Dai Xiao-Qun, Li Yi, Zhang Ming, Cheung Jason Tak-Man
Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, PR China.
Clin Biomech (Bristol). 2006 Mar;21(3):314-21. doi: 10.1016/j.clinbiomech.2005.10.002. Epub 2005 Nov 18.
Except the plantar pressure and gross joint motion, we know little about the mechanical state of a foot during walking. This study aimed at investigating the effect of wearing socks with different frictional properties on plantar shear, which is a possible mechanical risk factor of foot lesion development.
A 3-D finite element model for simulating the foot-sock-insole contact was developed to investigate the biomechanical effects of wearing socks with different combinations of frictional properties on the plantar foot contact. The dynamic plantar pressure and shear stress during the stance phases of gait were studied through finite element computations. Three cases were simulated, a barefoot with a high frictional coefficient against the insole (0.54) and two socks, one with a high frictional coefficient against the skin (0.54) and a low frictional coefficient against the insole (0.04) and another with an opposite frictional properties assignment.
Wearing sock of low friction against the insole to allow more relative sliding between the plantar foot and footwear was found to reduce the shear force significantly: at the rearfoot from 3.1 to 0.88 N, and at the forefoot from 10.61 to 1.61 N. The shear force can be further reduced to 0.43 N at the rearfoot, and 1.18 N at the forefoot, when wearing the sock with low friction against the foot skin and high friction set against the insole.
Wearing sock with low friction against the foot skin was found to be more effective in reducing plantar shear force on the skin than the sock with low friction against the insole. The risk of barefoot walking in developing plantar shear related blisters and ulcers might be reduced by socks wearing especially those with low friction against the foot skin.
除了足底压力和关节总体运动外，我们对步行过程中足部的力学状态了解甚少。本研究旨在探究穿着具有不同摩擦特性的袜子对足底剪切力的影响，足底剪切力是足部病变发展的一个可能的力学危险因素。
建立了一个用于模拟足部 - 袜子 - 鞋垫接触的三维有限元模型，以研究穿着具有不同摩擦特性组合的袜子对足底接触的生物力学影响。通过有限元计算研究了步态站立期的动态足底压力和剪切应力。模拟了三种情况，一种是与鞋垫具有高摩擦系数（0.54）的赤脚情况，以及两种袜子，一种是与皮肤具有高摩擦系数（0.54）且与鞋垫具有低摩擦系数（0.04）的袜子，另一种是摩擦特性相反的袜子。
发现穿着与鞋垫低摩擦的袜子，使足底与鞋类之间有更多相对滑动，可显著降低剪切力：在后足处从3.1 N降至0.88 N，在前足处从10.61 N降至1.61 N。当穿着与足部皮肤低摩擦且与鞋垫高摩擦的袜子时，后足处的剪切力可进一步降至0.43 N，前足处降至1.18 N。
发现穿着与足部皮肤低摩擦的袜子比与鞋垫低摩擦的袜子在降低皮肤表面的足底剪切力方面更有效。穿着袜子，尤其是与足部皮肤低摩擦的袜子，可能会降低赤脚行走时发生与足底剪切相关的水泡和溃疡的风险。
