Over the past year, I have been asked on several occasions to express my opinion on the benefits and risks of wearing unconventional footwear such as MBT™ (Masai Barefoot Technology) shoes , Sketchers “Shape Up”™ shoes and other similar shoes.
I have reviewed research presented at scientific seminars, talked to a MBT footwear medical representative and I have also received feedback from a few patients over the past year who have used MBT shoes or other similar shoes. In this blog I will discuss the design of MBT footwear and its effects on the thigh and lower leg muscles while standing and walking in MBT footwear. I will also discuss the effects on ankle joint motion while walking in MBT footwear.
MBT footwear was developed in Switzerland in 1996 and came to North America in 2003. The unstable MBT shoe has been promoted as the original “barefoot” function shoe. This shoe has a rounded sole starting from the heel and continues to the toe and a cushioned sensor under the heel area that creates a natural degree of instability. This instability is felt from both the back to front directions and from inside to outside directions. The basic concept behind the unstable shoe is to transform flat and hard surfaces such as concrete sidewalks into uneven surfaces such as grass or sand. The design of the MBT footwear has been promoted to provide some of the benefits of barefoot walking.
The features of MBT footwear are thought to specifically activate, strengthen and condition the smaller neglected extrinsic foot muscles that originate in the lower leg and attach via tendons into the foot. This muscle activation is thought to occur while standing or walking in MBT footwear. By activating these neglected muscles, posture and gait could be improved and the loads or stresses on the lower limb joints may be reduced to help prevent injuries and reduce pain.
MBT footwear has been studied by a few university based biomechanics research laboratories. It is important to note the findings of these research papers can only be applied to MBT shoes and cannot be compared to similar type shoes such as Sketcher™ “Shape Up” shoes because of the shoe design differences.
In 2005, the University of Calgary Biomechanics laboratory conducted one study observing the effect on muscle activity while subjects just stood while wearing MBT shoes. When we stand, the muscles in our legs and thighs are active to prevent us from buckling at our hips, knees and ankles. The results of this study demonstrated an increase in the activity of many of the lower leg and thigh muscles while subjects stood wearing MBT shoes. These results seem to be consistent with the muscle activation benefits as promoted by the makers of MBT shoes. The researchers also measured postural sway of the upper body while standing and wearing a MBT shoe. Postural sway is the phenomenon of constant displacement and correction of the position of the center of gravity within the base of support. In layman’s terms this describes is our ability to keep balanced without falling over. Using a MBT shoe is similar to balancing on a wobble board. Wobble boards are used for rehab after an ankle sprain which helps to strengthen muscles around an injured ankle joint and promote balance. Postural sway increased while wearing MBT shoes compared to a New Balance shoe.
In 2005, the University of Calgary Biomechanics Laboratory conducted a second study where they compared subjects wearing a New Balance 756 running shoe and subjects wearing MBT shoes while walking. The investigators measured the differences in muscle activity and ankle joint motion. They found increased muscle activity in the subjects in the MBT shoe group versus the subjects in the New Balance shoe group. Again these results were consistent with the muscle activation benefits as promoted by the makers of MBT shoes.
Wearing MBT shoes while walking caused an increase in ankle joint dorsiflexion (dorsiflexion of the ankle happens when you move your foot towards your leg) from initial heel contact through to midstance (midstance is the time when your swinging leg is even to your weight bearing foot and leg). Increased ankle dorsiflexion at contact to midstance makes your calf muscle stretch more while walking as compared to subjects wearing the New Balance shoe.
In 2009 researchers at Stanford University conducted a study examining what happened when individuals ran in MBT shoes versus New Balance 658 running shoes. They found running in MBT footwear led to a greater amount of ankle dorsiflexion from initial heel contact through to midstance. If you have tight calf muscles the use of MBT footwear while walking or running may cause strain on the tendo Achilles leading to tendinitis.
These increases in muscular activity that have been reported in these studies have led to the “Toning or Physiological” footwear category. A number of shoe companies have developed their own Toning or Physiological footwear to capitalize on the popularity of MBT footwear. Until research has been conducted on these other “Toning and Physiological” shoe brands you can not apply the MBT footwear research findings to other shoe brands.
In my next blog, I will outline the lower leg and foot problems that can be relieved by wearing MBT shoes and the lower leg and foot problems that will be aggravated if you wear MBT footwear.