Before the 1980s, alpine (or downhill only) skiing had a reputation for being a relatively dangerous sport, with the most prevalent injuries being ankle and tibia/fibula fractures. Releasable ski bindings were developed to reduce the likelihood of lower leg injury. In order to work effectively
Jeffrey R. Campbell, Irving S. Scher, David Carpenter, Bruce L. Jahnke and Randal P. Ching
Øyvind Skattebo and Thomas Losnegard
Biathlon is a complex Winter Olympic sport that combines intensive cross-country skiing with high-precision rifle marksmanship. Depending on the competition format, an event consists of 3 to 5 skiing laps of 2 to 4 km interspersed by 2 to 4 shootings, each consisting of 5 shots. The combination of
Wolfhart Hauser and Peter Schaff
In a state-of-the-art paper on skiing performance and on skiing safety, aspects of ski boot design are discussed. The influence of ski boots on the skier-bootbinding-ski system is described, and suggestions are made about improving ski boots regarding better skiing performance, less inadvertent binding releases, and less lower extremity equipment related injuries. The design of the boot sole and the boot shaft with its influence on binding release values is particularly described. Furthermore, in the forward lean the shaft stiffness of modern ski boots and their pressure distribution is very important for good skiing performance and reduction of injuries of the ankle joint and the tibia. The built-in forward lean and the stiffness to the rear can be related to the acting forces in the anterior cruciate ligament, and first approximations to reduce the risk of these injuries are given.
Mikko Virmavirta, Juha Kivekäs and Paavo Komi
The effect of skis on the force–time characteristics of the simulated ski jumping takeoff was examined in a wind tunnel. Takeoff forces were recorded with a force plate installed under the tunnel floor. Signals from the front and rear parts of the force plate were collected separately to examine the anteroposterior balance of the jumpers during the takeoff. Two ski jumpers performed simulated takeoffs, first without skis in nonwind conditions and in various wind conditions. Thereafter, the same experiments were repeated with skis. The jumpers were able to perform very natural takeoff actions (similar to the actual takeoff) with skis in wind tunnel. According to the subjective feeling of the jumpers, the simulated ski jumping takeoff with skis was even easier to perform than the earlier trials without skis. Skis did not much influence the force levels produced during the takeoff but they still changed the force distribution under the feet. Contribution of the forces produced under the rear part of the feet was emphasized probably because the strong dorsiflexion is needed for lifting the skis to the proper flight position. The results presented in this experiment emphasize that research on ski jumping takeoff can be advanced by using wind tunnels.
Pierre Gervais and Craig Wronko
In the past few years there has been a change from emphasizing the classical cross-country ski technique to introducing the skating technique. Use of the skating stride has led to the adoption of roller skates instead of the ratchet-type roller skis for dryland training. Therefore the question arises as to whether the roller skates simulate the movement pattern observed on snow. This study attempted to answer this question and to evaluate the movement similarity between a newly designed skating-specific roller ski and snow skis in performing the skating stride. The marathon skate was chosen for analysis as it was the most established and consistent skating stride. Biomechanical cinematography was used to acquire a sagittal and anterior view of the skiers. Temporal and angular kinematic data were collected. Both dryland devices approximated the snow skiing pattern, yet it was found that due to the discrepancies in the propulsion phase between the roller skates and the snow skis, the “Nordic Skate” roller skis proved to more closely simulate the on-snow technique.
Valeria Rosso, Laura Gastaldi, Walter Rapp, Stefan Lindinger, Yves Vanlandewijck, Sami Äyrämö and Vesa Linnamo
Paralympic cross-country (XC) sit-skiing is a Paralympic discipline in which athletes are skiing seated because they have an impairment in function or structure of the lower extremities, pelvis, and/or trunk. XC sit-skiers ski using a sledge mounted on a pair of XC skis, named sit-ski, and a couple
Pål Haugnes, Jan Kocbach, Harri Luchsinger, Gertjan Ettema and Øyvind Sandbakk
Cross-country (XC) skiing is regarded as one of the most demanding endurance sports and involves whole-body exercise of varying techniques through racing times ranging from a few minutes to several hours. The competition terrain fluctuates between uphill, flat, and downhill sections, in which the
Thomas D. Raedeke and Gary L. Stein
This study examined the relationship between felt arousal, thoughts/feelings, and ski performance based on recent arousal and affect conceptualizations. An eclectic integration of these perspectives suggests that to understand the arousal-performance relationship, researchers need to examine not only a felt arousal continuum (i.e., intensity or level ranging from low to high), but also a concomitant thoughts and feelings continuum (i.e., ranging from positive to negative). Recreational slalom ski racers completed a self-report measure examining felt arousal and thoughts/feelings prior to several ski runs. Results demonstrated a significant relationship between felt arousal level, thoughts/feelings, and subjective ski performance ratings, but not for actual ski times. In contrast to the inverted-U hypothesis for subjective performance ratings, high felt arousal is not associated with poor performance ratings if it is accompanied by positive thoughts and feelings.
Paavo V. Komi
To understand cross-country (X-C) siding it is important to record and identity forces of skis and poles separately and together. They both contribute to the forward progression, but their functional significance may be more complex than that of the ground reaction forces in running and walking. This report presents two methods to record forces on skis and poles during normal X-C skiing. A long force-platform system with four rows of 6-m long plates is placed under the snow track for recording of Fz and Fy forces of each ski and pole separately. This system is suitable especially for the study of diagonal technique under more strict experimental conditions. The second system consists of small lightweight Fz and Fy component force plates which are installed under the boot and binding. These plates can be easily changed from one ski to another, and telemetric recording allows free skiing over long distances and with different skiing techniques, including skating. The presentation emphasizes the integrated use of either system together with simultaneous cinematographic and electromyographic recordings.
Dieter Heinrich, Martin Mössner, Peter Kaps and Werner Nachbauer
The deformation of skis and the contact pressure between skis and snow are crucial factors for carved turns in alpine skiing. The purpose of the current study was to develop and to evaluate an optimization method to determine the bending and torsional stiffness that lead to a given bending and torsional deflection of the ski. Euler-Bernoulli beam theory and classical torsion theory were applied to model the deformation of the ski. Bending and torsional stiffness were approximated as linear combinations of B-splines. To compute the unknown coefficients, a parameter optimization problem was formulated and successfully solved by multiple shooting and least squares data fitting. The proposed optimization method was evaluated based on ski stiffness data and ski deformation data taken from a recently published simulation study. The ski deformation data were used as input data to the optimization method. The optimization method was capable of successfully reproducing the shape of the original bending and torsional stiffness data of the ski with a root mean square error below 1 N m2. In conclusion, the proposed computational method offers the possibility to calculate ski stiffness properties with respect to a given ski deformation.