This article presents a study of torsion stiffness of a specific racing cross-country ski boot for the skating technique conducted by means of numerical analyses and measurements. Its aim is to determine relative torsion stiffness contributions, relative mass contributions, and the ratios between them (torsion stiffness/mass ratios) for individual boot components of the torsionally most deformable part of the boot. These are basic data for torsion stiffness-mass optimization of the boot. For acquiring these data, a complex finite element model of the cross-country ski boot and an artificial silicone foot were created in different versions after an existing device designed for measurement of stiffness properties of the boots. Material properties employed in the model were acquired experimentally. The confirmed model was used for determination of the torsion deformation contributions of different regions of the boot. Focus was given to the middle region, whose contribution is the largest. The aforementioned data were determined for individual boot components of this region. The soles, which contribute the most to the middle region's torsion stiffness, turned out to have the highest potential for torsion stiffness-mass optimization, because of their lowest torsion stiffness/mass ratio and highest mass contribution. The shoe-upper has the highest torsion stiffness/mass ratio and is, therefore, the most worthwhile to be enlarged. The torsion stiffness/mass ratio of the strengthening bands is lower than expected and could likely be increased by their positioning.

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.

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The technologies for low-quantity production of sheet metal components and parts are applied mostly for thin single metal sheets. However, such technologies could also be applied as an additional procedure in multi-layer construction element production. Such individually produced construction elements must correspond to required standards, which are usually applied in serial production. Due to the immense testing work expected by custom-made production, it is reasonable to develop a methodology that would be capable of predicting the required results of an individually designed and produced construction block quickly, effectively and with minimal costs. In this investigation, a method of predicting the load capacity behavior of individual construction elements performed by incremental forming as an additional technology in multi-layer construction element production is presented. Special attention is dedicated to the definition of finite element model of a standardized four-point bending test and its correlation to real experimental results.