When is a ski jumper too skinny?

Lightweight formula solves difficult problem

Ski jumpers in the experiment © University of Graz
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Less is more - at least when it comes to body weight and jump in ski jumping. Because who is lighter, the flies on. But when is "little" actually "too little"? That could now determine a newly developed "Mass Index", which includes for the first time also the leg length of the athletes.

When does low weight become a competitive and pathological underweight and how can we counter these health problems in sport? Exactly this question was a team around Professor Wolfram Müller, Research Center Human Performance Research Graz of the Karl-Franzens- and Medical University of Graz, in the context of the project "underweight issue in competitive athletes" after. One of the results is now a significantly improved ability to assess underweight and overweight: The new measure of relative body weight is called mass index (MI) and is the body mass index (BMI), which does not take into account the body proportions and especially the individual leg length, supplement or replace in the future.

Long legs make you thin?

With his new method Müller offers a more accurate calculation of the relative body weight, as he explains: "Anyone who has long legs is rated too thin in the previous calculations, and conversely, people with extremely short legs are quickly labeled overweight, but both are Because the previous method of calculation only simplifies the size of humans, the mass index we calculated takes into account the proportion between the legs and the upper body. "

The results achieved in this project have already helped contain the underweight problem in ski jumpers. Because the investigations of the physical condition of the athletes in connection with aerodynamic measurements and calculations have convinced the international ski federation to change the ski jumping regulations from the season 2004/05: Extremely light athletes are now forced to jump with shorter skis. Since the implementation of these new competition rules, there are virtually no more underweight jumpers getting into this condition through starvation. This should count in the future, the performance of the athletes and not advantages by underweight.

Olympic field study

The diverse project results were only possible through extensive research, which was supported by the Olympic Committee in addition to the International Ski Federation. Prof. Karl Sudi, who developed the project together with Prof. Müller, commented: "We had a great opportunity to carry out a field study directly on the individual flying styles of the athletes during the 2002 Olympic Games in Salt Lake City The participation of almost all ski jumpers who started at the games allowed the basis for the regulation change to be made in ski jumping. " display

Particularly pleasing in this context is the fact that ultimately the athletes also benefited from the FWF project: In the course of measurements in wind tunnels, completely new forms of training were developed, which substantially contributed to the performance optimization of the ski jumpers and the Nordic Combined. Eight athletes who participated in these forms of training won gold at the Turin Olympics.

(University Graz, 20.02.2007 - NPO)