Effects of silicon-insole socks on pressure distribution and shear force of the foot.

Many problems of the foot are due to abnormal plantar pressure and shear force, but until now shear force could not be accurately measured. Different methods can be used to reduce foot pressure, such as foot orthosis or shoe modification. The purposes of our study were to propose a method for measuring the maximum shear force of the foot and also to investigate the effect of silicone-insole socks in reducing the peak plantar pressure and shear stress of the foot.Twenty-two healthy subjects were included in this study, each subject underwent 2 kinds of experiments to study the peak plantar pressure, the horizontal shear reaction force, and the maximum shear force under 3 conditions: barefoot, wearing 100% cotton socks, and wearing silicone-insole socks.Our results showed a significant decrease in midfoot peak plantar pressure while walking, and a decrease in horizontal shear reaction force and maximum shear force while wearing cotton socks and silicone-insole socks in walking and pulling. Silicone-insole socks were more significant in decreasing horizontal shear reaction force than cotton socks.Silicone-insole socks are better than cotton socks in reducing horizontal shear reaction forces and their friction coefficients. Because only normal subjects have been tested, further study is required to prove the efficacy of silicone-insole socks on different kinds of foot pathology.