{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,14]],"date-time":"2026-01-14T16:11:37Z","timestamp":1768407097998,"version":"3.49.0"},"reference-count":54,"publisher":"MDPI AG","issue":"15","license":[{"start":{"date-parts":[[2020,7,29]],"date-time":"2020-07-29T00:00:00Z","timestamp":1595980800000},"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, the Austrian Federal Ministry for Digital and Economic Affairs, and the federal state of Salzburg","award":["20715837"],"award-info":[{"award-number":["20715837"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In alpine skiing, four commonly used turning styles are snowplow, snowplow-steering, drifting and carving. They differ significantly in speed, directional control and difficulty to execute. While they are visually distinguishable, data-driven classification is underexplored. The aim of this work is to classify alpine skiing styles based on a global navigation satellite system (GNSS) and inertial measurement units (IMU). Data of 2000 turns of 20 advanced or expert skiers were collected with two IMU sensors on the upper cuff of each ski boot and a mobile phone with GNSS. After feature extraction and feature selection, turn style classification was applied separately for parallel (drifted or carved) and non-parallel (snowplow or snowplow-steering) turns. The most important features for style classification were identified via recursive feature elimination. Three different classification methods were then tested and compared: Decision trees, random forests and gradient boosted decision trees. Classification accuracies were lowest for the decision tree and similar for the random forests and gradient boosted classification trees, which both achieved accuracies of more than 93% in the parallel classification task and 88% in the non-parallel case. While the accuracy might be improved by considering slope and weather conditions, these first results suggest that IMU data can classify alpine skiing styles reasonably well.<\/jats:p>","DOI":"10.3390\/s20154232","type":"journal-article","created":{"date-parts":[[2020,7,30]],"date-time":"2020-07-30T03:36:38Z","timestamp":1596080198000},"page":"4232","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":31,"title":["Classification of Alpine Skiing Styles Using GNSS and Inertial Measurement Units"],"prefix":"10.3390","volume":"20","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2773-5034","authenticated-orcid":false,"given":"Christina","family":"Neuwirth","sequence":"first","affiliation":[{"name":"Salzburg Research Forschungsgesellschaft m.b.H., Techno-Z III, Jakob-Haringer-Stra\u00dfe 5, 5020 Salzburg, Austria"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2731-4662","authenticated-orcid":false,"given":"Cory","family":"Snyder","sequence":"additional","affiliation":[{"name":"Department of Sport and Exercise Science, University of Salzburg, Schlossallee 49, 5400 Hallein\/Rif, Austria"},{"name":"Athlete Performance Center\u2014Red Bull Sports, 5020 Salzburg, Austria"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9022-243X","authenticated-orcid":false,"given":"Wolfgang","family":"Kremser","sequence":"additional","affiliation":[{"name":"Salzburg Research Forschungsgesellschaft m.b.H., Techno-Z III, Jakob-Haringer-Stra\u00dfe 5, 5020 Salzburg, Austria"}]},{"given":"Richard","family":"Brunauer","sequence":"additional","affiliation":[{"name":"Salzburg Research Forschungsgesellschaft m.b.H., Techno-Z III, Jakob-Haringer-Stra\u00dfe 5, 5020 Salzburg, Austria"}]},{"given":"Helmut","family":"Holzer","sequence":"additional","affiliation":[{"name":"Atomic Austria GmbH, Atomic Strasse 1, 5541 Altenmarkt, Austria"}]},{"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":"Athlete Performance Center\u2014Red Bull Sports, 5020 Salzburg, Austria"}]}],"member":"1968","published-online":{"date-parts":[[2020,7,29]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1","DOI":"10.3389\/fphys.2018.00743","article-title":"A Critical Review of Consumer Wearables, Mobile Applications, and Equipment for Providing Biofeedback, Monitoring Stress, and Sleep in Physically Active Populations","volume":"9","author":"Peake","year":"2018","journal-title":"Front. 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