Flexion stiffness of a racing cross-country ski boot

Abstract

For greater energy efficiency of sports footwear, mass needs to be minimized while preserving other favourable characteristics. In this article, an analysis of the flexion stiffness of the foot region, precisely its middle region, of a specific racing cross-country ski boot for the skating technique regarding its mass was performed. On the basis of a complex finite element model of the ski boot and an existing boot stiffness measuring set-up, flexion stiffness portions, mass portions and flexion stiffness/mass portion ratios were determined for individual boot components regarding the middle boot region. These values were determined for the shoe-upper with strengthening bands and shoelaces (altogether S-U), the sole, the midsole and the glue layer between. The S-U turned out to contribute a high flexion stiffness portion to the boot’s middle region’s flexion stiffness and also its flexion stiffness/mass portion ratio turned out to be the highest. The midsole and the sole present the highest potential for flexion stiffness/mass optimization due to their lowest flexion stiffness/mass ratios and highest mass portions. In order to increase the flexion stiffness/mass ratio of the middle boot region, the sole’s and the midsole’s size portions should be reduced, while the S-U’s size portion should be increased. Beside these findings, other suggestions in order to increase the flexion stiffness/mass ratio of the boot’s middle region are also given.

Keywords

Footwear construction finite element analysis measurement flexion stiffness neutral bending axis metatarsophalangeal joint mass minimization component contribution stiffness/mass ratio skate cross-country skiing

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