INTRODUCTION: Ski length influences many on-snow characteristics, including stability, versatility and playfulness [1]. However, modern skis can vary from 145 to 195 cm, while a skier can easily use skis that vary by as much as 20 cm depending on the usage. As such, one of the most important questions customers are faced with is the selection of a suitable ski length. Existing selection rules typically use height to facilitate their application in shops, with various adjustments for terrain, skills, and skiing style. As the loads perceived by a ski depend on the skier`s mass and acceleration, better sizing rules are envisioned. Furthermore, as the mechanical properties also influence the perception of length, understanding their scaling would allow for a better description of skis (e.g., feel longer than expected). METHODS: A database of the mechanical properties of more than 5000 alpine skis is used (i.e., SoothSki [2]). Various length-related properties are investigated to find a length selection factor that would stay constant across all skis. Then, many mechanical properties (e.g., EI, GJ, mass, sidecut radius, stability) are normalized with different techniques to observe how they vary or stay constant across all lengths and widths. Percentile levels and spreads are extracted to better qualify these properties when compared to similar skis. RESULTS/DISCUSSION: Results show that the 10 and 90 percentile levels of sidecut length are uniform for skis between 80 and 110 mm wide, while the lengths vary by about 15 cm (left figure). This suggests that a percentile ranking of skiers` applied loads could be used for ski length selection. Furthermore, many mechanical properties are scaling in interesting ways with length and waist width. For example, the average bending stiffness (EI) is scaling approximately linearly with length uniformly across all waist widths (right figure). The spread of bending stiffnesses observed between the 20 and 80 percentile levels is also constant at about 25% while the torsional stiffness (GJ) varies and can reach up to 80%. CONCLUSION: A large dataset of mechanical properties was used to investigate constant length selection factors and the scaling of mechanical properties across all lengths and waist widths. One can imagine that skiers` applied loads could be mapped to these observed variations to select suitable lengths and mechanical property levels.
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