{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,8]],"date-time":"2026-02-08T18:25:57Z","timestamp":1770575157790,"version":"3.49.0"},"reference-count":36,"publisher":"MDPI AG","issue":"15","license":[{"start":{"date-parts":[[2022,8,2]],"date-time":"2022-08-02T00:00:00Z","timestamp":1659398400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Austrian Federal Ministry for Transport, Innovation and Technology"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Introduction: Ski deflection is a performance-relevant factor in alpine skiing and the segmental and temporal curvature characteristics (m\u22121) along the ski have lately received particular attention. Recently, we introduced a PyzoFlex\u00ae ski deflection measurement prototype that demonstrated high reliability and validity in a quasi-static setting. The aim of the present work is to test the performance of an enhanced version of the prototype in a dynamic setting both in a skiing-like bending simulation as well as in a field proof-of-concept measurement. Material and methods: A total of twelve sensor foils were implemented on the upper surface of the ski. The ski sensors were calibrated with an empirical curvature model and then deformed on a programmable bending robot with the following program: 20 times at three different deformation velocities (vslow, vmedium, vfast) with (1) central bending, (2) front bending, (3) back bending, (4) edging left, and (5) edging right. For reliability assessment, pairs of bending cycles (cycle 1 vs. cycle 10 and cycle 10 vs. cycle 20) at vslow, vmedium, and vfast and between pairs of velocity (vslow vs. vmedium and vslow vs. vfast) were evaluated by calculating the change in the mean (CIM), coefficient of variation (CV) and intraclass correlation coefficient (ICC 3.1) with a 95% confidence interval. For validity assessment, the calculated segment-wise mean signals were compared with the values that were determined by 36 infrared markers that were attached to the ski using an optoelectrical measuring system (Qualisys). Results: High reliability was found for pairs of bending cycles (CIM \u22120.69\u20130.24%, max CV 0.28%, ICC 3.1 &gt; 0.999) and pairs of velocities (max CIM = 3.03%, max CV = 3.05%, ICC 3.1 = 0.997). The criterion validity based on the Pearson correlation coefficient was r = 0.98. The accuracy (systematic bias) and precision (standard deviation), were \u22120.003 m\u22121 and 0.047 m\u22121, respectively. Conclusions: The proof-of-concept field measurement has shown that the prototype is stable, robust, and waterproof and provides characteristic curvature progressions with plausible values. Combined with the high laboratory-based reliability and validity of the PyzoFlex\u00ae prototype, this is a potential candidate for smart ski equipment.<\/jats:p>","DOI":"10.3390\/s22155768","type":"journal-article","created":{"date-parts":[[2022,8,3]],"date-time":"2022-08-03T00:15:26Z","timestamp":1659485726000},"page":"5768","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":10,"title":["Validation of a Sensor-Based Dynamic Ski Deflection Measurement in the Lab and Proof-of-Concept Field Investigation"],"prefix":"10.3390","volume":"22","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-5685-9821","authenticated-orcid":false,"given":"Christoph","family":"Thorwartl","sequence":"first","affiliation":[{"name":"Department of Sport and Exercise Science, University of Salzburg, Schlossallee 49, 5400 Hallein\/Rif, Austria"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Josef","family":"Kr\u00f6ll","sequence":"additional","affiliation":[{"name":"Department of Sport and Exercise Science, University of Salzburg, Schlossallee 49, 5400 Hallein\/Rif, Austria"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6472-2553","authenticated-orcid":false,"given":"Andreas","family":"Tschepp","sequence":"additional","affiliation":[{"name":"Joanneum Research Forschungsgesellschaft mbH, Franz-Pichler-Stra\u00dfe 30, 8160 Weiz, Austria"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Helmut","family":"Holzer","sequence":"additional","affiliation":[{"name":"Atomic Austria GmbH, Atomic Strasse 1, 5541 Altenmarkt, Austria"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Wolfgang","family":"Teufl","sequence":"additional","affiliation":[{"name":"Department of Sport and Exercise Science, University of Salzburg, Schlossallee 49, 5400 Hallein\/Rif, Austria"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6685-1540","authenticated-orcid":false,"given":"Thomas","family":"St\u00f6ggl","sequence":"additional","affiliation":[{"name":"Department of Sport and Exercise Science, University of Salzburg, Schlossallee 49, 5400 Hallein\/Rif, Austria"},{"name":"Red Bull Athlete Performance Center, Brunnbachweg 71, 5303 Thalgau, Austria"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,8,2]]},"reference":[{"key":"ref_1","first-page":"117","article-title":"Mechanics of the turning snow ski","volume":"Volume 1","author":"Johnson","year":"1985","journal-title":"Skiing Trauma and Safety: Fifth International Symposium"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"721","DOI":"10.1016\/0020-7403(89)90040-4","article-title":"A model for the turning snow ski","volume":"31","author":"Renshaw","year":"1989","journal-title":"Int. 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