The National Register of Personal Trainers has 1,000 members and is a commercial membership organisation. Tel: 0181 944 6688 * The Exercise Association the governing body for exercise and fitness, has just opened a register of personal trainers, and offers advice and help on diet and exercise on a special helpline number: 0981 6333499. For personal trainer help Tel: 0171 278 0811.

* Why bother? Regular exercise:reduces the risk of coronary heart disease and other chronic disorders; reduces stress; can help reduce cholesterol levels; helps keep weight down and improves body shape; strengthens muscles and bones.

* The Health Education Authority recommends 30 minutes of moderate exercise five times a week. Allow a couple of months before you expect to feel fitter or improve your body shape. As you get fitter, set yourself (or ask a personal trainer to set) realistic goals to help you progress. The activity you choose should leave you feeling slightly breathlessand warm.