Contact
Need help?
For technical questions about your Moticon products
Want to say hello?
Drop us a message for general questions or inquiries
Want a live demo?
See our products live and ask your questions
Interested in prices?
Get an individual quote with the items you need
Always just a call away
+49 89 2000 301 60

Sensors

| 2023

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 (𝑤″), demonstrating high reliability and validity. The value of 𝑤″ increases as a result of enlargement of the roll angle (𝑅𝐴) and the radial force (𝑅𝐹) and consequently minimizes the radius of the turn, preventing skidding. This study aims to analyze segmental 𝑤″ differences along the ski, as well as to investigate the relationship among segmental 𝑤″, 𝑅𝐴, and 𝑅𝐹 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 𝑅𝐴 and 𝑅𝐹, and six PyzoFlex® sensors were used to measure the 𝑤″ progression along the left ski (𝑤″1−6). All data were time normalized over a left-right turn combination. Correlation analysis using Pearson’s correlation coefficient (𝑟) was conducted on the mean values of 𝑅𝐴, 𝑅𝐹, and segmental 𝑤″1−6 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 (𝐿2vs. 𝐿3) and the three front sensors (𝐿4vs. 𝐿5, 𝐿4vs. 𝐿6, 𝐿5vs. 𝐿6) was mostly high (0.50) to very high (𝑟0.70). During carving turns, the correlation between 𝑤″ of the rear (𝑤″1−3) and that of front sensors (𝑤″4−6) of the outer ski was low (ranging between −0.21 and 0.22) with the exception of high correlations during COM DC II (𝑟= 0.51–0.54). In contrast, for parallel ski steering, the 𝑟 between the 𝑤″of the front and rear sensors was mostly high to very high, especially for COM DC I and II (𝑟= 0.48–0.85). Further, a high to very high correlation (𝑟 ranging between 0.55 and 0.83) among 𝑅𝐹
, 𝑅𝐴, and 𝑤″of the two sensors located behind the binding (𝑤″2,𝑤″3) in COM DC I and II for the outer ski during carving was found. However, the values of 𝑟 were low to moderate (𝑟= 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 𝑤″ 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.

Keywords

bending sensors, flexion, PyzoFlex, ski bending, ski deflection

Author/s

Christoph Thorwartl, Andreas Tschepp, Michael Lasshofer, Helmut Holzer, Martin Zirkl, Matthias Hammer, Barbara Stadlober, Thomas Stöggl

Institution / Department

Department of Sport and Exercise Science, University of Salzburg, Hallein

The form was sent successfully.

You will be contacted shortly.

moticon-rego-sensor-insole-live-event

Stay one step ahead!

Subscribe to our newsletter for the latest information on case studies, webinars, product updates and company news

Get support

Check our FAQ database for answers to frequently asked questions!


Describe your issue in as much detail as possible. Include screenshots or files if applicable.


Have a general inquiry?

Write us a message for general questions about products and solutions or if you’d like to discuss other topics.