Abstract
Ski jumping puts high demands on the athlete’s ability to control posture and movement. The athlete has to solve extremely difficult optimization problems. These implicit decisions and the resulting control manoeuvres can be understood by means of computer simulations. Computer simulations based on wind tunnel input data can identify the determinants for high performance and answer many questions of training methods, safety and health, role of weight, fairness, optimized hill design, sport development, and changes to the regulations.
Each of the performance determinants has to be seen in the context of all others in order to understand its importance; the predominant factors are: high in-run velocity, high momentum perpendicular to the ramp at take-off due to the jump and the lift force, accurate timing of the take-off with respect to the ramp edge, appropriate angular momentum at take-off in order to obtain an aerodynamically advantageous and stable flight position as soon as possible, choice of advantageous body and equipment configurations during the entire flight in order to obtain optimum lift and drag values, and the ability to control the flight stability.
Wind blowing up the hill increases the jump length dramatically and decreases the landing velocity, which eases the landing, and vice versa for wind from behind. Improvements to reduce unfairness due to changing wind are urgently needed. The current practice of the judges to reduce the score when the athlete has to perform body movements in order to counteract dangerous gusts is irrational. The athletes should rather be rewarded and not punished for their ability to handle such dangerous situations.
For the quantification of underweight it is suggested to use the mass index: MI = 0.28m/s2 (where m is the jumper mass and s is the sitting height), which indirectly considers the individual leg length. The MI formula is similar to the body mass index (BMI) formula: the height is replaced by the sitting height s and a factor of 0.28 effects that the MI is equal to the BMI for persons with average leg length. The classification of underweight is not only a question of the cut-off point, as much it is a question of the measure for relative bodyweight used.
Low weight is one of the performance determinants; however, it should be considered that very low weight can cause severe performance setbacks due to decreased jumping force, general weakness, reduced ability to cope with pressure, and increased susceptibility for diseases. In the past, several cases of anorexia nervosa among ski jumpers had come to light. The development toward extremely low weight was stopped in 2004 by new Fédération Internationale de Ski ski-jumping regulations, which relate relative body mass to maximum ski length. The 2006/7 and 2008/9 seasons showed that light athletes who had to use skis with just 142% of their height could still win competitions. A further increase of the borderline weight is being discussed. The current regulations are based on the well known BMI; the use of the MI instead of the BMI should be explored in future studies.
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References
Straumann R. Vom Skiweitsprung und seiner Mechanik. In: Jahrbuch des Schweizerischen Ski Verbandes. Bern:Selbstverlag des SSV, 1927: 34–64
Gasser HH. Grundlagen für die Projektierung einer Schisprungschanze [online]. FIS. Available from URL: http://www.fis-ski.com/ [Accessed 2008 Apr 17]
Müller W. Biomechanics of ski-jumping: scientific jumping hill design. In: Müller E, editor. Science and skiing. London: E&FN Spon (Chapman & Hall), 1997: 36–48
Müller W, Schmölzer B. The new jumping hill in Innsbruck: designed by means of flight path simulations. Proceedings of the IVth World Congress of Biomechanics. Calgary(AB): University of Calgary. Faculty of Kinesiology, 2002 Aug 4–9
Gilbertson WK. Ski jump profile optimization: incorporating blunt body ground effect [dissertation]. Boulder (CO): University of Colorado, 2003
Blumenbach T. GPS-Anwendungen in der Sportwissenschaft: Entwicklung eines Messverfahrens für das Skispringen [dissertation at the Bayerische Akademieder Wissenschaften; Reihe C 591]. München: C. H. Beck Verlag, 2005
Müller W, Gröschl W, Müller R, et al. Underweight in ski jumping: the solution of the Problem. Int J Sports Med 2006; 27: 926–34
Schwameder H, Müller E. Biomechanische Beschreibung und Analyse der V-Technik im Skispringen. Spectrum 1995; 1: 5–36
Müller W, Platzer D, Schmölzer B. Dynamics of human flight on skis: improvements on safety and fairness in skijumping. J Biomech 1996; 29 (8): 1061–8
Starosta W. The cause of fluctuations of performance in ski jumping. Leistungssport 2004; 34 (2): 15–9
Müller W, DeVaney TTJ. The influence of body weight on ski jumping performance. In: Haake E, editor. The engineering of sport. Rotterdam: Balkema, 1996: 63–9
Vaverka F. Somatic problems associated with the flight phase in ski-jumping. Studia i monografia AWF weWroclawiv 1994; 40: 123–8
Vaverka F. Research reports. Olomouc: University of Olomouc, 1987 and 1995
Becker AE, Grinspoon SK, Klibanski A, et al. Current concepts: eating disorders. N Engl J Med 1999; 340: 1092–8
Sudi K, Öttl K, Payerl D, et al. Anorexia athletica. Nutrition 2004; 20: 657–61
Sullivan PF. Mortality in anorexia nervosa. Am J Psychiatry 1995; 152: 1073–4
Sundgot-Borgen J. Eating disorders in female athletes. Sports Med 1994; 17: 176–88
WHO Expert Committee. Physical status, use and interpretation of anthropometry. Technical Report Series 1995; 854: 364
Müller W, Platzer D, Schmölzer B. Scientific approach to ski safety. Nature 1995; 375: 455
Müller W, Gröschl W, Schmölzer B, et al. Body weight and performance in ski jumping: the low weightproblem and a possible way to solve it. In: 7th IOCOlympic World Congress on Sport Science; 2003 Oct 7-10; Athens, 43 D
WHO Expert Committee. Physical status, use and interpretation of anthropometry. Technical Report Series 1995; 854: 355
Müller W, Schmölzer B. Computer simulated ski jumping: the tightrope walk to high performance. Proceedings CD. IV World Congress of Biomechanics. Calgary (AB): University of Calgary. Faculty of Kinesiology, 2002 Aug 2–4
Ettema GJC, Braten St, Bobbert MF. Dynamics of the inrun in ski-jumping: a simulation study. J Appl Biomech 2005; 21: 247–59
Virmavirta M, Kiveskäs J, Komi PV. Take-off aerodynamics in ski jumping. J Biomech 2001; 34 (4): 465–70
Virmavirta M, Komi PV. Measurement of take-off forces in ski-jumping:. part I and II. Scand J Med Sci Sports 1993; 3: 229–43
Kaps P, Schwameder H, Engstler C. Inverse dynamic analysis of take-off in ski-jumping: In: Müller E, Schwameder H, Kornexl E, et al., editors. Science and skiing. London: E&FN Spon (Chapman & Hall), 1997; 6: 72–87
Denoth J, Luethi SM, Gasser H. Methodological problems in optimisation of the flight phase in ski jumping. Int J Sport Biomech 1987; 3: 404–18
Vaverka F, Janura M, Elfmark M, et al. Inter- and intraindividual variability of the ski-jumper’s take-off. In: Müller E, Schwameder H, Kornexl E, et al., editors. Science and skiing. Austria: E&FN Spon (Chapman & Hall), 1996: 61–71
Arndt A, Brüggemann GP, Virmavirta M, et al. Techniques used by Olympic ski jumpers in the transition from take-offto early flight. J Appl Biomech 1995; 11: 224–37
Virmavirta M, Komi PV. Plantar pressure and EMG activity of simulated and actual ski jumping take-off. Scand J Med Sci Sports 2001; 11: 310–4
Virmavirta M, Perttunen J, Komi PV. EMG activities and plantar pressure during ski jumping take-off on three differentsized hills. J Electromyogr Kinesiol 2001; 11: 141–7
Müller E, Benko U, Raschner C, et al. Specific fitness training and testing in competitive sports. Med Sci Sport Exerc 2000; 32 (1): 216–20
Müller W. Performance factors in ski jumping. In: Nörstrud H, editor. Aerodynamics of sports. Centro Internazionaledi Scienze Meccaniche (Udine), CISM Series, vol. 506. Wien, New York: Springer, 2008: 139–60
Hoff J, Berdahl O, Braten S. Jumping height development and body weight considerations. In: Müller E, Schwameder H, Kornexl E, et al., editors. Science and skiing II. Hamburg: Dr. Kovac Verlag, 2001: 403–12
Bruhn S, Schwirtz A, Gollhofer A. Diagnose von Kraft- und Sprungkraftparametern zur Trainingssteuerung im Skisprung. Leistungssport 2002; 5: 34–7
Cronin J, Sleivert G. Challenges in understanding the influence of maximal power training on improving athletic performance. Sports Med 2005; 35 (3): 213–34
Müller W, Hofmann P. Performance factors in bicycling: human power, drag, and rolling resistance. In: Nörstrud H, editor. Aerodynamics of sports. Centro Internationale diScienze Meccaniche (Udine), CISM Series, vol. 506. Wien, New York: Springer, 2008: 49–91
Koenig H. Theorie des Skispringens angewandt auf die Flugschanze in Oberstdorf. In: Uhrentechnische Forschung. Stuttgart: Steinkopf Verlag, 1952: 235–53
Remizov LP. Biomechanics of optimal flight in ski-jumping. J Biomech 1984; 17: 167–71
Hubbard M, Hibbard RL, Yeadon MR, et al. A multi-segment dynamic model of ski-jumping. Int J Sport Biomech 1989; 5: 258–74
Seo K, Murakami M, Yoshida K. Optimal flight technique for V-style ski jumping. Sports Engineer 2004; 7 (2): 97–103
Seo K, Watanabe I, Murakami M. Aerodynamic force data for a V-style jumping flight. Sports Engineer 2004; 7 (1): 31–9
Schmölzer B, Müller W. The importance of being light: aerodynamic forces and weight in ski jumping. J Biomech 2002; 35: 1059–69
Schmölzer B, Müller W. Individual flight styles in ski jumping: results obtained during Olympic Games competitions. J Biomech 2005; 38: 1055–65
Reisenberger E, Meile W, Brenn G, et al. Aerodynamic behaviour of prismatic bodies with sharp and rounded edges. Exp Fluids 2004; 37: 547–58
Flachsbart O. Messungen an ebenen und gewölbten Platten. In: Ergebnisse der Aerodynamischen Versuchsanstalt zu Göttingen 4, 1932; 96–100
Meile W, Reisenberger E, Mayer M, et al. Aerodynamics of ski jumping: experiments and CFD simulations. Exper Fluids 2006; 41: 949–64
Yeadon MR. A method for obtaining three-dimensional data on ski jumping using pan and tilt cameras. Int J Sport Biomech 1989; 5 (2): 238–47
Müller W. Computer simulation of ski jumping based on wind tunnel data. In: Nörstrud H, editor. Aerodynamics of sports. Centro Internationale di Scienze Meccaniche (Udine), CISM Series, vol. 506. Wien, New York: Springer, 2008: 161–82
Ranta MA, von Hertzen R. Landing in ski-jumping, an expert report for the FIS Technical Board. Oberhofen, Schweiz: FIS, 1999 Apr 23
Hochmuth G. Telemark landing. FIS Bull 1999; 137 (2): 29–43
Virmavirta M, Isolehto J, Komi P, et al. Characteristics of the early flight phase in the Olympic ski jumping competition. J Biomech 2005; 38: 2157–63
Schmölzer B, Müller W. The influence of lift and drag on the jump length in ski jumping. In: Book of abstracts. First International Congress on Skiing and Science, 1996 Jan 7-13. St. Christoph a. Arlberg: E. Müller. p. 274.
Müller W. Physics of ski jumping: the lift and drag forces in the early flight phase have a pronounced impact onthe performance. Canadian Society for Biomechanics. Proceedings of the Ninth Biennial Conference, Simon Fraser University; 1996 Aug 21–24; Vancouver (BC), 246–7
Norgan NG. Population differences in body composition in relation to the BMI. Eur Clin Nutr 1994; 48: 10–27
Jelmini S. Modelling of distance in ski jumping using statistical models with random parameters [dissertation]. Lausanne: Swiss Institute of Technology, 2000
WHO Expert Consultation. Appropriate body-mass index for Asian populations and its implications for policy andinterventions strategies. Lancet 2004; 363: 157-6
Meile W, Müller W. Ski-jumping aerodynamics: modelexperiments and CFD-simulations. In: Nörstrud H, editor. Aerodynamics of sports. Centro Internationale di ScienzeMeccaniche (Udine), CISM Series, vol. 506. Wien, New York: Springer, 2008: 183–216
Acknowledgements
The author would like to thank all athletes and coaches for participating in the preceding projects, and the IOC, the FIS and the Austrian Research Funds FWF (15130 Med., 14388 Tec) for their support. The author also wishes to thank H. Ahammer and B. Schmölzer for their comments and A. Fürhapter-Rieger, G. Tschakert and T. Zarfl, who have contributed to the preparation of this manuscript. No funding was received for the preparation of this article, and the authors have no potential conflicts of interest that are directly relevant to the content of this article.
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Müller, W. Determinants of Ski-Jump Performance and Implications for Health, Safety and Fairness. Sports Med 39, 85–106 (2009). https://doi.org/10.2165/00007256-200939020-00001
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DOI: https://doi.org/10.2165/00007256-200939020-00001