MBT trainers seem like an unlikely item of footwear to catch the imagination of the young and trendy. With their thick, curved sole and sensible wide straps, they look like the sort of thing you need to wear if one of your legs is shorter than the other. Despite their distinct un-beauty, MBT trainers have, for the last eight years, been cited as the answer to modern-day solution for anything from back problems to cellulite on your bum.
As if the company were not doing a roaring trade as it is (MBTs are available in over 20 countries and sell one million pairs each year), they have now re-invented themselves as the "anti-shoe", by bringing out a new range that, although unconventional, are designed to look less like something prescribed by your doctor and more like something you might wear out of choice.
MBT stands for Masai Barefoot Technology and the shoes were invented by a Swiss engineer called Karl Müller in the early 1990s. He noticed, on a visit to Korea, that walking barefoot over some soft paddy fields alleviated his back, knee and Achilles tendon problems. He also discovered that the Kenyan Masai tribesmen don't suffer from back pain and are famous for their perfect posture. Putting these two pieces of information together, Muller reasoned that this was because they walk across ground that yields underneath their feet. Walking on hard surfaces, such as pavements, that don't have any "give", he concluded, has done our backs in. Not to mention our knees and ankles.
Muller decided that the answer was a shoe with a curved sole, effectively with no heel, which mimics the rocking motion of a foot walking on soft sand or grass.
The first prototype of the MBT trainer was constructed in 1996 and by 2000 approximately 20,000 pairs were sold in Switzerland, Austria and Germany, home to the ever-ugly Birkenstock – and even that was eclipsed in hideousness by the MBT.
Since then the shoe has exploded in popularity and despite its ugliness was leapt upon by celebrities such as Jemima Khan, Jodie Kidd, Sadie Frost - and anyone else who could afford the eye-watering £129 price tag.
In fact, the shoe has been so successful that other shoe manufacturers have taken up the idea. The FitFlop, launched last year, claims to lengthen and tone the leg with the sandal's built-in "micro-wobble board", which means the leg muscles have to work harder to stay balanced.
The claims of the MBT manufacturers are pretty bold. With correct usage, they say, MBTs will activate neglected muscles, improve your posture and gait, tone and shape your body, ease back, hip, leg and foot problems and help with joint, muscle, ligament and tendon injuries. There have also been claims that MBTs can help get rid of cellulite and burn extra calories (although these claims are no longer made by the manufacturers, the rumour persists, which may be why MBTs are predominantly bought and worn by women).
So do they really work? A Sheffield Hallam University study concluded that wearing MBTs was better for the knees, hips and ankles than wearing conventional shoes. "There was some reduction in strain on the body while walking in MBTs," says Tim Vernon, who led the study. "Also, if you walk properly in MBTs you should be making shorter strides than if you were wearing normal shoes and the more strides you take, the more work you're doing."
However, recently there has been speculation that MBTs may not be for everyone. "The claims as to assisting posture, back, hip and knee problems are not supported by evidence or any good rational explanation," says Dr David Johnson, consultant orthopaedic surgeon at St Mary's Hospital in Bristol. "Indeed the instability provoked [by the shoe] will increase the muscle activity and energy required to walk – thus increasing fatigue and tiredness. Technically, the increased need for this muscular activity in stabilising is not "natural" or "physiological" and would increase rather than decrease stress and pressure on all these areas of the body which, rather than be helpful, may be detrimental."
Laura Williams, diet and fitness expert, thinks that while wearing the shoe is better than nothing, nothing replaces learning good posture, permanently. "Of my clients who have tried MBTs, some have had to stop wearing them because they have aggravated bad backs and hips. The problem is that everyone has their own bio-mechanical quirks and if you wear these shoes without proper recommendation and instruction, they can make things worse. And then, what happens when you take the shoes off? I always think that if you were to go to a couple of Pilates classes then you would be able to improve your posture yourself, but some people simply aren't going to do that. And I've certainly seen anecdotal evidence that they do work for some people, just not for everyone."
However, she rejects any idea that the shoes beat cellulite. "I just can't see how they could help. Cellulite is just the way that women store fat. Specific weight training and some caffeine-based creams are the only things that have been shown to do anything to the appearance of cellulite. To make any difference to your muscle tone you have to be lifting quite a lot of weight at 20 repetitions; even if the shoes do, as they claim, activate your glutes [the bottom's muscles] by nine per cent, I can't see that making any difference."
Hannah Snow, 31, an events organiser, bought her MBT trainers five years ago and wore them daily for two years. "At my old job I walked into work four miles each way and I was finding it quite easy in normal trainers. I wanted to step up the work-out but I didn't want to run into work and so these trainers seemed like a good idea – and everyone else was raving about them. I wasn't convinced - and they were hideous - but I gave them a go. They toned my muscles but they didn't do anything about the fine layer of cellulite that covered some of the top parts of my leg – so I had all these toned muscles but you couldn't see them!"
Sammy Margo of the Chartered Society of Physiotherapists believes that MBTs are not necessarily a bad thing – but they're not for everyone. "They can possibly help people with stiff backs, who do jobs that involve a lot of standing. Ideally, you should get them only on the recommendation of a physiotherapist and should be trained to use them properly. They are not a cure-all for modern life."