Technique-Dependent Relationship between Local Ski Bending Curvature, Roll Angle and Radial Force in Alpine Skiing

Skiing technique, and performance are impacted by the interplay between ski and snow. The resulting deformation characteristics of the ski, both temporally and segmentally, are indicative of the unique multi-faceted nature of this process. Recently, a PyzoFlex(®) ski prototype was presented for measuring the local ski curvature ([Formula: see text]), demonstrating high reliability and validity. The value of [Formula: see text] increases as a result of enlargement of the roll angle ([Formula: see text]) and the radial force ([Formula: see text]) and consequently minimizes the radius of the turn, preventing skidding. This study aims to analyze segmental [Formula: see text] differences along the ski, as well as to investigate the relationship among segmental [Formula: see text] , [Formula: see text] , and [Formula: see text] for both the inner and outer skis and for different skiing techniques (carving and parallel ski steering). A skier performed 24 carving and 24 parallel ski steering turns, during which a sensor insole was placed in the boot to determine [Formula: see text] and [Formula: see text] , and six PyzoFlex(®) sensors were used to measure the [Formula: see text] progression along the left ski ([Formula: see text]). All data were time normalized over a left-right turn combination. Correlation analysis using Pearson’s correlation coefficient ([Formula: see text]) was conducted on the mean values of [Formula: see text] , [Formula: see text] , and segmental [Formula: see text] for different turn phases [initiation, center of mass direction change I (COM DC I), center of mass direction change II (COM DC II), completion]. The results of the study indicate that, regardless of the skiing technique, the correlation between the two rear sensors ([Formula: see text] vs. [Formula: see text]) and the three front sensors ([Formula: see text] vs. [Formula: see text] , [Formula: see text] vs. [Formula: see text] , [Formula: see text] vs. [Formula: see text]) was mostly high ([Formula: see text] > 0.50) to very high ([Formula: see text] > 0.70). During carving turns, the correlation between [Formula: see text] of the rear ([Formula: see text]) and that of front sensors ([Formula: see text]) of the outer ski was low (ranging between −0.21 and 0.22) with the exception of high correlations during COM DC II ([Formula: see text] = 0.51–0.54). In contrast, for parallel ski steering, the [Formula: see text] between the [Formula: see text] of the front and rear sensors was mostly high to very high, especially for COM DC I and II ([Formula: see text] = 0.48–0.85). Further, a high to very high correlation ([Formula: see text] ranging between 0.55 and 0.83) among [Formula: see text] , [Formula: see text] , and [Formula: see text] of the two sensors located behind the binding ([Formula: see text]) in COM DC I and II for the outer ski during carving was found. However, the values of [Formula: see text] were low to moderate ([Formula: see text] = 0.04–0.47) during parallel ski steering. It can be concluded that homogeneous ski deflection along the ski is an oversimplified picture, as the [Formula: see text] pattern differs not only temporally but also segmentally, depending on the employed technique and turn phase. In carving, the rear segment of the outer ski is considered to have a pivotal role for creating a clean and precise turn on the edge.