The effect of boot stiffness on field and laboratory flexural behavior of alpine ski boots

The aim of this work was to study the effect of boot stiffness on the field and laboratory flexural behavior of alpine ski boots. Ski boots have a direct influence on performance, safety, and comfort of alpine skiers. Despite their technological evolution during a number of years, the parameters used in the evaluation of boot stiffness are not yet standardized and still require a shared engineering approach to achieve common quantitative definitions to be used either in boot classification or in boot selection for the different users. This work reports the boot flexion angles between shell and cuff and between cuff and tibia, collected during slalom tests on three boots with different nominal Flex Index. The laboratory data collected on the same boots under conventional cyclic bending tests are reported and compared with the field data for the development of a new test method more representative of the field behavior. As a result, clear definitions of Flex Index and of boot stiffness are introduced: boot stiffness had a clear effect on both the field and the laboratory flexural behavior of boots.