Bakgrund: I dagens längdskidåkning har stakningen utvecklats till att bli en avgörande komponent till att prestera framgångsrikt, framförallt inom sprintåkningen där de höga hastigheterna ställer stora krav på överkroppsstyrka. Bålens styrka bör därför testas för att planera och utvärdera träning vilket endast sker genom statiska och uthållighetbaserade övningar som inte är speciellt idrottsspecifika. Ett isokinetiskt bålstyrkettest för elitskidåkare saknas i dagsläget men med Biodex System 3 är det möjligt att utveckla. Syftet med studien var att ta fram ett testprotokoll för isokinetisk bålstyrka i Biodex och analysera sambandet mellan isokinetisk, isometrisk och explosiv bålstyrka samt ställa resultatet mot FIS-punkter i sprint. Metod: Elva elitskidåkare deltog i studien där de efter ett testbatteri med explosiva och statiska styrketester genomförde ett isokinetiskt bålstyrketest i Biodex. I testet skulle forskningspersonerna fastspända i sittande position producera maximal koncentrisk kraft i 50-90° höftflexion under sex repetitioner under en standardiserad hastighet på 60° per sekund. Datat analyserades med Spearmans korrelationskoefficient (r) och signifikansvärdet var: p <0,05.  Resultat: Ett starkt positivt samband (r=0,79, p <0,05) fanns mellan det isokinetiska bålstyrketestet (Biodexₘₐₓ) och det isometriska bålstyrketestet (Isobålₘₐₓ). För de manliga åkarna påvisades ett starkt positivt samband mellan Biodexₘₐₓ och FIS-punkter i sprint (r=0.89, p<0.05) samt Biodexₘₐₓ och vikt (r=0,92 p <0,05). Inga fler statistiskt signifikanta samband kunde påvisas. Konklusion: Studien visar att det finns ett tydligt samband mellan Biodexₘₐₓ och Isobålₘₐₓ samt Biodexₘₐₓ och vikt bland män. Ingen signifikant koppling mellan Biodexₘₐₓ och bollkastet samt Biodexₘₐₓ och längd bland män kunde hittas. Sambandet mellan Biodexₘₐₓ och FIS-punkter i sprint bland män visar att högt resultat i biodextestet tyder på sämre prestationsförmåga i sprint. Inga stora slutsatser kan dras från resultatet på grund av för lågt deltagarantal. Däremot kan isokinetisk bålstyrka nu testas i Biodex och bidra till framtida forskning. / Backgrund: Double poling has developed into a crucial component for cross country skiing performance, especially in sprint where high velocities place great demands on upper body strength. Core strength should therefore be tested to evaluate training which only occurs through static and endurance-based exercises that are not particularly sports-specific. An isokinetic core strength test for elite skiers is currently not available but the Biodex System 3 makes it possible to develop. The purpose of the present study was to develop a protocol for isokinetic core strength and analyze the relationship between isokinetic, isometric and explosive core strength and also compare the result to FIS-points in sprint.  Method: Eleven cross country skiers participated in the study where they after a set of explosive and static tests completed an isokinetic core strength test in the Biodex. The subjects were strapped to the Biodex into a sitting position where they produced maximum concentric force in 50-90° hip flexion during six repetitions at a standardized speed of 60° per second. The data was analysed with Spearman korrelationskoeffizient (r) och the level of significance was: p <0,05. Result: A strong positive relationship (r=0,79, p <0,05) was found between the isokinetic core strength test (Biodexₘₐₓ) and the isometric core strength test (Isobålₘₐₓ). For male skiers a strong positive relationship was found between Biodexₘₐₓ and FIS-point in sprint (r=0.89, p<0.05) and Biodexₘₐₓ and weight (r=0,92 p <0,05). No more statistically significant results were observed. Conclusion: This study shows a strong relationship between Biodexₘₐₓ against Isobålₘₐₓ and Biodexₘₐₓ and weight among men. No statistically significant connection was found between Biodexₘₐₓ and the ball throw and Biodexₘₐₓ and length among men. The relationship between Biodexₘₐₓ and FIS-points in sprint among men indicates that high values in the Biodex means a decreased performance in sprint. No major conclusions can be made from the results due to the low numbers of participants. However, isokinetic core strength can now be tested in the Biodex and contribute to future recherch.

Author's first name and surname: Jan KMOCH Department: FTVS UK, Department of Outdoor Sports Supervisor: Mgr. Radka Bačáková Abstract Title: Comparative analysis of chosen skating techniques at cross-country skiing. Objective: Comparison of leg muscle coordination at different skating techniques in one locomotive cycle at cross-country skiing and free bipedal walk. Methods: Comparative analysis of electromyography records of muscle activation in combination with kinematography analysis of video record. Results: There were found similarities and differences in muscle activation timing at observed muscles. Keywords: skating at cross-country skiing, bipedal walk, surface electromyography

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...

Product testing and development are essential parts in sports and for the athletes in their quest to reach the podium. Manufacturers of sports equipment often use basic test methods which do not test the equipment in a sports specific way. Much of the equipment used by world-class athletes is chosen based only on subjective tests and the athletes’ feelings. One short term aim was therefore to develop test methods for objective tests of sports equipment that also tested the equipment in a sports  specific  way.  Another  aim  was  to  integrate  mechanics  and  simulations  to  enhance  the understanding of the test results. The more long term aims are to contribute to increased theoretical knowledge regarding test methods for sports equipment and to contribute to the development of test  methods  to  create  new  and  better  sports  equipment.  Experimental  tests  combined  with simulations  can  give  valuable  information  to  improve  the  performance  and  safety  of  sports equipment. Three studies dealt with the issue of objective yet sport specific test methods for sports equipment. The main methodological advancement is the modification of established test methods together  with  conventional  mechanics  calculations.  New  test  devices  and  methodologies  are proposed for alpine ski helmets and cross-country ski poles. Suggestions are given for improved test setups as well as theoretical simulation are introduced for glide tests of skis. The results show how sport   specific   test   methodologies   together   with   theoretical   calculations   can   improve   the objectiveness and relevance when testing sports equipment. However, the collected and used data require high precision to obtain high accuracy in the simulations. High data accuracy can be an issue in field measurements but also due to manufacturers not disclosing key material data. Still, the used methods  and  calculations  in  this  thesis  produce  relevant  and  reliable  results  which  can  be implemented to accurate evaluations of different sports equipment. Even though it has not been a first priority aim in this work, the results from the alpine helmet study have been used by helmet manufacturers to design new helmets with increased safety properties. This further show how an objective and sport specific test approach together with theoretical simulation can improve sports equipment and in the longer perspective, also the athletes’ performances. / <p>QC 20140423</p>

Bakgrund: Längdskidåkning är en sport med hög förekomst av överbelastningsskador i ländryggen. Anledningarna till besvärens uppkomst har diskuterats frekvent och flera faktorer har setts spela in. Att variera träningen har setts vara viktigt, inte minst under uppväxten, för att undvika skador längre upp i åldrarna.  Syfte: Att undersöka förekomsten av upplevda ländryggsbesvär de senaste 12 månaderna hos elever på längdskidgymnasium i Sverige. Studien undersökte även skillnader i träningsminuter och träningsvariation under åldern 10–12 år mellan elever utan ländryggsbesvär och elever med lindriga–svåra ländryggsbesvär. Metod: En deskriptiv jämförande tvärsnittsstudie gjordes där 11 av Sveriges 12 längdskidgymnasium deltog. Antalet studiedeltagare var 147, vilket motsvarade en svarsfrekvens på 46%. Könsfördelningen var 52,4% kvinnor och 47,6% män. En webbenkät besvarades angående ländryggsbesvär de senaste 12 månaderna baserat på frågeformuläret Nordic Musculoskeletal Questionnaire (NMQ). Även frågor gällande träning under åldern 10–12 och ländryggsbesvär under längdskidåkning besvarades. Utifrån svaren delades deltagarna in i grupper baserade på besvärsgrad.  Resultat: Förekomsten av ländryggsbesvär senaste 12 månaderna var 50,3%. Det fanns inga signifikanta skillnader gällande träningsminuter under uppväxten mellan grupperna “ej besvär” och “måttliga-svåra besvär” respektive “ej besvär” och “besvär”. Slutsats: Studiens resultat kunde bekräfta en hög förekomst av ländryggsbesvär hos längdskidgymnasieelever. Inga skillnader sågs i träningen under uppväxten mellan de med respektive utan besvär. Fler faktorer spelar in och vidare studier krävs för att få klarhet i varför besvären uppstår i en så hög grad. / Background: Cross-country skiing have a high prevalence of overuse injuries mainly located at the lower back. Low back pain (LBP) is frequently discussed among cross-country skiers and several factors may cause the problem. A variation in training has been seen to be important, especially during childhood, to avoid overuse injuries in higher ages.  Objective: To investigate the prevalence of LBP for the past 12 months in Swedish high school students specialized at cross-country skiing. The study also investigated the differences in training minutes and the variation in training during age 10–12 years between students without LBP and students with mild to severe LBP. Method: A descriptive comparative cross-sectional study was made, 11 of the 12 cross-country ski high schools in Sweden participated. The response rate was 46% which corresponds 147 participants, 52,4% women and 47,6% men.  The participants answered a web survey with questions regarding LBP the last 12 months and training during childhood. Groups based on the severity of LBP was formed.  Results: The prevalence of LBP the last 12 months was 50,3%. There were no significant differences regarding training in the age of 10–12 years between the groups. Conclusion: The study confirms that the prevalence of LBP is high in high school students specialized at cross-country skiing. No differences were found regarding training during childhood between the groups. More factors may affect the problem and further research is needed.

Cross-country skiing has turned into the most highly competitive winter sport, with skiers having the ability to win by merely milliseconds. Every year researchers, ski - technicians, and athletes come together to prepare the ski base surface that gives the best possible results. However, much current information is based on the ski technician’s experience. Therefore, this project has been carried out to help to bridge the gap between ski technician’s knowledge and experimental research. The ski bases are passed through several surface preparation steps before competitions. Stone grinding and hand texturing are two of them. Since grinding cannot be specifically applied as per the environmental conditions, it is followed by texturing. This application of grinding and texturing changes the surface topography of the ski base, which will affect the contact area between the ski base surface and snow/ice and the wettability of the ski base. For this project, work is focused on how the application of different grinds and hand textures affects the wettability of the ski base. This project illustrates the change in wettability of ultra-high molecular weight polyethylene (UHMWPE) and its composites under the application of ten different commercial grinds followed by three other hands texturing. Surface topography was observed under an Optical profilometer, and wettability was measured by measuring the contact angles of droplets on these ski base materials. It was found that the hydrophobicity of ski base materials can be increased to a certain level by increasing the Arithmetic mean roughness (Ra) of specimens. Different ski base materials showed different hydrophobic behaviour when roughness was increased. Applying hand textured to different ground specimens again improved the hydrophobic behaviour of the ski base.

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.

Syfte Undersöka biomekaniska och fysiologiska skillnader mellan modern och gammeldags stakteknik vid konstant submaximalt arbete på rullskidor. Metod Tolv manliga elitskidåkare rekryterades till studien (ålder: 21 ± 4 år, längd: 183,6 ± 9,3 cm, och vikt: 77,8 ± 10,3 kg). Efter en standardiserad uppvärmning genomfördes två deltester, om fyra minuter vardera, i modern och gammeldags stakning med en individanpassad hastighet och lutningen 2,5°. Syreförbrukningen och ventilation analyserades under testen och efter varje deltest togs ett laktatprov och skattning av ansträngning utifrån Borgs RPE. Testerna filmades, där vinklar sedan plockades ut i ett videoanalysprogram. De olika testvärdena analyserade sedan med Paired samples t-test samt Paired samples Wilcoxon signed-ranked test. Resultat Ingen signifikant skillnad påvisades mellan modern och gammeldags stakning för syreförbrukning, energiförbrukning, rörelseekonomi, andningsfrekvens samt laktathalt. Signifikanta skillnader påvisades för hjärtfrekvens, ventilation, respiratory exchange ratio (RER) samt Borg RPE, där gammeldags stakning uppvisade högre värden för samtliga variabler förutom RER. Även i en del ledvinklar samt för tiden i den kraftskapande- och återhämtningsfasen stakcyklerna och tyngdpunktsförflyttningen. Slutsatser Studien visar inga signifikanta skillnader i energikostnad, syrekonsumtion, rörelseekonomi samt blodlaktatskoncentration mellan modern och gammeldags stakning vid submaximalt arbete. Däremot finns signifikanta skillnader i hjärtfrekvens, ventilation samt den skattade tröttheten som tyder på att gammeldags stakning upplevs något mer ansträngande. Framtida forskning behövsför att avgöra om detta skiljer sig i annan lutning och hastighet. / Purpose Examine whether biomechanical and physiological variables differ between modern and old-fashioned double poling technique (OFDP) at a constant submaximal work rate during roller skiing. Methods Twelve male elite cross-country skiers were recruited (age: 21 ± 4 years, length: 183,6 ± 9,3 cm, and weight: 77,8 ± 10,3 kg). After a standardized two subtests followed, in modern and OFDP technique at an individual velocity and the incline 2,5°. Oxygen consumption and ventilation were measured during the testand lactate concentration as well as estimation of Borg RPE were measuredafter every subtest. The test was recorded and angles were analysed. Test values were analysed using Paired samples t-test as well as Paired samples Wilcoxon signed-ranked test. Results No significant difference in energy expenditure (EE), O2 consumption, gross efficiency (GE), breathing frequency (BF) and lactate were shown. Significant differences were shown between heart rate (HR), ventilation, RER and Borg RPE, where higher values were shown for OFDP at all variables except RER. Significant differences were shown in some joint angles as well as the time of the power creating phase,returning phase of the pole stroke and the centre of mass (COM) displacement. Conclusions No significant difference in EE, O2 consumption, GE and lactate between modern and OFDP during a submaximal work rate. Differences in HR and estimated exhaustion gives a hint of the OFDP being more exhausting. Future research is required to determine if this differs in other inclines and velocities.

Elite athletes of today use specialized, scientific training methods and the increasing role of science in sports is undeniable. Scientific methods and equipment has even found its way into the practice of everyday exercisers, a testament to the impact of sport science. From the experiential, personal training regimes of the first half of the 20th century to the scientific training theories of the 1970s, the ideas about training and the athletic body shifted. The rationalization process started in endurance sports in the 1940s. It was part of a struggle between two models of training; natural training and rational training. Physiologists wanted to rid training of individual and local variations and create a universal model of rational, scientific training. The rationalization of training and training landscapes is here understood as an aspect of sportification, a theory commonly used to describe similar developments in sports where increasing regimentation, specialization and rationalization are among the main criteria. This dissertation adds the concept of technologies of sportification to explain the role that micro-technologies and practices (such as training logs, training camps and scientific tests) have in the scientization of training. This thesis thus sets out to analyze the role that science has played in training during the 20th century. It is a history about the rationalization of training, but also about larger issues regarding the role of personal, experiential knowledge and scientific knowledge. The main conclusions are that the process of scientization never managed to rid training of components from natural, experiential training, and that the effort by Swedish physiologists to introduce rational training was part of the larger rationalization movement at the time. In the end, training knowledge was a co-production between practitioners and theoreticians, skiers and scientists. / <p>QC 20161114</p> / Rationell träning: vetenskapliggörandet äv träning för längdskidåkning

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...