Aerts P, De Clercq D
Department of Biology, University of Antwerp (UIA), Ghent, Belgium.
J Sports Sci. 1993 Oct;11(5):449-61. doi: 10.1080/02640419308730011.
Impact tests using a pendulum were performed on the shod heel region of nine subjects. Both soft- and hard-soled shoes were used. The deformations involved were calculated from the registered decelerations during impact. Thus, load-deformation cycles were recorded for various impact velocities. In contrast to in vivo force-platform recordings, peak loadings for the soft- and hard-soled conditions differed significantly (614 +/- 29 N vs 864 +/- 49 N, respectively), thus challenging the evidence for compensation at the level of the heel pad. Moreover, computation of the compression of the heel pad in the shoe showed an unexpected inverse relationship between shoe midsole hardness and degree of heel pad compression: the harder the midsole, the smaller the compression (soft shoe 7.6 +/- 0.9 mm; hard shoe 6.7 +/- 0.9 mm). This can be explained by assuming a loading rate dependent stiffness of the heel pad in the shod condition (stiffness in N.m-1 = 51.25x (loading rate in N.s-1)0.76; R2 = 0.90), determined by the visco-elastic nature of the heel pad and the spatial confinement of the heel counter of the shoe.
对9名受试者穿着鞋子的脚后跟区域进行了摆锤冲击试验。使用了软底鞋和硬底鞋。所涉及的变形是根据冲击过程中记录的减速度计算得出的。因此，记录了不同冲击速度下的载荷-变形循环。与体内测力平台记录不同，软底和硬底条件下的峰值载荷有显著差异（分别为614±29 N和864±49 N），这对足跟垫水平补偿的证据提出了挑战。此外，计算鞋子中足跟垫的压缩量显示，鞋中底硬度与足跟垫压缩程度之间存在意想不到的反比关系：中底越硬，压缩越小（软底鞋7.6±0.9 mm；硬底鞋6.7±0.9 mm）。这可以通过假设在穿鞋状态下足跟垫的刚度与加载速率有关来解释（刚度单位为N.m-1 = 51.25x（加载速率单位为N.s-1）0.76；R2 = 0.90），这是由足跟垫的粘弹性性质和鞋子后跟围的空间限制决定的。
