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Pacing and predictors of performance during cross-country skiing races:A systematic review

Journal of Sport and Health Science 2018年第4期7卷 381-393页

作者： Thomas Stogg barbara pellegrini Hans-Christer Holmberg Department of Sport and Exercise Science University of SalzburgHallein/Rif 5400Austria CeRiSM Research Centre＂Sport Mountainand Health＂Rovereto 36068Italy Department of Neuroscience Biomedicine and MovementUniversity of VeronaVerona 37100Italy Swedish Winter Sports Research Centre Mid Sweden UniversityOstersund 83128Sweden School of Sport Sciences UiT Arctic University of NorwayTroms（）9037Norway School of Kinesiology University of British ColumbiaVancouverBC V6T 121Canada Department of Physiology and Pharmacology Karolinska InstitutetStockhol 17177Sweden Corresponding author.E-mail address：thomas.stoeggl@sbg.ac.at

Background： Cross-country skiing （XCS） racing, a popular international winter sport, is complex and challenging from physical, technical, and tactical perspectives. Despite the vast amount of research focusing on this sport, no review has yet addressed the pacing strategies of elite XCS racers or the factors that influence their performance. The aim was to review the scientific literature in an attempt to determine the effects of pacing strategy on the performance of elite XCS racers. Methods： Four electronic databases were searched using relevant subject headings and keywords. Only original research articles published in peerreviewed journals and the English language and addressing performance, biomechanics, physiology, and anthropometry of XCS racers were reviewed. Results： All 27 included articles applied correlative designs to study the effectiveness of different pacing strategies. None of the articles involved the use of an experimental design. Furthermore, potential changes in external conditions （e.g.,weather, ski properties） were not taken into consideration. A comparable number of studies focused on the skating or classical technique. In most cases, positive pacing was observed, with certain indications that higher-level athletes and those with more endurance and strength utilized a more even pacing strategy. The ability to achieve and maintain a long cycle length on all types of terrain was an important determinant of performance in all of the included studies, which was not the case for cycle rate. In general, uphill performance was closely related to overall race performance, with uphill performance being most closely correlated to the success of female skiers and performance on flat terrain being more important for male skiers. Moreover, pacing was coupled to the selection and distribution of technique during a race, with faster skiers employing more double poling and kick double poling, less diagonal stride, and more V2 （double dance） than V1 （single d

关键词： Classic style Competition Cycle characteristics Positive pacing Skating

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Biomechanical analysis of the "running" vs. "conventional" diagonal stride uphill techniques as performed by elite cross-country skiers

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Journal of Sport and Health Science 2022年第1期11卷 30-39页

作者： barbara pellegrini Chiara Zoppirolli Federico Stella Lorenzo Bortolan Hans-Christer Holmberg Federico Schena CeRiSM(Research Centre of Mountain Sport and Health) University of VeronaRovereto 38068Italy Department of Neuroscience Biomedicine and MovementUniversity of VeronaVerona 37129Italy Swedish Winter Sports Research Centre Department of Health SciencesMid Sweden UniversityÖstersund 83125Sweden School of Kinesiology University of British ColumbiaVancouver BC V6T 1Z1Canada Biomechanics Laboratory Beijing Sport UniversityBeijing 100084China

Purpose:This study aimed to compare biomechanical aspects of a novel"running"diagonal stride(DSRUN)with"conventional"diagonal stride(DSCONV)skiing techniques performed at high ***:Ten elite Italian male junior cross-country skiers skied on a treadmill at 10 km/h and at a 10°incline utilizing both variants of the diagonal stride *** 3-dimensional kinematics of the body,poles,and roller skis;the force exerted through the poles and foot plantar surfaces;and the angular motion of the leg joints were ***:Compared to DSCONV,DSRUN demonstrated shorter cycle times(1.05±0.05 s vs.0.75±0.03 s(mean±SD),p<0.001)due to a shorter rolling phase(0.40±0.04 s vs.0.09±0.04 s,p<0.001);greater force applied perpendicularly to the roller skis when they had stopped rolling forward(413±190 N vs.890±170 N,p<0.001),with peak force being attained earlier;prolonged knee extension,with a greater range of motion during the roller ski-stop phase(28°±40 vs.16°±3°,p=0.00014);and more pronounced hip and knee flexion during most of the forward leg *** mechanical work performed against friction during rolling was significantly less with DSRUN than with DSCONV(0.04±0.01 J/m/kg vs.0.10±0.02 J/m/kg,p<0.001).Conclusion:Our findings demonstrate that DSRUN is characterize by more rapid propulsion,earlier leg extension,and a greater range of motion of knee joint extension than DSCONV-Further investigations,preferably on snow,should reveal whether DSRUN results in higher acceleration and/or higher peak speed.

关键词： Classical skiing Kinetics Roller skiing

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Methodological Guidelines Designed to Improve the Quality of Research on Cross-Country Skiing

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Journal of Science in Sport and Exercise 2021年第3期3卷 207-223页

作者： barbara pellegrini Øyvind Sandbakk Thomas Stoggl Matej Supej NielsØrtenblad Axel Schürer Thomas Steiner Angelica Lunina Chris Manhard Hui Liu Olli Ohtonen Chiara Zoppirolli Hans-Christer Holmberg CeRiSM University of VeronaRoveretoItaly Neuroscience Biomedicine and Movement Science DepartmentUniversity of VeronaVeronaItaly Centre for Elite Sports Research Department of Neuromedicine and Movement ScienceNorwegian University of Science and TechnologyTrondheimNorway Department of Sport Science and Kinesiology University of SalzburgSalzburgAustria Laboratory of Biomechanics Faculty of SportUniversity of LjubljanaLjubljanaSlovenia Department of Sports Science and Clinical Biomechanics University of Southern DenmarkOdenseDenmark Institute for Applied Training Science LeizpigGermany Swiss Federal Institute of Sport MagglingenSwitzerland Department of Theory and Methods in Ski Sports Russian State University of Physical EducationSportYouth and Tourism(SCOLIPE)MoscowRussia School of Kinesiology University of British ColumbiaVancouverB.CCanada Biomechanics Laboratory Beijing Sport UniversityBeijingChina Department of Biology of Physical Activity University of JyvaskylaJyväskylaFinland Swedish Winter Sports Research Centre Department of Health SciencesMid Sweden UniversityOstersundSweden

Cross-country(XC)ski races involve a variety of formats,two different techniques and tracks with highly variable topography and environmental *** addition,XC skiing is a major component of both Nordic combined and biathlon *** in this area,both in the laboratory and field,encounters certain difficulties that may reduce the reliability and validity of the data obtained,as well as complicate comparisons between ***,13 international experts propose specific guidelines designed to enhance the quality of research and publications on XC skiing,as well as on the biathlon and Nordic combined *** consider biomechanical(kinematic,kinetic and neuromuscular)and physiological methodology(at the systemic and/or muscle level),providing recommendations for standardization/control of the experimental *** describe the types of measuring equipment and technology that are most suitable in this ***,we also deal with certain aspects of nomenclature of the classical and skating *** addition to enhancing the quality of stud-ies on XC skiing,Nordic combined and biathlon,our guidelines should also be of value for sport scientists and coaches in other disciplines where physiological and/or biomechanical measurements are performed in the laboratory and/or outdoors.

关键词： Biomechanics Measurement Physiology Reliability Technology Validity

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Choroidal vascularity index in thyroidassociated ophthalmopathy:a crosssectional study

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Eye and Vision 2021年第4期8卷 175-182页

作者： Pasquale Loiudice Marco pellegrini Michele Marinò barbara Mazzi Ilaria Ionni Giuseppe Covello Michele Figus Marco Nardi Giamberto Casini Department of Surgical Ophthalmology UnitMedicalMolecular and Critical Area PathologyUniversity of PisaVia Savi1056126 PisaItaly Ophthalmology Unit S.Orsola-Malpighi University HospitalUniversity of BolognaBolognaItaly Department of Clinical and Experimental Medicine Endocrinology Unit IUniversity Hospital of PisaPisaItaly

Background:Hemodynamic changes have been observed in patients with Graves’*** aim of our study was to evaluate choroidal vascular change using the choroidal vascularity index(CVI)in patients with thyroidassociated ophthalmopathy(TAO).Methods:In this cross-sectional observational study,40 patients affected by TAO were *** healthy individuals,matched for age and sex,served as *** enhanced-depth imaging optical coherence tomography scans were obtained from all *** were binarized using the ImageJ software and luminal area(LA)and total choroidal area(TCA)were *** was calculated as the proportion of LA to *** relation between CVI or subfoveal choroidal thickness(SFCT)and clinical activity score,exophthalmometric value,diplopia status,gender,and age was ***:CVI was significantly higher in patients with TAO(P=0.004).No significant difference was observed in SFCT(P=0.200)and TCA(P=0.153)comparing TAO patients and healthy *** was significantly higher in TAO group(P=0.045).On multiple regression analysis,CVI was associated with TCA(P=0.043).No association was found between SFCT or CVI and TCA,clinical activity score,exophthalmometric value,Inami value,diplopia status,gender or age(P>0.05).Conclusions:This is the first study that has demonstrated an increase in CVI in eyes with TAO compared with healthy controls and has assessed its association with clinical features.

关键词： Choroidal vascularity index Choroidal vasculature Enhanced depth optical coherence tomography Image binarization Luminal area Subfoveal choroidal thickness Thyroid-associate ophthalmopathy

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