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  • 1.
    Bäckström, Mikael
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Kuzmin, Leonid
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Rännar, Lars-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Wiklund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Critical Factors Influencing Loss of Time after Shooting - A Case Study Performed During the 2008 IBU Biathlon World Championships2009In: The Impact of Technology on Sport III, 2009, p. 33-37Chapter in book (Other academic)
    Abstract [en]

    The final result during a biathlon race is a composition of skiing, shooting and in some cases penalty time or rounds. One of the most decisive parts of the competition is the shooting component. The shooting component itself can be subdivided into separate parts: Actions just before shooting, the shooting itself and actions after the shooting. In the case of a slow approach to the firing line partially caused by dismounting of ski poles, time loss is tactically accepted by some skiers – heart rate decreases and a mental focus can be obtained. A slow departure from the firing line and the subsequent loss of time is on the contrary absolutely not desirable. A part of the lost time after shooting is observed to be related to mounting the ski poles. Modern ski poles can be divided into three groups of strap systems: 1. Simple loop; 2. Strap with Velcro fastener; 3. Click-in (typically Leki).

    The paper presents a case study aimed at finding how the ski pole strapping system influences time loss after shooting. The study was performed during the IBU Biathlon World Championship 2008 in Östersund, Sweden. Time measurements were made over a defined distance allowing the athletes to approach cruising speed after the last shot in a series. The measurements for each athlete have been normalized relative his/her racing performance. The results clearly indicate time differences between strap systems. In some cases the differences could mean achieving podium place or not.

  • 2.
    Bäckström, Mikael
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Rännar, Lars-Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Kuzmin, Leonid
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Influencing factors on time-loss after shooting in Biathlon2011In: Moderns systems for application in Biathlon, Omck: Russian Sports Federation , 2011, p. 154-159Conference paper (Refereed)
  • 3.
    Dahlen, Leon
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Carlsson, Peter
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Kuzmin, Leonid
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Olsson, Nils
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Tinnsten, Mats
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Adventure technology and sport science - A research project at Mid Sweden University: 5th international engineering of sport. 13-16 september, UC Davis, USA.2004Conference paper (Other scientific)
  • 4.
    Koptyug, A.
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Kuzmin, Leonid
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Experimental field studies of the cross-country ski running surface interaction with snow2011In: Procedia Engineering, Elsevier, 2011, Vol. 13, p. 23-29Conference paper (Refereed)
    Abstract [en]

    The ability of the cross-country skis to glide freely is of very high importance for both sports and recreational skiing. Significant body of research and development is nowadays devoted to the materials and treatment methods for improving gliding of the ski running surfaces, as well as to the related skiing techniques for optimal use of ski gliding. One of the common concepts here is that the most significant energy loss contribution in such interaction is caused by the pure interfacial friction of the ski running surface and the snow. But this interaction is quite complex and we have proposed that other channels of the energy loss can be of significance. Among the possibilities one can point out to the effects of the snow deformation under the skis, "dragging" of snow by the skis and damping of the ski vibrations by the snow. Present paper reports on the field experimental studies of the ski interaction with the snow. These studies are aiming at developing the measurement technology allowing the assessment of gliding properties of the cross-country skis when data are collected from the sensors placed into the ski track.

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  • 5.
    Kuzmin, Leonid
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Interfacial kinetic ski friction2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    It is no doubt, that the ski glide over the snow is a very complicated object of

    research. However, ski glide is just a one area of many other areas of human

    knowledge. As a rule, the scientists and practitioners, who work in these areas,

    operate with some publicly expressed more or less solid hypotheses. These

    researchers work with one hypothesis until another and a better one comes up.

    Our literature studies and our own observations regarding modern skis

    preparations, did not give us any solid hypotheses, which are able to explain the

    actual form and content of this procedure. The present work is an attempt to reveal

    such hypotheses.

    Conclusion: To achieve an optimal glide on skis with the base (the ski sole)

    made of some high hydrophobic durable polymer, e.g. UHMWPE, PTFE; we only

    have to create an adequate topography (texture) on the ski running surface,

    adequate to the actual snow conditions.

     

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  • 6.
    Kuzmin, Leonid
    Luleå University of Technology, Departament of Applied Physics and Mechanical Engineering, Division of Computer Aided Design.
    Investigation of the most essential factors influencing ski glide2006Licentiate thesis, comprehensive summary (Other scientific)
    Abstract [en]

    There are many different parameters of a ski running surface (material, roughness, hydrophobicity, etc.). All the parameters have an influence on ski glide, some more and some less. Furthermore, some parameters with only minor relevance are commonly declared as critical, while truly critical parameters, as far as we know, never been investigated. In this thesis, we try to identify and structure the different stages of ski running surface preparation. In our experiments, we have applied well-established, commonly used treatments parallel with alternative preparations. The unexpected result of our experiments is that the treatments commonly used today are not as good as alternative treatments, namely; stone grinding and glide wax application are far from an optimal ski treatment if minimising friction over a given distance is the major goal.

  • 7.
    Kuzmin, Leonid
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Carlsson, Peter
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Tinnsten, Mats
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    The relationship between the type of machining of the ski running surface and its wettability and capillary drag2010In: Sports Technology, ISSN 1934-6182, E-ISSN 1934-6190, Vol. 3, no 2, p. 121-130Article in journal (Refereed)
    Abstract [en]

    This paper considers the mechanically treated dry ski running surface. The difference in the shear wettability of ski running surfaces treated using different types of machining was studied by measuring the advanced and receding contact angles on two different ski base materials. The hypothesis regarding relationship between the shear wettability and the capillary drag of ski running surface have been presented. The study found, that ski running surfaces with a lower roughness (e.g. flattened by a steel drum or sliced) have a lower wettability factor and seem to be more effective in reducing capillary drag under homogenous wetting conditions.

  • 8.
    Kuzmin, Leonid
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Dahlén, Leon
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Ebrahimzadeh, Reza
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Wiklund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Comparison of Ski Running Surfaces Machined by Various Stone Grinding Equipments2009In: The Impact of Technology on Sport III, Melbourne, Australia: RMIT University , 2009, p. 27-31Chapter in book (Other academic)
    Abstract [en]

    Stone-grinding is an important part of the process of preparing the ski running surface (SRS). The ski base is stone-ground in order to achieve a level surface and to give the SRS a specific pattern texture, depending on the snow conditions, in order to reduce the capillary drag, which is a part of total ski friction. In this study, skis were ground using three different machines (Mantec, Tazzari and Wintersteiger), each with distinctive pattern. The stone-grinding was performed in the same way and by the same operator on each of the machines. The roughness and the hydrophobic characteristics of the SRS produced by the machines were measured. The results of the experiment show that stone-grinding is able to change the magnitude of the capillary drag dramatically, up to 74% in the case studied.

  • 9.
    Kuzmin, Leonid
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Danvind, Jonas
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Carlsson, Peter
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Tinnsten, Mats
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Estimating surface hydrophobicity by introducing a wettability factor based on contact anglesManuscript (preprint) (Other academic)
  • 10.
    Kuzmin, Leonid
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Tinnsten, Mats
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Contact angels on the running surface of cross-country skis2005In: The Impact of Technology on Sport / [ed] Subic, A & Ujihashi, S, Melbourne: Australasian Sports Technology Alliance Pty Ltd , 2005, p. 318-323Chapter in book (Other academic)
    Abstract [en]

    The importance of high hydrophobicity for minimising snow-ski friction has been discussed in a number of scientific papers. The chemical modification of surface forces using fluoropolymeric coatings can result in water contact angles of up to 120°, but not more. To reach extreme values of the contact angle, a second factor has to be modified, namely surface structure. In this study a number of cross-country skis were treated with a modern method of stone grinding and with old-fashioned steel scraping. The surface roughness (3D) and the surface (solid-liquid) contact angle were then measured. After this, the skis were treated with a hot glide wax and new measurements were made. This study also examines the contact angles (solid-liquid) of the flowed surface of a sample of glide wax and the surface of a sample of solid press-sintered running base (UHMWPE). Unexpectedly low hydrophobicity was observed after stone grinding.

  • 11.
    Kuzmin, Leonid
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Tinnsten, Mats
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Contamination, wettability and the ski running surface gliding ability2006In: International congress on science and Nordic skiing, June 18.-20. 2006 Vuokatti, Finland: ICSNS 2006, Jyväskylä: Univ. Jyväskylä, Department of physical activity , 2006Conference paper (Other academic)
  • 12.
    Kuzmin, Leonid
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Tinnsten, Mats
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Dirt absorption on the ski running surface - quantification and influence on the gliding ability2006In: Sports Engineering, ISSN 1369-7072, E-ISSN 1460-2687, Vol. 9, no 3, p. 137-146Article in journal (Refereed)
    Abstract [en]

    We propose a thesis that minimizing dirt on the running surface of skis improves the surface glide. Waxing usually improves the gliding ability of skis in the short term. But how does waxing affect pollution absorption in the long term? In this study a number of skis with a transparent base and a white background were treated by steel scraping and with different glide waxes. The gliding ability of waxed and unwaxed skis, the sliding surface whiteness and the hydrophobicity were tested and documented. Tests were performed before and after the skis had been used for different distances. It was observed that all the waxed skis (regardless of the wax used) absorbed more dirt than unwaxed and as result all waxed skis lose their glide ability sooner then unwaxed (fresh scraped) skis on wet snow conditions.

  • 13.
    Kuzmin, Leonid
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Tinnsten, Mats
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Estimation of dirt attraction on running surfaces of cross-country skis2008In: IMPACT OF TECHNOLOGY ON SPORTS II, London, UK: Taylor & Francis, 2008, p. 851-856Conference paper (Other academic)
    Abstract [en]

    Methods for analysing impurities in snow are used in glaciology and ecological studies. However, the relationship between the dirt accumulation on the ski running surface and the concentration of pollution in the snow is not straightforward, since the interaction between the top layer of snow in the ski track and the ski running surface is responsible for the dirt accumulation on the running surface. In this paper the dirt film accumulated on the gliding surface is studied. A number of XC skis with a transparent base and a white background were examined after undergoing different treatments. Measurements of the whiteness of the running surface of the skis were carried out and glide tests were performed. The measurements and tests were repeated after skiing various distances on a ski track under varying snow conditions. The following observations were made during the study: - The experimental setup could deliver a reliable value of the whiteness of the ski running surface. We achieved 0,3% standard deviation in a test on a control sample; - The correlation between the ski glide and the amount of dirt is obvious and significant.

  • 14.
    Kuzmin, Leonid
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Tinnsten, Mats
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Hot Glide Wax Treatment and the Hardness of the Ski Running Surface2008In: ENGINEERING OF SPORT 7, VOL 2 / [ed] Estivalet, M; Brisson, P, Paris: Springer, 2008, p. 135-141Conference paper (Refereed)
    Abstract [en]

    In the cross country skiing community, hot wax treatment of the ski running surface (SRS) is used in order to influence the surface hardness of the skis in relation to the hardness of the snow crystals. This is discussed in a number of scientific papers and recommended in almost every ski waxing manual. The general idea is to decrease (soften) the surface hardness by the use of a soft glide wax treatment for wet snow conditions and to increase (harden) the hardness of the surface by a hard (synthetic) glide wax treatment for cold, dry snow conditions. The question is; does the hot glide wax treatment of the ski running surface influence the surface hardness? And if so, in what way?In our experiment, ski base specimens of UHMWPE (transparent and “graphite”) were treated with ski glide wax. Half of the specimens were treated with soft yellow glide wax, and half with hard green glide wax. After the wax treatment, the surface hardness (Shore D) was measured with a durometer. The study revealed that: both soft glide wax and hard glide wax treatment make the SRS softer; after a long immersion (12 hours) in the bath of melted glide wax, both the hardness of the specimens treated with soft glide wax and of those treated with hard glide wax decreased significant. Conclusion: The hot wax treatment of the SRS with available glide waxes cannot make the SRS harder than it was initially (unwaxed).

  • 15.
    Kuzmin, Leonid
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Tinnsten, Mats
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    The contamination, wettability and gliding ability of ski running surfaces2007In: Science and Nordic Skiing / [ed] Linnamo, V, Komi, P V & Müller, E, Oxford: Meyer & Meyer Sport, 2007, p. 340-Chapter in book (Other academic)
    Abstract [en]

    The UHMWPE (press-sintered) ski base and ski glide waxes are very similar substances. Hence, it should be possible to achieve a same or even better glide on a bare ski base. In this study we examined waxed and unwaxed skis before and after skiing for the purpose of gliding ability, dirt accumulation and wettability. We observed that the skis with unwaxed running surface did retain a same or higher comparative level of all three tested parameters. We can assume that it is a consequence of a soft wax dirt accumulation under warm conditions and of the excessively hot ski base treatment under cold and dry conditions.

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