To see the other types of publications on this topic, follow the link: Cross country skiing.
Dissertations / Theses on the topic 'Cross country skiing'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Cross country skiing.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Holmberg, Joakim L. "Computational Biomechanics in Cross‐country Skiing." Licentiate thesis, Linköping University, Linköping University, Department of Management and Engineering, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-10671.
Full textAbstract:
Traditionally, research on cross‐country skiing biomechanics is based mainly on experimental testing alone. Trying a different approach, this thesis explores the possibilities of using computational musculoskeletal biomechanics for cross‐country skiing. As far as the author knows, this has not been done before.
Cross‐country skiing is both fast and powerful, and the whole body is used to generate movement. Consequently, the computational method used needs to be able to handle a full‐body model with lots of muscles. This thesis presents several simulation models created in the AnyBody Modeling System, which is based on inverse dynamics and static optimization. This method allows for measurementdriven full‐body models with hundreds of muscles and rigid body segments of all major body parts.
A major result shown in the thesis is that with a good simulation model it is possible to predict muscle activation. Even though there is no claim of full validity of the simulation models, this result opens up a wide range of possibilities for computational musculoskeletal biomechanics in cross‐country skiing. Two example of new possibilities are shown in the thesis, finding antagonistic muscle pairs and muscle load distribution differences in different skiing styles. Being able to perform optimization studies and asking and answering “what if”‐questions really gives computational methods an edge compared to traditional testing.
To conclude, a combination of computational and experimental methods seems to be the next logical step to increase the understanding of the biomechanics of crosscountry skiing.
Traditionellt har biomekaniska forskningsstudier av längdskidåkning baserats helt och hållet på experimentella metoder. För att prova ett annat angreppssätt undersöks i denna avhandling vilka möjligheter som beräkningsbaserad biomekanik kan ge för längdskidåkning. Så vida författaren vet, har detta inte gjorts tidigare.
Längdskidåkning innehåller snabba och kraftfulla helkroppsrörelser och därför behövs en beräkningsmetod som kan hantera helkroppsmodeller med många muskler. Avhandlingen presenterar flera simuleringsmodeller skapade i AnyBody Modeling System, som baseras på inversdynamik och statisk optimering. Denna metod tillåter helkroppsmodeller med hundratals muskler och stelkroppssegment av de flesta kroppsdelarna.
Ett resultat som avhandlingen visar är att med en bra simuleringsmodell är det möjligt att förutsäga muskelaktiviteten för en viss rörelse och belastning på kroppen. Även om ingen validering av simuleringsmodellen ges, så visar ändå resultatet att beräkningsbaserad biomekanik ger många nya möjligheter till forskningsstudier av längdskidåkning. Två exempel visas, hur muskelantagonister kan hittas samt hur lastfördelningen mellan musklerna förändras då skidåkaren förändrar stilen. Att kunna genomföra optimeringsstudier samt fråga och svara på ”vad händer om”‐ frågor ger beräkningsbaserad biomekanik en fördel i jämförelse med traditionell testning.
Slutsatsen är att en kombination av beräkningsbaserade och experimentella metoder borde vara nästa steg för att addera insikt om längdskidåkningens biomekanik.
Report code: LIU‐TEK‐LIC‐2008:4. On the day of the defence date the status of article V was: Submitted.
2
Holmberg, L. Joakim. "Computational biomechanics in cross-country skiing /." Linköping : Department of Management and Engineering, Linköping University, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-10671.
Full text
3
Holmberg, L. Joakim. "Musculoskeletal Biomechanics in Cross-country Skiing." Doctoral thesis, Linköpings universitet, Mekanik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-76148.
Full textAbstract:
Why copy the best athletes? When you finally learn their technique, they may have already moved on. Using muscluloskeletal biomechanics you might be able to add the "know-why" so that you can lead, instead of being left in the swells. This dissertation presents the theoretical framework of musculoskeletal modeling using inverse dynamics with static optimization. It explores some of the possibilities and limitations of musculoskeletal biomechanics in cross-country skiing, especially double-poling. The basic path of the implementation is shown and discussed, e.g. the issue of muscle model choice. From that discussion it is concluded that muscle contraction dynamics is needed to estimate individual muscle function in double-poling. Several computer simulation models, using The Anybody Modeling System™, have been created to study different cross-country skiing applications. One of the applied studies showed that the musculoskeletal system is not a collection of discrete uncoupled parts because kinematic differences in the lower leg region caused kinetic differences in the other end of the body. An implication of the results is that the kinematics and kinetics of the whole body probably are important when studying skill and performance in sports. Another one of the applied studies showed how leg utilisation may affect skiing efficiency and performance in double-poling ergometry. Skiing efficiency was defined as skiing work divided by metabolic muscle work, performance was defined as forward impulse. A higher utilization of the lower-body increased the performance, but decreased the skiing efficiency. The results display the potential of musculoskeletal biomechanics for skiing efficiency estimations. The subject of muscle decomposition is also studied. It is shown both analytically and with numerical simulations that muscle force estimates may be affected by muscle decomposition depending on the muscle recruitment criteria. Moreover, it is shown that proper choices of force normalization factors may overcome this issue. Such factors are presented for two types of muscle recruitment criteria. To sum up, there are still much to do regarding both the theoretical aspects as well as the practical implementations before predictions on one individual skier can be made with any certainty. But hopefully, this disseration somewhat furthers the fundamental mechanistic understanding of cross-country skiing, and shows that musculoskeletal biomechanics will be a useful complement to existing experimental methods in sports biomechanics.Varför ska man kopiera de som är bäst inom sin idrottsgren? När man väl har lärt sig deras teknik så har de antagligen redan gått vidare. Vore det inte bättre att öka sin förståelse så att man kan ligga i framkant, istället för i svallvågorna? Med biomekaniska simuleringar som ett komplement till traditionella experimentella metoder finns möjligheten att få veta varför prestationen ökar, inte bara hur man ska göra för att öka sin prestation. Längdskidåkning innehåller snabba och kraftfulla helkroppsrörelser och därför behövs en beräkningsmetod som kan hantera helkroppsmodeller med många muskler. Avhandlingen presenterar flera muskeloskelettära simuleringsmodeller skapade i The AnyBody Modeling System™ och är baserade på inversdynamik och statisk optimering. Denna metod tillåter helkroppsmodeller med hundratals muskler och stelkroppssegment av de flesta kroppsdelarna. Avhandlingen visar att biomekaniska simuleringar kan användas som komplement till mer traditionella experimentella metoder vid biomekaniska studier av längdskidåkning. Exempelvis går det att förutsäga muskelaktiviteten för en viss rörelse och belastning på kroppen. Detta nyttjas för att studera verkningsgrad och prestation inom dubbelstakning. Utifrån experiment skapas olika simuleringsmodeller. Dessa modeller beskriver olika varianter (eller stilar) av dubbelstakning, alltifrån klassisk stil med relativt raka ben och kraftig fällning av överkroppen till en mer modern stil där åkaren går upp på tå och använder sig av en kraftig knäböj. Resultaten visar först och främst att ur verkningsgradsynpunkt är den klassiska stilen att föredra då den ger mest framåtdrivande arbete per utfört kroppsarbete, dvs den är energisnål. Men ska en längdlöpare komma så fort fram som möjligt (utan att bry sig om energiåtgång) verkar det som en mer modern stil är att föredra. Denna studie visar också att för att kunna jämföra kroppens energiåtgång för skelettmusklernas arbete mellan olika rörelser så krävs det en modell där muskler ingår. Andra studier som presenteras är hur muskelantagonister kan hittas, hur lastfördelningen mellan muskler eller muskelgrupper förändras när rörelsen förändras samt effekter av benproteser på energiåtgång. Några aspekter av metoden presenteras också. Två muskelmodeller och dess inverkan på olika simuleringsresultat visas. En annan aspekt är hur muskeldekomposition och muskelrekryteringskriterium påverkar beräkningarna. Normaliseringsfaktorer för olika muskelrekryteringskriterium presenteras.
Beräkningsbaserad biomekanik inom längdskidåkningen - möjligheter och begränsningar
4
Barberis, Marc Francois. "Biomechanics of cross-country skiing locomotion." Thesis, University of Leeds, 2007. http://etheses.whiterose.ac.uk/801/.
Full textAbstract:
Cross-country skiing constitutes ancestral method for moving along in a snow environment.A number of techniques have been developed to facilitate this. Among these techniques, one of them; namely the Diagonal Stride Technique( DST) has been described by authors as an extension of walking and running. Most biomechanical research studies have analysed the DST as a sporting activity leaving the locomotor strategies poorly described. This relationship to walking and running and the involvement of a gliding phase make the DST an interesting locomotion which may reflect a locomotor adaptation of human to the environment. The overall purpose of the research undertaken in this work was to determine the strategies employed by skiers to progress along the ground in the DST. Different analytical approaches were used to test the research question: those involved cycle patterns, joint angular kinematics,coordination and mechanical analyses of different skiing conditions. The DST with poles was tested for two different speeds. In addition,the DST was investigated without poles. The description of the joints angular kinematics showed that specific movement patterns and segmental organisation were required for skiing with a reference to walking and running. The DST locomotion was mechanically similar to running but involved a gliding phase. The generation of forward displacement was carried out using an effective sequencing of hip extension and knee and ankle extension. Poles were reported to contribute to the generation of upper and lower body propulsion strategies. They were also supposed to increase the balance of the skier by providing additional supports. The increase of speed was achieved through faster limb movements without change in the joints range of motion. The overall conclusion of this work is that although the DST could be related to running, the skiers developed some specific body segmental organisations to progress along the ground,in response to the properties of the environment and of the material.
5
Bakkman, Frida. "Calculation of mechanical energy in cross country skiing." Thesis, KTH, Mekanik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-101940.
Full textAbstract:
Cross country skiing is considered to be one of the most demanding sports in terms of endurance. Therefore the skiers are attractive subjects for physiological and biomechanical research whose interest has increased a lot during the 21 stcentury. The results are used to improve the mechanical knowledge about the body and to improve the capacity and technique for the competitors. The aim with this study is to implement a method for mechanical energy calculation in cross country skiing. This is based on data from 15 skiers using the double poling technique, where the potential, rotational and translational energies are calculated. The measurements are made in a lab using a treadmill with stepwise increased velocity. The system used is Vicon MX where the skiers wear re- ective markers, whose positions is calculated from data from infra-red light cameras. The positions of the joint centres are calculated used as input data to the program. Joint centres and marker data divide the body into segments where the energies of each segment are calculated and possible to sum up for the whole body. The results are examples of obtainable data from the model. It is possible to compare chosen subjects' total mechanical energy but also the energies and segments separately. The results can be used to analyse the dierent techniques to improve the capacity of the competitors.
6
Carlsson, Magnus. "Physiological demands of competitive elite cross-country skiing." Doctoral thesis, Högskolan Dalarna, Idrotts- och hälsovetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-102878.
Full textAbstract:
Introduction Researchers have, for decades, contributed to an increased collective understanding of the physiological demands in cross-country skiing; however, almost all of these studies have used either non-elite subjects and/or performances that emulate cross-country skiing. To establish the physiological demands of cross-country skiing, it is important to relate the investigated physiological variables to the competitive performance of elite skiers. The overall aim of this doctoral thesis was, therefore, to investigate the external validity of physiological test variables to determine the physiological demands in competitive elite cross-country skiing. Methods The subjects in Study I – IV were elite male (I – III) and female (III – IV) cross-country skiers. In all studies, the relationship between test variables (general and ski-specific) and competitive performances (i.e. the results from competitions or the overall ski-ranking points of the International Ski Federation (FIS) for sprint (FISsprint) and distance (FISdist) races) were analysed. Test variables reflecting the subject’s general strength, upper-body and whole-body oxygen uptake, oxygen uptake and work intensity at the lactate threshold, mean upper-body power, lean mass, and maximal double-poling speed were investigated. Results The ability to maintain a high work rate without accumulating lactate is an indicator of distance performance, independent of sex (I, IV). Independent of sex, high oxygen uptake in whole-body and upper-body exercise was important for both sprint (II, IV) and distance (I, IV) performance. The maximal double-poling speed and 60-s double-poling mean power output were indicators of sprint (IV) and distance performance (I), respectively. Lean mass was correlated with distance performance for women (III), whereas correlations were found between lean mass and sprint performance among both male and female skiers (III). Moreover, no correlations between distance performance and test variables were derived from tests of knee-extension peak torque, vertical jumps, or double poling on a ski-ergometer with 20-s and 360-s durations (I), whereas gross efficiency while treadmill roller skiing showed no correlation with either distance or sprint performance in cross-country skiing (IV). Conclusion The results in this thesis show that, depending on discipline and sex, maximal and peak oxygen uptake, work intensity at the lactate threshold, lean mass, double-poling mean power output, and double-poling maximal speed are all externally valid physiological test variables for evaluation of performance capability among elite cross-country skiers; however, to optimally indicate performance capability different test-variable expressions should be used; in general, the absolute expression appears to be a better indicator of competitive sprint performance whereas the influence of body mass should be considered when evaluating competitive distance performance capability of elite cross-country skiers.
7
Andersson, Erik. "PHYSIOLOGICAL AND BIOMECHANICAL FACTORS DETERMINING CROSS-COUNTRY SKIING PERFORMANCE." Doctoral thesis, Mittuniversitetet, Avdelningen för hälsovetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-27898.
Full textAbstract:
Cross-country (c.c.) skiing is a complex sport discipline from both physiological and biomechanical perspectives, with varying course topographies that require different proportions of the involved sub-techniques to be utilised. A relatively new event in c.c. skiing is the sprint race, involving four separate heats, each lasting 2-4 min, with diverse demands from distance races associated with longer durations. Therefore, the overall aim of the current thesis has been to examine the biomechanical and physiological factors associated with sprint c.c. skiing performance through novel measurements conducted both in the field (Studies I-III) and the laboratory (Studies IV and V). In Study I sprint skiing velocities and sub-techniques were analysed with a differential global navigation satellite system in combination with video recording. In Studies II and III the effects of an increasing velocity (moderate, high and maximal) on the biomechanics of uphill classical skiing with the diagonal stride (DS) (Study II) and herringbone (HB) (Study III) sub-techniques were examined. In Study I the skiers completed the 1,425 m (2 x 712 m) sprint time trial (STT) in 207 s, at an average velocity of 24.8 km/h, with multiple technique transitions (range: 21-34) between skiing techniques (i.e., the different gears [G2-7]). A pacing strategy involving a fast start followed by a gradual slowing down (i.e., positive pacing) was employed as indicated by the 2.9% faster first than second lap. The slower second lap was primarily related to a slower (12.9%) uphill velocity with a shift from G3 towards a greater use of G2. The maximal oxygen uptake ( O2max) was related to the ability to maintain uphill skiing velocity and the fastest skiers used G3 to a greater extent than G2. In addition, maximal speed over short distances (50 and 20 m) with the G3 and double poling (DP) sub-techniques exerted an important impact on STT performance. Study II demonstrated that during uphill skiing (7.5°) with DS, skiers increased cycle rate and cycle length from moderate to high velocity, while cycle rate increased and cycle length decreased at maximal velocity. Absolute poling, gliding and kick times became gradually shorter with an elevated velocity. The rate of pole and leg force development increased with elevated velocity and the development of leg force in the normal direction was substantially faster during skiing on snow than previous findings for roller skiing, although the peak force was similar in both cases. The fastest skiers applied greater peak leg forces over shorter durations. Study III revealed that when employing the HB technique on a steep uphill slope (15°), the skiers positioned their skis laterally (“V” between 25 to 30°) and planted their poles at a slight lateral angle (8 to 12°), with most of the propulsive force being exerted on the inside forefoot. Of the total propulsive force, 77% was generated by the legs. The cycle rate increased across all three velocities (from 1.20 to 1.60 Hz), while cycle length only increased from moderate to high velocity (from 2.0 to 2.3 m). Finally, the magnitude and rate of leg force generation are important determinants of both DS and HB skiing performance, although the rate is more important in connection with DS, since this sub-technique involves gliding. In Studies IV and V skiers performed pre-tests for determination of gross efficiency (GE), O2max, and Vmax on a treadmill. The main performance test involved four self-paced STTs on a treadmill over a 1,300-m simulated course including three flat (1°) DP sections interspersed with two uphill (7°) DS sections. The modified GE method for estimating anaerobic energy production during skiing on varying terrain employed in Study IV revealed that the relative aerobic and anaerobic energy contributions were 82% and 18%, respectively, during the 232 s of skiing, with an accumulated oxygen (O2) deficit of 45 mL/kg. The STT performance time was largely explained by the GE (53%), followed by O2 (30%) and O2 deficit (15%). Therefore, training strategies designed to reduce energetic cost and improve GE should be examined in greater detail. In Study V metabolic responses and pacing strategies during the four successive STTs were investigated. The first and the last trials were the fastest (both 228 s) and were associated with both a substantially larger and a more rapid anaerobic energy supply, while the average O2 during all four STTs was similar. The individual variation in STT performance was explained primarily (69%) by the variation in O2 deficit. Furthermore, positive pacing was employed throughout all the STTs, but the pacing strategy became more even after the first trial. In addition, considerably higher (~ 30%) metabolic rates were generated on the uphill than on the flat sections of the course, reflecting an irregular production of anaerobic energy. Altogether, a fast start appears important for STT performance and high work rates during uphill skiing may exert a more pronounced impact on skiing performance outdoors, due to the reduction in velocity fluctuations and thereby overall air-drag.Vid tidpunkten för disputationen var följande delarbeten opublicerade: delarbete 5 inskickat
At the time of the doctoral defence the following papers were unpublished: paper 5 submitted
8
Atkinson, William Drew. "CARBON FIBER LEAF SPRINGS FOR ADAPTIVE CROSS COUNTRY SKIING." DigitalCommons@CalPoly, 2009. https://digitalcommons.calpoly.edu/theses/370.
Full textAbstract:
This work describes the development of a custom sit ski for US Ski Team paralympian Greg Mallory from concept through prototype fabrication. The ski consists of a custom seat molded specifically for the athlete, carbon fiber leaf springs, and a custom binding attachment system compatible with NNN style cross country bindings. The sit ski is designed to maximize poling power through the use of an upright rather than reclined seating position, allowing for increased utilization of core muscle strength. The springs were designed based on information gathered by a custom National Instruments data acquisition system, and stiffness analysis was conducted using Castigliano’s theorem applied to classical laminate theory.
9
Jacobson, Erik Andrew. "Effect of ski pole stiffness on upper body power output in cross-country skiers." Thesis, Montana State University, 2008. http://etd.lib.montana.edu/etd/2008/jacobson/JacobsonE0508.pdf.
Full textAbstract:
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).
10
Alsobrook, Nathan Gabriel. "The role of upper body power in classical cross-country skiing performance." Thesis, Montana State University, 2005. http://etd.lib.montana.edu/etd/2005/alsobrook/AlsobrookN0805.pdf.
Full text
11
Camenisch, Karin. "Flexibility as a determinant of rollerskiing economy in cross-country skiers." Thesis, Montana State University, 2007. http://etd.lib.montana.edu/etd/2007/camenisch/CamenischK0807.pdf.
Full text
12
Andersson, Bror Erik Petrus. "Biomechanical analysis of the herringbone technique in classical cross-country skiing." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for bevegelsesvitenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-13154.
Full textAbstract:
Purpose: To investigate the mechanics of the cross-country herringbone technique and to enhance the understanding of adaptations in kinematics and kinetics due to increasing velocity. Method: Eleven male elite cross-country skiers performed the herringbone technique at three different velocities; moderate, high and maximal. The slope covered a total distance of 50 m. The first 35 m, at ~7.5° incline, was utilized for acceleration using the diagonal stride technique to reach the desired velocity, followed by an 8 m measuring section (~15° incline) using the herringbone technique. All trials were filmed synchronously using two video cameras placed perpendicular along the section and one moving panning camera. Two photocells were used in order to obtain average section times and velocities. All subjects used ski poles that were constructed for force measurements and the forces directed along the poles was recorded with a sampling rate of 1500 Hz. Vertical plantar pressure was recorded at a rate of 100 Hz using the Pedar Mobile System. The plantar pressure was further converted to plantar ("leg") force. Results: Cycle rate and cycle length increased synchronously from moderate to high velocity, whereas the increase from a high to a maximal velocity was achieved by a higher cycle rate. The poling and the leg thrust times decreased gradually as velocities increased, whereas the relative poling and leg thrust times were constant; ~50% and ~40%. From moderate to maximal velocities the peak pole forces increased by 74%, in association with a 75% shorter time to peak force. The peak leg force increased by 7% from moderate to high velocity with no further changes at maximal velocity. The time to peak leg force decreased 24%, from moderate to maximal velocity. The force impulse ratio between pole and leg remained constant at ~8% from moderate to maximal velocity and the ratio for propulsion was ~30% due to the higher relative propulsive components from the poles. Changes in joint kinematics across the velocities were negligible, except for the total body lean and the lower leg angle. The angle of the lower leg, at end of the push off, decreased with increased velocity and was negatively correlated to maximal pole/leg force, cycle length and maximal velocity. Strength parameters correlated positively to force distribution between upper and lower body, as well as to maximal velocity. Conclusions: The adaptation of herringbone velocity between moderate and high velocity was achieved by increased cycle rate and cycle length, whereas the adaptation from high to maximal velocity was achieved only by increased cycle rate. The latter is explained by increased force generation from the upper and lower body, despite decreased poling and leg thrust times, with a constant impulse ratio between the upper and lower body. Higher skiing velocity was primarily assisted by constant body segment and joint angles. Key Words: CYCLE LENGTH, CYCLE RATE, HERRINGBONE, IMPULSE RATIO, LEG FORCE, POLE FORCE, PROPULSION
13
Sundström, David. "Optimized Pacing Strategies in Cross-Country Skiing and Time-Trial Road Cycling." Licentiate thesis, Mittuniversitetet, Avdelningen för kvalitetsteknik, maskinteknik och matematik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-18634.
Full textAbstract:
This thesis is devoted to the analysis and optimization of pacing strategies in cross-country skiing and time-trial road cycling. In locomotive sports, it is well known that variable pacing strategies using changes in the distribution of power output are beneficial when external forces vary along the way. However, there is a lack of research that more in detail investigates the magnitude of power output alteration necessary to optimize performance.A numerical program has been developed in the MATLAB software to simulate cross-country skiing and time-trial road cycling, as well as pacing strategy optimization in these two locomotive sports. The simulations in this thesis are performed by solving equations of motion, where all the main forces acting on the athlete are considered. The motion equations also depend on the course profile, which is expressed as a connected chain of cubical splines.The simulation process is linked to an optimization routine called the Method of Moving Asymptotes (MMA), which strives to minimize the finishing time while altering the power output along the course. To mimic the human energetic system, the optimization is restricted by behavioural and side constraints.Simple constraints like maximum average power output are used for cross-country skiing in Papers I and II. In Paper III a more sophisticated and realistic constraint is used for the power output in time-trial road cycling. It is named the concept of critical power for intermittent exercise and combines the aerobic and anaerobic contributions to power output.In conclusion, this thesis has demonstrated the feasibility of using numerical simulation and optimization in order to optimize pacing strategies in two locomotive sports. The results are clearly showing that these optimized pacing strategies are more beneficial to performance than an even distribution of power output.Denna avhandling är dedikerad att analysera och optimera farthållningsstrategier i längdskidåkning och tempocykling på landsväg. I idrotter som bygger på kontinuerlig framåtdrivning är det väl känt att farthållningsstrategier med variabel effekt är fördelaktiga om de yttre krafterna varierar längs banan. Ändå saknas forskning som mer i detalj utreder hur mycket effekten ska variera för att optimera prestationen.Ett numeriskt program har utvecklats i programvaran MATLAB för att simulera längdskidåkning och tempocykling samt optimera farthållningsstrategin i dessa idrotter. Simuleringarna använder sig av rörelseekvationer som består av de huvudsakliga krafter som verkar på idrottsutövaren under färd. Rörelseekvationerna påverkas också av banprofilen, som är uppbyggd av en sammankopplad kedja av tredjegradspolynom.Simuleringsprogrammet är kopplat till en optimeringsalgoritm med namnet Method of Moving Asyptotes (MMA), som strävar efter att minimera tiden mellan start och mål genom att ändra effekten längs med banan. Optimeringen begränsas av bivillkor i ett försök att efterlikna den mänskliga kroppens fysiologiska begränsningar.Enkla begränsningar såsom maximal medeleffekt används för längdskidåkningen i artikel I och II. I artikel III används mer sofistikerade och realistiska bivillkor för att begränsa uteffekten vid landsvägscykling. Här används modellen för kritisk effekt vid intervallträning, som kombinerar aerobt och anaerobt arbete.Sammanfattningsvis har denna avhandling visat på möjligheterna med att använda numerisk simulering och optimering för att optimera farthållningsstrategin i två idrotter. Resultaten visar tydligt att dessa optimerade farthållningsstrategier med varierande effekt är mer fördelaktiga för prestationen jämfört med en farthållningsstrategi med helt jämn effektfördelning.
14
ROSSO, VALERIA. "Biomechanics in Paralympic Cross-Country sit skiing: Evidence-based tests for classification." Doctoral thesis, Politecnico di Torino, 2019. http://hdl.handle.net/11583/2744153.
Full text
15
Silletta, Thomas. "The effects of pole length variation on the skiing performance of elite cross-country skiers using V-skating techniques /." Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66130.
Full text
16
Whiteman, John P. "Impacts of snow compaction from human recreation on the biota of snowy regions." Laramie, Wyo. : University of Wyoming, 2008. http://proquest.umi.com/pqdweb?did=1597631071&sid=3&Fmt=2&clientId=18949&RQT=309&VName=PQD.
Full text
17
Daley, Phillipa J., and n/a. "The acute physiological responses of elite cross country skiers to exercise at sea level and moderate altitude." University of Canberra. Sports Studies, 1999. http://erl.canberra.edu.au./public/adt-AUC20060704.113716.
Full textAbstract:
Nine Australian male cross country ski team members (19.8±2.5 years,
(X±SD),76.6±6.4kg, 184.8±4.9cm) completed both an incremental maximal exercise
test and a 45 minute time trial performance test using a dryland ski striding technique
with poles on a treadmill. Testing occurred at 610m in a chamber that was supplied
with either an 02 enriched (p02 = 152mmHg) or an N2 enriched (p02 = 132mmHg) gas
mixture to simulate sea level (SL) or 1800m (A) conditions respectively. A 48 hour rest
interval was provided between tests and the testing conditions were randomised,
counterbalanced and double blind. At maximum effort there were significant
differences in V02 max (70.2±4.0 v 61.7±2.9 ml.kg-1.min-1), PaO2 (97.2±12.7 v
77.1±11.2 mmHg) and SaO2 (90.6±4.9 v 77.8±3.9%); but not in HR (194.1±8.1 v
191.7±7.4 bpm), VE (133.1±12.8 v 132.6±11.3 L.min-1 STPD) or [La] (14.2±2.3 v
13.7±3.3 mM) at SL v A. There was a decrease of 7.6% in overall time trial
performance between the conditions (4005±378 v 3702±301 m, p = 0.08), although
performance was significantly lower at A during the latter period of the test, >25
minutes. During the steady state stage of the time trial performance test, (=75% SL
VO2 max) there were no significant differences between SL and A in any of VO2
(52.9±5.9 v 52.1±4.9 ml.kg-'.min-' at 15 minutes for SL and A respectively); HR
(173.1±12.8 v 176.1+10.1 bpm); or [La] (3.0±1.0 v 4.8±2.2 mM). However, there
was a significant reduction in PaO2 between SL (111.2±25.5 mmHg at 15 minutes) and
A (72.6±24.3 mmHg at 15 minutes), resulting in a significant reduction in SaO2
(96.6±1.1 v 84.6±6.8% at 15 minutes) between the conditions. At the end of each lap
of the variable workload stage of the time trial performance test there were significant
reductions in VO2 (65.3±6.9, 64.2±6.3 and 66.4±5.9 v 54.6±5.6, 56.0±4.6 and
57.9±3.2 ml.kg-'.min-1 at 25, 35 and 45 minutes at SL v A); and HR (190.1 ±9.2,
192.4±8.6 and 195.9±7.6 v 181.8±12.4, 186±8.1 and 189.6±9.2 bpm) under A
conditions. There were no significant differences in [La] at the end of each lap of the
time trial performance test between SL and A, although [La] did increase over time
during the test at both SL and A (6.2±2.0, 8.9±2.8 and 10.6±4.1 v 7.6±2.0, 8.4±2.2
and 9.9± 1.8 mM). At the end of each lap of the time trial performance test, there was a
significant reduction in PaO2 (120.9±24.4, 108.8±25.9 and 103.0±23.0 v 86.0±31.4,
94.9±22.3 and 71.1±3.2 mmHg); and SaO2 (94.6±2.4, 94.3±2.4 and 92.3±3.4 v
85.9±5.8, 84.3±6.4 and 81.7±6.1%) and both PaO, and SaO2 decreased over time
during the test at both SL and A. This study has indicated that as well as the extent of
hypoxia induced by altitude, both exercise intensity and duration may impact on the
magnitude of the response to sustained exercise at altitude, such as in cross country ski
racing.
18
Бурла, Антон Олександрович, Антон Александрович Бурла, Anton Oleksandrovych Burla, and Ю. О. Лянной. "О выносливости юных лыжников гонщиков." Thesis, Видавництво СумДУ, 2006. http://essuir.sumdu.edu.ua/handle/123456789/21817.
Full text
19
Markinhuhta, Annelie. "Förbättrar intensiv träning prestationen hos motionärer?" Thesis, Halmstad University, School of Business and Engineering (SET), 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-1298.
Full textAbstract:
Syftet med den här studien är att undersöka huruvida en stor andel av intensiva grenspecifika pass utvecklade den aeroba kapaciteten hos motionärer som tränar inför Vasaloppet. Två testmetoder användes; ett maximalt laktattest på rullskidor utomhus och ett maximalt cykeltest på en cykelergometer inomhus. En utav fp genomförde ett tidstest på rullskidor på en given sträcka istället för laktattestet. Båda testerna genomfördes före och efter en 11-veckors träningsperiod som bestod av 41 procent medel- och högintensiva pass som genomfördes grenspecifikt. Det betyder intervaller på rullskidor eller i skidgång samt snabbdistanspass på rullskidor. Övriga 59 procent av träningspassen genomfördes på en lågintensiv nivå, vilket är mindre än de 70-80 procent som normalt förespråkas för en uthållighetsidrottare. 4 försökspersoner (fp) på motionsnivå deltog (4 män och 1 kvinna). Fp 3 förbättrade prestationen markant med 20 procent genom en minskning av blodlaktatkoncentrationer vid givna hjärtfrekvenser (HR), sålunda en förbättring av dels den aeroba laktattröskeln (LT) som den anaeroba laktattröskeln (AT). Fp 4 förbättrade prestationen med 15 procent genom att åka den givna sträckan under tidstestet på en snabbare tid vid andra tillfället. Fp 2 avverkade en 500m längre sträcka under andra rullskidtestet och förbättrade på så sätt sin prestation med 10 procent, fp fick dock en försämring av AT och hade högre blodlaktatkoncentrationer vid andra testtillfället. Fp 1 förbättrade LT men försämrade AT. Sammanfattningsvis, visar studien att ett 11-veckors träningsprogram bestående av mycket grenspecifik träning på högre intensiteter ledde till en klar prestationsförbättring hos två av fp, gällande alla parametrar som testades. De övriga två fp uppvisade vissa förbättringar men högre laktatkoncentrationer vid några mättillfällen.
20
Kristjánsson, Kristinn. "Emigration of Icelandic elite skiers:In search for opportunities to achieve their goals." Thesis, Mittuniversitetet, Institutionen för hälsovetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-39435.
Full text
21
Lund, Ohlsson Marie. "New methods for movement technique development in cross-country skiing using mathematical models and simulation." Licentiate thesis, Sundsvall : Mittuniversitetet, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-10041.
Full text
22
Swarén, Mikael. "Experimental test setups and simulations in skiing mechanics." Licentiate thesis, KTH, Strukturmekanik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-144408.
Full textAbstract:
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.QC 20140423
23
Johansson, Agnes. "Airway responses to cold air exercise in junior cross-country skiers." Thesis, Mittuniversitetet, Institutionen för hälsovetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-39440.
Full text
24
Formenti, Federico. "Paleo-biomechanics and paleo-energetics of cross-country skiing and ice skating (3200 BC to date)." Thesis, Manchester Metropolitan University, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.434060.
Full textAbstract:
This thesis originated from the interest in understanding features characterizing the development of human locomotion on snow and on ice since their very beginning. No evidence could be found on how performance changed through history and there was no ground for reasonable assumptions to be made on the energy cost of these forms of transport. The thesis aims at estimating sustainable speeds over a range of distances by adopting different ski and skate sets, belonging to subsequent epochs. Particular focus has been posed on understanding which technical and technological changes could determine an improvement in performance, quantified by means of speed and metabolic energy cost measurements. Numerous studies focused on the determinants of cross-country skiing and ice skating performance in modern competitions, but no data can be found in literature on the cost of human locomotion on snow and ice since its very beginning. Measuring the cost of skiing and skating for past epochs would not only give the opportunity to understand which parameters humans empirically identified as the greatest limiting factors, but would also give a general idea of lifestyle, showing distances people could travel for their daily activities. During the long winters, when travelling on snow or on ice was not as effective as on dry ground, people inhabiting Northern regions were forced to develop tools in order to go hunting and look for food. Limiting the cost of locomotion would allow for a more efficient travelling: humans could cover the same distance in a shorter time or reach further destinations. More importantly, in the harsh conditions imposed by nature, saving energy while moving might have been crucial in increasing survival chances. Chapters 2 and 4 will show how performance on snow and ice changed since their very beginning five thousand years ago. Apparently, the first humans trying to use skis lived in Scandinavia, where heavy snowfalls covered the ground for several months per year. The oldest skis found and dated support this hypothesis. Differently, the oldest ice skates, dating back to about 2000BC, were found in many European regions and can not be clearly ordered chronologically. Therefore, a precise correspondence between where and when humans first tried to travel on ice can not be achieved at present. In chapter 3, I try to show how using skates might lead to a greater energy saving in Finland than in any between the other countries where the oldest bone skates were found.
25
Holmberg, Hans-Christer. "The physiology of cross-country skiing: with special emphasis on the role of the upper body /." Stockholm, 2005. http://diss.kib.ki.se/2005/91-85910-95-3/.
Full text
26
Carlsson, Tomas. "The importance of body-mass exponent optimization for evaluation of performance capability in cross-country skiing." Doctoral thesis, Högskolan Dalarna, Idrotts- och hälsovetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-102872.
Full textAbstract:
Introduction Performance in cross-country skiing is influenced by the skier’s ability to continuously produce propelling forces and force magnitude in relation to the net external forces. A surrogate indicator of the “power supply” in cross-country skiing would be a physiological variable that reflects an important performance-related capability, whereas the body mass itself is an indicator of the “power demand” experienced by the skier. To adequately evaluate an elite skier’s performance capability, it is essential to establish the optimal ratio between the physiological variable and body mass. The overall aim of this doctoral thesis was to investigate the importance of body-mass exponent optimization for the evaluation of performance capability in cross-country skiing. Methods In total, 83 elite cross-country skiers (56 men and 27 women) volunteered to participate in the four studies. The physiological variables of maximal oxygen uptake (V̇O2max) and oxygen uptake corresponding to a blood-lactate concentration of 4 mmol∙l-1 (V̇O2obla) were determined while treadmill roller skiing using the diagonal-stride technique; mean oxygen uptake (V̇O2dp) and upper-body power output (Ẇ) were determined during double-poling tests using a ski-ergometer. Competitive performance data for elite male skiers were collected from two 15-km classical-technique skiing competitions and a 1.25-km sprint prologue; additionally, a 2-km double-poling roller-skiing time trial using the double-poling technique was used as an indicator of upper-body performance capability among elite male and female junior skiers. Power-function modelling was used to explain the race and time-trial speeds based on the physiological variables and body mass. Results The optimal V̇O2max-to-mass ratios to explain 15-km race speed were V̇O2max divided by body mass raised to the 0.48 and 0.53 power, and these models explained 68% and 69% of the variance in mean skiing speed, respectively; moreover, the 95% confidence intervals (CI) for the body-mass exponents did not include either 0 or 1. For the modelling of race speed in the sprint prologue, body mass failed to contribute to the models based on V̇O2max, V̇O2obla, and V̇O2dp. The upper-body power output-to-body mass ratio that optimally explained time-trial speed was Ẇ ∙ m-0.57 and the model explained 63% of the variance in speed. Conclusions The results in this thesis suggest that V̇O2max divided by the square root of body mass should be used as an indicator of performance in 15-km classical-technique races among elite male skiers rather than the absolute or simple ratio-standard scaled expression. To optimally explain an elite male skier’s performance capability in sprint prologues, power-function models based on oxygen-uptake variables expressed absolutely are recommended. Moreover, to evaluate elite junior skiers’ performance capabilities in 2-km double-poling roller-skiing time trials, it is recommended that Ẇ divided by the square root of body mass should be used rather than absolute or simple ratio-standard scaled expression of power output.Incorrect ISBN in printed thesis: 973-91-7601-270-3
27
Svensson, Daniel. "Scientizing performance in endurance sports : The emergence of ‘rational training’ in cross-country skiing, 1930-1980." Doctoral thesis, KTH, Historiska studier av teknik, vetenskap och miljö, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-195830.
Full textAbstract:
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.QC 20161114
Rationell träning: vetenskapliggörandet äv träning för längdskidåkning
28
Birkegård, Christoffer, and Nicodemus Åstrand. "Idrottsrörelsens syn på förutsättningar för elitidrottsmiljöer : En intervjustudie med representanter från SDF, föreningar och elitidrottare från individuell- och lagidrott." Thesis, Umeå universitet, Pedagogiska institutionen, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-124765.
Full textAbstract:
This study was about the elite sport environment in a city in the north of Sweden. The purpose of the study was to understand what support and resources that already exists and also are needed for the athletes in floorball and cross-country skiing to proceed to the absolute elite in their sports. The purpose was also to get knowledge about what economic, human and material resources that are deeming to have in order to create a good elite sport environment and finally, when an organization or athlete are successful. The study analyzed the current situation and how an organization can create an even greater environment that produces top athletes. To answer the purpose of the study, interviews were conducted with representatives from special sport districts federation, sport clubs and athletes from the chosen sports in the study. The result showed many similarities and differences between the two sports. The two sport clubs does not make enough money to fully support their athletes as in football for example. Differences in the chosen sports were mainly in the cooperation were floorball had far better cooperation between special sport districts federation and sport clubs in comparison to cross country-skiing.
29
Alricsson, Marie. "The elite cross-country skier : clinical and sports related functional tests, dance training, injuries and self-related health /." Stockholm, 2003. http://diss.kib.ki.se/2003/91-7349-495-X/.
Full text
30
Hållmarker, Ulf. "Epidemiological Studies on Long Distance Cross-Country Skiers : Participants in the Vasaloppet 1955-2010." Doctoral thesis, Uppsala universitet, Uppsala kliniska forskningscentrum (UCR), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-260994.
Full textAbstract:
The overall aim of this thesis was to study the influence of physical activity on health. Risks and benefits of physical activity is of particular interest since there is a global trend of less physical activity among youths and adults. In order to investigate this aim we used a database from a large cross country ski race, Vasaloppet, with participants with a wide age range, and with both elite athletes and ordinary people who exercise and promote their health. The most serious risk of strenuous exercise is sudden death and it is challenging to identify preventive effects of major endemic diseases. Using epidemiological methodology we studied 200 000 Vasaloppet skiers and compared them with the general population. Based on personal identification numbers we added data from Swedish national personal and health registers, clinical registers as the cancer register, Swedeheart, or Swedish stroke register, and socioeconomic information from Statistics Sweden. In the Vasaloppet database we collected data on age, gender, finish time and number of races during the period 1989 to 2010. We evaluated risk of death during the race in two papers (I,II). During 90 years of annual races, cardiac arrest occurred in 20 skiers, of which five survived. The death rate is in average two per 100 000 skiers. We also studied the association with cancer incidence (paper III). The overall reduction of cancer was modest among skiers compared with the general population, but for cancers related to lifestyle the risks were markedly lower. We investigated the risk for recurrent myocardial infarction and found a 30% reduction among skiers (paper IV). In paper V we showed that skiers with a first stroke have a lower incidence of all-cause death. The skiers had a higher frequency of atrial fibrillation but had less severe stroke and no increased risk of recurrent stroke. Thus our data suggest that a lifestyle with a high level of physical activity may work as a protection after a cardiovascular event. Summary: The short excess mortality in endurance physical activity is by far outweighed by the long term protective effect of exercise in cardiovascular diseases and cancer.
31
Larsson, Emelie. "Wax-accessory for cross-country skiers : Development of a wax-bench that collect waste." Thesis, Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-70833.
Full textAbstract:
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.
32
Persson, Anton, and Gilberto Panisi. "Analysis of men’s sprint prologues in cross-country skiing World Cup : An outlook of how the best male skiers approach the sprint prologues." Thesis, Högskolan Dalarna, Idrotts- och hälsovetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:du-36494.
Full textAbstract:
SyfteDenna studies syfte var att undersöka om det finns ett samband mellan mellantid och sluttid på sprint prologer för herrar i världscuptävlingar, samt undersöka om förklaringsgraden för detta samband skiljer sig mellan tävlingsbanor med olika banprofil baserat på antal höjdmeter fram till mellantiden (CTC).MetoderAnalysen gjordes genom att ladda ner samtliga resultat från prologer från världscupen innehållande en mellantid efter 500-1000 m från säsongen 2017/2018 till 2019-2020. Sluttid, slutplacering och tid och placering vid mellantidsstation användes i den statistiska analysen. CTC beräknades genom att dividera klättrade höjdmeter från start till mellantid med respektive banas distans från start till mellantid. Baserat på olika banors CTC delades banorna in i 2 grupper, Level 1 (L1) banor med CTC ≤ 0,040 m/m och Level 2 (L2) CTC > 0,040 m/m. För att bestämma om datan var normalfördelad användes Kolmogorov-Smirnov test. Datan analyserades sedan med hjälp av Pearsons korrelation för att beräkna korrelationskoefficienten (r) vilken sedan kvadrerades för att få förklaringsgraden (r2).ResultatKorrelationsanalysen som genomförts visar ett signifikant resultat mellan mellantid och sluttid för alla analyserade prologer (0,63 < r < 0,95; alla p < 0,001). Mellantiden förklarar 76 ± 12 % av variationen i sluttid, men ingen signifikant skillnad sågs för förklaringsgraden mellan tävlingsbanor med olika CTCSlutsatserSlutsatserna som kan dras av denna studie är att ett bra resultat vid mellantiden med stor sannolikhet kommer ge ett bra slutresultat, oberoende av banprofil. Framtida forskning behövs för att utvärdera vilken taktik åkarna väljer.PurposeThe aim of this present study was to investigate if there is any correlation between intermediate station time and finish time in men’s cross-country ski sprint World Cup prologue. The second purpose was to identify if the correlation could depend on the morphology of the analysed courses. Methods Analyses were made on sprint prologues in World Cup, involving an intermediate time after 500-1000m from season 2017/2018 to 2019-2020. Intermediate time and finish time were used in statistical analysis. A coefficient of terrain characteristics (CTC) was calculated by dividing the high difference (HD) from the start to the position of the intermediate time station by the respectively covered distance. Based on CTC the different courses were categorized in two groups. Leve 1 (L1) courses with a CTC ≤ 0,040 m/m and Level 2 (L2) courses with a CTC > 0,040 m/m. To identify if data were normally distributed Kolmogorov-Smirnov test was used. The data were analysed using Pearson’s correlation to calculate the coefficient of variation (r) which was then squared to obtain the coefficient of determination (r2).ResultsThe correlation analysis shows that there were significant relationships between intermediate time and finish time for all analysed sprint prologues (0,63 < r < 0,95; all p < 0,001). Intermediate time explains 76 ± 12 % of the variation in finish time, while no significant difference was seen for the determination coefficients between race tracks with different CTCConclusionsFast times at the intermediate time stations will most likely give good finish times, independent of terrain characteristics (CTC). Further researches are needed to evaluate which pacing profile skiers are using.
33
Löfström, Håkan. "Sambandet mellan svenska elitlängdskidåkares kroppsvikt och tävlingsprestation." Thesis, Högskolan Dalarna, Idrotts- och hälsovetenskap, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:du-28157.
Full textAbstract:
Syfte Denna studie syftar till att undersöka och beskriva hur det förhåller sig med korrelationen vad beträffar svenska elitlängdskidåkares prestationsförmåga under längdskidtävlingar relaterat till längdskidåkares kroppsvikter. Metod Totalt deltog 23 kvinnliga och 21 manliga svenska elitlängdskidåkare i studien. Kroppsvikt och kroppslängd samlades in via ett frågeformulär som skickades till var och en av individerna. Resultat från tävlingar samlades in via en tiddatabas på nätet. Svenska skidförbundet gör kapacitetsanalyser på tider från Svenska FIS tävlingar och publicerar dessa på webbsiten www.skidtid.se. All data analyserades för att fastställa korrelationer mellan tider och individernas kroppsvikt. Resultat Endast en svag korrelation mellan längdskidåkares kroppsvikt och prestation kunde fastställas när det gäller placering i mål samt placering på platta partier, utförspartier och uppförspartier. Slutsatser Denna studie visar att elitlängdskidåkares kroppsvikt inte är en avgörande faktor till framgång.Purpose statement The purpose of the study is to examine if Swedish elite cross-country skiers body mass is correlated to the results on competitions. Method Twenty female and thirty male swedish elite cross-country skiers took part in the study. Body mass and body height were collected by a questionnaire which was sent to the skiers. Competition results was collected from a database. The swedish ski federation make capacity analysis from swedish FIS competitions and present them on the webpage www.skidtid.se. All data was analyzed to describe correlations between times and the individual body weight. Results Only weak correlation between swedish elite cross-country skiers bodyweight and race performance at finish, on flat course sections, downhill and uphill sections were found. Conclusions This study shows that elite cross-country skiers bodyweight is not the determinant factor for race performance.
34
Swarén, Mikael. "Objective Analysis Methods in the Mechanics of Sports." Doctoral thesis, KTH, Mekanik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-193044.
Full textAbstract:
Sports engineering can be considered as the bridge between the knowledge of sports science and the principles of engineering and has an important role not only in improving the athletic performance, but also in increasing the safety of the athletes. Testing and optimization of sports equipment and athletic performance are essential for supporting athletes in their quest to reach the podium. However, most of the equipment used by world-class athletes is chosen based only on subjective tests and the athletes’ feelings. Consequently, one of the aims of this thesis was to combine mechanics and mathematics to develop new objective test methods for sports equipment. Another objective was to investigate the possibility to accurately track and analyse cross-country skiing performance by using a real-time locating system. A long term aim is the contribution to increased knowledge about objective test and analysis methods in sports. The main methodological advancements are the modification of established test methods for sports equipment and the implementation of spline-interpolated measured positioning data to evaluate cross-country skiing performance. The first two papers show that it is possible to design objective yet sport specific test methods for different sports equipment. New test devices and methodologies are proposed for alpine ski helmets and cross-country ski poles. The third paper gives suggestions for improved test setups and theoretical simulations are introduced for glide tests of skis. It is shown, it the fourth paper, that data from a real-time locating system in combination with a spline model offers considerable potential for performance analysis in cross-country sprint skiing. In the last paper, for the first time, propulsive power during a cross-country sprint skiing race is estimated by applying a power balance model to spline-interpolated measured positioning data, enabling in-depth analyses of power output and pacing strategies in cross-country skiing. Even though it has not been a first priority aim in this work, the results from the first two papers have been used by manufacturers to design new helmets with increased safety properties and cross-country ski poles with increased force transfer properties. In summary, the results of this thesis demonstrate the feasibility of using mechanics and mathematics to increase the objectiveness and relevance when analysing sports equipment and athletic performance.QC 20160927
35
Strolia, Mantas. "Lietuvos slidininkų sprinterių rengimas metiniu priešolimpiniu treniruočių ciklu." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2010. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2010~D_20100709_134428-77299.
Full textAbstract:
XXI olimpinės žiemos žaidynės, vykusios 2010 metais Kanados Vankuverio mieste buvo jau šeštos, kuriose startavo Lietuvos sportininkai. XIX olimpinėse žiemos žaidynėse Solt Leik Sityje 2002 metais pirmą kartą į slidinėjimo lenktynių programą buvo įtrauktos sprinto lenktynės, o XX olimpinėse žiemos žaidynėse Turine buvo vykdomos individualios ir komandinės sprinto lenktynės. Vankuverio žiemos olimpinėse žaidynėse Lietuvos slidininkai pirmą kartą startavo komandinio sprinto rungtyje. Šioms sprinto rungtims Lietuvos slidininkai rengėsi specialiai, vykdydami programoje „Vankuveris-2010“ numatytus uždavinius. Vankuverio žiemos olimpinėse žaidynėse tiriamųjų slidininkų sprinterių pasiekti rezultatai sprinto distancijose buvo įvertinti patenkinamai.
Tyrimo tikslas ir uždaviniai - ištirti Lietuvos didelio meistriškumo slidininkų sprinterių rengimo ypatumus metiniu priešolimpiniu ciklu, nustatyti Lietuvos slidininkų sprinterių fizinio išsivystymo, fizinių ir funkcinių galių rodiklių kaitą metiniu rengimosi ciklu, apibendrinti Lietuvos slidininkų sprinterių varžybų sezono rezultatus.
Slidininkų sprinterių rengimo technologija iš esmės skiriasi nuo slidininkų rengimosi ilgesniems nuotoliams. Visgi tai reikėtų pagrįsti moksliniais tyrimais.
Buvo organizuotas dviejų Lietuvos slidininkų sprinterių veiklos tyrimas. Išanalizuotas fizinis krūvis, atliktas metiniu treniruočių ciklu. Atskirų mezociklų veiksmingumui įvertinti buvo atliekami laboratoriniai tyrimai. Buvo matuojami fizinio... [toliau žr. visą tekstą]XXI Olympic Winter Games were held in 2010 in Vancouver, Canada. That was already the sixth Games for the Lithuanian athletes. First time individual sprint was included in the cross-country skiing program in XIX Olympic Winter Games in Salt Lake City in 2002, after four years in XX Olympic Winter Games in Turin the cross-country skiing program had two sprint events: individual and team sprint. Lithuanian cross-country skiers first time took part in the team sprint event in Vancouver Winter Olympics Games. Lithuanian skiers were prepared specifically for the performance of the program "Vancouver-2010" objectives. The results of the Lithuanian skiers in individual and team sprints events in Vancouver Winter Olympics were assessed as satisfactory. The aims and objectives of research - to explore the cross-country skiing training program features of Lithuanian athletes in the last training macrocycle before Olympics, to estimate changes of physical and functional characteristics of Lithuanian cross-country skier’s sprinters physical development on preparations for the macrocycle, and summarize the results of Lithuanian skiers. Training Technology of cross-country skiers sprinters is basically different than cross-country skiers of longer distant. However, it should be based on scientific research. Sports action research of two Lithuanian cross-country skiers’ sprinters was organized. physical activity of training macrocycle were analyzed. Laboratory tests were conducted to... [to full text]
36
Björklund, Glenn. "Metabolic and Cardiovascular Responses During Variable Intensity Exercise." Doctoral thesis, Mittuniversitetet, Institutionen för hälsovetenskap, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-11744.
Full textAbstract:
Previous research investigating endurance sports from a physiological perspectivehas mainly used constant or graded exercise protocols, although the nature ofsports like cross-country skiing and road cycling leads to continuous variations inworkload. Current knowledge is thus limited as regards physiological responses tovariations in exercise intensity. Therefore, the overall objective of the present thesiswas to investigate cardiovascular and metabolic responses to fluctuations inexercise intensity during exercise. The thesis is based on four studies (Studies I-IV);the first two studies use a variable intensity protocol with cardiorespiratory andblood measurements during cycling (Study I) and diagonal skiing (Study II). InStudy III one-legged exercise was used to investigate muscle blood flow duringvariable intensity exercise using PET scanning, and Study IV was performed toinvestigate the transition from high to low exercise intensity in diagonal skiing,with both physiological and biomechanical measurements. The current thesisdemonstrates that the reduction in blood lactate concentration after high-intensityworkloads is an important performance characteristic of prolonged variableintensity exercise while cycling and diagonal skiing (Studies I-II). Furthermore,during diagonal skiing, superior blood lactate recovery was associated with a highaerobic power (VO2max) (Study II). Respiratory variables such as VE/VO2, VE/VCO2and RER recovered independently of VO2max and did not reflect the blood lactate oracid base levels during variable intensity exercise during either cycling or diagonalskiing (Studies I-II). There was an upward drift in HR over time, but not inpulmonary VO2, with variable intensity exercise during both prolonged cyclingand diagonal skiing. As a result, the linear HR-VO2 relationship that wasestablished with a graded protocol was not present during variable intensityexercise (Studies I-II). In Study III, blood flow heterogeneity during one-leggedexercise increased when the exercise intensity decreased, but remained unchangedbetween the high intensity workloads. Furthermore, there was an excessiveincrease in muscular VO2 in the consecutive high-intensity workloads, mainlyexplained by increased O2 extraction, as O2 delivery and blood flow remainedunchanged. In diagonal skiing (Study IV) the arms had a lower O2 extraction thanthe legs, which could partly be explained by their longer contact phase along withmuch higher muscle activation. Furthermore, in Study IV, the O2 extraction in botharms and legs was at the upper limit during the high intensity workload with nofurther margin for increase. This could explain why no excessive increase inpulmonary VO2 occurred during diagonal skiing (Study II), as increased O2extraction is suggested to be the main reason for this excessive increase in VO2(Study III).
37
Tärnklev, Julius, and Wilhelm Kindblad. "Faktorer som upplevs vara viktiga för en talangutvecklingsmiljö i en idrottsligt framgångsrik längdskidförening." Thesis, Högskolan i Halmstad, Hälsa och idrott, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-44458.
Full textAbstract:
The purpose of this study was to examine what main factors are perceived as important for the talent development environment in a successful cross-country skiing association. Data were collected through semi-structured interviews conducted with eight participants with different positions within the cross-country ski association. All participants were over 18 years old. The models Athletic Talent Development Environment (ATDE) and The Environment Success Factors (ESF) were used as theoretical frameworks. Using thematic content analysis, the interview results were analyzed, and the results were later divided into the following main themes; the micro-level sports area, micro-level non-sports area, macro level, conditions, process, organizational development and culture, individual development and performance, team performance, and environmental efficiency. The three overarching factors that were perceived as important for a good talent development environment were: To conduct good youth activities with supportive relationships and competent coaches. That sports goals are supported by the environment through the association, family and sports-oriented high schools and universities. To focus on long-term development through a permissive environment and a high degree of autonomy. Future research of interest would have been to study other cross-country skiing environments as well as environments where associations' activities are not conducted in connection with upper secondary school or universitySyftet med studien var att undersöka faktorer som upplevs vara viktiga i en talangutvecklingsmiljö hos en idrottsligt framgångsrik längdskidförening.Insamlingen av data skedde genom semistrukturerade intervjuer som genomfördes med åtta deltagare med olika positioner inom längdskidföreningen. Samtliga deltagare var över 18 år. Som teoretiskt ramverk användes modellerna Athletic Talent Development Environment (ATDE) samt The Environment Success Factors (ESF). Med hjälp av tematisk innehållsanalys analyserades intervjuresultaten och resultatet delades in i följande huvudteman; det mikronivå-idrottsliga området, mikronivå-icke idrottsliga området,makronivå, förutsättningar, process, organisationsutveckling och kultur, individuell utveckling och prestationer, lagprestationer, samt miljöns effektivitet. Resultatet visade tre övergripande faktorer som upplevdes vara viktiga för en bra talangutvecklingsmiljö vilka var: Att bedriva en bra ungdomsverksamhet med stödjande relationer och kompetenta tränare. Att idrottsliga mål stöds av omgivningen genom föreningen, familj samt idrottsinriktade gymnasium och universitet. Likväl att fokus riktas på långsiktig utveckling genom en tillåtande och stöttande miljö och en hög grad av autonomi. Intressant framtida forskning hade varit att studera andra längskidåkningsmiljöer samt miljöer där föreningars aktiveter inte bedrivs i samband med gymnasium eller högskola.
38
Pettersson, Annie, and Ludvig Gropp. "”Dette kan være prisen for å være moralens vokter i alle sammenhenger” : En kvalitativ studie om rapporteringen kring Therese Johaugs dopingfall i svenska och norska medier." Thesis, Linnéuniversitetet, Institutionen för medier och journalistik (MJ), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-70140.
Full textAbstract:
The aim of this study is to examine in which way nationalistic influences plays a prominent part in the news coverage of larger media houses. This by studying how two newspapers, Swedish Aftonbladet and Norwegian Verdens Gang, portrays and reports about Therese Johaug after she was tested positive for doping. We performed a critical discourse analysis of a total of 20 web-based news articles. These articles were chosen from the date the news appeared and one week forward. This in order to see if the the two newspapers were characterized with nationalistic tendencies as well as comparing them to see what the differences and similarities might be. By using theories such as national identitets, nationalism, ”us and them” and imagined communities we came to the conclusion that a nationalistic discourse is very much present. The subjects in the articles often become representatives of either Norway or Sweden - depending on the nationality. Johaug is mostly characterized as a national hero and sympathies are often shown from the norwegian news-articles. The opposite meaning were shown in the swedish news-articles. Described as an antagonist and a cheat - the complete opposite of a national hero. Imagined communities are also present as a nationalistic discourse. The people of Norway and Sweden are often involved - in order to justify this imagined community which occurs within the nation's borders. The similarities and differences between the two newspapers are quite subtle - but present nonetheless. This with a nationalistic discourse which confirms both previous research and our theoretical framework.
39
Brändström, Sara. "Olika chans beroende på födelsemånad : En kvantitativ undersökning av relative age effect på svenska längdskidgymnasier." Thesis, Högskolan Dalarna, Idrotts- och hälsovetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:du-18411.
Full textAbstract:
Syfte Syftet med studien var att undersöka om relative age effect förekommer på svenska längdskidgymnasier bland antagna elever och hur eventuell förekomst ser ut bland flickor och pojkar samt hur det ser ut vid Riksidrottsgymnasierna och de Nationell Idrottsutbildningarna. Metod För att besvara syftet har statistisk data analyserats med hjälp av ett Pearson Chi2-test. Analysen har skett genom att undersöka födelsemånad, kön och inriktning bland antagna elever vid svenska längdskidgymnasier mellan åren 2010-2015. Resultat Resultatet visar att det finns signifikanta bevis på att relative age effect förkommer på svenska längdskidgymnasier (p= <0,05). Vid uppdelning av respektive utbildningsinriktning kunde det endast konstateras förekomst av relative age effect vid Riksidrottsgymnasierna, vid uppdelning av kön går det inte att säkerställa en signifikant förekomst av relative age effect. Slutsatser Studiens resultat visar att det förekommer relative age effect på svenska längdskidgymnasier, dock varierar den mellan de analyserade undervariablerna. Tydligast förekommer relative age effect vid Riksidrottsgymnasierna, medan det vid Nationell Idottsutbildning, kunde det inte konstateras bevis för en signifikant överrepresentation av elever födda under första kvartalet. När flickor och pojkar analyserades separat kunde ingen relative age effect konstateras. Det behövs mer forskning inom området för att få en överblick av konsekvenserna av relative age effect på längdskidgymnasier men även konsekvenserna för svensk längdskidåkning i stort.Aim The purpose of this study was to investigate if relative age effect occurs at Swedish cross-country ski schools and if there were a differences in the presence among boys and girls, and between Riksidrottsgymnasier (Country-wide sport academy) and Nationell Idrottsutbildning (National sport academy). Method To answer the aim, statistical data were analyzed using a Pearson Chi2-test. The analysis has been done by examining birth month, sex and education among students at Swedish cross-country ski schools between 2010-2015. Results The result shows that there is a significant evidence of relative age effect at Swedish cross-country ski schools (p= <0,05). When the results were partial between Riksidrottsgymnasier and Nationell Idrottsutbildning, the relative age effect was only seen at Riksidrottsgymnasierna. There were no significant evidence for relative age effect when boys and girls where analyzed separately. Conclusion The results show that relative age effect appears on Swedish cross-country ski schools; however, there were some varies between analyzed variables. Strongest evidence for relative age effect was seen at Riksidrottsgymnaiserna. Further research is needed to get a overview of the consequences of relative age effect at cross-country ski schools, and the consequences it has in Swedish cross-country skiing overall, both for younger and older skiers.
40
Duberg, Axel, and Sanna Larsson. "”Det måste vara minst två svenska damer på pallen när vi jobbar, annars gör vi inte damsprint” : En kritisk diskursanalys av SVT:s ideologiska liverapportering av internationell längdåkning." Thesis, Uppsala universitet, Medier och kommunikation, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-414001.
Full textAbstract:
The overall aim of this thesis is to analyze the presence of nationalism and patriotism in the live reporting of the 2019–2020 season of the FIS Cross-Country World Cup, reported by the Swedish national public service broadcaster, SVT. Thereby, the following research questions have been constructed: 1. Are patriotism and nationalism to be found in the live reporting by SVT of the 2019– 2020 season of the FIS Cross-Country World Cup? 2. If found, how is it manifested? The theoretical framework of this thesis consists of banal nationalism, patriotism, framing and us and them theory. The investigation has been limited to studying one of the several disciplines of cross country competitions. The material has been collected through ethnographic observations of the recordings online. For analysis, critical discourse analysis has been applied. The study shows a strong presence of both banal nationalism and patriotism in the live reporting of SVT. This can be concluded by the identified discursive and social practices in the text, such as discourses regarding justice and Swedish centrism. The results of this thesis are of importance for further comparative research projects of ideological reporting as well for sports media consumers to understand how ideology affects the reporting of a public service broadcaster.
41
Nelson, Lars. "App based ski management with performance predictions." Thesis, Mittuniversitetet, Institutionen för data- och systemvetenskap, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-37949.
Full textAbstract:
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.
42
Stenberg, Simon. "Ett nytt isokinetiskt bålstyrketest för elitskidåkare." Thesis, Umeå universitet, Avdelningen för idrottsmedicin, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-184797.
Full textAbstract:
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.
43
Nilsson, Mattias. "En böjd stavdesigns påverkan på stakfasens egenskaper." Thesis, Högskolan Dalarna, Idrotts- och hälsovetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:du-22623.
Full textAbstract:
Syfte Studien syftar till att klarlägga hur stavisättningen och stakfasen påverkas vid användandet av en böjd jämfört med en rak stavdesign vid stakning i hög hastighet på rullskidor på rullband. Följande frågeställningar har undersökts: Leder en böjd stavdesign till att stavisättningen sker längre fram? Leder en böjd stavdesign till att stakfasens absoluta längd förändras? Leder en böjd stavdesign till att stakfasens relativa längd förändras? Metod Tio manliga längdskidåkare (ålder 25,3 ± 5,1 år, kroppslängd 182,1 ± 8,6 cm, kroppsvikt 78 ± 6,5 kg) deltog i studien. Forskningspersonerna genomförde ett Vmax-protokoll stakning på rullskidor på rullband, med rak såväl som med böjd stavdesign. Rörelsedata samlades in och analyserades för att fastställa eventuella skillnader i stavisättning, stakfas, återförandefas och total cykeltid. Resultat En signifikant skillnad kan påvisas gällande stavisättning, där en böjd stavdesign leder till en stavisättning längre framför bindningen jämfört med en rak stavdesign. Ingen signifikant skillnad kan påvisas rörande stakfasen, återförandefasen eller total cykeltid. Slutsatser Studiens visar att stavspetsens rörelsebana flyttas vid nyttjande av en böjd stavdesign i riktning framåt. Dock påverkas inte stakfasen, återförandefasen eller total cykeltid, vilket innebär att stakfasens längd, i absoluta såväl som relativa termer, är densamma vid stakning med rak och böjd stavdesign.Purpose statement The purpose of the study is to examine how the pole plant and pole phase are affected by using a pole of curved, compared to straight, design for double poling at high speed on roller skis at a treadmill. The following research questions have been examined: Does a curved pole design result in a pole plant further forward? Does a curved pole design result in a change in the absolute length of the pole phase? Does a curved pole design result in a change in the relative length of the pole phase? Methodology Ten male cross country skiers (age 25,3 ± 5,1 years, height 182,1 ± 8,6 cm, BW 78 ± 6,5 kg) took part in the study. The test subjects performed a Vmax-test double poling on roller skis on a treadmill, with straight and curved poles. Movement data was collected and analysed to examine potential differences regarding pole plant, pole phase, recovery phase and total cycle time. Results A significant difference was found regarding the pole plant, as a curved pole design resulted in a pole plant further forward compared to a straight design. No significant difference was found related to the pole phase, recovery phase or total cycle time. Conclusion The study shows that the path of the pole tip is moved forward when using poles of a curved design. There is no change in the pole phase, the recovery phase or the total cycle time, thus the length of the pole phase, absolute as well as relative, is unaffected by pole design when double poling.
44
Tullbrink, Agestam Hanna. "Hög puls i kallt klimat : Produktutveckling av jacka för längdskidåkning, med fokus på mönsterkonstruktion för rörelsefrihet och termisk komfort." Thesis, Högskolan i Borås, Akademin för textil, teknik och ekonomi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-11097.
Full textAbstract:
Uppsatsen beskriver vidareutveckling av en längdskidåkningsjacka till en värmande, mer multi- funktionell jacka med avslappnad passform, i samarbete med ett svenskt konfektionsföretag specialiserat på längdskidåkning. I uppdraget ingick att undersöka hur användningsområdet kan breddas utan att jackans funktion vid längdskidåkning försämras. En kravspecifikation utformades med hänsyn till synpunkter från utövare och återförsäljare samt produktionsmässiga förutsättningar. Arbetsprocessen dokumenterades och förankrades i vetenskaplig litteratur och resultatet validerades genom framtagning av en herrjacka som möter de framtagna kriterierna. Ett funktionellt plagg måste framför allt ha riktigt bra passform och komfort; specialiserade finesser kan bli störningsmoment för den som inte behöver dem. Funktionskläder för sport, träning och friluftsliv måste ofta uppfylla höga och motsägelsefulla krav; det kan krävas extrem rörelsefrihet, hög slitstyrka men låg vikt, väderskydd men effektiv ventilation under intensiv ansträngning. Högpulsaktivitet i vinterklimat ställer särskilda krav på klädsystemets temperaturreglerings- förmåga och rörelsefrihet; båda är avgörande för såväl komfort som prestation. Litteratur- översikten behandlar därför termisk och ergonomisk komfort, mönsterkonstruktion för rörlighet, passformsutvärdering, och beräkning av viddtillägg. Jag diskuterar även behoven av konstruktionsunderlag applicerbara på funktionsplagg, systematisering av passforms- utvärdering, och preciserad terminologi. Idag krävs ofta många prototyper för att uppnå god passform, komfort och funktionalitet; denna tidskrävande och kostsamma process bör kunna effektiviseras genom dokumentation och metodstandardisering.This bachelor’s thesis describes the development of a cross-country skiing jacket for a Swedish niche brand. The assignment required investigation of possibilities to diversify the garment’s usage range while maintaining functionality for the original target group. The concept is a warm, multifunctional men’s jacket in a relaxed fit, complementing the present collection. Market research and literature studies were used to clarify user needs, retailer requests and production constraints. Functional requirements for sportswear are tough and often contradictory: high durability at low weight, weatherproof yet breathable. It is essential, both for comfort and performance, that clothing systems for high intensity activities in cold climate have outstanding thermoregulatory properties and mobility; literature on thermal and ergonomic comfort, patternmaking for mobility, fit evaluation and garment ease is reviewed. The results were validated through the production of a sample garment, while striving to document the process methodically. Numerous samples are usually required to achieve good fit, comfort and functionality; this process tends to be especially time-consuming and costly for quality functional clothing. Benefits of consistent documentation and standardized methods are discussed, as well as the lack of precise terminology and of patternmaking texts applicable to functional garments, systematization of fitting, and fit evaluation.
45
Tynell, Rikard. "Delkropp- eller helkroppsarbete som återhämtningsstrategi efter upprepade högintensiva arbetsbelastningar på stakergometer hos svenska elitlängdskidåkare. : En kvantitativ studie om återhämtningsstrategier." Thesis, Högskolan Dalarna, Idrotts- och hälsovetenskap, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:du-28158.
Full textAbstract:
Syfte: Studiens syfte var att undersöka skillnaden mellan två olika återhämtningsstrategier, delkroppsarbete (cykelergometer) och helkroppsarbete (rullskidor), avseende effektutveckling vid upprepade högintensiva arbeten på stakergometer. Vidare syftar studien till att undersöka om hjärtfrekvensen och blodlaktatkoncentrationen skiljer sig åt mellan återhämtningsstrategierna. Metod: Sju elitaktiva manliga skidåkare på nationell nivå rekryterades till studien där en crossovermetod tillämpades. En prolog och tre heat med tre minuter högintensivt arbete genomfördes under varje prestationstillfälle. Återhämtningsstrategierna genomfördes med 16 min arbete på en arbetsbelastning vid ≈ 55% av VO2max. De testvariabler som samlades in var laktatkoncentration, effektutveckling samt hjärtfrekvens. Resultat: En signifikant lägre laktatkoncentration påvisades efter helkroppsarbete som återhämtningsstrategi. Dock kunde ingen skillnad mellan strategierna påvisas avseende effektutveckling under heaten. Det kunde heller inte påvisas någon skillnad i hjärtfrekvens före eller under heaten. Slutsatser: Ingen utav de undersökta återhämtningsstrategierna kan rekommenderas framför den andra avseende att optimera sprintprestationsförmågan i längdskidåkning. Däremot visade det sig att helkroppsarbete medförde en lägre blodlaktatkoncentration inför nästkommande heat jämfört mot delkroppsarbete som återhämtningsstrategi.Purpose: The purpose of the study was to investigate the difference between two recovery strategies, lower-body work (cycle) and whole-body work (roller skiing), regarding to power development in repeated maximum workout on double-poling ergometer. Moreover, the study also aims to investigating whether the heart rate and the blood-lactate concentration differ between the recovery strategies. Method: Seven elite-active male skiers at national level were recruited to the study where a crossover method was applied. A prologue and three heats with three minutes of high-intensity work were performed during each performance. Recovery strategies were carried out with 16 min work at a workload for ≈ 55% of VO2max. The collected test variables in this study were lactate concentration, effect development, and heart rate. Results: A significant difference was found in the lactate concentration after whole-body work as a recovery strategy. However, there was no difference between the strategies in power development during the heats. Furthermore, no difference in heartrates was detected before or during the heats. Conclusions: None of the investigated recovery strategies can be recommended above the other in order to optimize the sprint performance in cross-country skiing. However, whole-body work resulted in a lower blood-lactate concentration prior to next heat compared to lower-body work as recovery strategy.
46
Persson, Ellen, and Gerd Waldheim. "Spridningen av poly-och perfluorerade ämnen från skidvalla : En litteraturstudie om hur användningen av fluorvalla inom längdskidåkning påverkar mark och vatten." Thesis, KTH, Hållbar utveckling, miljövetenskap och teknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-298192.
Full textAbstract:
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.
47
Bergström, Max, and David Glader. "Betydelsefulla faktorer för framgångsrika idrottskarriärer inom längdskidåkning och skidskytte." Thesis, Högskolan Dalarna, Idrotts- och hälsovetenskap, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:du-28143.
Full textAbstract:
Längdskidåkning är en av de mest krävande uthållighetsidrotterna där tävlingstiderna kan variera mellan tre minuter till närmare fyra timmar. Om en idrottsutövare ska nå toppen av sin förmåga krävs det vanligtvis att denne avsätter 20 till 30 timmar per vecka åt träning och tävling under flera års tid. Inom skidskytte behöver utövarna, utöver att vara duktiga längdskidåkare, dessutom bära ett gevär på ryggen och skjuta på måltavlor under högintensiv belastning. Syftet med studien var att kartlägga utövares upplevelser av avgörande och betydelsefulla faktorer för långa framgångsrika idrottskarriärer inom längdskidåkning och skidskytte. I studien användes en kvalitativ metod med semistrukturerade intervjuer, där totalt nio individer deltog. Deltagarna hade tävlat på nationell eller internationell nivå inom längdskidåkning eller skidskytte under minst en tio årsperiod som seniorer. Ett antal övergripande betydelsefulla och avgörande faktorer för framgångsrika idrottskarriärer inom längdskidåkning kunde identifieras. Dessa var: träning och organisation, socioekonomiska faktorer, talang och genetisk potential samt återhämtning. För att nå nationella och internationella framgångar och bedriva en elitsatsning krävs inte bara många års träning, utan även stöd från omgivning i form av familj, tillgång till rätt kompetens och ekonomiskt bidrag eller lön.Cross country skiing is one of the most demanding endurance sports where the duration of physical effort during a competitive event usually lasts from three minutes up to four hours, or sometimes even longer. To reach national or international elite level, an athlete generally needs to invest 20 to 30 hours of training a week over many years. In biathlon, an athlete not only has to be a good skier, but also be able to carry a rifle and shoot on targets during high intense work load. The aim of this study was to identify athletes' own experiences of the crucial factors that allow for long and successful sport careers in cross country skiing. The study was qualitatively orientated, where semi-structured interviews were used to collect the athlete's perceptions. In total, nine individuals with at least 10 years of competitive cross country skiing or biathlon experience as adults at national or internationallevel participated. The interviews revealed several factors that athletes believe are crucial for achieving long and successful careers. These factors were: 1. Training and organization, 2. Socioeconomic factors, 3. Talent and genetic potential and 4. Recovery. To maintain long and successful careers in cross country skiing, athletes perceive that in addition to factors associated with the training process, support from family, their team and sponsors play important roles.
48
Barkegren, Hanna, and Minna Sunesson. "Att tävla eller inte tävla, det är frågan : En studie om varför unga längdskidåkare i Dalarna slutar tävla." Thesis, Högskolan Dalarna, Idrotts- och hälsovetenskap, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:du-28148.
Full textAbstract:
Aim This study aimed to investigate at what age young adolescence in Dalarna stops competing in cross-country skiing. Furthermore, to explore possible reasons to why they decide to stop competing. Method To answer the aim a mixed-method was applied. The data collection comprised a quantitative statistical study of when young adolescence from five different teams stopped competing. Additionally, 10 qualitative interviews were conducted with six young adolescence, three coaches and Dalarnas ski associations head of management training. Results The results show that most young adolescents in Dalarnas association stops competing when they reach the age of 12-13. Furthermore, the results suggest that there isn’t just one specific reason to why young adolescence in Dalarnas stops competing. Instead five reoccurring themes: performance, other sports, parents, interpersonal relationships and physical prerequisites were found. Conclusion The results show that the age where most young adolescents stops competing is 12-13 years. Additionally that here is no simple answer to why young adolescent in Dalarna stops competing. Instead the reasons why they decide to stop competing consists of many different factors. With background from the result a conclusion can be made that there is need of improvement, from the association as well as the teams, concerning how to make competition more attractive to youth in Dalarna. The two most common areas to talk about amongst the interview subjects were performance and interpersonal relationships. Therefore those two areas might be a good starting point in the process of keeping youth in competition context.Syfte Syftet med studien var att undersöka vid vilken ålder barn och ungdomar inom Dalarnas Skidförbund slutar att delta i längdskidtävlingar. Vidare att undersöka möjliga bakomliggande orsaker till att barn och ungdomar slutat tävla. Metod För att besvara syftet med studien applicerades en blandad metod. Delstudie ett är av kvantitativ karaktär och innehåller data gällande vid vilken ålder som unga längdskidåkare inom Dalarnas Skidförbund slutar tävla. Delstudie 2 är av kvalitativ karaktär och består av tio intervjuer. Sex av dessa var med ungdomar som valt att sluta, tre var med aktiva ledare och den sista intervjun var med den utbildningsansvariga i Dalarnas Skidförbund. Resultat Resultatet visar på att barn- och ungdomar inom Dalarnas Skidförbund slutar tävla när de når 12- 13 års ålder. Vidare tyder resultatet på att det inte finns någon specifik enskild anledning till att barn och ungdomar inom Dalarnas Skidförbund slutar att tävla på längdskidor. Istället identifierades fem återkommande teman: Prestation/resultat, andra idrotter, föräldrar, social samhörighet och fysiska förutsättningar. Slutsatser Resultatet visar att de flesta barn och ungdomar inom Dalarnas Skidförbund slutar vid 12-13 års ålder. Vidare att det inte finns något enkelt svar på varför barn och ungdomar i Dalarnas Skidförbund slutar att tävla på längdskidor. Istället grundas deras beslut att sluta tävla på ett flertal olika faktorer. Utifrån studiens resultat går det att dra slutsatsen att det finns förbättringspotential både inom klubbarna men även hos förbundet när det gäller arbetet för att behålla tävlingsaktiva längdskidåkare i distriktet. Det som intervjudeltagarna pratade mest om var prestation/resultat och social samhörighet. Därför kan dessa två områden vara en bra startpunkt att utgå från i arbetet för att behålla tävlingsaktiva inom distriktet.
49
Israelsson, Johan. "Ett badhus i Umeå." Thesis, KTH, Arkitektur, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-99180.
Full textAbstract:
Umeå kommun har sedan 1995, med varierande intensitet, planerat för en ny simhall som ska ersätta den gamla från 1970. Det nu liggande förslaget har mötts med skiftande åsikter och de många kritiska handlar om både förslagets placering (mitt i centrala staden på en all- deles för trång tomt) och programmets omfattning (för lite). Eftersom jag delar dessa kritiska åsikter så har detta gett mig ett ypperligt tillfälle att som mitt examensarbete titta på hur jag anser att placeringen, omfattningen och gestaltningen av ett nytt badhus i Umeå ska se ut. Mina huvudsakliga frågeställningar har varit just placeringen, programmets omfattning samt naturligtvis även gestaltningen av ett badhus för Umeå kommun med sina 110 000 invånare. Jag har utvärderat de alternativa placeringar som föreslagits och samtliga platser har naturligtvis både sina för- och nackdelar men jag har kommit fram till att jag vill placera ett nytt badhus på samma plats som den nuvarande simhallen som planeras att rivas. Det som fick min jämförelse att väga över för min valda plats är att det ligger på randen av Gam- mliaskogen, ett rekreationsområde helt omgivet av stad men där det finns flera skid- och joggingspår. Detta är en möjlighet som är för bra för att försitta.Umeå municipality have, since 1995, at varying intensity, been planning for a new bath house to replace the existing from 1970. The current proposal has been met with mixed critique and the more critical ones fokus on both the placement (in the city centre on a too narrow lot) and the extent of the programme (too small). Since I share these critical opinions it has given me an excellent opportunity for this thesis work to examine the placement, extent and figuration of a new bath house in Umeå.
50
Sundström, David. "Numerical optimization of pacing strategies in locomotive endurance sports." Doctoral thesis, Mittuniversitetet, Avdelningen för kvalitetsteknik, maskinteknik och matematik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-26925.
Full textAbstract:
This thesis is devoted to the optimization of pacing strategies in two locomotive endurance sports; cross-country skiing and road cycling. It has been established that constant pace and variable power distributions are optimal if purely mechanical aspects of locomotion are considered in these sports. However, there is a lack of research that theoretically investigates optimal pacing for real world athletes who are constrained in their ability to generate power output through the bioenergetics of the human body. The aims of this thesis are to develop numerical pacing strategy optimization models and bioenergetic models for locomotive endurance sports and use these to assess objectives relevant in optimal pacing. These objectives include: Investigate the impact of hills, sharp course bends, ambient wind, and bioenergetic models on optimal pacing and assess the effect of optimal pacing strategies on performance. This thesis presents mathematical models for optimization of pacing strategies. These models are divided into mechanical locomotion, bioenergetic, and optimization models that are connected and programmed numerically. The locomotion and bioenergetic models in this thesis consist of differential equations and the optimization model is described by an iterative gradient-based routine. The mechanical model describes the relation between the power output generated by an athlete and his/her locomotion along a course profile, giving the finishing time. The bioenergetic model strives to mimic the human ability to generate power output. Therefore, the bioenergetic model is set to constrain the power output that is used in the mechanical locomotion model. The optimization routine strives to minimize the finishing time in the mechanical locomotion model by varying the distribution of power output along the course, still satisfying the constraints in the bioenergetic model. The studies contained within this thesis resulted in several important findings regarding the general application of pacing strategies in cross-country skiing and road cycling. It was shown that the constant pace strategy is not optimal if ambient conditions change over the course distance. However, variable power distributions were shown beneficial if they vary in parallel with course inclination and ambient winds to decrease variations in speed. Despite these power variations, speed variations were not eliminated for most variable ambient conditions. This relates to the athlete’s physiological restrictions and the effect of these are hard to predict without thorough modeling of bioenergetics and muscle fatigue. Furthermore, it vi was shown that substantial differences in optimal power distributions were attained for various bioenergetic models. It was also shown that optimal braking and power output distributions for cycling on courses that involve sharp bends consisted of three or four phases, depending on the length of the course and the position of the bends. The four phases distinguished for reasonably long courses were a steady-state power phase, a rolling phase, a braking phase, and an all-out acceleration phase. It was also shown that positive pacing strategies are optimal on relatively long courses in road cycling where the supply of carbohydrates are limited. Finally, results indicated that optimal pacing may overlook the effect of some ambient conditions in favor of other more influential, mechanical or physiological, aspects of locomotion. In summary, the results showed that athletes benefit from adapting their power output with respect not only to changing course gradients and ambient winds, but also to their own physiological and biomechanical abilities, course length, and obstacles such as course bends. The results of this thesis also showed that the computed optimal pacing strategies were more beneficial for performance than a constant power distribution. In conclusion, this thesis demonstrates the feasibility of using numerical simulation and optimization to optimize pacing strategies in cross-country skiing and road cycling.Avhandlingen handlar om optimering av farthållningsstrategier inom längdskidåkning och landsvägscykling. Det finns ett utbrett stöd för att konstant fart och varierande effektfördelningar är optimala om endast mekaniska aspekter beaktas i dessa sporter. Ändå saknas teoretiska studier som undersöker optimal farthållning för verkliga idrottsutövare som är begränsade i sin förmåga att generera effekt genom kroppens bioenergetiska system. Målen med den här avhandlingen är att utveckla metoder för bioenergetik och optimering av farthållningsstrategier i uthållighetsidrott. Dessutom är målet att undersöka påverkan av backar, svängar, omgivande vind och bioenergetisk modellering på den optimala farthållningsstrategin samt att utreda potentialen till prestationsförbättring med optimala farthållningsstrategier. Avhandling presenterar matematiska modeller för optimering av farthållningsstrategier. Dessa modeller delas in i en mekanisk modell för förflyttning, en bioenergetisk modell och en optimeringsmodell. De mekaniska och bioenergetiska modellerna som presenteras i avhandlingen består av differentialekvation och optimeringsmodellen utgörs av en gradient-baserad algoritm. Den mekaniska modellen beskriver förhållandet mellan utövarens effekt och den resulterande rörelsen längs banan som ger tiden mellan start och mål. Den bioenergetiska modellen beskriver människokroppens olika energisystem och dess begränsningar att generera effekt. Den bioenergetiska modellen interagerar med optimeringsmodellen genom att utgöra dess begränsningar för vad den mänskliga kroppen klarar av. Sammanfattningsvis försöker optimeringsmodellen minimera tiden mellan start och mål i den mekaniska modellen genom att variera effekten längs banan. Samtidigt ser optimeringsmetoden till att denna effektfördelning inte kränker den bioenergetiska modellen. Studierna som ingår i avhandlingen resulterade i flera viktiga upptäckter om generella tillämpningar av farthållningsstrategier inom längdskidåkning och landsvägscykling. Det visade sig att konstant fart inte är optimalt om omgivande betingelser varierade längs banans sträckning. Däremot var varierande effektfördelning fördelaktig om den varierar parallellt med banlutning och omgivande vindpåverkan för att minska fartens variationer. Trots denna variation, visade resultaten att fartvariationerna inte eliminerades helt. Detta har att göra med utövarens fysiologiska begränsningar, vars påverkan är svår att förutspå utan genomgående modellering av bioenergetik relaterat till muskeltrötthet. Dessutom viii visade resultaten att olika bioenergetiska metoder gav upphov till betydande skillnader i de optimala farthållningsstrategierna. Resultaten i avhandlingen visade också att optimal effektfördelning vid kurvtagning i landsvägscykling innehåller tre eller fyra faser. The fyra faser som var utmärkande på relativt långa banor var en tröskelfas, en rullfas, en bromsfas och en maximal accelerationsfas. Resultaten visar också att positiv farthållning är optimal på relativt långa banor i landsvägscykling där tillgången på kolhydrater är begränsad. Samtidigt visade resultaten på optimala farthållningsstrategier ibland att inverkan av omgivande betingelser förbisågs till fördel för med inflytelserika betingelser som påverkar framdrivningen. Sammantaget visar resultaten i denna avhandling att utövare gagnas av att anpassa effekten med hänsyn till varierande terräng, omgivande vind, atletens egen fysiologiska och biomekaniska förmåga, banans längd och hinder såsom kurvor. Resultaten visar också att de optimala farthållningsstrategier med varierande effektfördelning som beräknats i denna avhandling förbättrar prestationen jämfört med konstanta effektfördelningar. Sammanfattningsvis visar denna avhandling på möjligheterna att använda numerisk simulering och optimering för att optimera farthållningsstrategier i längdskidåkning och landsvägscykling.
Vid tidpunkten för disputationen var följande delarbeten opublicerade: delarbete 5 accepterat, delarbete 6 manuskript.
At the time of the doctoral defence the following papers were unpublished: paper 5 accepted, paper 6 manuscript.