A simple biomechanical observation started what is now the biggest innovation in footwear since the running shoe technology developments in the 1970's. The rocker sole shoe trend started in 1996 after Swiss engineer Karl Muller discovered that walking barefoot in the paddy fields of Korea changed his posture and relieved his back, knee and Achilles tendon pain. He also discovered that the Masai tribesman of East Africa don't suffer from back pain and are well known for their excellent posture. In both cases, the ground is soft and results in a soft landing heel strike. He realized that walking on hard modern surfaces like pavements is what causes much of the back, knee and heel pain we suffer from. So he set about to design a shoe with a different approach to imitate a soft landing. Hence the first curved sole Masai Barefoot Technology (MBT) shoe was born.
The basic premise of MBT's is that because of their rocker bottom, they result in an active rolling movement from heel to toe, decreasing impact forces, spreading the load across the foot more evenly and minimizing stresses up the kinetic chain.
By 2000, roughly 20,000 MBTs were sold in Europe alone and they gained popularity when celebrities started wearing them. Their popularity drew many other shoe manufacturers to design their own versions and to make marketing claims based on the instability underfoot concept, such as "Toning Shoes", "Total Body Shoes", Gyms for the Feet", all claiming to tone muscles, burn calories and even reduce cellulite. They based these claims on a study conducted by Sheffield Hallam University which showed an 18% increase in lower extremities muscle activity and a 2.5% increase in oxygen intake while walking (in MBT shoes as compared to conventional shoes) and a 38% increase in lower limbs muscle activity and a 28% increase in buttocks muscle activity while standing (in MBT shoes as compared to conventional shoes).
So, do they really work? The Sheffield Hallam University study certainly does indicate that wearing MBTs engages your muscles more and to some extent reduces strain on the body while walking. But there is no evidence that MBTs can help get rid of cellulite and burn extra calories. In fact, these claims are no longer made by manufacturers, but the perception still exists.
There is certainly anecdotal evidence from wearers that they have noticed improved tone in their legs and buttocks or have experienced relief from Achilles Tendonitis, heel pain or back pain. But there are also many people who have had to stop wearing them because they have aggravated or even caused bad backs or hips.
Dr Chris Kassaris, a board certified podiatrist in Connecticut, says that the smooth rocking motion can help certain patients who suffer from arthritic ankles, inflexible big toes or pain on the ball of the feet. But he quickly points out that there is no real evidence that changing your gait so dramatically will tone your muscles and help you lose weight. The only way to really do that, he says, is with good old fashioned diet and exercise. And he adds that if you notice any discomfort or pain after you start wearing rocker shoes, stop use immediately to avoid serious injury.
While MBTs and rocker bottoms are not for everyone, one thing is for sure, they are here to stay. They are available in many shapes and colors including the original MBTs, the most popular and affordable Sketchers Shape Ups and Reebok's Easytone. More recently, manufacturers have launched styles that are more dressy and there are even rocker flip-flops and sandals called Fit-Flops, so you can tone your legs all summer long!