ICSNS 2015 Congress Proceedings_FINAL 250515

ICSNS 2015 3rd International Congress on Science and Nordic Skiing, 5−8 June 2015, Vuokatti, Finland

CONGRESS PROCEEDINGS

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Linnamo

Congress Proceedings Editors: Anni Hakkarainen, Stefan Lindinger and Vesa Linnamo

Congress Venue Vuokatti Sports Institute Opistontie 4, 88610 Vuokatti, Finland

Organized by Department of Biology of Physical Activity, Sports Technology Unit, University of Jyväskylä, Finland Department of Sport Science and Kinesiology, University of Salzburg, Austria Vuokatti Sports Institute Municipality of Sotkamo The Centre for Measurement and Information Systems

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3 International Congress on Science and Nordic Skiing - ICSNS 2015 5-8 of June 2015, Vuokatti, Finland

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ISBN: 978-951-39-6216-6

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PREFACE The 3rd International Congress on Science and Nordic Skiing will be organized by the Sports Technology Unit (Vuokatti) of the Department of Biology of Physical Activity, University of Jyväskylä, Finland, together with the Department of Sport Science and Kinesiology, University of Salzburg, Austria and with Vuokatti Sports Institute, The Centre for Measurement and Information Systems (CEMIS) and Municipality of Sotkamo. We are very pleased that so many of the world leaders in research related to the Congress are coming to Vuokatti as keynote and invited speakers and congress participants. The program will consist of 15 invited presentations, 30 oral, 10 poster presentations, panel discussion and laboratory demonstrations, overall representing 12 different countries. The Congress program consists of familiar topics such as biomechanics, physiology, biathlon, ski jumping and technology. In addition, Paralympic Sport in Nordic Skiing, Snowboarding as well as an exciting Young Investigator Award competition will have their own sessions. We would like to very much welcome also all the international coaches to the Congress sharing ideas, experience, discussions and expertise. On behalf of the organizers we are honored to present this Congress Proceedings. The organizers are committed to give their best effort to make your visit in Vuokatti a successful and memorable one. We are looking forward to the presentations and active participation of all the participants which will finally determine the success of the Congress. With great pleasure we welcome you all to enjoy the latest scientific knowledge and social activities and the Finnish summer in the beautiful and relaxing atmosphere of Vuokatti. Anni Hakkarainen, Stefan Lindinger and Vesa Linnamo, Editors

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3rd International Congress on Science and Nordic Skiing ICSNS 2015 5-8 of June 2015, Vuokatti, Finland

CONGRESS ORGANIZATION Congress Chair Professor Vesa Linnamo University of Jyväskylä, Finland Department of Biology of Physical Activity Sports Technology, Vuokatti

Congress Vice-Chair Professor Stefan Lindinger University of Salzburg, Austria Department of Sport Science and Kinesiology

Chair of YIA Committee Professor Gerald Smith Colorado Mesa University, USA Department of Kinesiology

CONGRESS TOPICS Paralympics Biomechanics in cross-country skiing Technology Snowboarding Physiology in cross-country skiing Biathlon and shooting Ski jumping

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The ICSNS 2015 is sponsored by:

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CONGRESS PROGRAM DAY 1 – Friday 5th of June 14:00 -

REGISTRATION

16:00

Vesa Linnamo; Opening of the Congress

16:15 OPENING LECTURE

Hans-Christer Holmberg; Research on cross-country skiing: Where we´re coming from, where we are and where we´re going? [p. 17]

Session 1:

Paralympics

16:45 KEYNOTE

Laura Gastaldi; Research in Paralympic XC-skiing [p. 18]

17:15 INVITED

Walter Rapp; Role of muscle activation in the sit-skiing performance and classification process [p. 31]

17:35

COFFEE AND TECHNICAL EXHIBITION

Session 2:

Young Investigator Award (YIA) Competition

18:00

Kimmo Lajunen; Effect of sitting posture on sit-skiing economy in non-disabled athletes (YIA) [p. 43]

18:15

Valeria Rosso; Differences in skiing speed among male and female sit-skiers in simulated and natural skiing (YIA) [p. 44]

18:30

Florian Schillinger; A descriptive video analysis of classified Nordic disabled sit-skiers during the Nordic World Championships 2013 (YIA) [p. 45]

18:45

Chiara Zoppirolli; Does a short-term high-intensity double poling exercise elicit fatigue and alter the movement biomechanics in highlevel cross (YIA) [p. 46]

19:00

Øyvind Gløersen; Center of mass estimation in the V2-technique using a single IMU-setup (YIA) [p. 47]

19:15

Christina Mishica; Ski economy and physiological responses while double poling – curved vs. straight poles (YIA) [p. 48]

19:30

Tuija Kallio; Blood and salivary cortisol and testosterone in young cross-country skiers (YIA) [p. 49]

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19.45

Julian Fritz; Correlation between strength related parameters and ski-jumping performance in junior ski-jumpers (YIA) [p. 50]

20:00

GET TOGETHER EVENING AND TECHNICAL EXHIBITION

DAY 2 – Saturday 6th of June

Session 3:

Biomechanics in cross-country skiing

10:00 KEYNOTE

Barbara Pellegrini; Biomechanics of cross country-skiing, from single segment to whole body movement [p. 20]

10:30 INVITED

Caroline Göpfert; Calculation of propulsive forces in ski skating [p. 33]

10:50

John Bruzzo; Determination of propulsive forces from kinematic data in cross country skiing [p. 51]

11:05

Alexandr Chikov; Propulsive efficiency of technique of cross country skiers [p. 52]

11:20

Jørgen Danielsen; Mechanical energy fluctuations and propulsion in double poling [p.53 ]

11:35

Arrigo Canclini; 3D kinematic in freestyle cross country skiing (XCS) technique during world championships (Val di Fiemme 2013) [p. 54]

11:50

LUNCH

13:15

TECHNICAL EXHIBITION

Session 4:

Technology

14:00 KEYNOTE

Kamiar Aminian; Applications of Inertial Measurement Units (IMUs) in Nordic Skiing [p. 21]

14:30 INVITED

Olli Ohtonen; Online feedback system for athletes and coaches [p. 35]

14:50

Gertjan Ettema; Comparison of center of mass energy fluctuations by use of force and motion capture recordings [p. 55]

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15:05

Finn Marsland; Measuring macro kinematics of classical crosscountry skiing during on-snow training using a single micro-sensor unit [p. 56]

15:20

Mathias Scherge; Molecular effects of gliding [p. 57]

15:35

Veli-Matti Nurkkala; Development of Exergaming Simulator for Athletes' Training and Exercise Testing [p. 58]

15:50

Fredrik Andersson; A portable Douglas bag system [p. 59]

16:05

COFFEE, POSTERS AND TECHNICAL EXHIBITION

Session 5:

Posters

16:05 – 17:05

Ebru Çetin; Effect of aerobic high-intensity interval training on leg strength in cross country skiers [p. 75] Lauri Hakola; The effect of friction conditions on the simulated ski jumping take-off [p. 76] Henna Karvonen; The biomarkers of oxidative stress in young crosscountry skiers [p. 77] Susanne Kumpulainen; Neuromuscular motor tasks between skill and endurance trained athletes [p. 78] Renzo Pozzo; 3D kinematic and dynamic analysis of diagonal stride in elite backcountry skiing (SKIALP) [p. 79] İmdat Yarım; Effect of aerobic high-intensity interval training on VO2max and anaerobic power in cross country skiers [p. 80] Ritva Taipale; High-intensity combined strength and endurance training in women: effect of hormonal contraceptive use [p. 81] Lorenzo Bortolan; Kinect based system for self-adjusting treadmill speed in cross-country indoor ski [p. 82] Julia Koriagina; Effect of hyperoxic gas mixture on functional status and performance of skiers and biathletes [p. 83] Matthias Olvermann; Isokinetic upper body strength testing – a useful tool for diagnostics and classification in paralympic sit skiing? [p. 84]

19:00

VISIT TO ANGRY BIRDS PARK AND DINNER

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DAY 3 – Sunday 7th of June

Session 6:

Snowboarding

09:00 KEYNOTE

Veit Senner; The challenging approach towards a science –based standard for snowboard wrist guards [p. 22]

09:30 INVITED

Jussi Räsänen; Skill Teaching in Snowboarding [p. 37]

Session 7

Physiology in cross-country skiing

10:00 KEYNOTE

Esa Hynynen; Monitoring skier’s stress and recovery – listen to the heart [p. 25]

10:30 INVITED

Øyvind Sandbakk; The physiology of world-class cross-country skiers – a reappraisal of the success factors for performance [p. 36]

10:50


11:30

Gerald Smith; Mechanical energy comparison of V1 and V2 skating [p. 60]

11:45

Thomas Losnegard; Pole length affects O2-cost and performance in double poling [p. 61]

12:00

Adama Sesay; Biosensors for non invasive monitoring of physiological biomarkers related to fitness, sports and wellbeing [p. 62]

12:15

Marianne Mäki; Plasma amino acid profiles in young cross-country skiers [p. 63]

12:30

Masaki Takeda; Resting heart rate as an index for monitoring physical condition during high altitude training in cross-country skiers [p. 64]

12:45

Markus de Marées; Influence of high intensity interval training under hypoxic conditions on acute regenerative capacity during a set of four minutes time trails [p. 65]

13:00

LUNCH

Session 8:

Biathlon and shooting

14:30 KEYNOTE

Thomas Finkenzeller; Biathlon shooting as a model from a biomechanical, kinesiological and sports psychological perspective – a multidisciplinary approach [p. 27] rd


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15:00 INVITED

Gerold Sattlecker; Effects of biathlon specific fatigue on shooting performance [p. 38]

15:20

Michael Buchecker; Dynamical structure of rifle trajectories in biathlon shooting [p. 66]

15:35

Sabine Würth; Psychological influences on biathlon shooting performance [p. 67]

15:50

Kerstin Hödlmoser; Preparatory EEG spectral power and coherence in biathlon rifle shooting - A pilot study [p. 68]

16:05

Sami Kuitunen; Holding ability determines 54% of air rifle shooting scores [p. 69]

17:00

GUIDED HIKE, X-C SKIING (TUNNEL) + FREE EVENING

DAY 4 – Monday 8th of June

Session 9:

Ski Jumping

08:30 KEYNOTE

Harald Haim; Issues, concepts and structures in juvenile ski jumpers [p. 28]

09:00 INVITED

Mika Kojonkoski; Science and ski jumping – what next? [p. 39]

09:20

Jošt Bojan; The flying hill profile as a limitation factor in development of world record in ski flying [p. 70]

09:35

Janez Vodičar; Correlation between the height of the flight curve and the length of the jump at Planica ski flying competitions of 2009, 2010, and 2013 [p. 71]

09:50

Sören Müller; Analysis of take-off executions of top athletes in ski jumping [p. 72]

10:05


Session 10:

Panel discussion and Closing

10:30

Panel Discussion; “From Science to Practice”

11:15

YIA awards and Closing

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Session 11:

Laboratory demonstrations

12:00 Snowpolis Treadmill environment and equipment testing 15:00

CLOSING BARBECUE and DJ MUSIC at the lake Vuokatti Sports Institute

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KEYNOTE LECTURES

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RESEARCH ON CROSS-COUNTRY-SKIING: WHERE WE’RE COMING FROM, WHERE WE ARE AND WHERE WE’RE GOING H-C Holmberg Swedish Winter Sports Research Centre, Department of Health Sciences, Mid Sweden University, Östersund, Sweden KEY WORDS: athlete, elite, biomechanics, performance, physiology, sport, winter

Our long tradition of research on cross-country skiing in connection with exercise science has taken advantage of the extraordinary physical capacities and unique quadripedal patterns of movement of the athletes involved. Such investigations of physiological and biomechanical responses have not only provided new insights into the factors that limit human performance, but also new knowledge about physiology, biomechanics and motor control in general. Although most early research on the physiological characteristics of cross-country skiers focused primarily on aerobic capacity, recent developments in this sport have also placed emphasis on the optimization of anaerobic capacity as well as strength/power. These changes have challenged certain current approaches to monitoring elite skiers in the laboratory. Considerably more attention is being placed on employing integrative physiological and biomechanical approaches in combination to gain novel insights that can contribute significantly to faster racing speeds and better overall performance. From the biomechanical perspective, the combination of varying terrain and a multiplicity of skiing techniques presents major challenges, both technical and cognitive (decision-making), to the individual athlete. Recent technological advances now allow researchers to investigate the dynamics of various physiological and biomechanical parameters during crosscountry skiing in greater detail and under more realistic conditions. Cross-country skiing, which is both physiologically and mechanically complex, has so far been studied mainly in the laboratory, where the combination of applied and more basic research has contributed considerably to advancements in this sport. Now more experiments in the field/on snow and/or during competition, focusing both on biomechanical and physiological approaches with the help of modern technology, are highly desirable and promise to improve the performance of crosscountry skiers even further.

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RESEARCH IN PARALYMPIC XC-SKIING Laura Gastaldi Dept. of Mechanical and Aerospace Engineering Politecnico di Torino, Torino, Italy KEY WORDS: Paralympics, sport for disable, literature search, para-athletes

INTRODUCTION: Over the years, adapted cross country skiing (XC-skiing) has quickly grown from a form of physical therapy and medical rehabilitation for veterans to a gratifying recreational pursuit for individuals of all ages and disability. Predictably, recreation gave birth to agonistic sport. Disabled XC-skiing is, since its first appearance in Ornskoldsvik games in 1976, a dominant sport in the winter Paralympic games. Currently XC-skiers with disabilities compete, under the rules of the International Paralympic Committee (IPC), in three medal categories: visually impaired, locomotor standing and sitting, The increasing popularity of XC-skiing, unfortunately, has not encouraged significant scientific research. The aim of this lecture is to take stock of the research in Paralympic XC-skiing. METHOD: A systematic search of the peer-reviewed literature was performed using key words (such as cross country skiing, Nordic skiing, Paralympic, disabled athletes, adapted sport and so forth) in the databases PubMed, Scopus, Science Direct and Google Scholar. The reference lists of relevant articles were then examined to find additional articles. Retrieved articles were screened and assessed for relevance to the biological, biomechanical, equipment, classification and sport medicine aspects. In addition, bibliography and records of the International Paralympic Committee (IPC), from the Official Post Games Reports and the Internet were consulted. RESULTS: Retrieved articles were screened and assessed for relevance to the biological, biomechanical, equipment, classification and sport medicine aspects. In most cases a net cataloging is not possible, because all the before mentioned aspects partially overlap and interlace. DISCUSSION: In general all authors agree upon the fact that results from able bodied results cannot be extended to Paralympic athletes, moreover the inter and intra athlete differences of disability type and severity degree makes very difficult a standardization. This uniqueness of the Paralympic athlete entails a challenge for researchers, classifiers, coaches and event organizer. Skiers in XC are divided in visual, standing and sitting categories. In each category, in order to assure equal and fair competition, athletes compete in several different classes, depending on the functional potential performance resulting from impairment, interrelated to the XC-ski activity. This process, known as classification, involves clinical evaluation and in some cases functional tests; actually there is ongoing research in order to have a classification process sport-specific and evidence based. Considering athletes performances, different aspects have to be taken into account, under the perspective of the dynamical systems theory. This states that the interaction of the three constraints (environmental, task and organism) under which the movement is performed, may alter the coordination strategy employed by the individual and hence influence performances. Studies had been conducted by independent researchers on biomechanics of the gesture, on evaluation of physical fitness, on athletes training, on environment conditions, on fatigue, etc.; but so far the research in that field lack of an holistic approach. Studies had been conducted both in equipped laboratory and in field, both during training and competitions. Special reference also needs to be made to equipment; in particular sit ski and prostheses (including sockets) have significantly progressed in order to satisfy the demands of elite athletes to ski, to compete in safe conditions and to achieve performances approaching those of able-bodied athletes. The controversial aspect of equipment standardization used in XC-skiing event is ruled by IPC and it involves also ethical issues, for these reasons it will not be discussed in this lecture. Instead another interesting aspect is the athlete-equipment interface. A change in used devices also means a variation of the coordinative and personal compensatory strategies employed and rd


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hence performances variations. A systematic research study of equipment optimized in function of athlete’s impairment is missing, although lately considerations on the position of sit skiers had been made. Usually changes in equipment are the result of individual perceptions, coach suggestions and change-and-try philosophy, but without or very few scientific evidences. Risk of injuries in XC-ski Paralympic athletes, per se, appears no greater than those of the Olympic ones. Competition and training injuries, mostly related to falls involving visually impaired athletes, are well documented. Other risk factors, such as the overuse of muscles and upper limb joints, interface with equipment, skin breakdown etc, may not be reported, but they heavily affect subject’s daily mobility and independence. Limitations of all the studies are small size of samples; furthermore the different types of impairment fragment samples even more. CONCLUSION: An overview of the scientific literature on Paralympic XC-skiing indicates that research has not kept up-to-date with the growth of the Paralympic movement and with athletes’ performances. Paralympic XC-skiing presents many challenges to coaches, sports science, sports medicine and sport engineering. Bearing in mind impairments and their degree variability, compensatory and coordination strategy employed by the athletes, equipment interaction and the small number of elite Paralympic athletes, a coordinate, multidisciplinary and international research effort would be greatly welcome and beneficial. REFERENCES Bernardi M, Carucci S et al.(2012) Physical fitness evaluation of Paralympic winter sports sitting athletes. Clin J Sport Med., 22(1),26–30. Bhambhani Y, Forbes et al (2012) Physiologic responses of competitive Canadian cross-country skiers with disabilities. Clin J Sport Med. 22(1):31-8. Burkett B.(2012) Paralympic sports medicine--current evidence in winter sport: considerations in the development of equipment standards for paralympic athletes. Clin J Sport Med. 22(1):46-50 Gastaldi L, Pastorelli S et al. (2012) A biomechanical approach to paralympic cross-country sit-ski racing, Clin J Sport Med. 2012,;22(1),58-64. Moore, C. & Info, E.Z. (2001). A survey of authors of rejected conference papers. Journal of Useful Information, 50, 105-11. Nasuti, G.& Temple V.A. (2010) The risks and benefits of snow sports for people with disabilities: a review of the literature., Int J Rehabil Res.33(3),193-8. Pernot HFM, Lannem AM et al. (2011) Validity of the test–table–test for Nordic skiing for classification of Paralympic sit-ski sports participants. Spinal Cord, 49(8),935–41. Rapp W., Lappi T.et al (2015) Force production, balance control and muscle activation in different sitting positions – pilot study for disabled sit sledge cross-country skiers.Science and skiing VI, 453-64 Van De Vliet, P, (2012), Paralympic athlete's health, British Journal of Sports Medicine 46 (7),458-9 Vanlandewijck Y, Thompson W (2011) Paralympic Athlete - Handbook of Sports Medicine and Science, Wiley-Bòackwell. Sussex, United Kindom http://www.paralympic.org/

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BIOMECHANICS OF CROSS COUNTRY SKIING, FROM SINGLE SEGMENT TO WHOLE BODY MOVEMENT Pellegrini Barbara, Zoppirolli Chiara, Bortolan Lorenzo, Schena Federico CeRiSM and Department of Neurological and Movement Science, Università degli Studi di Verona, Italy KEY WORDS: Energy, body COM

Movement analysis of cross-country ski techniques has always been of great importance due to its influence on skiing performance. Understanding how a skier moves through the space involves measuring and analyzing a great number of parameters describing linear and angular motion, velocity and acceleration of many body segments. Researchers have chosen different way to accomplish this task. In the last 5 years, a great number of investigations on biomechanics of cross country skiing have measured at least parameters of skiing cycle timing. About 40% reported data on pole force and on ski or plantar force, 20% investigated the muscle activation and 36% reported some data on upper or lower body angular kinematics. Some researchers have always tried to simplify the task of describing technical and biomechanical issue on cross country skiing by capturing an analyzing the motion of body center of mass (COM). COM is the point at which the entire weight of a body may be considered as concentrated. If the segments were rigid, the resultant of all forces acting on the body can be considered as applied on COM. The impossibility of directly measuring magnitude and point of application of forces involved in locomotion inspired many researchers to analyze COM motion to derive some mechanical aspect of animal and human movement [1]. Looking at COM, would mean catching the skiers whole motion and analyzing its acceleration would give an idea of the effect of the forces acting on him/her. The vertical range of motion of COM has been studied in some recent publication [2], [3]. Potential (PE) and kinetic (KE) energy associated to movement of body COM can be moreover computed from COM movement data. A further application, based on the work-energy principle, that states that the work done on an object is equal to the change in its energy [1], made it possible to approximately estimate the work required to move COM in different cross country skiing techniques and conditions. The analysis of the fluctuation of the energy of COM in cross country skiing has been recently adopted to identify the underling mechanism of classic technique. Kehler and coworkers [4] and Pellegrini and coworkers [5] observed that for diagonal stride (DS) PE and KE fluctuations were inphase making DS resemble the pattern of running, although a significant part of energy in DS is lost to rolling resistance [2]. Norman and Komi in 1987 [6] and Minetti and coworkers [7] years later, applied the work-energy principle to segment motion data of skiers on snow to estimated theirs mechanical output. Although part of the mechanical work done in skiing can be calculated by accounting for slope, average speed and friction; the additional calculation of the within-cycle COM displacements and speed fluctuations, although affected by some limitations and criticism, allow to reach a more complete estimation of the amount of mechanical work performed by the skier to sustain his/her locomotion with respect to the surroundings [3]. REFERENCES [1] Zatsiorsky VM (2000) Kinetics of human motion. Human Kinetics, Champaign, Il.; Leeds [2] Zoppirolli et al. Eur J Appl Physiol.2014 Dec 17 [3] Stoeggl et al. Book of Abstract ICSS 2010, p 43 [4] Kehler et al. J Exp Biol. 2014 Nov 1;217(Pt 21):3779-85. [5] Pellegrini et al.,J Exp Biol. 2014 Nov 1;217(Pt 21):3910-8 [6] Norman RW and Komi P.V. Int.J.Sport Biomech. (1987) 3:353-369. [7] Minetti et al., (2001) in Science and Skiing II pp 30-43, Meyer & Meyer Sport, Hamburg

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APPLICATIONS OF INERTIAL MEASUREMENT UNITS (IMUS) IN NORDIC SKIING Kamiar Aminian Ecole Polytechnique Federale de Lausanne (EPFL), Laboratory of Movement Analysis and Measurement, Switzerland KEY WORDS: IMU, accelerometer, gyroscope, speed, joint angle, classic cross-country skiing

Considering current issues in complex instrumentation (e.g., treadmill, marker-based motion capture system and force sensors), which restricts the movement analysis in laboratory setting, a convenient solution for motion capture in field activity and snow sport is the use of body worn sensors. Wearable systems using inertial measurement units (accelerometers and gyroscopes) have been proposed in a variety of sport disciplines, but their application to skiing and particularly Nordic skiing is new. Starting with results obtained in ski jumping based on wearable inertial measurement unit (IMU), this presentation highlights the relevance of IMUs for Nordic skiing movement analysis. New methods based on IMUs fixed on skis, poles and body segments are proposed to align sensors with body segments and to estimate spatio-temporal parameters and lower limbs angles for the diagonal stride in classical cross-country skiing. Inspired from IMU-based techniques for gait analysis, algorithms for drift free estimation of speed and angles are outlined and validated against a marker based motion capture system during treadmill skiing. Good accuracy and precision were obtained for detecting each cycle, thrust and pole push phases as well as for estimating cycle speed, cycle length, shank and thigh angles. The system was also sensitive to changes of speeds and inclines and offers a very easy setup to provide an unlimited capture volume for measurements on snow. Possibilities for extension to the skating style are discussed.

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THE CHALLENGING APPROACH TOWARDS A SCIENCE – BASED STANDARD FOR SNOWBOARD WRIST GUARDS Veit Senner, Stefan Lehner, Othmar Brügger* Sport Equipment and Materials, Technische Universität München, Germany * bfu - Swiss Council for Accident Prevention, Berne, Switzerland KEY WORDS: protection equipment, injury prevention, computer simulation, multibody dynamics, finite element analysis

INTRODUCTION: Snowboarding is one of the most popular winter sports, particularly among adolescents and young adults. In the US estimated 7.3 million people participated in snowboarding during the 2012/2013 season, compared to 8.2 million skiers [1]. Among all snowboarding injuries, the upper extremities comprise the body region most frequently reported injured. The risk of wrist injuries is higher in snowboarding than in alpine skiing [2]. 96% of wrist injuries are induced by falls [3]. Experienced athletes tend to have fewer wrist injuries than beginners; 72% of all wrist injuries occur within the first 7 days of learning to snowboard [4]. Based on a literature review, backward falls result in twice as many fractures as forward falls [5]. A backward fall with outstretched upper extremity joints was evaluated as the worst case scenario [6]. In his white paper on the efficacy of wrist protectors, Michel et al. [7] list several studies which see a reduction of wrist injuries due to the use of protectors [3, 4, 8, 9]. In consequence their application is recommended - however, it remains unclear which specific wrist protector design or protective component provides the most protective potential. Currently there are no national and international standards available which define minimum requirements and appropriate test procedures for snowboarding wrist protectors. To achieve a significant reduction in injury risk, a protector should provide sufficient impact attenuation and resistance to (hyper-)extension [10]. In order to systematically investigate how design and material factors influence the wrist guards’ protection capacity, we developed computer models and performed simulations of backward falls, particularly looking at the biggest target groups, children and adolescents. METHOD: First a scalable multi-segment model of the human body with detailed 3D model of the upper extremity was developed using multibody simulation (MBS) software (SIMPACK AG, Gilching, Germany). The exact surface models of the arm, hand and finger bones and the solid portions of the radius and ulna had been created based on computed tomography (CT) data. Second a total of 20 different CAD models of wrist protection devices were designed in CATIA (Dassault Systèmes, Vélizy-Villacoublay, France) and “fixed” to the model of the lower arm and wrist joint. The fixations of the dorsal and palmar splints (in real-life fixed to the forearm with Velcro® fastener) are modelled with four spring-damper elements, located on the circumference of the CAD surface of the forearm. The number of modelled hook-and-pile fasteners was varied; one was used for the short splints and two for the medium and long splints. In the third step backward falls with outstretched elbow joint and an 80° retroversion of the shoulder joint were simulated for the anthropometry of male 9 year old children, 13-14 year old adolescents and young adults with 20 years of age. The outputs of these simulations were the resulting wrist joint contact forces for the different wrist protectors as well as for the unprotected case. In the last step a detailed analysis of the loading forces on the forearm bones was conducted with finite element analysis (FEA) (ANSYS Inc., USA).

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We used FEA models of the os radius and os ulna (Fig. 1), taking into account that bone strength changes with age and gender in children and adolescents The major change is in the epiphyseal plate, a hyaline cartilage plate in the metaphysis at each end of the long bones, present in children and adolescents. In adults, when growth has stopped, the plate is replaced by an epiphyseal line. RESULTS: Our bending results showed that the short splint versions provided insufficient protection, but Figure 1. FEA of the stress distribution protection increased with the longer versions (Fig. 2). The in the radius of the adult model, when dorsal splint and the sandwich splint showed a slightly wearing the medium length dorsal decreased wrist angle at impact compared to the palmar protector splint. This protective effect was enhanced with padding, but there was no significant difference between the 10-mm and the 5-mm padding thicknesses. For the adults in the unprotected condition, the maximum shear stress occurred at the palmar radius, just above the joint space. With protectors, one maximum was located above the styloid process of the radius, and with increasing shear stress, a second maximum was observed in the shaft. For the adolescent and child models, the long dorsal protector reduced the maximum shear stress at the hyaline cartilage plate significantly, for the 9-yearold by 54% (compared to unprotected situation). CONCLUSION: This study identified the wrist joint extension and the resulting bone stress for different age groups with and without the use of different type of wrist protection for backward falls. It provides the basis for design requirements and testing procedures of such devices thus making the formulation of ISO standards possible. The detailed description of this investigation is submitted for publication at the Journal of Sports Engineering and Technology [11] Figure 2: Relative reductions (%) in wrist extension when different protector versions were used, compared to the reference model without a protector (0.0)

REFERENCES [1] Wijdicks CA, Rosenbach BS, Flanagan TR, et al. Injuries in elite and recreational snowboarders. Br J Sports Med 2014; 48(1):11-17. [2] Kim S, Endres NK, Johnson RJ, et al. Snowboarding injuries: trends over time and comparisons with alpine skiing injuries. Am J Sports Med 2012; 40(4):770-776. [3] Idzikowski JR, Janes PC, Abbott PJ. Upper extremity snowboarding injuries: ten-year results from the Colorado Snowboard Injury Survey. Am J Sports Med 2000; 28(6):825–831. [4] Hagel BE, Goulet C, Platt RW, et al. Injuries among skiers and snowboarders in Quebec. Epidemiology 2004; 15:279-286. [5] Deady LH, Salonen D. Skiing and snowboarding injuries: a review with a focus on mechanism of injury. Radiol.Clin North Am 2010; 48:1113-1124. [6] Lehner S, Geyer T, Michel FI, et al. Wrist injuries in snowboarding – Simulation of a worst case scenario of snowboard falls. Engineering of Sport 10, Procedia Engineering 2014; 72:255-260. [7] Michel FI, Schmitt KU, Greenwald RM, et al. White Paper: Functionality and efficacy of wrist protectors in snowboarding - Towards a harmonized international standard, Sports Engineering 2013; 16(4):197-210. [8] Kim S, Lee SK. Snowboard wrist guards-use, efficacy, and design - a systematic review. Bulletin of the NYU Hospital for Joint Diseases 2011; 69:149-157. [9] MacDermid JC. Do wrist guards decrease injuries among snowboarders? Clin J Sport Med 2008; 18:178179.

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MONITORING SKIER’S STRESS AND RECOVERY – LISTEN TO THE HEART Esa Hynynen KIHU – Research Institute for Olympic Sports, Jyväskylä, Finland KEY WORDS: Heart rate variability, autonomic modulation, follow-up, training response

Almost 60 years ago Selye introduced “the general adaptation syndrome”, where he investigated several internal and external stressors that may disturb the homeostatic balance. Among these stressors was, for example, strenuous exercise. The general adaptation syndrome is made up of three stages: Alarm reaction, stage of resistance, and state of exhaustion (Selye 1956). In athletic training, which can be considered as a mainly physical stress model, the overload principle is widely used. The overload training principle is intended to disturb the homeostasis of the body through the physical stress of a training session (alarm reaction). During the subsequent recovery phase, the physical capacity is recovered, possibly to a higher level than before the training session (resistance or adaptation phase). This process needs coordination of various systems that are appropriate to counteract the threats to homeostasis. The autonomic nervous system, including both the parasympathetic and sympathetic pathways, is highly responsible for this regulation of homeostasis. In the beginning of stress research, investigations concentrated on responses of the endocrine system to different stressors. During late 20th century studies on usage of autonomic cardiac indices as an indicator of autonomic modulation have increased. In addition to clinical cardiac autonomic tests in laboratory, more practical methods for real-life situations have been developed. Heart rate and heart rate variability have been recorded during rest, in an active orthostatic test, or as a response to some other known challenge. As levels of heart rate variability indices and their responses are highly individual, it is extremely important to build a large database of an athletes’ own values. While building this kind of individual database, sources of stress should be also recorded. For international level athletes, the physiological training stress is commonly the most important stressor, but there can be others, too. When analyses are done from data collected during wakefulness, many different issues may have effects on autonomic modulation. Issues like the time of day can be standardized, but e.g. thoughts are more difficult to control. Therefore, cognitions may play a role in these recordings. When recording heart rate variability during nocturnal sleep, we have somewhat freedom of external disturbance, and are able to analyze the most important period of recovery, too. During rest, the parasympathetic activity is normally high and this is reflected in high values of heart rate variability indices. As a response to overload training, diminished values of heart rate variability are typically seen. After suitable rest or easier training, recovery to high values can be found. Responses to different stressors are dependent not only acutely on the power and duration of the stressor, but it is also possible that the stress effects are sustained or even cumulated for a longer period of time. An example of one skier’s follow-up figure shows variation of so-called “recovery index”, where high values are reflecting good recovery and lower values reflect stress responses after hard training sessions and/or races (Figure 1).

Figure 1. An example of a follow-up curve of an individual skier’s nocturnal heart rate variability analysis

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It should be reminded that it is a good thing, when reduced values of heart rate variability is found after hard training sessions or periods. This is the phenomenon targeted, but as important is that the level of heart rate variability is recovered after easier training or rest. In conclusion, nocturnal HRV may be used to estimate changes in autonomic modulation during the recovery phase from acute endurance exercises. These methods can be utilized in individual follow-ups of stress management or athletic training programs. REFERENCES Selye, H. (1956). The stress of life. New York: McGraw-Hill.

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BIATHLON SHOOTING AS A MODEL FROM A BIOMECHANICAL, KINESIOLOGICAL AND SPORT PSYCHOLOGICAL PERSPECTIVE – A MULTIDISCIPLINARY APPROACH Thomas Finkenzeller, Gerold Sattlecker, Sabine Würth, Michael Buchecker, Kerstin Hoedlmoser*, Stefan Josef Lindinger and Günter Amesberger Dep. Sport Science and Kinesiology, University of Salzburg, Austria *Centre for Cognitive Neuroscience, University of Salzburg, Austria KEY WORDS: holistic approach, basic-applied research continuum, shooting

INITIAL SITUATION: Since more than 15 years, shooting performance of Austrian and international biathletes is tested at the department of sport science and kinesiology of the University of Salzburg. The focus of diagnostics was attached to biomechanical parameters in order to provide knowledge about the athletes’ shooting technique. This resulted in a refined practical knowledge about shooting in biathlon over the years. Consequently, it was pursued the goal to evaluate biomechanical data of shooting diagnostics scientifically. In the following years, conference papers, master theses and articles were published (e. g. Sattlecker, Buchecker, Birklbauer, Müller, & Lindinger, 2013; Sattlecker, Buchecker, Müller, & Lindinger, 2014). The intensive preoccupation with the aiming process of biathletes created the need to perform research from a multidisciplinary perspective. COMPLEXITY OF BIATHLON: The combination of cross country skiing with shooting offers the possibility to identify innovative research questions that go beyond the scope of peak performance. For example, the influence of fatigue on focused attention as it represents shooting is an issue that is addressed by biathlon coaches in our specific setting and is also of interest to researchers for answering basic research questions. Under the latter perspective, biathlon is regarded as a model to test basic theories in a setting of high ecological validity. ACTUAL STATE OF RESEARCH: A team of biomechanics, kinesiologists and sport psychologists developed a comprehensive test battery in order to cope with the multifaceted demands on biathletes at the rifle range. The test battery was administered to biathletes in August 2014. A further study was conducted in October 2014 with the purpose to investigate the influence of fatigue on shooting performance and the related changes in eletrocortical activity. The results of these examinations will be presented in this session. PERSPECTIVES: At present, we pursue a multidisciplinary approach. Each subgroup of the team aims at answering research question related to the epistemological concepts of their discipline. In future, we want to meet the requirements for interdisciplinary research. A framework will be presented that seems to be appropriate to achieve an interdisciplinary approach (Deinhammer & Group, 2003). Examples of the practical implementation in our shooting project will be provided. REFERENCES Deinhammer, R., & Group, U. S. P. R. (2003). Was heißt interdisziplinäres Arbeiten [What is interdisciplinary work]?: FWF (Austrian Science Fund): Research project Y 164: University of Salzburg/Poverty Research Group. Sattlecker, G., Buchecker, M., Birklbauer, J., Müller, E., & Lindinger, S. J. (2013). Effects of fatigue on shooting performance and biomechanical patterns in elite biathletes. In E. Müller, J. Kröll, S. J. Lindinger, J. Pfusterschmied & T. Stöggl (Eds.), SCIENCE AND SKIING VI (pp. 527-533). Aachen: Meyer & Meyer Sport. Sattlecker, G., Buchecker, M., Müller, E., & Lindinger, S. J. (2014). Postural Balance and Rifle Stability During Standing Shooting on an Indoor Gun Range Without Physical Stress in Different Groups of Biathletes. International Journal of Sports Science and Coaching, 9(1), 171-184.

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ISSUES, CONCEPTS AND STRUCTURES IN JUVENILE SKI JUMPING Mag. Harald Haim Schigymnasium Stams, Austria KEY WORDS: ski jumping, talent recruitment, youth, training

INTRODUCTION: Many nations try to find concepts and structures to find and educate young talents from beginners to world class athletes. They seek for appropriate training methods, create national competition systems, cooperate with other countries to organize international youth competitions and use the system of the International Ski Federation up to the annually performed World Championships for Juniors. Austria is the most successful nation in youth ski jumping with a simple structure from clubs to regional teams, education centers like “Schigymnasium Stams” and the national teams. DEVELOPMENT OF SKI JUMPERS IN AUSTRIA: In general, there are several phases from the first contact with the sport to the participation in world class competitions for each ski jumper in Austria. 1. Getting in touch with the sport: events for testing the sport under safe and structured conditions (8 to 10 years of age) 2. Learning the technique and developing skills and strength for the consecutive training in ski jumping and Nordic combined (10 to 14 years of age). 3. Proving of the talent when entering an education center at the age of 14. Key point for the talent finding system in Austria. Decision for the specific discipline. 4. Increasing the training and competing in the first international competitions. Entry in the two FIS Competition series for adults (World Cup and Continental Cup). There are different details in all phases of the development and education of a young ski jumper between the different nations. Depending on the “culture of skiing” some are using Alpine Skiing (Austria, Germany) or Cross Country Skiing (Norway, Finland) as the entry to the sport. It seems to be important to have the right competitions for the different age groups and levels of skills. Also the equipment rules are slightly different from youth to adult ski jumping. Looking at the system of searching a talent there are some connections between motor skills at the age of 14 and the later success on international level. Performance in tests like the standing long jump has a high significance with winning a medal some years later. The results of the entry exam from the “Schigymnasium Stams” show the development in several tests over the past 30 years. In connection with the achieved level of excellence it is an interesting point for coaches in clubs and regional teams, who get some knowledge of standards for this age. INTERNATIONAL ASPECTS: The international Ski Federation has created some rules for youth competitions supporting young athletes, who are not grown up yet to learn not only the take-off, but also flight technique. In this field there is the highest potential for performance enhancement and developments.

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INVITED LECTURES

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ROLE OF MUSCLE ACTIVATION IN THE SIT-SKIING PERFORMANCE AND CLASSIFICATION PROCESS Walter Rapp, Valeria Rosso1,2, Olli Ohtonen1, Laura Gastaldi2, Yves Vanlandewijck3, Stefan Lindinger4, Vesa Linnamo1 Department of Sport and Sport Sciences, University of Freiburg, Germany 1 Department of Biology Physical Activity, University of Jyväskylä, Finland 2 Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Italy 3 Department of Movement & Rehabilitation Sciences, Katolieke Universiteit Leuven, Belgium 4 Department of Sport Science and Kinesiology, University of Salzburg, Austria KEY WORDS: sit-skiing performance, EMG, classification

INTRODUCTION: Classification is a critical aspect of the Paralympic sport since it determines who is and who is not eligible to compete in Paralympic Sport (van de Vliet 2012). Therefore the decisions determining eligibility into Paralympic sport are getting more important. Determining the minimum disability criteria, and furthermore a framework to classify the athletes based on their individual limitations, should be based on empirical evidence as the class allocation based on functional limitations may leave room for interpretations (Vanlandewijck et al. 2011). As it was shown in non disabled skiers in different sitting positions (Rapp et al. 2014), stabilizing the trunk muscles is essential in order to achieve good core stability for an effective pole impact. In disabled sit skiers a coordinated activation of trunk and arm muscles is therefore expected to be a pre requirement for good skiing performance. Neuromuscular activation characteristic are well known in non disabled cross country skiers (Lindinger et al. 2009, Holmberg et al. 2005). In disabled sit skiing, however, research is lacking at present. Therefore research in Paralympic Nordic sit skiing should focus to get more insight into the activation characteristics in the functionality of skiing performance in sit skiers from different levels of impairment. METHOD: In the last 2 years a test battery was established to evaluate neuromuscular activation from non disabled and as well elite disabled sit ski athletes. The test consists of an ergometer test, simulating double poling with maximal velocity and a balance test. In the balance test unforeseen forward and backward movements were elicited in the individual sitting position of each athlete, sitting in his/her own sledge. For non disabled participants an adjustable chair was constructed to simulate the sitting positions commonly used in competition. Pulling forces and ground reaction forces were recorded synchronously with surface EMG from arm and from different trunk, hip and thigh muscles. Kinematic analyses were done by video analyzing. For comparison of the laboratory situation with real skiing performance disabled athletes performed in Vuokatti Ski tunnel trials with maximum velocity and sub maximum velocity in a flat and uphill terrain. RESULTS: In the perturbation test a muscular response to the forward motion of the platform was shown in the abdominal muscle group at about 200 ms after the perturbation which is interpreted as reflex activity. In a functioning neuromuscular system this reflex mediated muscle response is therefore essential to maintain the sitting balance. No such activation was visible in disabled athletes from classes lower LW11. Preliminary results utilizing cluster analysis support that than trunk activation is an important factor in grouping the athletes. Comparing the performance at the ergometer test in the laboratory and the maximum speed in the tunnel it could be shown, that the fastest athletes in ergometer performed also best in the tunnel. DISCUSSION & CONCLUSION: From a methodological point of view neuromuscular recording with surface EMG in disabled athletes is challenging, especially in spinal cord injury persons with a high lesion. The perturbation test and cluster analysis seem to be applicable to be used in the classification process in the future. It needs to be tested if the information related to trunk activity can be obtained by using inertial measurement units (IMU) instead of EMG. Furthermore, measurement of MVC contraction for normalization the neuromuscular activity is a point for further discussion. rd


32 REFERENCES 1. Van de Vliet, P. 2012. Paralympic Research in Nordic Sports. In: Hakkarainen A, (Eds.) 2nd International Congress on Science and Nordic Skiing (ICSNS). 2. Vanlandewijck Y., Verellen J., Tweedy S. 2011. Towards evidence-based classification in wheelchair sports: Impact of seating position on wheelchair acceleration. Journal of Sports Sciences vol 29, 10891096 3. Rapp, W. et al., 2014. Force production, balance control and muscle activation in different sitting position - pilot study for disabled sit sledge cross-country skiers. In E. Müller et al., eds. Science and skiing VI. Meyer and Meyer sport, ISBN 978-1-78255-066-2, pp. 453–464. 4. Lindinger S., Holmberg H-C., Mueller E., Rapp W. 2009. Changes in upper body muscle activity with increasing double poling velocities in elite cross-country skiing. European Journal of Applied Physiology, 106, 353-363. 5. Holmberg, H.-C., Lindinger, S., Stöggl, T., Eitzlmair, E., Müller, E. 2005. Biomechanical Analysis of Double Poling in Elite Cross-Country Skiers. Medicine & Science in Sports & Exercise 37, 807-818.

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CALCULATION OF PROPULSIVE FORCES IN SKI SKATING Caroline Göpfert1,3, Mikko V. Pohjola1, Vesa Linnamo1, Olli Ohtonen1, Walter Rapp2, Stefan J. Lindinger3 1

Department of Biology of Physical Activity, University of Jyväskylä, Finland 2 Department of Sport and Sport Science, University of Freiburg, Germany 3 Department of Sport Science and Kinesiology, University of Salzburg, Austria KEY WORDS: propulsion; 3D motion analysis; system acceleration; centre of mass

INTRODUCTION: To generate propulsion efficiently is an essential goal in cross-country skiing and largely determines the athlete’s performance (Smith, 2008). Great effort has been made in cross-country (XC) skiing research to develop force measurement systems and to determine the propulsive force component acting in the direction of skiing (Smith, 2008). However, which share of applied ground reaction forces (GRF) ultimately lead to acceleration of the center of mass (COM) in skiing direction, thus to propulsion of the athlete, is unclear. The propulsion of the XC-skier could fundamentally be measured by video or motion capture systems investigating the movement of the COM. However, to gather information on the contribution of each thrust phase, components of propulsion have to be determined independently. Thus, this work is aimed at (1) calculating the propulsion of the skier, represented by his COM, from 3D force and motion capture data, (2) applying the calculation on an example in V2A skating, (3) comparing the calculation of propulsion and propulsive forces and (4) testing, if propulsion can be calculated also from pressure insole data or 1D/2D force binding data. METHOD: Eight highly skilled XC skiers performed leg skating (Fig.1) at maximal speed in the Vuokatti ski tunnel. Whole body 3D motion was recorded by the VICON Nexus system and COM position was calculated. On one ski GRFs were measured vertical and medio-lateral by a specially designed binding for force measurements (Ohtonen et al., 2013). The other ski was equipped with a binding for measurements of vertical and anterior-posterior GRFs. The remaining force components were estimated based on frictional force calculation and contralateral side’s data. The share of GRFs which accelerates the COM in the intended skiing direction was calculated. Resistive forces were included in the calculation and considered in their respective direction of action to obtain the propulsion of COM (FCOM) which overcomes gravity, drag and incline. This leads to a value, which can be compared with the considered as best possible reference, the acceleration of COM detected with motion capture and multiplied with the athlete’s mass (FM). To examine if the COM should be included in the calculation of propulsion, net propulsive force acting at the push-off leg was determined (FNP) and compared to FM. In order to investigate the role of input data in the calculation, propulsion was additionally calculated from force binding data using only vertical (FV) or vertical plus medio-lateral (FVML) or vertical plus anterior-posterior (FVAP) force data. Simultaneously to the force binding measurements, leg forces were captured with the Pedar pressure insole system and the force leading to acceleration of the COM was calculated from that data (FPI), to gather information about the role of the measurement system when recording legforces. For one subject, the calculation of propulsion was exemplary applied to V2A skating (FV2A), including pole and leg thrusts. Similarity coefficients (SC) were calculated between timenormalized force curves. Differences for maximum and average forces were checked using paired samples t-test or Wilcoxon u-test, for not normal-distributed data. RESULTS: Maximum and average of FCOM during push-off were 12.5 ± 3.3 %BW and 1.4 ± 3.5 %BW in skiing direction, respectively. This did not differ from maximum (12.1 ± 1.4 %BW) and average (2.6 ± 1.7 %BW) of FM (all P>0.05). Similarity of curve time histories was high between FM and FCOM, during leg push-off (SC = 0.92; Fig.1) and gliding (SC = 0.94). When exemplarily applied to V2A, maximum and average of FV2A were 27 %BW and 12 %BW while values of FM were 24 %BW and 12 %BW, respectively. Similarity of force time curves during the thrust phase was low with SC = 0.17 showing a distinct time shift between curves.

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Maximum (35.5 ± 6.4 %BW) and average (19.8 ± 6.1 %BW) FNP were greater (both P0.05). However, FV and FVAP were lower compared to FCOM (both P 0.7): 1) trigger variables, 2) rifle stability and 3) shoulder pressure. In standing shooting 4-5 factors were extracted (loadings > 0.7): Triggering was constant over all conditions while shoulder pressure, body and rifle sway split up differently for each condition. The regression analyses indicated shoulder pressure as a predictor for the score in rest- (p=0.006) and fatigue-shooting 1 (tendency: p=0.10), while in fatigue-shooting 2 no factor could be exhibited. In the standing situation the following predictors for the shooting performance were found: 1) body sway (y-axis) and rifle sway for rest-shooting (p=0.001), 2) rifle sway in x-axis for the first fatigue-shooting (p=0.034) and 3) no prognosticator for fatigue-shooting 2. DISCUSSION: For prone shooting the shoulder pressure seems to be a predictor for the score, while in the standing condition body and especially rifle sway appear to be relevant. Interestingly, in fatigue-condition 2 no predictors could be found in both, standing and prone shooting. Thus, it can be speculated that biathletes create individual strategies and patterns with increasing fatigue and therefore, no general predictor could be discovered. CONCLUSION: It seems to be relevant to detect the individual pattern of each athlete in order to find strategies for fatigue-situations like the last shooting in a competition. Interdisciplinary investigations with additional performance determining factors might expose further details in biathlon shooting, particularly under highly fatigued conditions. REFERENCES 1. Hoffman, M. D./Gilson, P. M./Westenburg, T. M./Spencer, W. A. (1992). Biathlon shooting performance after exercise of different intensities. In: Int. Journal of Sports Medicine, 13 (3), 270-273. 2. Groslambert, A., Candau, R., Hoffman, M.D., Bardy, B., Rouillon, J.D. (1999). Validation of simple tests of biathlon shooting ability. International Journal of Sports Medicine, 20 (3), 179.

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SCIENCE AND SKI JUMPING – WHAT NEXT? Mika Kojonkoski Finnish Olympic Committee KEY WORDS: Ski jumping, biomechanics, coaching

Research in ski jumping in Finland has started in the turn of 1970’s and since then the University of Jyväskylä has played an important role in this area. Many studies have been published related to biomechanics in ski jumping by Paavo Komi and Mikko Virmavirta as the main researches. Ground reaction forces, pressure distribution, muscle activation have been measured and combined with motion analysis in laboratory, wind tunnel and in field conditions. International co-operation has taken place in several winter Olympics over the past decades. Scientific knowledge obtained from these studies has been utilized in coaching in Finland as well as in many other countries. It has also had an impact to the rules and regulations end equipment development. The main focus in ski jumping research has been on take-off forces and aerodynamical forces. In the teams where I have coached also our coaching philosophy and practice has been based on the research findings. E.g. related to the crucial influence of the force impulse in obtaining high vertical velocity of the center of mass of the jumper during the last phase of take-off and to the behavior of aerodynamical forces during the flight phase. In order to take this information closer to practice we have used different technical equipment for the development of simulated jumping and training and testing in wind tunnel. The challenge in ski jumping is to estimate what is the importance of different parts of the jump to the final outcome. It is known that the horizontal velocity on the ski jumping table is the most important part of the successful jump (Virmavirta & Kivekäs 2012) but it is difficult to improve it by coaching. From a coaching point of view it would be important to know the potential energy of the jumper during the early part of the flight phase (about 30m) in real-time. This way it would be possible to differentiate the impact of jumping and transition phase from the flying and aerodynamics (including equipment). In coaching it would be possible understand what kind of series of individual movement will lead to optimal outcome for each athlete and thus would help to aim the focus of training on the correct part of the jump. Finland has a long and successful history in ski jumping. During the past decades Finland has won several Olympic and World Championship medals. Over the past years, however, other countries have dominated the competitions and there is clearly a need to take some actions to bring Finland back to the top. Going back to the basic research can be one way of helping our country to become successful again. It would be of interest with the current methodology to examine the state of the central nervous system during the crucial phases of the jump, how individual is this behavior and how it can be affected by training. From a bigger perspective it would be extremely important to attract more young athletes to the sport. Science can be of help in doing the correct things in training for physical attributes and proper jumping technique but it is critical that the amount of training can also stand in the competition with the other countries. REFERENCES Virmavirta M & Kivekäs J (2012) The effect of wind on jumping distance in ski jumping-fairness assessed. Sports Biomech. 11(3):358-69

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ORAL PRESENTATIONS

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EFFECT OF SITTING POSTURE ON SIT-SKIING ECONOMY IN NON-DISABLED ATHLETES Kimmo Lajunen, Walter Rapp*, Juha P. Ahtiainen, Stefan Lindinger**, Vesa Linnamo Department of Biology Physical Activity, University of Jyväskylä, Finland * Department of Sport and Sport Science, University of Freiburg, Germany ** Department of Sport Science and Kinesiology, University of Salzburg, Austria KEY WORDS: sit-skiing, sitting position, economy

INTRODUCTION: In Paralympic sit-skiing to achieve a stable sitting posture athletes with high impairment are using a posture where the knees are higher than the pelvic (“knee high”). Another common posture, “kneeing”, offers more extensive hip range of motion (ROM) (1) which in nondisabled athletes has been shown to be most advantageous for good performance (2). To make sure that disabled athletes can compete equitably with each other they are classified based on their impairment and functional capability. The classification process may not take into account the additional disadvantage that some skiers face due to their sitting postures. The aim of this study was to examine the differences in physiological and biomechanical variables between “kneeing” and “knee-high” postures during simulated sit-skiing. METHOD: Ten non-disabled male cross country skiers participated in the study. Subjects performed 3 x 4 min incremental testing protocol with both postures at a ski ergometer simulating sit-skiing. The loads corresponded to 50 %, 60 % and 70 % of the velocity achieved during maximal spurt in “kneeing” position. During the loads subjects’ respiratory gases and heart rate were measured. In addition blood lactate, pulling forces and motion capture recordings were collected. RESULTS: Oxygen consumption was 4.4 % (p5 m·s-1). RESULTS: DP with SS+7.5 cm resulted in a beneficial effect on O2-cost and 1000-m time compared to SS, with no effect on HR or RPE (Table 1). In the DIA, no significant effects of pole length were seen in O2-cost or HR (P>0.05) while a tendency towards a higher RPE was found for the SS+7.5 (P = 0.12). With the SS+7.5, a longer poling time (PT) and shorter recovery time (RT) compared to the SS was found while the cycle time (CT) was similar. Table 1: O2-cost, heart rate (HR), RPE, cycle time, poling time (PT) and recovery time (RT) from submaximal loads (average from 3, 3.5 and 4 m·s-1) and 1000-m time SS SS+7.5 Change in % P-value Mean ± SD Mean ± SD Effect ± 90% CI -1 -1 O2-cost (mL·kg ·min ) 47.8 ± 1.8 46.3 ± 1.2 -2.8 ± 1.3 0.01 -1 HR (beat·min ) 152 ± 9 151 ± 10 -0.7 ± 2.6 0.65 RPE (6-20) 12.4 ± 0.9 12.4 ± 1.0 -0.3 ± 2.3 0.82 CT (ms) 1214 ± 26 1213 ± 25 -0.2 ± 1.7 0.86 PT (ms) 455 ± 13 464 ± 16 2.0 ± 1.9 0.02 RT (ms) 759 ± 26 748 ± 25 -1.5 ± 1.6 0.08 1000-m time (s) 195.5 ± 13.9 192.9 ± 12.3 -1.3 ± 0.8 0.04

DISCUSSION: This study indicates that choice of pole length affects DP technique and performance in competitive skiers. Longer poles results in technical modifications and seems beneficial in order to reduce O2-cost and improve performance. CONCLUSION: Pole length affects highly trained skiers cycle characteristics, O2-cost and performance during DP on a rollerski treadmill. REFERENCES Hansen EA, Losnegard T (2010). Pole length affects cross-country skiers’ performance in an 80-m double poling trial performed on snow from standing start. Sports Eng 12: 171–178. Myklebust H, Losnegard T, Hallén J. Differences in V1 and V2 ski skating techniques described by accelerometers (2014). Scand J Med Sci Sports. 24(6):882-93.

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BIOSENSORS FOR NON INVASIVE MONITORING OF PHYSIOLOGICAL BIOMARKERS RELATED TO FITNESS, SPORTS AND WELLBEING Pirkko Tervo, Elisa Ohtonen, Satu Pääkkönen, Marianne Mäki, Susanna Sonny, Mika Mahosenaho, Vesa Virtanen and Adama M Sesay CEMIS-Oulu, Kajaani University Consortium, University of Oulu, Finland KEY WORDS: Biosensor, point of care diagnostics, physiological biomarkers, competitiveness

INTRODUCTION: Biosensors are analytical devices that combine a biological component, such as an enzyme or an antibody to a physicochemical transducer to detect an analyte of interest (1). In the field of sport sciences, monitoring the status of athletic fitness and sporting performance can be evaluated by applying biosensor technology, as they offer rapid and sensitive detection of relevant biological physiological markers from biological samples. The use of saliva and sweat as noninvasive biological samples can offer an easy and stress-free way for monitoring metabolic, immunological, nutritional, and stress biomarkers that are highly correlated with their concentration levels in blood (2). Current developments in biosensing technology and the availability of new novel materials, flexible electronics and wireless mobile technology; should enable a new generation of devices that will operate on the cutting edge sports science research in understanding fitness and athletic performance. METHOD: Surface modification of electrochemical and optical transducers with biological receptors and nanomaterial have been performed to fabricate sensitive biosensors for the detection of physiologically relevant biomarkers related to sports, fitness and wellbeing. Physiological biomarkers significant to health and fitness such as lactate, cortisol and insulin were chosen as they are present in non-invasive biological sample matrix such as saliva and sweat. These biosensors have been evaluated with spiked and real samples.

Table 1. Physiological biomarker sensors Biomarker 1. Lactate 2. alpha amylase 3. Cortisol 4. Insulin

RESULTS: Several biosensors have been developed and optimised for monitoring physiological biomarkers in non-invasive biological samples. The evaluation of these sensor in real saliva and sweat samples have shown good sensitivity and performance. Initial development of these sensors into usable devices are currently being pursued; with cortisol and insulin immunosensing biosensors are being transformed in to lateral flow/electrochemical devices; alpha amylase into a hand held device and lactate into a flexible wearable patch. DISCUSSION: For the past ten years, The Unit of Measurement Technologies CEMIS-Oulu have developed several biosensors for the detection of physiological biomarkers in non-invasive biological samples. Biosensor developmental work has been in collaboration with companies and research partners including the University of Jyväskylä. Further development work and optimisation in developing them into user friendly formats is required. CONCLUSION: Biosensor technology could be the new frontier for sports research as biochemical physiological data of sporting individuals could be collected in the field and in real time. Multiple data set that combine parameters such as heart rate, acceleration and position, muscle fatigue, stress and inflammation will not only be useful for improving performance and competitiveness but also educational in devising individual training programs and effective recovery periods. REFERENCES Mahosenaho, M., Caprio, F., Micheli, L., Sesay, AM., Palleschi, G. &Virtanen, V. (2010) A disposable biosensor for the determination of alpha-amylase in human saliva. Microchimica Acta, 170(3/4): 243-249. Arvinte, A., Sesay, A.M., Virtanen, V. & Bala, C. (2008). Evaluation of Meldola Blue-Carbon Nanotube-SolGel composite for electrochemical NADH sensors and their application for lactate dehydrogenase-based biosensors. Electroanalysis, 20, 2355-2362.

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PLASMA AMINO ACID PROFILES IN YOUNG CROSS-COUNTRY SKIERS Marianne Mäki, Mari Jaakkola, Tuija Kallio, Henna Karvonen, Pekka Kilpeläinen and Vesa Virtanen CEMIS-Oulu Measurement Technology Unit, Kajaani University Consortium, University of Oulu, Kajaani, Finland KEY WORDS: amino acids, training load, athletes

INTRODUCTION: Exercise is accompanied by increased protein catabolism and changes in the plasma amino acid concentrations, as amino acids both influence on and reflect muscle protein synthesis and breakdown (van Loon 2014). For example, branched-chain amino acids leucine, isoleucine and valine affect protein synthesis in human skeletal muscles (Blomstrand et al. 2006) and ultra-endurance exercise causes muscle protein breakdown elevating plasma phenylalanine and tyrosine concentration (Borgenvik et al. 2012). In addition prolonged exercise and overtraining may decrease plasma glutamine concentration (Parry-Billings et al.1992). METHOD: Four young males (18.5 ± 1.05 years) and four young females (17.9 ± 0.86 years) participated in the study, all of them cross-country skiers from the Vuokatti-Ruka Sports Academy. During their training and competition season (Aug. 2014 – Mar. 2015) plasma amino acid profiles of the study subjects were determined eight times. The plasma samples were deproteinized (Borgenvik et al. 2012) and free amino acids were analysed by HPLC (Agilent 1100) connected to a fluorescence detector using commercially available Waters AccQ●Tag Amino Acid Analysis Method with modifications. RESULTS: A total of 12 amino acids were identified from plasma. A typical amino acid profile in a plasma sample is represented in Fig. 1. The amino acid profiles of the athletes were compared with routine clinical laboratory analyses conducted to them and with their training load. In the presentation, we will show the most typical and interesting changes in the amino acid profiles of the study subjects.

Figure 1. Representative plasma profile showing identified amino acids. 1. Glu, 2. Gly, 3. Thr, 4. Ala, 5. Pro, 6. Tyr, 7. Val, 8. Met, 9. Lys, 10. Ile, 11. Leu, 12. Phe

DISCUSSION: There is ongoing debate on the necessity of protein and amino acid supplements for athletes training strenuously. Research on the subject is especially important when the nutrition of young and developing athletes is considered. This study provides valuable data on amino acid profiles of a small group of young cross-country skiers over a relatively long period when their physical stress and training load varied significantly. REFERENCES Blomstrand, E., Eliasson, J., Karlsson, H.K.R. & Köhnke, R. (2006). Branched-chain amino acids activate key enzymes in protein synthesis after physical exercise. J Nutr, 136:269S-73S. Borgenvik, M., Nordin, M., et al., & Ekblom, B. (2012). Alterations in amino acid concentrations in the plasma and muscle in human subjects during 24 h of simulated adventure racing. Eur J Appl Physiol, 112:3679-88. Parry-Billings, M., Budgett, R., et al., & Newsholme, E.A. (1992), Plasma amino acid concentrations in the overtraining syndrome: possible effects on the immune system. Med Sci Sports Exerc, 24(12):1353-8. van Loon, L.J.C. (2014). Is there a need for protein ingestion during exercise? Sports Medicine, 44:S105-11. rd


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RESTING HEART RATE AS AN INDEX FOR MONITORING PHYSICAL CONDITION DURING HIGH ALTITUDE TRAINING IN CROSS-COUNTRY SKIERS Masaki Takeda1, Hisashi Kato1, Tatsuya Mimura2, Hdieki Shimamoto3, Hiroshi Endoh4, and Zsolt Radak5 1

Doshisha University (Kyoto, Japan), 2Osaka Sangyo University (Osaka, Japan), Osaka University (Osaka, Japan), 4Ryukyu University (Okinawa, Japan), 5University of Physical Education (Budapest, Hungary)

3

KEY WORDS: high altitude training, heart rate, cross-country ski

INTRODUCTION: Because of the fact that there are benefits and risks in high altitude training (Wilber, 2003), it is reasonable to have an index for monitoring physical condition and acclimatization status in high altitude training. In this study, we have evaluated physiological meanings of resting heart rate for monitoring the physical condition and acclimatization status during 2 weeks of high altitude training in cross-country skiers. METHOD: Collegiate cross-country skiers (8 males, 6 females, 20.0 ±1.0 yrs.) lived 1 day at sea level and lived and trained for 14 days at 2,200 m. Just soon after getting up, the following items were measured in every 2 days, i.e., heart rate (HR) during orthostatic test, hemoglobin concentration (Hb), and HR and blood lactate concentration (La) during 3 minutes of submaximal cycling test at the intensity of 75% of maximal HR of each subject and 3 minutes of recovery. Erythropoietin (EPO), ferritin, red blood cell (RBC), hematocrit (Hct) were measured at sea level and day 2 and day 14. One way repeated measure of variance and correlation analyses were used for the statistical evaluations. RESULTS: Supine and standing HR significantly increased at day 2 (vs sea level) and, after that, it gradually decreased during 2 weeks of high altitude training. Supine HR significantly decreased at day 14 (vs. day 2). Salivary cortisol was significantly increased at day 2 (vs sea level) and, after that, significantly decreased at day 14 (vs day 2 and 8). EPO was significantly increased after 48 h at 2,200 m (vs. before altitude training) and significantly returned to the same level with sea level at day 14. Hb concentration significantly increased day14 (vs. con, day 2). No significant changes were found in other hematological parameters. HR during submaximal exercise significantly increased from sea level to day 2 and the increased HR at day 2 significantly decreased at day 8. Interestingly, the amount of changes (⊿) in supine HR from day 2 to 14 significantly correlated with ⊿cortisol (from pre to 14), ⊿average HR during cycling test (from day 2 to 14) and ⊿La after cycling (from day 2 to 14). The amount of change in HR (standing) x Cortisol standing HR from day 2 to 14 significantly correlated ΔCortisol 800 600 with ⊿EPO (from pre to 48 hours), ⊿Hb (from day 2 to 400 day 14), and ⊿average HR (from day 2 to 14) during 200 submaximal cycling test, and ⊿cortisol (from day 2 to ΔHR(b/min) 0 14) (Fig. 1). -40

CONCLUSION: It is suggested that HR at supine and standing reflected physical condition and adaptation status to 2 weeks high altitude training in cross country skiers.

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REFERENCES Wilber R. (2003). The Science of Altitude Training. In: Altitude Training and Athletic Performance. Human Kinetics.

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Figure 1. Correlation between ⊿standing heart rate and ⊿salivary cortisol


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INFLUENCE OF HIGH INTENSITY INTERVAL TRAINING UNDER HYPOXIC CONDITIONS ON ACUTE REGENERATIVE CAPACITY DURING A SET OF FOUR MINUTES TIME TRAILS Markus de Marées, Bastian Abel, Joachim Mester Institute of Trainings Science and Sport Informatics, German Sport University Cologne, Cologne Germany KEY WORDS: Hypoxia, training, regeneration

INTRODUCTION: Among elite level endurance athletes hypoxic training became increasingly popular during the last decades. However the effectively in terms of improving the performance under normoxic conditions is still doubtful, especially by using the intermittent hypoxic training design. Recent studies show an enhancing effect of high intensity interval training under hypoxic (HIITH) conditions on repeated sprint ability (1). So we questioned whether HIIT under hypoxic compared to normoxic conditions may lead to a greater acute regenerative capacity during a set of four minutes of high intensive exercise. The ability to regenerate is one major factor for competing successfully in sports like Paralympic cross country sprint events, where athletes perform three to five time trails separated by 20 min breaks. METHODS: 10 endurance athletes were blinded and randomly divided into a hypoxic (HG FiO2 15± 0, 4 %) and normoxic (NG FiO2 19, 7± 0, 6 %) group. Ahead and after the training period performances tests were conducted on a cycle ergometer which consists of a ramp test followed by three four minutes time trails (TT) with a break of 20 minutes between each trail. VO2max, heart rate (HR) and tissue saturations index (TSI) detected at the musculus vastus lateralis were measured. The HIIT consists two sessions per week for three weeks. The session were built of 10 min of low intensity cycling followed by 12 for the first four sessions respectively 14 “15 sec. all-outsprints” in for the last two bouts interrupted by a break of 45 sec. RESULTS: VO2max increased by 1, 0 (pre 50, 0; post 51 (ml/kg/min)) for NG and 2, 0 (pre 53, 0; post 55 (ml/kg/min)) the HG respectively. During the breaks between the TTs HR decreases faster compared to pre values for both groups (6 ± 2 (b/min) NG; 3 ± 3 (b/min) HG). For TSI were no differences detected between both groups. CONCLUSION: HIIT under hypoxic conditions compared to identical trainings under normoxic conditions leads to a greater increase in VO2max, but isn´t advantageous in terms of an improved TSI or an acute regenerative capacity during a set of TT. These findings could base on the ineffective training load or the location of the post test, which may have displayed different results when conducted ten days after the end of the trainings period compared to six. REFERENCES 1 Faiss R, Léger B, Vesin JM, Fournier PE, Eggel Y, Dériaz O, Millet GP., Significant molecular and systemic adaptations after repeated sprint training in hypoxia. 2013 PLoS One.

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DYNAMICAL STRUCTURE OF RIFLE TRAJECTORIES IN BIATHLON SHOOTING Michael Buchecker1, Gerold Sattlecker1, Stefan Wegenkittl2, Stefan Lindinger1 & Erich Müller1 1

Department of Sport Science and Kinesiology / USI, University of Salzburg, Austria 2 Department of Applied Image and Signal Processing, University of Applied Sciences Salzburg, Austria KEY WORDS: sample entropy, motor control, variability, sport

INTRODUCTION: Physiological-behavioral complexity emerges from the confluence of organismic, environmental and task constraints and can be assessed through tools evaluating the shape of neurobiological signals; thus, they provide a window into the organization of motor control1,2. Since a profound description of pattern dynamics in sports, and in biathlon in particular, is missing, the aim of the current study was (1) to analyze the time-varying properties of rifle motion and (2) to evaluate whether different settings or techniques would affect underlying coordinative strategies. METHODS: Medio-lateral (GUNx) and up-down (GUNz) rifle fluctuations were captured with a Noptel (Sport II, Oulu, Finland) device at 66 Hz and acquired for 16 Austrian biathletes while prone and standing shooting at rest (3 x 5 shots / position) and during a simulated race on ski rollers (2 x 5 shots / position). Post-processing included the construction of artificial trajectories, reflecting five vertically aligned 80 data point segments of pre-selected aiming intervals for each shooting mode, followed by low-pass filtering (cut-off: 6 Hz) of the resultant time series. Structure-related variability characteristics were calculated using the sample entropy (SEn) algorithm and the obtained indices finally checked by multivariate analyses of variances (MANOVA) – with Alpha fixed at 0.05. RESULTS: MANOVA included both spatial directions and confirmed significant effects for position (F2,15 = 45.5, P < 0.001), condition (F2,15 = 7.2, P < 0.01) and the interaction between position and condition (F2,15 = 4.9, P < 0.05). Subsequent univariate procedures revealed (a) throughout higher SEn indices in the prone than in the stance position (position: all P < 0.001), (b) an increase of SEn for GUNz (condition: P < 0.01) and by tendency also for GUNx (condition: P = 0.12; f = 0.41) when competing, and (c) a stronger influence of preceding physiological load on the structuredness of GUNz sequences in prone compared to standing shooting (interaction: P < 0.01). No such interdependencies were found for SEn values concerning GUNx (interaction: P = 0.71; f = 0.09). DISCUSSION: Findings from the presented experiment have demonstrated a more regular, predictable rifle sway in stance vs. prone shooting, suggesting that subjects intuitively compressed active degrees of freedom into lower-dimensional functional synergies to overcome the greater task demands induced by the former condition. However, the increased SEn outcomes in consequence of fatigue may not echo an optimal performance state – as previously hypothesized in the context of aging and disease1. Instead the noticed less periodic-like rifle tremor, especially in the prone position, shall be regarded as unwanted departures from an otherwise rhythmical intrinsic aiming behaviour, and may therefore be indicative of a loss of flexibility or adaptability in “real” biathlon shooting2. Accordingly, coaches may incorporate specific forms of intrinsic or extrinsic constraints in training and testing for purposefully enriching an athletes’ repertoire of movement solutions, which could in case attenuate the impact of (unforeseeable) perturbations. REFERENCES 1. Stergiou N. & Decker L.M. (2011). Human movement variability, nonlinear dynamics, and pathology: Is there a connection? Hum Mov Sci, 30, 869-888. 2. Vaillancourt D.E. & Newell K.M. (2002). Changing complexity in human behaviour in physiology through aging and disease. Neurobiol Aging, 23, 1-11.

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PSYCHOLOGICAL INFLUENCES ON BIATHLON SHOOTING PERFORMANCE Sabine Würth, Thomas Finkenzeller, Michael Buchecker, Gerold Sattelecker, Stefan Lindinger and Günter Amesberger Department of Sport Science and Kinesiology, University of Salzburg, Salzburg, Austria KEY WORDS: Biathlon, cognitive inhibition, stress, recovery, mental toughness, exertion

INTRODUCTION: Biathlon shooting is a complex task that is determined by many factors. Besides biomechanical and kinesiological aspects like stability of the body-rifle system or postural control, psychological parameters might play a crucial role in shooting performance, especially under competition conditions. However, little is known how personality traits and cognitive abilities (mental toughness, cognitive inhibition), actual mental fitness during competition days (perception of stress and recovery), and immediate psychological states before shooting (well-being, perceived exertion) influence shooting performance in biathlon. Hence, the aim of this exploratory study was (a) to investigate whether elite biathletes display typical patterns of psychological traits and states, and (b) how these psychological parameters influence their shooting performance. METHOD: On day 1 of a practice camp period, 22 elite Austrian biathletes filled in the MTQ48 (assessing mental toughness) and the RESTQ (assessing recovery and stress during the last three days). Cognitive inhibition was measured three times (under rest, before and after a training competition) using an Erikson flanker task with 20 congruent, 20 neutral, and 20 incongruent cues. During the training session consisting of six shootings under rest (3 prone, 3 standing), and a training competition with 2 prone and 2 standing shootings, perceived subjective well-being (visual analogue scale), perceived exertion (Borg scale) and actual pulse rate were assessed 5 times, immediately before each shooting and at finish. RESULTS: Cluster analyses (Ward and k-means clustering) depict particular types of athletes with regard to mental toughness (high vs. low), cognitive inhibition (slow and precise vs. fast and less precise performers), stress-recovery balance (good vs. bad balance), and actual psychological state during performance (high discrepancy between perceived exertion and pulse rate vs. low discrepancy). Clusters are independent from each other (Spearmans Rho ranging from -.23 to .38; n.s.). MANOVAs on shooting performance (% of targets under rest vs. performance condition) reveal a significant effect of cognitive inhibition [F(1, 17) = 4.40, p = .045, η2 = .22] with fast and less precise Flanker performers performing better in shooting than slow and precise Flanker performers (89,00% vs. 82,16%). Additionally, athletes with a good stress-recovery balance trend to perform better than their colleagues [88,91% vs. 82,22%; F(1, 17) = 4.40, p = .051, η2 = .21]. DISCUSSION: This study showed that biathletes clearly depict different clusters of psychological traits and states. In addition, the independency of the clusters reflects the complex nature of psychological patterns in terms of personal dispositions, actual mental fitness, and immediate influences on shooting performance. MANOVA results reveal small to moderate effects of cognitive abilities and stress management on shooting in biathlon. CONCLUSION: The complex nature of biathlon shooting is mirrored in a complex relationship of psychological trait and state patterns. Further studies are needed in order to detect systematic interdependencies between psychological patterns on the one hand, and physical aspects on the other hand. In particular, longitudinal data are needed to address aspects of psycho-physical development and performance stability.

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PREPARATORY EEG SPECTRAL POWER AND COHERENCE IN BIATHLON RIFLE SHOOTING: A PILOT STUDY Kerstin Hoedlmoser1, Gerold Sattlecker2, Thomas Finkenzeller2 & Germano Gallicchio1 1

Centre for Cognitive Neuroscience, University of Salzburg, Austria Department of Sport Science & Kinesiology, University of Salzburg, Austria

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KEY WORDS: shooting, physical exercise, electroencephalography (EEG)

INTRODUCTION: Expert shooting performance is preceded by an increase in frontal midline theta (Fmθ), suggesting an increase in the top-down working memory activation1, and by lower left temporal-frontal upper alpha (α) coherence2, suggesting lower engagement in conscious processing of explicit knowledge to control motor execution. The aim of the present pilot study was to assess the feasibility of processing EEG data recorded in conditions of high physical load, such as in biathlon. We expected shooting performance to be preceded by changes in Fmθ power and in left temporal-frontal upper α coherence. We further hypothesized the intense physical exercise to impair shooting performance and disrupt preparatory cortical activity. METHODS: 2 adolescent expert biathletes completed 12 blocks of 5 repeated shots under (i) a resting condition and (ii) an exercise condition (i.e. each shooting block was preceded by 3min on a cycle ergometer at 90% of maximum heart rate). 64 channel EEG was recorded using the ANT Neuro eegosport™ system. Shooting accuracy was measured through a computer controlled device and a sound threshold criterion allowed the identification of the timing of each shot. θ power and cross-channel upper α coherence (short-time FFT, Welch's method) were computed over the last 3 seconds preceding each shot (3 intervals each lasting 1 second). The 10 best and 10 worst trials were clustered on the basis of shooting accuracy. RESULTS: A 2 Performance Outcome (best, worst) × 2 Condition (rest, exercise) ANOVA showed that shooting accuracy was impaired by physical exercise (p=.003). A 2 Performance Outcome × 2 Condition × 3 Time (-3 s to -2 s, -2 s to -1 s, -1 s to 0 s) ANOVA revealed that Fmθ (Fz) power increased over time, with lower values following physical exercise in the last time bin (p=.005). Ttests demonstrated that best (vs. worst) shots were preceded by marginally higher Fmθ power in the last time bin (p=.073). A 2 Performance Outcome × 2 Condition × 3 Time ANOVA revealed that left temporal (T7) - frontal (Fz) upper α coherence was lower following physical exercise in the last time bin (p=.009). T-tests showed that best (vs. worst) shots were preceded by lower T7-Fz upper α coherence in the last time bin (p=.025). DISCUSSION: Consistently with previous findings1,2 the best shooting performance was preceded by higher Fmθ power and lower left temporal-frontal upper α coherence. Additionally, these findings imply a modulatory effect of physical exercise on the cortical activity preceding expert sport performance. In particular, it is suggested that performance following intense physical exercise is preceded by lower top-down working-memory activation and lower explicit processing. Following these preliminary results, a full study will be conducted with the aim of further clarifying the cortical activity pattern in preparation to rifle shooting following physical exercise on a larger cohort. REFERENCES 1. Doppelmayr, M., Finkenzeller, T., & Sauseng, P. (2008). Frontal midline theta in the pre-shot phase of rifle shooting: Differences between experts and novices. Neuropsychologia, 46(5), 1463-1467. 2. Deeny, S. P., Hillman, C. H., Janelle, C. M., & Hatfield, B. D. (2003). Cortico-cortical communication and superior performance in skilled marksmen: an EEG coherence analysis. Journal of Sport and Exercise Psychology, 25(2), 188-204.

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HOLDING ABILITY DETERMINES 54% OF AIR RIFLE SHOOTING SCORES Simo Ihalainen, Sami Kuitunen, Kaisu Mononen and Vesa Linnamo* KIHU - Research Institute for Olympic Sports, Jyväskylä, Finland *Department of Biology of Physical Activity, University of Jyväskylä, Jyväskylä, Finland KEY WORDS: biomechanics, technique, optoelectronic measures, postural balance

INTRODUCTION: Air rifle shooting studies have focused on holding ability and postural balance (Ball et al. 2003, Konttinen et al. 1999). Other technical aspects, such as aiming accuracy and cleanness of triggering, have not been studied in air rifle shooting. Therefore, the aim of this study was to identify the most important performance determining factors in elite-level air rifle shooting. METHOD: Forty international (INT) and national (NAT) level air rifle shooters volunteered to participate in the study. The measurements consisted of an unlimited number of sighting shots followed by a simulated competition series. Hit point, aiming point trajectory and center of pressure were collected from every shot. RESULTS: A total of 13 795 shots in 319 tests were analyzed for this study. Holding ability, aiming accuracy, cleanness of triggering and timing of triggering were identified as the most important shooting technical components, accounting for 81 % the variance in shooting score (Figure 1). INT group athletes had better mean shot scores, more stable hold and postural balance, cleaner triggering action, and better aiming accuracy compared with the NAT group athletes. DISCUSSION: The results of the present study emphasize the importance of holding ability in achieving superior shooting technique, since 54% of the variance in shooting score could be explained by the holding ability in horizontal direction. The elite-level athletes’ ability to decrease the amount of postural sway in anteroposterior direction during the last second before the shot seems to be related to the more stable holding ability of the elite level athletes. DISCUSSION: This study identified the most important determinants of air rifle shooting technique. In the future shooting studies, it should be noted that in addition to stability of hold and postural balance, measures of aiming accuracy, cleanness of triggering, and timing of triggering should be included in order to acquire more comprehensive description about the shooting task.

Figure 1. Mean test shot score and regression prediction (Y = 5.110 + (−0.502) × DevX + 0.315 × TIRE + 0.465 × COGhit + (−0.582) × ATV)

REFERENCES Ball KA, Best RJ & Wrigley TV. (2003). Body sway, aim point fluctuation and performance in rifle shooters: inter- and intra-individual analysis. Journal of Sports Sciences, 21, 559–566. Konttinen N, Lyytinen H & Era P. (1999). Brain slow potentials and postural sway behavior during sharpshooting performance. Journal of Motor Behavior, 31, 11–20.

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THE FLYING HILL PROFILE AS A LIMITATION FACTOR IN DEVELOPMENT OF WORLD RECORD IN SKI FLYING Bojan Jošt and Janez Vodičar Faculty of Sport, University of Ljubljana, Slovenia KEY WORDS: ski flying, flying hill, world record

INTRODUCTION: The current ski flying world record of 246.5 meters was set at the Vikersund Ski Flying Hill in 2011 by Johan Reemen Evensen of Norway. In 2014 ski flying hills of the same size, i.e. HS225, were constructed in Kulm and Planica. The aim of this paper is to study the possibility of a new world record being set at the newly-reconstructed Planica hill. The study uses the flight curves determined from the kinematic properties of flights performed at the Planica World Cup Ski Flying competitions (2008/2009 and 2012/2013 seasons) and the 2010 Ski Flying World Championship. METHODS: The simulation of the new world record flight curve is based on Simon Ammann's 236metre-long flight which earned Ammann the title of 2010 World Ski Flying Champion (Figure 1). The geometric features of the HS225 Planica hill are adapted from the structure's official FIS profile. RESULTS: Figure 1 presents a simulation of the new world record. The angle of the landing slope of HS225 at a world record of 247m is very low (approx. 25 arc degrees), which would cause large forces to be applied to the ski flier during landing. DISCUSSION: The analysis of the basic geometric properties of Planica's enlarged HS225 profile showed that attempting to set an new world record on this hill would be both difficult and risky. In order to break the record, ski fliers would have to fly at least 22m past the hill size point (225m). Landing at the 247m mark would be rather dangerous for jumpers. The flight incidence angle before landing would be 12 degrees, and the safety of the landing as well as outrun would be compromised due to large forces acting at the contact point with the surface (Jost & Vodicar, 2013). Setting new world records at the reconstructed Kulm and Planica hills will be highly demanding and dangerous. Safe world-record flights are possible at the HS240 (ZU= min 140m) hill. Figure 1. Simulation of Simon Ammann's 236m flight on the large hills: HS225m, HS230m and HS240m

CONCLUSION: Currently, the ski jumping technique used enables jumpers to fly safely past the world record mark of 246.5m, but the size of ski flying hills does not. Unfortunately, recent reconstructions of the Kulm and Planica hills to a 225m size are unlikely to meet the expectations of the sports world for record-breaking flights. Such flights would only be possible if the FIS allowed hill sizes to be increased to an HS240m size, with the minimum distance between the edge of the jump and the lowest point at radius r2 is at least 140m. REFERENCES Jost, B. & Vodicar, J. (2013). Design of a Ski Flying Hill with the Profile HS300m – A Kinematic Analysis of the Flying Curve of Ski Jumpers. VERLAG DR. KOVAČ GMBH, Hamburg.

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CORRELATION BETWEEN THE HEIGHT OF THE FLIGHT CURVE AND THE LENGTH OF THE JUMP AT PLANICA SKI FLYING COMPETITIONS OF 2009, 2010, AND 2013 Janez Vodičar, Maja Ulaga, Bojan Jošt Faculty of Sport, University of Ljubljana, Slovenia KEY WORDS: ski flying, height of flying, correlation, successfulness

INTRODUCTION: The height of the flying curve can be affected by a number of factors, including the ski jumpers' equipment. In recent years, permitted jump suit sizes changed frequently (from + 6cm in the 2012/2013 season, to + 2cm in the 2012/2013 season, and + 4cm in the 2014/2015 season). Ski jumpers raised the issue of smaller jump suits, claiming that as a result of poorer aerodynamic efficiency, these suits negatively affected their flying sensations and increased the risk of falls during landing, as particularly evident in the long jumps past the hill size point. The aim of this paper is to determine the correlation between the height of the flying curve and the length of the jump at World Cup Finals in the seasons of 2008/2009 and 2012/2013, and at the 2010 Planica Ski Flying World Championship. METHODS: The heights of the flying curves were determined by means of a kinematic analysis of flights made at the HS215m hill at the Planica Ski Flying Competition. Ski jumpers were recorded in flight with a camera placed perpendicular to the direction of flying (distance approx. 30m) at the expected average flight height above the profile of the out-run (4.5m) and at a distance of 112m from the take-off. For each ski jumper, the height of the flying curve was measured from the difference between the hip joint axis and the reference point for the expected average flight height. Reference data were used to calculate the aerodynamic index of the flight. Variable data, e.g. flight length, in-run speed, wind speed, and direction, were based on the official FIS records. RESULTS: In Planica, the average height of the flying curve rose considerably in the 2012/13 season, when the allowed jump suit size was lowered to + 2cm (Figure 1). The correlation coefficients between the flight variables and jump lengths in the season of 2012/13 were significant (r = .34 - 0.72) DISCUSSION & CONCLUSION: The results showed that the reduction in the size of jump suits (+ 2cm in 2012/2013) had a considerable effect on the increase of the average height of flights on the Planica hill. This led to an increase in the incidence angles in the second part of the flight and the angles at the point of landing and, as a result, intensified the pressure forces exerted on the jumper upon contact with the surface. There were very few extremely long flights past the 225m mark. In the longest-ever jump in Planica, Anders Bardal of Norway grazed the snow on landing at 231m, in favorable winter conditions. The height of the flying curve in the central part of the flight was constantly in statistically significant correlation with the jump length, although its relevance changed and was lowest at afternoon time. The reduction in the size of jump suits to + 2cm, introduced in the season of 2012/2013 led to a considerable increase in the height of the flying curve on the Planica hill, in particular in the afternoon time when the conditions for flying on the Planica hill are much worse.

Figure 1. Height of flying curve at 112 m (above), % of total variance of flight distance at World Cup finals in Planica 2013 (below)

REFERENCES Jost, B. & Vodicar, J. (2013). Design of a Ski Flying Hill with the Profile HS300m – A Kinematic Analysis of the Flying Curve of Ski Jumpers. rd


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ANALYSIS OF TAKE-OFF EXECUTIONS OF TOP ATHLETES IN SKI JUMPING Sören Müller, Sascha Kreibich & Ilka Seidel Institute for Applied Training Science Leipzig, Germany KEY WORDS: ski jumping, take-off, force measurement

INTRODUCTION: In ski jumping the take-off is a key position within the entire movement. The execution of take-off and the jump intensity (vertical take-off velocity) have a direct impact on the take-in of the flight posture and of the flight distance. Due to the changes in the materials (jump suits, ties, shoes) but also the use of standardized (ice) track systems realize the best athletes in the inrun position and in take-off an ever-increasing submission of the center of gravity (Müller, Kreibich & Wiese, 2014). In the analysis of the take-off-execution interested the question of how the action of force under these conditions, and whether there are differences between the top athletes. METHOD: With dynamometric measurement platforms (Dickwach & Wagner, 2004) we analyzed 21 elite athletes (25.0 years ± 4.0) at the jumping hill in Klingenthal for the force-length curve at the last 14 m in the inrun (curve and takeoff) in 2012/13 and 2013/14. From all jumps per athlete (n=36) the average force-length curve was determined for each. On the basis of take-off intensity (vertical take-off velocity), the maximum force (Fmax) and the force-length curve characteristic of all 21 Springer were analyzed. RESULTS AND DISCUSSION: The analysis of the force-length curve based on the location of the maximum force shows three different characteristics: A - an “explosivesloping” curve with Fmax at the beginning of the jump (n=6); B - a stable high level of force over the take-off (n=9); C - a rising trend with Fmax at the end of the jump (n=6). The vertical take-off velocity is almost equal in all three groups (A: 2.73 ± 0.06 m/s; B: 2.67 ± 0.10 m/s; C: 2.70 ± 0.15 m/s) and the average of the world's best (ranked 1-10) 2010-2014 (Müller et al., 2014). The differences in the force curve are due to the ability to produce from deep inrun-position quickly high forces with a large submission of Figure 1. Three different characteristics of the forcelength curves in relation to location of maximum the center of gravity. Due to its smaller vertical component of the force top athletes succeed to achieve high vertical take-off velocity. The athletes of groups A and B show better race results, even over the whole season and thus form the absolute world class. CONCLUSION: By using dynamometric measurement platforms in the curve and takeoff we can analyse the force development during take-off and diagnose the force-length curve characteristic type. In combination with cinematic analyses an overall assessment of the take-off executions is possible which allows to make recommendations on effective training. REFERENCES: Müller, S., Kreibich, S. & Wiese, G. (2014). Analyse der nationalen und internationalen Leistungsentwicklung im Skispringen. [Olympiaanalyse]. Leipzig: IAT. Dickwach, H. & Wagner, K. (2004). Neue Möglichkeiten der Analyse und Technikkorrektur im Skispringern durch die Kopplung visueller Informationen und Kraftverläufen. Leistungssport, 34 (1), 12-17.

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EFFECT OF AEROBIC HIGH-INTENSITY INTERVAL TRAINING ON LEG STRENGTH IN CROSS COUNTRY SKIERS Ebru Çetin*, İmdat Yarım*, Bahar Ateş** *Gazi University School of Physical Education and Sports, Ankara, Turkey ** Faculty of Sport Science, Uşak University, Uşak, Turkey KEY WORDS: Cross-country skiing, strength, Interval training

INTRODUCTION: Competitive cross-country skiing has recently experienced rapid changes, with the addition of several new racing forms. The increase in the speed factor in races puts forward the importance of strength among other motoric features of the neuromuscular apparatus (Sandbakk, 2011). The purpose of this study was to assess the effect of 2km uphill training on leg strength. METHOD: 10 male (age, 18,28±2,1 years; height, 171,26±4,12 cm; weight, 61,39±6,28 kg) and 8 female (age, 16,05±0.3 years; height, 158,3±6,47 cm; weight, 49,34±0.7 kg) junior cross country skiers participatedin this study. Eight weeks training model has been done after the winter season during the preparation period. Roller ski trainings applied 3 days in a week in a 2 km uphill track where the height difference is 144 mt. All-out exercise protocol have been applied as 2x2 km and 10 min active rest between the bouts. Heart rates are recorded (Polar Oy Finland) during the pre and post measurements. One day before and after the training session quadriceps and hamstring isokinetic muscle powers of all athletes were tested. Pre and post tests values statistically are checked via “Wilcoxon Test (2 related samples)”. Also differences among the results of a pre and a post tests, analyzed from the aspect of percentage changes. RESULTS: Averages and percentage differences have been presented on table 1. Table.1 Comparison Between Pre and Post Test in Female and Male Athletes MALE

FEMALE

Pre-test

Post-Test

p

%

Pre-test

Post-test

p

%

HRmax. (beats.min )

185,9±13,24

181,4±12,7

0,005*

-2,42

187,75±9,5

184,75±8,7

0,011*

-1,6

RL/Quadriceps N.m

180,5±19,94

198,5±22,7

0,005*

9,97

98,12±28,7

108,25±26, 3

0,012*

10,32

RL/Hamstring N.m

88,1±15,95

100,7±13,1

0,005*

14,3

45,88±14,82 55,5±14,54

0,011*

20,97

LL/Quadriceps N.m

175,9±25,66

194,9±22,8

0,005*

10,8

91,63±16,81

101,37±17

0,012*

10,63

LL/Hamstring N.m

84,9±13,03

96,2±12,5

0,005* 13,31

47,5±10,88

56,75±11,2 3

0,011*

19,47

2-km time trial (sn)

13,45±2,15

12,78±1,1

0,005*

17,3±2,15

16,58±0,88

0,012*

-4,16

Parameters -1

-4,98

DISCUSSION & CONCLUSION: It has been determined that athlete have shown indications of development in leg strength and apart from these 2 km roller skiing performance, as a result of 8 weeks high intensity aerobic interval exercises. Our results indicate the only before and after training session in all subjects. Future research should include a control group for conclusive results. With reference to the training effects found in our study, we suggest that the skiers should integrate the roller ski aerobic high-intensity intervals uphill models in their training programs for developing to leg strenght. REFERENCES Sandbakk Ø, Holmberg HC, Leirdal S and Ettema G. 2011. The physiology of world class sprint skiers. Scand J Med Sci Sports 21: 9-16.

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THE EFFECT OF FRICTION CONDITIONS ON THE SIMULATED SKI JUMPING TAKE-OFF Lauri Hakola and Mikko Virmavirta Department of Biology of Physical Activity, University of Jyväskylä, Finland KEY WORDS: ski jumping, simulation jumps, friction conditions, ground reaction forces

INTRODUCTION: In ski jumping the take-off is the most important phase. Good take-off is a complex series of movement and it is performed in extreme and altering conditions. Several significant differences between hill and simulation jumps have been found in several biomechanical analyses (e.g. Virmavirta et all. 2000; Schwameder 2008), and the differences occur mainly due to very different performance conditions. Therefore, the purpose of this study was to examine the effect of friction conditions on the simulated ski jumping take-off. METHOD: National (8) and international (7) level ski jumpers participated in this study. Three simulation jumps in three different friction conditions (µ1-3= 1,00, 0,23, 0,07) were measured from each subject. Take-offs were performed from a force plate, which was placed on a moving sledge. By locking the wheels and changing material between wheels and surface, the friction could be altered. All three force components (x, y, z) under the ball and heel of both feet were recorded. The force data was synchronized with a video (fig. 1), which was used for kinematic analysis. The measuring equipment is part of the ski jumping feedback system of Vuokatti Sports Institute. RESULTS: Several kinetic and kinematic changes were found especially in the lowest friction condition. For example take-off angle increased as the friction decreased (fig.1). In some cases the changes were more pronounced in the national level jumpers.

Figure 1. Left: Take-off angle in different friction conditions. Right: Example of the feedback system

DISCUSSION & CONCLUSION: The measuring system used in this study proved to be appropriate for the given research questions. It was somewhat surprising that the most beneficial results were found on the take-off surface with a lowest friction, which was assumed to be too slippery for proper simulation take-offs. For the proper learning process and motor control it is obvious that the technique in simulation take-offs should be as close as possible to the technique in actual hill conditions. The advantage of the smallest friction condition is that it well reveals the errors in the direction of the force production, which is very difficult to observe even by the experienced coaches in the normal friction conditions. Based on the results of this study it can be recommended that the athletes repeat the simulated take-offs on the surface, which is very close to the actual hill conditions. However, friction conditions are only one element of the differences between the simulated and actual hill jumps and more information is needed to adjust the simulated training closer to the actual hill conditions. REFERENCES: Schwameder, H. (2008). Biomechanics research in ski jumping, 1991–2006. Sports Biomechanics 7 (1), 114–136. Virmavirta, M. & Komi, P.V. (2000). Plantar pressure and EMG activitiy of simulated and actual ski jumping take-off. Scandinavian Journal of Medicine & Science in sports 11, 310–314. rd


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THE BIOMARKERS OF OXIDATIVE STRESS IN YOUNG CROSS-COUNTRY SKIERS Henna Karvonen, Tuija Kallio, Pirkko Tervo, Marianne Mäki, Jouko Käsmä, Pekka Kilpeläinen and Vesa Virtanen CEMIS-Oulu Measurement Technology Unit, Kajaani University Consortium, University of Oulu, Kajaani, Finland KEY WORDS: Reactive oxygen species, oxidative stress, protein carbonyl content, isoprostane

INTRODUCTION: Oxidative stress is characterized by an imbalance between antioxidants and oxidizing species of the body. Increased production of free radicals overwhelms antioxidant defenses resulting in cellular damage and oxidation of biomolecules (Wood et al. 2006). In athletes, prolonged exercise and physical stress lead to increased levels of oxidative stress indicators in blood. It may be seen as reduced performance, tissue damage and even overtraining syndrome if recovery periods are not sufficient (Finaud et al. 2006). Oxidative stress can be quantified by measuring metabolites formed by oxidation. Several metabolites have been introduced in the literature, such as the carbonyl groups, isoprostanes and 8hydroxydeoxyguanosine (8-oxodG) which can be used to estimate the oxidation of proteins, lipids and DNA, respectively. In addition, the amount of reactive oxygen species (ROS) or the antioxidant potential can be assayed (Wood et al. 2006). METHOD: Study population was composed of 4 male (18.5 ± 1.05 yr) and 4 female (17.9 ± 0.86 yr) cross-country skiers recruited from the Vuokatti-Ruka Sports Academy. The volunteers donated blood samples 8 times during their training and competition season (Aug, 2014 – Mar, 2015). ROS formation, protein carbonyl content (PCC) as well as isoprostane and 8-oxodG levels were analysed. In addition, routine clinical laboratory analytics was conducted. RESULTS: Preliminary data show that there are individual and seasonal differences in PCC, isoprostane levels and ROS formation. There is a slight increasing trend in all of the biomarker levels during the training season. A correlation was observed between different indicators of oxidative stress. Later on, the results will be correlated with other physiological markers. The changes in the oxidative stress biomarker levels appear to be at least partially connected to the training load. DISCUSSION: The study subjects had individual differences in the biomarker levels, but further studies are required to draw any conclusion on their health and training load based on these markers. It is important to note that the ROS and oxidative stress have also essential role in immune defense, cell signaling and possibly in the induction of muscle synthesis (Jackson 2008). Measuring of immediate ROS values in training would be very interesting, but it requires portable laboratory instrumentation. The study provided valuable data also for evaluation of analytical methodology. REFERENCES Jackson MJ (2008) Free radicals generated by contracting muscle: By-products of metabolism or key regulators of muscle function? Free Rad Biol Med 44:132-41. Finaud J, Lac G, Filaire E (2006) Oxidative stress: relationship with exercise and training. Sports Med. 36(4):327-58. Wood LG, Gibson PG & Garg ML (2006) A review of the methodology for assessing in vivo antioxidant capacity. J Sci Food Agric 86:2057-66.

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NEUROMUSCULAR MOTOR TASKS BETWEEN SKILL AND ENDURANCE TRAINED ATHLETES Susanne Kumpulainen1,2, Natalie Mrachacz-Kersting2, Jussi Peltonen1, Vesa Linnamo1, Janne Avela1 1

Neuromuscular Research Center, Department of Biology of Physical Activity, University of Jyvaskyla, Finland 2 Center for Sensory-Motor Interaction, Aalborg University, Denmark KEY WORDS: motor learning, training adaptations, neuromuscular motor tasks

INTRODUCTION: It is well known that different types of physical exercise produce experiencespecific alterations in the corticomotorneuronal system (Adkins et al. 2006). Furthermore, previous study by Kumpulainen et al. 2014 showed that skill trained athletes have higher plasticity on the leg area of motor cortex compared to endurance trained athletes. Thus, it was hypothesized that skill and endurance trained athletes would perform differently in certain neuromuscular motor tasks. The purpose of this study was to compare 15 skill and 14 endurance trained athletes in 3 different motor tasks performed with plantar-flexors, which are training-relevant muscles for both groups. The tasks assessed rate of force development (RFD), reaction time, accuracy of force control and learning during the accuracy task. METHODS: Subjects sat on an ankle dynamometer with their right foot resting on a pedal. First, subjects performed 3 isometric maximal plantarfexions with maximal speed to quantify maximal voluntary contraction (MVC) and RFD. Go signal for reaction task was a pedal perturbation. Subjects reacted as rapidly as possible to the go signal with isometric plantar flexion contraction. In 20 s. force control task, subjects followed the target trace as accurately as possible with isometricly contracting their plantar flexors. Tracing error was calculated in 5 second intervals as difference between the target trace and the subject’s response trace and it was normalized to MVC. RESULTS: There were no differences (P > 0.05) between the groups in MVC (skill, 1250 ± 430 N; endurance, 1180 ± 270 N), RFD (skill, 6000 ± 2260 N/s; endurance, 5300 ± 2280 N/s), or reaction time (skill, 137 ± 22 ms; endurance, 141 ± 28 ms). But there was a significant difference (P < 0.05) in the 20 s tracing error at the force control task (skill, 6.2 ± 1.6 %; endurance, 7.7 ± 2.1 %). There was no difference between the groups in the tracing error during the first 5 seconds (skill group 13 % superior) but there was significant difference during the last 5 seconds (skill group 27 % superior). DISCUSSION: Skill group was better in the accuracy of the force control. In addition, there was no difference between the groups in the beginning but at the end of the force control task suggesting better learning. Possible reason for this could be the aforementioned different training induced adaptations in the motor cortex because increased plasticity is known to enhance motor learning. The findings of the current study suggest that skill training augments motor learning. REFERENCES Adkins DL, Boychuk J, Remple MS, Kleim JA. (2006). J Appl Physiol 101:1776-1782. Kumpulainen S, Avela J, Gruber M, Bergmann J, Voigt M, Linnamo V, Mrachacz-Kersting N. (2014). Eur. J. Appl. Physiol. 1-9.

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3D KINEMATIC AND DYNAMIC ANALYSIS OF DIAGONAL STRIDE IN ELITE BACKCOUNTRY SKIING (SKIALP) Renzo Pozzo1,3, Arrigo Canclini1, Antonio Canclini2, Guido Baroni2 1) FISI (I) – Ski Liceum Bormio; 2) Politecnico Milan (I); 3) Uni. Med. Udine (I) KEY WORDS: skialp, classical technique, 3d analysis, foot force

INTRODUCTION: In recent years the backcountry-skiing (SKIALP) has become more and popular and SKIALP skiers improved their technical and physiological performances. Due to the complex multiparametric environment conditions (air and snow temperature, track, techniques, gradients, boots, ski) and the relatively recent development of the discipline, there is a lack of specific studies especially under race conditions. On the other hand, technique and physiological analysis comparing normal race and treadmill conditions have been undertaken (Canclini 2007, Haselbacher 2014, Duc 2011, Tosi 2009). The purpose of this study is to investigate the kinematics and in part the dynamics patterns of elite SKIALP skiers under normal competition conditions. METHODS: Data collection was performed in 2014 during a test competition. Dedicated software for video analysis (DLT method) was used (Baroni 1998). A total of 15 skiers of the Italian Ski Team (10 male, 5 female) were analyzed on an uphill section race (30 m, ≈14%) where the athletes performed Diagonal Stride (DS). Additionally, force applied by the feet was recorded via Pedar pressure insoles operating at 50 Hz. Fig. 1: Parameters in diagonal stride at 14% in skialp

RESULTS: Figure 1 shows an example of stick diagram model, the typical pattern of the principal kinematic parameters and the force acting on the feet. Specific kinematics and dynamic parameters were calculated for each athlete and with respect to the left/right symmetry patterns (s. tab.) and were reported as the mean value averaged on 4 movement cycles. Angles-vs-angles plots were used to investigate individual coordination patterns. Terrain/ Technique – gear Subject R.A. CL (m) (cycle length) CT (s) (cycle time) % Time-Poling / CT CoG Vertical Displacement (m) Vave (m/s) Vmin / Vmax (m/s) - left Vmin / Vmax (m/s) - right Elbow Angle (°) at PP - left Elbow Angle (°) at PP- right Poles Angle (°) at PP Force (N) gliding / peak- lef Force (N) gliding / peak- right

Uphill 14% - DS N= 4 cycles 2,76 ± 0.17 1.01 ± 0.07 47% ± 1% 0.07 ± 0.02 2,72 ± 0,28 2,30 ± 0,22 /3,04± 0,23 2,34 ± 0.09 /3,21 ± 0,12 80,7 ± 8,1 67,2 ± 5,7 30 ± 6 377,6 ± 28,5 / 1176± 48,3 285,9 ± 44,5 / 1043± 43,9

DISCUSSION & CONCLUSION: Some of the considered parameters seem to correspond with those related to classical cross/country performance, e.g. CL, CT, Vave. However, the inter-subject variability in SKIALP is greater than in CC (Canclini 2007). This investigation represents a preliminary global biomechanical analysis of SKIALP during a competition, with a certain degree of approximation. The obtained results need to be reinforced by additional data to be collected about selected elite skiers.

REFERENCES Canclini,A (2007)-3D biomechanical analysis of the classical technique in ski touring. Proc. ICSS IV. Duc,S. (2011)- Physiology of ski mountaineering racing. Int J Sports Med. Haselbacher,M (2014)- Effect of ski mountaineering track on foot sole loading pattern. Wild. En. Med. Tosi,P (2009) - The energy cost of ski mount.: effects of speed and ankle loading. J S Med Phys Fit. rd


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EFFECT OF AEROBIC HIGH-INTENSITY INTERVAL TRAINING ON VO2MAX AND ANAEROBIC POWER IN CROSS COUNTRY SKIERS İmdat Yarim*, Ebru Çetin*, Bahar Ateş** *Gazi University School of Physical Education and Sports, Ankara, Türkiye ** Faculty of Sport Science, Uşak University, Uşak, Turkey KEY WORDS: Cross-country skiing, VO2max, anaerobic power, interval training

INTRODUCTION: As an endurance sport the cross-country skiing requires high VO2max, high oxidative enzyme activities and high anaerobic threshold [Millet et all, 2003]. A number of studies have investigated different factors and training methods relevant for cross-country skiing performance. To our knowledge, studies have investigated the effects of sport specific interval training on performance in cross-country skiers [Nilsson et all, 2004]. The aim of the study was evaluate the effect of high- intensity uphill interval training on some physiological parameters. METHOD: 10 male (age, 18,28±2,1 years; height, 171,26±4,12 cm; weight, 61,39±6,28 kg) and 8 female (age, 16,05±0.3 years; height, 158,3±6,47 cm; weight, 49,34±0.7 kg) junior cross country skiers participated Eight weeks training model has been done after the winter season during the preparation period. While basic trainings are loaded for preparation to winter at the same time with the purpose for preparation to roller skiing uphill races additional to all these trainings 3 days in a week. All-out roller ski exercise has been applied on the 2 km distance uphill track where the height difference is 144 mt. The training consists of 2x2 km and 10 min rest. Before and after the eight week training session VO2max and anaerobic performances of all athletes were tested. Pre and post tests values statistically are checked via “Wilcoxon Test (2 related samples)”. Also differences among the results of a pre and a post tests, analysed from the aspect of percentage changes. RESULTS: Averages and percentage differences have been presented on table 1. Table.1 Comparison Between Pre and Post Test in Female and Male Athletes MALE Pre-test

Parameters -1

VO2max (ml.kg.dk )

Post-Test

FEMALE p

%

Pre-test

Post-test

p

%

63,43±3,07

66,85±2,82 0,005*

5,39

54,92±3,07

57,84±2,99

0,012*

5,32

HRmax. (beats.min ) 185,9±13,24

181,4±12,7 0,005*

-2,42

187,75±9,5

184,75±8,7

0,011*

-1,6

Max Anaerobic -1 Power (Watt-kg )

10,12±0,77

11,16±0,67 0,005* 10,28

7,68±0,88

8,29±0,76

0,012*

7,94

Average Anaerobic -1 Power (Watt-kg )

7,39±0,58

7,73±0,45

4,6

5,84±0,78

6,02±0,73

0,726

3,08

2-km time trial (sn)

13,45±2,15

12,78±1,11 0,005*

-4,98

17,3±2,15

16,58±0,88

0,012*

-4,16

-1

0,037*

DISCUSSION & CONCLUSION: It has been determined that athlete have shown indications of development in VO2max, anaerobic power and capacity, and apart from these 2 km roller skiing performance, as a result of 8 weeks high intensity aerobic interval exercises. Our results indicate the only before and after training session in all subjects. Future research should include a control group for conclusive results. With reference to the training effects found in our study, we suggest that the skiers should integrate the roller ski aerobic high-intensity intervals uphill models in their training programs. REFERENCES Millet, G.P., Boissiere, D., and Candau, R. (2003). Energy cost of different skating techniques in crosscountry skiing. Journal of Sports Science, 21, 3-11. Nilsson, J. E., and Holmberg, HC. (2004). Effects of 20-s and 180-s double poling interval training in crosscountry skiers. European Journal of Applied Physiology, 92, 121-127.

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HIGH-INTENSITY COMBINED STRENGTH AND ENDURANCE TRAINING IN WOMEN: EFFECT OF HORMONAL CONTRACEPTIVE USE Ritva S. Taipale, Johanna K. Ihalainen, Moona Myllyaho, Jaakko Forssell, Jake P. Jones, Keijo Häkkinen and Heikki Kyröläinen Department of Biology of Physical Activity, University of Jyväskylä, Finland KEY WORDS: strength training, endurance training, hormones

INTRODUCTION: The use of hormonal contraceptives (HC) modifies the menstrual cycle, decreases basal levels of estrogen, and increases basal levels of sex-hormone binding globulin (SHBG). Serum concentrations of sex hormones are associated with trainability including muscle mass and strength (Häkkinen et al. 2000) while levels of SHBG affect androgen availability. We hypothesized that use of HC may negatively influence adaptations to combined strength (S) and endurance (E) training, particularly on development of strength and lean mass (LM). The purpose of this study was to examine the possible influence of HC on adaptations to 10 weeks of highintensity combined S and E training in women. METHODS: 19 women participated in the study, 10 using HC (UHC, age: 29±4 years, height 167±5cm, body mass: 59±5kg) and 9 not using HC (NHC, 31±6,168±5, 61±6). The women completed 10 weeks of high intensity combined S and E training consisting of 2 S and 2 E sessions/week. S included maximal and explosive exercises: back squat, leg press, step-ups, and a variety of bilateral and unilateral jumps. E consisted of 4x4minute intervals and 3x3x100m high intensity sprints. Pre and post training intervention, S of the lower extremities was assessed by maximal isometric leg press (MVC) and countermovement jump height (CMJ). A 3km time trial assessed E performance. Body composition was assessed by dual-energy X-ray absorptiometry (DXA) including LM and fat mass (FM). RESULTS: MVC and CMJ increased in both UHC and NHC (MVC by 15±15%, p