People who walk a lot barefoot have thick and hard skin on their feet. Nevertheless, the calluses do not limit the sensitivity to the background. From this, researchers want to derive insights for optimal shoe soles.
In the endless dispute over the right running shoe – hard or soft, high or low or even completely without – adds a work in the journal Nature now add a new aspect. Properly demanded, researchers from Harvard, Chemnitz and several African universities found out, the foot builds an optimal shoe. It is called cornea and apparently manages to provide simultaneous protection and sensitivity to the ground. The scientists studied the feet of 81 Kenyans, 35 of whom were mostly barefoot, the rest mostly wearing shoes. Ultrasound measurements revealed that the soles of the barefoot runners had about 30 percent thicker and harder corneas than those of the shoe wearers. The researchers then used a vibrating device to stimulate two types of sole soles that are also required while walking. It turned out that the feet – whether full of calluses or with tender skin – were equally sensitive to stimuli. That the cornea does not affect the sensitivity, explain the researchers with their nature. It is hard and stiff and does not dampen the signals that affect the feet when touching the ground. This is different for shoes with soft soles and padded footbeds, which could affect walking and balance. From this point of view, it could make sense to wear shoes based on the model of the cornea and wear hard, flat soles. “Cornea is a remarkable example of a construction that was created in natural selection,” the researchers write. After all, man and his ancestors walked barefoot for six million years before putting on their shoes for the first time some 40,000 years ago.