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Int J Sports Med 2006; 27(11): 926-934
DOI: 10.1055/s-2006-923844
Nutrition

© Georg Thieme Verlag KG Stuttgart · New York

Underweight in Ski Jumping: The Solution of the Problem

W. Müller1 , W. Gröschl1 , R. Müller1 , K. Sudi2
  • 1Human Performance Research Graz and Department of Biophysics Karl-Franzens University and Medical University of Graz, Austria
  • 2Human Performance Research Graz and Institute for Sports Sciences Karl-Franzens University and Medical University of Graz, Austria
Further Information

Publication History

Accepted after revision: November 28, 2005

Publication Date:
30 May 2006 (online)

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Abstract

Underweight is becoming increasingly prevalent in many sports. Among world class ski jumpers, the body mass index BMI has decreased by 4 units since 1970. The BMI ignores different body properties of individuals. Particular care should be taken in groups with unusual leg length to avoid classifying them inappropriately as thin or overweight (WHO). The improved measure MI (mass index) for relative body weight overcomes this shortcoming. Anthropometric data of ski jumpers was collected during the Olympic Games in Salt Lake City (2002; participation 81 %, n = 57), during the Summer Grand Prix in Hinterzarten (2000; participation 100 %, n = 92), and during the World Cup in Planica (2000; n = 56). The BMI and the MI were determined. The MI considers the individual leg length: A person with longer legs than average has an MI > BMI, and vice versa: MI = 0.28 m/s2 (m: mass in kg, s: sitting height in meters). BMI classes of ski jumpers in the season 2004/2005 were calculated from their official individual ski length limitation which is a function of their BMI. BMI means were 19.84 in Planica, 19.58 in Hinterzarten, and 19.43 kgm-2 in SLC. Lowest BMI was 16.4 kgm-2. The percentage of underweight ski jumpers (BMI < 18.5 kgm-2) decreased from 22.8 % at the Olympic Games 2002 to 8.7 % in the season 2004/2005 due to the new ski jumping regulations. The ratio s/h = C (s = sitting height, h = height, C = cormic index) ranged from 0.49 to 0.57. Accordingly, the MI values (which are leg length corrected BMI values according to MI = BMI (C¯/C)k with k = 2 and C¯ = 0.53) deviated remarkably from BMI values. For the 49 cases with BMI or MI or both below 18.5 kgm-2, the classification to be underweight or not changed in 69 % when the MI was used instead of the BMI. Underweight or overweight is not only a question of cut-off points; the measure used determines the classification accuracy. A substantial improvement of weight analyses in sports medicine, public health, and general medicine as well can be obtained by using the MI instead of the BMI.

Key words

Anorexia athletica - underweight - body mass index - mass index - ski jumping

References

  • 1 Becker A E, Grinspoon S K, Klibanski A, Herzog D B. Current concepts: eating disorders.  New Engl J Med. 1999;  340 1092-1098
    CrossrefPubMedGoogle Scholar
  • 2 International Ski Federation .Book III, Ski Jumping. The International Ski Competition Rules, approved by the 44th International Ski Congress, Miami (USA),. 2004 § 413
    Google Scholar
  • 3 Müller W, Platzer D, Schmölzer B. Scientific approach to ski safety.  Nature. 1995;  375 455
    PubMedGoogle Scholar
  • 4 Müller W, Platzer D, Schmölzer B. Dynamics of human flight on skis: improvements on safety and fairness in ski jumping.  J Biomech. 1996;  29 1061-1068
    CrossrefPubMedGoogle Scholar
  • 5 Müller W, Schmölzer B. Computer simulated ski jumping: the tightrope walk to high performance. In: IV World Congress Biomechanics (WCB), Proceedings CD. University of Calgary, Canada, Faculty of Kinesiology. 2002
    Google Scholar
  • 6 Müller W. A scientific approach to address the problem of underweight athletes: a case study of ski jumping. Sixth IOC World Congress on Sport Sciences 2002.  Med Sci Sports Exerc. 2002;  34 124
    CrossrefPubMedGoogle Scholar
  • 7 Müller W. Body weight and performance in ski jumping: the low weight problem and a possible way to solve it. In: Proceedings of the Seventh IOC World Congress on Sport Sciences, 2003; 43D. Athens. 
    Google Scholar
  • 8 Norgan N G. Population differences in body composition in relation to the BMI.  Eur J Clin Nutr. 1994;  48 10-27
    PubMedGoogle Scholar
  • 9 Schmölzer B, Müller W. The importance of being light: aerodynamic forces and weight in ski jumping.  J Biomech. 2002;  35 1059-1069
    CrossrefPubMedGoogle Scholar
  • 10 Schmölzer B, Müller W. Individual flight styles in ski jumping: results obtained during Olympic Games competitions.  J Biomech. 2005;  38 1055-1065
    CrossrefPubMedGoogle Scholar
  • 11 Sudi K. Anorexia athletica.  Nutrition. 2004;  20 657-661
    CrossrefPubMedGoogle Scholar
  • 12 Sullivan P F. Mortality in anorexia nervosa.  Am J Psychiat. 1995;  152 1073-1074
    PubMedGoogle Scholar
  • 13 Sundgot-Borgen J. Eating disorders in female athletes.  Sports Med. 1994;  17 176-188
    PubMedGoogle Scholar
  • 14 Vaverka F. Somatic problems associated with the flight phase in ski-jumping.  Studia i monografia AWF we Wroclawiv. 1994;  40 123-128
    PubMedGoogle Scholar
  • 15 Vaverka F. Research reports, Olomouc personal communication. 1987 and 1995. 
    Google Scholar
  • 16 WHO Expert Consultation . Appropriate body-mass index for asian populations and its implications for policy and interventions strategies.  Lancet. 2004;  363 157-163
    CrossrefPubMedGoogle Scholar
  • 17 WHO Expert Consultation . Physical status, use and interpretation of anthropometry.  Technical Report Series. 1995;  No. 834 364
    PubMedGoogle Scholar
  • 18 WHO Expert Consultation . Physical status, use and interpretation of anthropometry.  Technical Report Series. 1995;  No. 834 355
    PubMedGoogle Scholar

Mag. Dr. Wolfram Müller Associate Prof.

Human Performance Research Graz Karl-Franzens University and Medical University of Graz

Max Mell Allee 11

8010 Graz

Austria

Phone: + 43 31 63 80 41 32

Fax: + 43 31 63 80 96 61

Email: wolfram.mueller@meduni-graz.at

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