The physics of ski jumping

The Olympian ideal of going faster, jumping further and leaping higher than the opposition is central to competitive sports. Winning or losing in sport is related to a number of factors, and biomechanics, anthropometrics, and aerodynamics play a major role in many sports. This lecture focuses on ski jumping. Performance in ski jumping is determined not only by the motor abilities of the athlete, but also to a large extent by the aerodynamic features of the equipment used and by a low body weight. Many ski jumpers were extremely underweight to the point of having a body mass index (BMI = m/h2 of 16.4 kgm−2 (height h = 1.73m, body massm = 49 kg). Severe eating disorders (e.g., anorexia nervosa, bulimia; [1]) were health problems of major concern in this sport. Strategies for improving the health, fairness, and safety of the athletes by modifying the regulations have been developed by the lecturer and his research team in close co-operation with the International Ski Federation (FIS), the International Olympic Committee (IOC), and the Austrian Research Funds (FWF). Based on our scientific studies the FIS has passed changes to the ski jumping regulations which relate relative body weight (in terms of BMI) to the maximum ski length permitted. Shorter skis (i.e., ‘smaller wings’) compensate for the advantage of very low weight and thus it is not attractive for the athletes to be underweight any more [2]. Our analyses of contemporary ski jumping employ field studies during World Cup and Olympic Games competitions, wind tunnel measurements, computational fluid dynamic (CFD) modelling of aerodynamic forces and torques, computer simulations of the flight trajectory, and computer-modelling-based design of jumping hills [3–7].