Towards more valid simulations of slopestyle and big air jumps: Aerodynamics during in-run and flight phase

Wolfsperger, Fabian; Meyer, Frédéric; Gilgien, Matthias

doi:10.1016/j.jsams.2021.05.005

Cited by 6 publications

(5 citation statements)

References 32 publications

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“…These studies seek to inform jump construction and course design—and hence athlete safety—through the collection and use of new data. Wolfsperger et al documented the air drag and lift during the in-run and flight phase of ski and snowboard slopestyle and big air, across various disciplines, postures and apparel 29. They also combined, for the first time, kinematic athlete data and comprehensive snow-surface measurements to infer the coefficient of friction of freestyle skis and snowboards across a wide range of snow conditions, from very fast to very slow snow conditions 30.…”

Section: Discussionmentioning

confidence: 99%

“…Wolfsperger et al documented the air drag and lift during the in-run and flight phase of ski and snowboard slopestyle and big air, across various disciplines, postures and apparel. 29 They also combined, for the first time, kinematic athlete data and comprehensive snow-surface measurements to infer the coefficient of friction of freestyle skis and snowboards across a wide range of snow conditions, from very fast to very slow snow conditions. 30 Both the air drag and the ski/snowboard friction have direct influence on the athlete's take-off speed and therefore landing impact, and, hence, ultimately their injury risk.…”

Section: Implications For Research and Practicementioning

confidence: 99%

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Olympic Games during nationwide lockdown: sports injuries and illnesses, including COVID-19, at the Beijing 2022 Winter Olympics

Soligard,

Palmer,

Steffen

et al. 2023

Br J Sports Med

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ObjectiveThe objective of this study is to describe the incidence of injuries and illnesses sustained during the Beijing Winter Olympic Games from 4 February 2022 to 20 February 2022.MethodsWe recorded the daily number of athlete injuries and illnesses (1) through the reporting of all National Olympic Committee (NOC) medical teams and (2) in the polyclinic and medical venues by the Beijing 2022 medical staff.ResultsIn total, 2848 athletes (1276 women, 45%; 1572 men, 55%) from 91 NOCs were followed prospectively for the occurrence of injury and illness. NOC and Beijing 2022 medical staff reported 289 injuries and 109 illnesses, equalling 10.1 injuries and 3.8 illnesses per 100 athletes over the 17-day period. The injury incidence was highest in ski halfpipe (30%), ski big air (28%), snowboard slopestyle (23%) and ski slopestyle (22%), and lowest (1%–2%) in curling, alpine mixed team parallel slalom, Nordic combined and alpine super-G. The illness incidence was highest in ski aerials (10%), skeleton (8%), cross-country skiing (8%) and Nordic combined (7%). In the study period, COVID-19 affected 32 athletes, accounting for 29% of all illnesses affecting 1.1% of all athletes.ConclusionOverall, 10% of the athletes incurred an injury and 4% an illness during the Beijing Winter Olympic Games. The incidence of illnesses overall, which was the lowest yet recorded in the Winter Olympic Games, and COVID-19 was mitigated through comprehensive countermeasures.

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Section: Discussionmentioning

confidence: 99%

Section: Implications For Research and Practicementioning

confidence: 99%

Olympic Games during nationwide lockdown: sports injuries and illnesses, including COVID-19, at the Beijing 2022 Winter Olympics

Soligard,

Palmer,

Steffen

et al. 2023

Br J Sports Med

Self Cite

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“…Athletes wore the same, regular-fit personal ski or snowboard apparel for each test day (Figure 2). For the athletes taking part in this study aerodynamic drag areas were quantified in a wind tunnel experiment using the same posture and apparel as during the gliding tests (Wolfsperger et al, 2021). Athletes' kinematics, wind velocity, meteorological parameter, and snow parameters were captured as described below.…”

Section: Test Designmentioning

confidence: 99%

“…The relative airflow velocity (v rel ) resulted from the sum of wind and athlete velocity. Speed dependent drag and lift area (c D A, c L A) were determined by wind tunnel measurements for each athlete considering their personal apparel and posture characteristics (Wolfsperger et al, 2021). This allowed an accurate calculation of the aerodynamic force components of drag and lift throughout each run (Eq.…”

Section: Kinematicsmentioning

confidence: 99%

The Snow-Friction of Freestyle Skis and Snowboards Predicted From Snow Physical Quantities

Wolfsperger¹,

Meyer

Gilgien

2021

Front. Mech. Eng.

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Previous research has shown that friction between ski and snow can vary substantially due to changes in snow conditions. The variation of friction affects the speed a freestyle skier or snowboarder (athlete) reaches during the in-run of a jump. Athletes risk severe injuries if their take-off speed is not within the right margin to land in the “sweet spot” zone. To reduce the risk of injury, snow park designers and competition managers need to calculate the speed athletes reach during the in-run. However, despite multiple attempts over the last decades, to date no model can predict ski-snow friction from snow physical quantities. Hence, simulations of in-run speeds suffer from insufficient validity. For the first time, this work combines kinematic athlete data and comprehensive snow surface measurements to infer the coefficient of friction of freestyle skis and snowboards across a wide range of snow conditions. Athletes’ point mass kinematics were recorded at more than 200 straight gliding runs with differential global navigation satellite systems. The subjects’ air drag and lift were deployed from wind tunnel measurements. Along with the kinematic data and data from wind measurements, a mechanical model of the athlete was established to solve the equation of motion for the coefficient of friction between ski/snowboard and snow. The friction coefficients for ski (snowboard) ranged from 0.023 ± 0.006 (0.026 ± 0.008) to 0.139 ± 0.018 (0.143 ± 0.017) and could be explained well (Radj2 = 0.77) from the measured snow parameters using a multivariate statistical model. Our results provide a new quantitative tool for practitioners to predict the friction of skis and snowboard on snow of various conditions, which aims to increase athletes’ safety in slopestyle and big air.

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“…In order to evaluate the influence of the field wind environment on cross-country skiing athletes' performance, the first step is to obtain the wind-induced aerodynamic drag of the athletes in the ski field wind environment. In recent years, many researchers have carried out research work on the acquisition of athletes' wind-induced aerodynamic drag through numerical calculation methods based on computational fluid dynamics (CFD) and wind tunnel experiments [6][7][8][9]. Chen [10] used steady and unsteady models to simulate 2D athlete models, and the results indicated that wind and posture affect the aerodynamic performance of a skier during the flight stage.…”

Section: Introductionmentioning

confidence: 99%

A Method for Evaluating the Influence of the Field Wind Environment on Cross-Country Skiing Performance

Zhu

et al. 2022

Applied Sciences

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Aerodynamic drag plays an important role in high-speed skiing. The wind-induced thrust or resistance of athletes, the sliding speed, and the work to overcome the aerodynamic drag are greatly affected by wind; therefore, reducing wind-induced drag is a focus of sport science. This paper proposes a method for evaluating the influence of wind on cross-country skiing performance, which is based on the athlete’s aerodynamic-drag-work relative to the environmental wind field and the establishment of a racetrack wind field model. Aiming at an athlete’s typical sport posture in the Yabuli Ski Field, the impact of field wind on the skier’s speed, the work done by the athlete to overcome aerodynamic drag, and the ratio of the field wind-induced work to the athlete’s total work are analyzed. Through the analysis of the athlete’s work to overcome aerodynamic drag and the wind resistance energy dissipation ratio in three training cases, it is shown that the field wind has a great influence on the athlete’s performance during sliding, which verified the effectiveness of the method. This method will provide coaches and sport researchers with accurate wind resistance energy dissipation data and provide a scientific basis for routine athletic training.

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Towards more valid simulations of slopestyle and big air jumps: Aerodynamics during in-run and flight phase

Cited by 6 publications

References 32 publications

Olympic Games during nationwide lockdown: sports injuries and illnesses, including COVID-19, at the Beijing 2022 Winter Olympics

Olympic Games during nationwide lockdown: sports injuries and illnesses, including COVID-19, at the Beijing 2022 Winter Olympics

The Snow-Friction of Freestyle Skis and Snowboards Predicted From Snow Physical Quantities

A Method for Evaluating the Influence of the Field Wind Environment on Cross-Country Skiing Performance

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