The geometry of Alpine skis used to be long, straight, and narrow. These shapes started to change in ski season 1958-59 when skis became shorter with the introduction and acceptance of the Graduated Length Method (GLM) (Taylor, 1978). By the 1980s the straight shape of alpine skis started to disappear when several ski Companies first experimented with the deeper parabolic side-cut allowing greater carving (Masia, 2005). The last geometric alteration was introduced by Atomic in 1988, a wide ski, 115mm underfoot. This increased the ski surface area allowing increased floatation in powder snow. Ski geometry evolved in response to skier demand. Shorter to facilitate learning, increased side-cut to enhance carving, and lastly, increased width, to augment the skier's powder experience. To our knowledge short skis have not been scientifically challenged. Shaped ski have been compared to conventional side-cut ski by Bachrach et al. (2002) and Sahashi & Ichino (2001) compared conventional skis. Only Zorko et al. (2015) and Seifert et al. (2018) and Seifert et al. (2019) have examined skis of differing widths. While most of these geometric alterations have been advantageous to ski industry hard goods sales (SIA, 2017) in that they make skiing more "fun" (Freeskier, 2019), the width dimension is of concern to the ski racing community (Pisot et al., 2010; Supej & Holmberg, 2019). Ski width is dictated by the FIS (2018), although only the minimum width. This minimum width is reguiated because ski racing involves steep ski edge angles on hard snow. To accomplish this, a narrow ski underfoot is the desired tool (Vaverka & Vodickova, 2010). Even with a narrow ski, many training hours over many years are involved with a young skier acquiring optimal ski racing technique. There may be concern that a wide ski may not offerthe same learning Stimulus as the narrow race type ski (Fajen et al., 2008; Supej & Flolmberg, 2019). Ski racers may have concerns about the difference in kinematics on wide skis versus the narrow race ski width. Seifert et al. (2018) found less muscle activity of the gluteus medius, rectus femoris, vastus medialis, and tibialis anterior with the wide ski (WS) while free skiing. While during race Simulation, however, they found less musde activity with the rectus femoris, vastus medialis, peroneus longus, and tibialis anterior with the narrow ski (NS). Also, the WS resulted in greater knee extension by 15% which was similar to the 14% found by Zorko et al. (2015). Additionally, Seifert et al. (2018) found an increase muscle activity of gluteus maximus and peroneus longus on the WS free skiing and in the race course compared to the NS. From a ski characteristic perspective, peak edge angles were greater on the NS compared to the WS while free skiing and race Simulation. Past research with wide skis has been performed on hard or compacted snow (Seifert et al., 2018; Zorko et al., 2010) which may explain the difference in muscle activity, knee kinematics, and ski edge angle. The purpose of this study was to study the NS and WS in groomed (GR) and powder (POW) conditions. Specifically turn time, peak edge angle, where that peak edge angle occurred in the turn, and the peak angular velocity of the ski around its longitudinal axis.
© Copyright 2020 Science and Skiing VIII. Book of the 8th International Congress on Science and Skiing. Julkaistu Tekijä University of Jyväskylä; Vuokatti Sports Technology Unit of the Faculty of Sport and Health Sciences of the University of Jyväskylä. Kaikki oikeudet pidätetään. / Kääntänyt https://www.DeepL.com/Translator