The makers of whole-body vibration machines claim they tone your muscles and hone your thighs. Scientists say they may have some remedial effects but the jury is still out.

Being shaken vigorously, pneumatic-drill style, is something of a departure from the holistic road to health that we have been guided along in recent years. But the latest fitness machine to take the sporting and celebrity world by storm is the Power Plate - the makers of the device claim it gets you trim in sessions of just 12 to 15 minutes by vibrating your body so intensely that you can feel your tonsils buzz.

Madonna reportedly used the device to hone her 48-year-old body into looking half its age for her last tour. The material girl is now said to take all her telephone calls while standing on one.

Celebrities such as Sean "P. Diddy" Combs and Claudia Schiffer have declared vibrational devices to be part of their fitness regimes. It is also a favourite of the German football team, which used it extensively throughout the World Cup, and Collingwood Football Club is said to have adopted the treatment.

A Power Plate fitness studio recently opened in Harrods department store in London, where groups of four can book 25-minute sessions with a qualified trainer. An estimated 10,000 of these or similar vibration exercise machines - the VibroGym and the Soloflex Platform, which cost about $5000 - were sold for private use across Europe during the past year. In Australia, the Personal Power Plate costs $6100, with the deluxe model, the Next Generation, a whopping $17,000. Despite the price, HF Industries, which supplies the Power Plate in Australia, claims most sales have been to private homes.

According to information on the powerplateusa.com website, the machines vibrate at between 30 and 50 times a second, which transfers energy to the body and triggers rapid muscle contractions. The upshot is that you work harder all over when you're on it. In a 12-minute workout, the makers of the Power Plate claim that it trains every muscle in your body and contracts them to the same degree each time.

If the machine is set to its lowest level - 30 hertz - it means your muscles are doing 30 contractions a second. This means it is a more regulated and more intense form of exercise, says Casey Bawden, from HF Industries.
It can also work if you are standing still. This way the device can be used to improve the conditions of those who are unable to exercise rigorously due to age or infirmity.

"It helps reverse the effects of conditions such as osteoporosis and has been used to benefit people who cannot exercise regularly or who are in rehabilitation," Bawden says.

"We don't believe it should be used as an alternative to regular exercise - this is not an excuse to give up walking your dog - but it can enhance your existing training and give relief to some medical conditions."

The osteoporosis claim is backed by research from Leuven University in Belgium, which compared the results of three groups of healthy post-menopausal women over six months to assess the effects of body vibration training on bone mineral density compared with conventional resistance training.

The vibration group used the Power Plate and its body vibration technology as its training method three times a week for sessions lasting up to 20 minutes. The resistance group carried out conventional resistance training also three times a week but with sessions lasting up to one hour, while the control group did not engage in any training regimen.

The study measured bone-mineral-density effects on the hip and revealed a net increase of 1.51 per cent in the vibration group compared with no increases in bone mineral density in the resistance group.

Whole-body vibration, the term for the Power Plate effect, is not a new concept. Exercise scientists have been studying the effects of intense vibrations for four decades. Russian scientists discovered its benefits in the '70s when trying to find a workout that could be done in space. Until then, the weightless atmosphere had predisposed astronauts to osteoporosis but scientists found that standing on a vibrating platform stimulated muscle and bone development.

Since then, some trials have shown that regular use of vibration training methods increases muscle strength by 20 to 30 per cent more than ordinary weightlifting - and in 85 per cent less time.

In the medical world, there is growing acceptance of vibration machines for the treatment of cerebral palsy, osteoporosis, chronic pain and back injuries. Specialists treating people with spinal injuries and multiple sclerosis at the Royal National Orthopaedic Hospital in north London have had some promising results using the Power Plate.

George Waylonis, a clinical professor of physical medicine and rehabilitation at Ohio State University in the US, studied the effects of whole-body vibration on patients with fibromyalgia, a disease that causes constant full-body pain. He used the Power Plate and the Galileo, another vibration exercise machine, in his trials and was impressed by the results. It "seems to be a way for people in pain to exercise their muscles and feel better", he says.

Less convincing is the claim that it will get you fit in the time it takes to get changed for your usual gym session. Will standing on such a machine really tone muscle, increase flexibility and generally buff up your body in little more than 10 minutes, as the manufacturers would have us believe?

Cedric Bryant, chief exercise physiologist for the American Council on Exercise, a watchdog for the US fitness industry, has been looking into the benefits of such equipment. He says "conceptually, it has merit" but there is insufficient scientific research to support the fitness claims.

"This is not a magic bullet that helps people to lose weight without doing anything," he says. "If you are a healthy individual, whole-body vibration training should be a supplement to a sensible diet and exercise programme."

And while it might be good for one muscle group, it could strain another. "Those types of questions haven't been addressed sufficiently," he says.

Fiona McMahon, the health and wellness manager at the Melbourne Sports and Aquatic Centre - one of the few gyms in Australia that have the Power Plate - says the machine has a loyal following.

"Most of the members who use it do so to supplement their existing activity or to boost their fitness regimes," she says. "Those who are using it say they do feel a benefit, although we haven't been able to measure it exactly, but they love it and keep coming back, some of them several times a week.

"We have even had a member in a wheelchair who uses it by resting her feet upon it and she believes there is a benefit there."

Associate professor Aurelia Nattiv, a sports medicine specialist at the University of California in Los Angeles, says more research is needed.
"We have data but the results are inconsistent. Most of the studies have looked at one specific area such as knee extensor strength and jump height. And the results on those tests have been mixed."

Some researchers, such as Philip Clifford, professor of physiology at the Medical College of Wisconsin in the US, cite animal studies showing that extreme vibration is linked to circulatory problems, raising the question of whether the same problems might arise in people who use these machines.

Bryant and others also question whether whole-body vibration devices will get you fit quickly. "We don't know what the optimal training protocol would be in terms of frequency and duration and what types of exercises and positions are most effective," he says.

You cannot stand still on the Power Plate and hope to step off with abs and legs like Madonna's. "In some European countries it's been promoted as the only fitness tool you will ever need, but we don't believe that to be the case at all,'' Bawden says.

"It can enhance your regime and cater for those people who don't enjoy or who cannot exercise as they wish, but we don't pretend that it's a be all and end all to fitness training.''

- The Guardian, Additional reporting by Kylie Davis