MBTs have been described as 'physiological footwear' and 'cellulite busters' because the structure of the sole of the shoes - designed to replicate a soft, natural surface - make walking harder. Walking in them is like walking on sand. Whereas conventional shoes support and lead the foot, stabilising the body, MBTs introduce an instability that must be constantly compensated for. They were created by Swiss engineer Karl Muller, who - after realising that walking barefoot on soft ground relieved his back pain - researched the Masai tribe (above) in Africa. They walk barefoot and have to balance their bodies with every step. Having used them for a year, I can vouch that you do work harder when walking because you use your leg and buttock muscles more.

What about the workout?

It's run by Lisa Cattermole Watkins, who introduced MBTs to Hong Kong. Cattermole Watkins is an instructor and MBT convert. The session starts with some light stretching and simple movements (legs to the side, squats, lunges and so on). Mat exercises - in which the MBT shoe is used to create drag and give the thighs a tough time - follow. What would otherwise be simple repetitive movements become increasingly difficult. The simple squat is also more of a challenge because of the imbalance created with an MBT, so righting yourself is part of the regime and requires more use of muscles in flabby areas. It's sure to get you working and toned if you stick with it and wear the shoes at other times of the day.

Any down side?

The shoes aren't exactly the height of fashion with their thick heels and soles (above), although some insiders say that they're the new cool thing on other shores. The growing range of colours - including black and pale blue - are giving them wider appeal.

How do I join a class?

Booking is essential. A single session is $150, but new clients get their first one for a knock-down $100. A four-class pass is $480 and eight classes are $920.

Do I need MBTs?

You can borrow a pair for two trial classes and then you have to buy - and they aren't cheap at $1,850 (for sports style) and $1,950 (lifestyle range) a pair. Having said that, when you're feeling the burn during a stroll or while shopping, they seem well worth it. Cattermole Watkins will also train you in how to walk in them.

Where's the workout?

At the MBT Bodyworks Studio, Unit 307, 3/F Westlands Centre, 20 Westlands Rd, Quarry Bay. Inquiries: 2335 1230. Classes are held Mon-Sat.