Dissertationen zum Thema „Cross-country skis“

Cross-country skiing has developed to become one of the most competitive winter sports, where a skier can win by fractions of seconds. Joint efforts between ski technicians and scientist have allowed the development of methodologies to prepare the ski surface, yet much of the knowledge up to date is based on the experience of the technicians.  In this sense, much attention is focused on the ski base, given that the friction at the base is an important factor that will define how fast a ski can glide. Ski base preparation is an extensive procedure, due to the several parameters that have to be taken into account. Much disagreement has risen regarding the best way to optimize the base. Thus, a complete characterization of the ski base can help to provide some clarity on the factors that affect friction.   This work presents the results of the characterization of the ski base through the preparation process by observing and measuring different aspects, using characterization techniques such as LOM, optical profilometry, contact angle, DSC and XCT. The results suggest that the mechanical machining of the surface can influence wax retention and hydrophobicity. Furthermore, it is seen that wax is present after the first waxing step, despite the constant brushing and scraping. No major changes were observed for the crystallinity. Finally, the amount of graphite on the surface was quantified. This is hoped to be helpful for ski technicians and athletes alike to improve the performance of their skis.

The purpose of this study was to determine whether increased pole stiffness corresponds with higher measures of upper body power in competitive cross-country skiers. Fifteen elite/college level cross-country ski racers (8 men, 7 women) tested UBP on a custom-built double-poling ergometer. Ski poles tested were two models of the same brand with different factory-specified stiffness ratings. Subjects underwent three 10 s UBP tests (W10, W) and one 60 s UBP test (W60, W) for each pole type. UBP measures were defined as the average power output over the length of each test. Video recordings of the 10 s and 60 s tests were analyzed with digital imaging software to determine the maximum bend angle for each pole type. Ergometer and kinematic measures were compared by ski poles tested (stiff vs. less stiff) using a multivariate RMANOVA (α=0.05).

The aim of this thesis was to investigate roller ski characteristics; classical and freestyle roller skis’ rolling resistance coefficients (μR) and classical style roller skis’ static friction coefficients (μS), and to study the influence of different μR and μS on cross-country skiers’ performance and both physiological and biomechanical indices. The aim was also to study differences in skiing economy and efficiency between recreational skiers, female and male junior and senior elite cross-country skiers.The experiments showed that during a time period of 30 minutes of rolling on a treadmill (warm-up), μR decreased significantly (p<0.05) to about 60-65 % and 70-75 % of its initial value for freestyle and classical roller skis respectively. Also, there was a significant influence of normal force on μR, while different velocities and inclinations of the treadmill only resulted in small changes in μR.The study of the influence on physiological variables of a ~50 % change in μR showed that during submaximal steady rate exercise, external power, oxygen uptake, heart rate and blood lactate were significantly changed, while there were non-significant or only small changes to cycle rate, cycle length and ratings of perceived exertion. Incremental maximal tests showed that time to exhaustion was significantly changed and this occurred without a change in maximal power, maximal oxygen uptake, maximal heart rate and blood lactate, and that the influence on ratings of perceived exertion was non-significant or small.The study of classical style roller skis μS showed values that were five to eight times more than the values of μS reported from on-snow skiing with grip-waxed cross-country skis.The subsequent physiological and biomechanical experiments with different μS showed a significantly lower skiing economy (~14 % higher v̇O2), higher heart rate, lower propulsive forces coming from the legs and shorter time to exhaustion (~30 %) when using a different type of roller ski with a μS similar to on-snow skiing, while there was no difference between tests when using different pairs of roller skis with a (similar) higher μS.The part of the thesis which focused on skiing economy and efficiency as a function of skill, age and gender, showed that the elite cross-country skiers had better skiing economy and higher gross efficiency (5-18 %) compared with the recreational skiers, and the senior elite had better economy and higher efficiency (4-5 %) than their junior counterparts, while no differences could be found between the genders.
Syftet med denna avhandling var att undersöka fristils- och klassiska rullskidors rullmotståndskoefficienter (μR) och klassiska rullskidors statiska friktionskoefficienter (μS) samt effekter av olika μR och μS på längdskidåkares prestation vid rullskidåkning på rullande band. Syftet var även att undersöka s.k. åkekonomi och mekanisk verkningsgrad mellan motionärer och kvinnliga och manliga junior- och seniorlängdskidåkare på elitnivå.Experimenten visade att under en period av 30 minuters kontinuerligt rullande, på rullande band, så sjönk μR signifikant (p<0.05) till 60-65 % och 70-75 % av initiala värden, för fristils- respektive klassiska rullskidor. Undersökandet av olika normalkrafter, hastigheter och lutningars påverkan på μR resulterade i en signifikant, negativ korrelation för μR som funktion av normalkraft, medan olika hastigheter och lutningar endast medförde små förändringar av μR.Studien som undersökte fysiologiska effekter av olika μR visade, vid submaximala konstanta arbetsbelastningar, att yttre effekt, syreupptagning, hjärtfrekvens och blodlaktat förändrades signifikant vid ~50 % förändring av μR. Försökspersonernas frekvens och sträcka per frekvens samt skattning av upplevd ansträngning resulterade dock i mestadels icke signifikanta eller små förändringar. Protokollen med successivt ökande arbetsbelastning (maxtest) resulterade i signifikant förändrad tid till utmattning, vid ~50 % förändring av μR. Detta inträffade utan signifikant skillnad i maximal syreupptagning, hjärtfrekvens och blodlaktat, vilket även mestadels gällde för skattning av upplevd ansträngning.Experimenten som undersökte klassiska rullskidors μS visade att dessa erhöll värden som är fem till åtta gånger högre än vad som rapporterats från studier av μS på snö med fästvallade skidor.Den efterföljande studien som undersökte fysiologiska och biomekaniska influenser av olika μS visade, vid submaximala konstanta arbetsbelastningar, att åkekonomin försämrades (~14 % högre syreförbrukning), hjärtfrekvensen ökade, den framåtdrivande kraften från benen på rullskidorna minskade samt att det blev kortare tid till utmattning (~30 %), vid maxtest, när skidåkarna använde rullskidor med en μS i likhet med vad som rapporterats för skidåkning på snö. För arbetsförsöken med olika rullskidor av olika fabrikat med en högre, och likartad, μS förelåg ingen skillnad i de undersökta variablerna.Studien som undersökte åkekonomi och mekanisk verkningsgrad som funktion av prestationsnivå, ålder och kön, visade att elitskidåkarna hade bättre åkekonomi och verkningsgrad (5-18 %) i jämförelse med motionärerna, att seniorerna hade bättre åkekonomi och verkningsgrad (4-5 %) än juniorerna och att ingen skillnad kunde konstateras mellan könen.

Att utöva fysiska aktiviteter ska vara möjligt för alla.Genom parasporten, som är sporter anpassade förpersoner med olika funktionsnedsättningar, görs dettamöjligt för alla, oavsett vilka fysiska förutsättningar manhar. Cross-country sitskiing är en gren inom parasportensom växer mer och mer i antalet utövare. Vid utövandetav Cross-country sitskiing sitter åkaren i en typ av kälkesom kallas sitski. Denna är anpassad efter individen ochkan därför se mycket olika ut. Vid tävling är det viktigtatt utrustningen passar bra och håller en låg vikt.Med syftet att förbättra prestationen för en åkare, samtgöra det enklare för andra att göra detsamma, gav SportsTech Research Centre rapportförfattarna i uppdrag attutvärdera och utveckla en sitskiåkares nuvarande sitski.Målet med arbetet är att ta fram ett produktionsunderlagför en ny sitski utifrån åkarens önskemål.Arbetet har skett genom de fyra faserna förstudie,konceptgenerering, konceptval och detaljkonstruktion. Iförstudien undersöktes marknaden i stort och enförståelse för sporten och sitskin skapades. Vidare ikonceptgenereringen undersöktes mer detaljer av desitskis som redan finns på marknaden och möjligalösningar började tas fram, dessa kombinerades till olikakoncept. I konceptvalet kontrollerades koncepten ochjämfördes mot satta krav samt mot varandra. De tvåkoncepten som togs vidare förädlades för att kunna väljaett slutgiltigt koncept. Detta koncept togs vidare till densista fasen, detaljkonstruktion, där det bearbetadesytterligare för att sedan kontrolleras med FEM-analyser.Resultatet gav en ny sitski med väldigt likvärdig viktmot den tidigare. Dock har den nya en öppnare vinkel ihöften, då detta var önskat för att försöka ökaåkeffektiviteten. Den nya sitskin är även merergonomisk än den tidigare, har bättre passform och ärmer personanpassad.
Performing physical activities should be possible foreveryone. Through parasport, i.e. sports adapted forpeople with disabilities, this becomes possible foreveryone - despite differences in physical conditions.Cross country sit-skiing is a competitive sport in theparasport community which has been growing a lot interms of number of athletes. Performing Cross countrysit-skiing, the skier sits in a type of sledge, which is calleda sit-ski. The sit-ski is usually fitted after each individualand can therefore have big differences in appearance andfunctionality. In competitive sports, it is important tohave well-adjusted equipment that also holds a lowweight.With the purpose to improve one skiers performancewhilst also making it possible for others to do the same,the task given by Sports Tech Research Centre was toevaluate and develop a sit-ski used by an athlete incompetition. The aim being to produce a documentationof production for a new sit-ski, adjusted to the skierspreferences.The work has gone through the four phases: prestudy,concept generation, concept selection and detail design.The prestudy analyzed the market in general and anunderstanding for the sport and sit-skis generally wasestablished. The concept generation consisted ofexamining details in sit-skis already on the market, andbeginning to produce possible solutions, which werecombined into different concepts. In the conceptselection, the concepts were checked and compared tothe requirements and to each other. The two conceptswere further refined, to finally be able choose a final one.The final concept was developed further in the detaildesign phase and checked with further FEM-analysis.The result being an improved sit-ski, although with aweight comparable to the old one, a wider angle at thehip to hopefully improve skiing efficiency. The new sit-ski is more ergonomic than the original one, better fittedand more personalized.

Betyg 2020-07-08/2020-08-13

This report aims to solve a problem for the   waxers in the Swedish National Cross-country Ski Team, which hereafter will   be referred to as the national team. The problem in hand is that currently,   the national team lacks a system for book-keeping of ski pairs and ski tests.   Also, the project intends to provide a tool for predicting the best ski pairs   in given conditions. The report describes cross-country skis and factors that   affect the performance of these skis. Moreover, this report presents the   testing procedure of the national team. The project provides a solution to   the problem in hand by developing a web service based on Django and Django   REST Framework and an iOS application to handle the user interaction. The app   was tested and approved by the waxers of the national team. To predict the   best performing skis in given conditions, the three Machine Learning   algorithms Support Vector Machine (SVM), Decision Tree, and Artificial Neural   Network (ANN) is implemented and evaluated. Experimental results indicate   that the ANN algorithm has better accuracy than the Decision Tree, and that   the SVM algorithms and that the SVM was performing slightly worse than the   other two, when applied on test data which is artificially generated based on   the experience of the national team. All three Machine Learning algorithms   perform better in terms of mean accuracy which is significantly higher   compared to the accuracy of a baseline algorithm. The report suggests that   the accuracy of the ANN algorithm is high enough to be useful for the   national team.

The Long Term Athlete Development (LTAD) model is an innovation created in response to the Canadian Sport Policy (Canadian Heritage, 2007). The LTAD is an “athlete centered, coach driven, and administration, sport science, and sponsor supported” (Canadian Sport Centres, 2006, p. 33) athlete-development model. Since little research has been completed focusing on this model (viz., Black & Holt, 2009) this thesis had the purpose to better understand the adoption of the LTAD by cross-country ski (XCS) coaches. Two articles present a case study of three XCS club’s coaches, and a descriptive qualitative analysis of XCS coaches (N=13). Both analyses used Rogers’ (2003) Diffusion of Innovations theoretical framework to structure the narrative-interview guide, coding structure, and thematic analysis. Two key results of the thesis were an understanding of the link between a club’s characteristics and a coach’s perceived attributes of the LTAD, and secondly a proposed classification system for XCS coaches.

This is a master thesis report for MSc in Industrial Design Engineering at Luleå University of Technology. It is a development project where a wax-bench for cross-country skiing has been developed. The wax-bench have been developed to facilitate the clean-up for the user and to gather all wax-accessories at one place. In this report the entire project can be followed from start to finish, how the requirements were found, who is the user, what should the product handle and how was the ideas ge- nerated. The final result is a wax- box that is vacuum formed and folded in the middle. In the box there are adjustable profiles to place the ski on and an adjustable attachment part in the center that attaches to the skis binding. The box acts as a collector of the waste that is produced when waxing skis, and as storage of waxing accessories when not in use. How to install the accessory in the box is not yet determined, but the idea is to develop a specific bag that fits perfectly in the wax-box and includes all the usual accessories. This bag should then be taken out when you wax and put back in the box after complete the waxing.
I den här rapporten kan man följa ett examensarbete för civilingenjörsprogrammet Tek- nisk Design på Luleå Tekniska Universitet. Projektet består av ett utvecklingsarbete där en vallabänk för längdskidåkning har utvecklas. Vallabänken har utvecklats för att underlätta städningen för användaren och för att samla alla vallatillbehör på en och samma plats. I den här rapporten kan man följa hela projektet från start till mål, hur kraven hittades, vem är användaren, vad ska produkten klara av och hur genererades ideer. Det slutgiltiga resultatet är en valla-låda som är vakuumformad och viks ihop på mitten. I lådan finns det justerbara profiler att placera skidan på samt ett justerbart fäste i mitten som fäster i skidans bindning. Lådan fungerar som uppsamlare av skräpet som bildas när man vallar skidor och som förvaring av vallatillbehör när den inte används. Hur valla-tillbehöret ska placeras är ännu inte fastställt men tanken är att det ska utvecklas en specifik väska som passar in perfekt i valla-boxen och som har plats för alla de vanliga tillbehören. Denna väska ska sedan gå att plocka ur när man vallar och placera tillbaka i boxen efter utförd vallning.

Peak fingertip blood lactate values obtained following maximal intensity simulated double poling ski exercise (PBLa(A)), were compared with peak fingertip blood lactate values obtained following maximal intensity simulated combined arm and leg ski striding exercise (PBLa(A + L)). The combined arm and leg protocols were performed on two different types of treadmills, a walking treadmill and a ski treadmill. Phase one combined arms and legs ski striding protocol (A + L)$\sb1$, involved ski walking on a treadmill with simultaneous arm poling movements achieved through a rope pulley system. Phase two combined arms and legs ski striding protocol (A + L)$\sb2$, whereby skiers using skis and poles performed a diagonal stride on a carpeted treadmill. The arms only double poling exercise protocol(A), was conducted identically in both test phases. Kneeling on a trolley or rollerboard, skiers pulled themselves up a 95 inch inclined track using rope pulleys at a cadence of one pull every 2.5 seconds. Peak blood lactate values represented the highest blood lactate value obtained from the post exercise samples. Differences in phase one and two PBLa(A + L) and MVO$\sb2$ values were related to the degree of sports specificity of the A + L protocol to cross-country skiing. (Abstract shortened by UMI.)

Poly- och perfluorerade ämnen, även kallad PFAS, har både globalt och i Sverige upptäckts i höga halter i mark samt i yt-och grundvatten de senaste åren. Kemikalierna är svårnedbrytbara och studier visar på att de bland annat är reproduktionsstörande hos djur. Källorna till utsläpp av PFAS är många, men något som uppmärksammats den senaste tiden är fluorvallor som används inom längdskidåkning. I den här studien undersöks hur användningen av skidvalla innehållande PFAS påverkar ett område samt hur dessa ämnen sprids. För att undersöka detta har tidigare mätningar utförda i anslutning till längdskidspår använts, för att se hur spridningen skett vid dem samt vilka koncentrationer som kan påträffas.  Mätningarna var utförda vid skidspår i Oslo, Trondheim, vid Vasaloppet samt vid en tävling i Maine, USA. För att visualisera var i Sverige påverkade områden skulle kunna finnas gjordes dessutom en karta där orter togs ut på två olika sätt. Skidvalla bidrar till att orsaka högre lokala koncentrationer av PFAS, och kan få en stor påverkan i de områden där mycket skidåkning pågår. Samtidigt är det svårt att dra tydliga slutsatser då det finns fåtal studier och många diffusa källor som kan bidra till spridningen av PFAS.
Per- and polyfluoroalkyl substances (PFAS) are man-made chemicals used for their water, grease, and dirt repellent properties. Today these substances are widespread due to their ability to spread through both air and water. PFAS are long-term persistent and have hazardous environmental impact. Among others, affecting the reproduction of animals and has been shown to accumulate in the food chain. One product containing PFAS that has recently gained attention is fluorinated ski wax, due to the ban imposed on fluorinated ski wax by the International Ski Federation (FIS) from the season 2021/2022.  To investigate how the use of ski wax containing PFAS spreads and affects the environment at areas with cross-country skiing, results from previous studies have been analyzed. The previous studies were located at cross-country ski areas in Oslo and Trondheim in Norway, Maine in the USA and at the location of the Swedish competition Vasaloppet. A map has also been made to visualize where in Sweden there might be areas who have been contaminated with per- and polyfluoroalkyl substances by the use of ski wax. To find the locations for these areas two different methods have been used.  The results of the previous studies shows that the use of fluorinated ski waxes gives higher local concentrations of PFAS at the locations of cross-country ski areas that are frequently used. However, it is still difficult to draw clear conclusions about how big the spread of PFAS contamination is, since the substances can be found in many different products and are easily spread. In the future there is a need for more studies and investigation to reach clearer conclusions. In addition, there is a need for more tests around different ski areas to see the impact that competitions have, but also how everyday skiing affects the spread of PFAS.

This diploma thesis is divided into a theoretical part and a practical one. The theoretical part deals with the characteristics of sport events and presents the International Ski Federation FIS, including its structure, and marketing and technical concept of the races in the FIS Tour de Ski. The introduction to the practical part focuses on the history of cross-country skiing, the structure of the most important cross-country races in the world, and presents the town of Nove Mesto na Morave and the race Golden Ski. Then follows the description of the allocation process of the World Cup race and possibilities of its abolition. The main part of the diploma thesis is a detailed analysis of the Golden Ski race in the Tour de Ski. The analysis deals with the topics related to the organizing committee, technical support, scoring, invitations, accreditation, accommodation, marketing, transportation, and accompanying program of Golden Ski. The thesis concludes with financial background and short mention of Slavic Cup.

Title: Characteristics and description of cross-country skiing resorts in the Czech Republic Aim: The aim of this work is to look for cross-country ski resorts in the Czech republic which are suitable for cross-country trainings and competitions of various categories. The extension of this work is the creation of a written and electronic list featuring these areas and including a brief description of their background. The electronic version of the overview of the cross-country resorts, mentioned in this work would be/will be/is posted on the internet for the needs of the ski clubs and cross-country skiing lovers. Methods: The basis of this work is data collection performed by analysis of documents referred to in the literature and on websites. A large amount of the information was provided by the skiers, administrators of sites and their operators. Another method used in this work to determine the actual technical details, especially concerning the individual ski resorts and cross-country skiing routes, was the survey. Given the low responding rate, and because of a very narrow range of questions asked, it was not appropriate to use a method of data collection by questionnaire. Results: Assessment of individual sites based on the offered training opportunities and organization of competitions for...

The thesis is focused on the origin and history of ski societies, clubs and ski centres in the Ore Mountains. For finding those facts and the events I had used and studied chronicles, annual reports, literature, start lists and photographs that document skiing in the Ore Mountains. The relevant part of this thesis are visits to ski museums and especially conversations with contemporaries and participants of ski competitions. The dissertation deals with the history of skiing as a whole and subsequently focuses on the sphere of the Karlovy Vary part of Ore Mountains, especially the region of Abertamy and its vicinity.

Name: Complex Evaluation of Primary School Ski Courses in the Czech Republic Objective: The objective of this diploma thesis is a complex evaluation of a representative primary school ski courses in the Czech Republic according to the five following criteria, which are staffing of the course, content and organisation of the course, health and safety of the pupils, methodology of the training and economic side. The crucial aspect of the evaluation is the fact whether the working hypotheses will be proved or disproved. Methodology: Our thesis has the character of a qualitative research. Data that refer to the topic are collected in the form of non anonymous survey of at random chosen primary schools in all regions of the Czech Republic. For this purpose, a non-standardized questionnaire is used. It consists of open-ended, semi close-ended and close-ended questions. The questionnaire is compiled to enable a complex evaluation of ski courses in accordance with the areas of interest, which are staffing of the course, content and organisation of the course, health and safety of the pupils, methodology of the training and economic safeguarding. Collected data are analysed in Survio and Microsoft EXCEL® programmes; they are supplemented with graphs and commentaries. Results: Primary school ski courses were...

1 Abstract Name: Complex evaluation of the basic school ski courses in the Czech republic Objective: The objective of this diploma thesis is to evaluate complexly a chosen basic school ski school courses in the Czech republic according to five above mentioned criteria and to confirm or dismiss hypothesisses. Methodology: I created a non-standardized questionnare with open-ended, semi close-ended and close- ended questions to evaluate ski courses according to the above mentioned criteria. This questionnare was sended non-anonymously online via survio.com to randomly chosen basic schools in every single province of the Czech republic. Collected data were statistically analysed in the Survio and Microsoft EXCEL® programm and the results were eriched with graphs and commentary. Results: In this diploma thesis basic school ski courses were evaluated according to determined criteria, at least one hypothesis was related to every criterion. I could confirm that the majority of ski course leaders are ski instructors (50 hours training, no trade licence). I could confirm four other hypothesisses as well, i. e. cross-country skiing is an essential part of more than 50% ski courses, less than 50% of pupils attend basic school ski courses, the majority of ski course instructors are teaching in accordance with the...

Title: A comparison of dynamic abilities in nordic ski disciplines Aim: This dissertation aims to compare the dynamic abilities of cross country skiers and ski jumper in age between 12 to 15. Clarification of whether or not a training process of those two athlete groups has a crucial impact on the development of mentioned abilities compared to the other hobby sports group (target group). Methodology: This dissertation is conceived as empiric-theoretical. It analyses the results of samples to verify the hypothesis. There were three groups consisting of 10 samples (athletes) in total. The samples were tested in horizontal jumps (long jump, triple jump, multiple jumps) and vertical jumps (squat jump, counter movement jump). In all tests, it was decided to use only the best of all three attempts for the results. Findings: Development of dynamic abilities during the training process has a positive impact on their development in general. Both cross country skiers and ski jumpers achieved better results than the target group. Furthermore, ski jumpers performed better than cross country skiers. Keywords: physical health, sport performance, cross country skiing, ski jumping, squat jump (SJ), countermovement jump (CMJ), long jump, triple jump, multiple jumps