Cross-country skiing
A cross-country ski is a ski that is used in cross-country skiing .
construction
In contrast to an alpine ski, a cross-country ski is significantly narrower, often not or only slightly tailored, significantly lighter and usually longer. There are several reasons for this: Since a cross-country skier draws his kinetic energy primarily from his physical strength and not from the slope of the mountain, significantly lower forces act, which enable a lighter construction. In addition, the running technique requires that the ski is constantly accelerated and braked, which makes a low inertia and thus a low weight necessary. Since you run at a slower speed and mostly in prefabricated cross-country ski trails , you don't need to be particularly easy to turn, so the ski can be longer, does not need to be tailored and has no steel edges. To reduce friction, the track and thus the ski is kept narrow.
Cheap cross-country skis have foam inside, while expensive models have box or honeycomb structures made of wood or plastic, which are lighter with the same stability.
length
The earlier first Norwegian skis were 3.40 m in length. The running skis used since the 1990s are based on the height of the athlete (equal or larger) and must be of the same length. The best length is determined using a point table that takes into account the weight of the athlete and the target group (cross-country skiing, downhill skiing, jumping). Some details for cross-country skiing are compiled in the following table.
| parameter | Dimensions | comment |
|---|---|---|
| Length [cm] | 140-220 | Classic: youth skis 160–180, adults 180–220, free technique: youth skis 140–170, adults 170–190 |
| Blade width [mm] | 47 | |
| Center dimension (waist) [mm] | 43 | |
| Outsole | 1-3 guide grooves. See also ski base | |
| Mass [kg] | 0.75-0.9 | |
| material | PUR special resin or glass fiber laminate with PE covering , multi-layer; valid until 1999; then a mix of materials was allowed; Revolutionized in 1995 by the Carbon air (carbon fiber and glass fiber laminates coated with epoxy resins ) by the Thuringian company Germina : these skis are a third lighter than the previous ones, technically optimized in shape and have a beautiful design |
The skis have different hardnesses for the different techniques, so that the least amount of friction can always be achieved.
Tread
Classic style skis have a climbing zone under the binding; in front of and behind is a sliding zone. The ski is shaped in such a way that when gliding, ie when the cross-country skier is standing on the snow with both skis, the climbing zones do not touch the snow; If, however, the body weight is shifted onto a ski when pushing, its climbing zone reaches the snow and ensures that the ski cannot slide back. Skating skis , on the other hand, have a continuous gliding zone on the running surface, as they are pushed off laterally with the edges.
The sliding zone is treated with sliding wax to reduce friction (sliding friction). There are several methods of increasing static friction in the climbing zone: climbing wax, scales (in different designs, e.g. as micro-scales and with different grinds), fur strips or grip tape .
So that the climbing zone only touches the snow when the skis for the classic style are fully loaded, the ski must be adapted to the weight of the athlete. In addition, the skis must not be pressed together with a clip for a long time, because then the tension in the profile is lost - the climbing zone then touches down more often and impairs the gliding properties.
Shoes
The sole of the cross-country ski boot is differently stiff depending on the application. Skating shoes have very firm soles. Competition shoes for the classic technique, on the other hand, have very flexible soles so that you can keep more feeling for the impression. There are facilities for the binding mechanism on the sole. All other properties are variable; Cross-country ski boots usually reach to the ankle, are made of a flexible material (in contrast to alpine ski boots with a hard plastic shell ) and are tightened with shoelaces or a twist lacing mechanism. Buckles like those on alpine ski boots are unusual. Skating shoes also have a plastic reinforcement, which stabilizes the ankle during the lateral push-off movement.
binding
In principle, the boot is only attached to the ski with the tip via the ski binding and can be moved vertically so that the foot can sit completely on the ski and the heel can be lifted (when pushing off). Manufacturers also call this attachment a beak tie. Special self-releasing safety bindings are not used in cross-country skiing. There is a website on the Internet that shows the development of cross-country skis.
NN - Nordic Norm
Until the early 1980s, the Nordic Norm or Touring Norm binding was the most widely used binding for cross-country skis. A distinction is made between NN 75 and NN 50 bindings with a width of 75 or 50 mm. While this type of binding is still used by the majority of cross-country skiers in Scandinavia, it has been very limited in Germany since the 21st century. The binding consists of a trapezoidal metal plate with three metal pegs and side parts that are bent upwards. The pegs, together with a foldable bracket, fix the tab of the ski boot sole on the front of the boot. For inexperienced users, the somewhat more difficult operation is disadvantageous - in order to be able to close the binding, the shoe flap has to be positioned very neatly in the metal guide so that the bar can then be pressed down with the ski pole. In return, the binding is extremely robust and can do without the long guide rails required for the newer bindings. However, the binding is a little bit over the side of the cross-country ski. This is why the bindings and the shoe can brake sideways on the snow, especially on icy trails.
SNS profile and NNN
In the 1980s, many companies developed new binding systems, but most of them were incompatible. It was not until around 1990 that two systems, the “SNS Profil” (Salomon Nordic System) from Salomon and “NNN” (New Nordic Norm) from Rottefella , established themselves as the standard. Both of them have a metal axis under the toe of the shoe around which the shoe rotates in the binding. A kind of compression spring made of rubber puts the ski back under the foot. These two systems are not compatible with each other. The SNS binding has a wide middle bar, the NNN binding can be recognized by two narrow side bars. In contrast to old ski bindings, both new binding systems have a continuous rail from the tip to the heel, which stabilizes the boot against lateral forces when it is put on. This is necessary because the much narrower binding would otherwise be exposed to stronger lateral leverage.
SNS pilot
The SNS Pilot skating binding from Salomon, which has been available since 1999 , also has a second metal axle in the metatarsal area, with which the ski is returned under the foot by means of a steel tension spring. This binding offers better stabilization against lateral forces even when the foot is raised, but it is heavier, more susceptible to failure and not downwardly compatible with previous uniaxial shoes. However, the SNS Pilot shoes are downwardly compatible with SNS Profil bindings, as these bindings have a notch in the middle pitch instead of the second metal axis.
Sticks
The material of the sticks is not prescribed. According to the DWO, the maximum length of the sticks may not be longer than the body size for skating and, with classic technique, no longer than 83 percent of the body size of the athlete. The recommendation is that sticks for the classic technique go just below the shoulder; Sticks for free technique should reach to the chin. The main materials used are aluminum , carbon or fiberglass . Compared to the alpine ski poles , cross-country ski poles are significantly longer. But they are not provided with safety loops. Because of the lower transverse, but higher pressure load, the poles are thinner, lighter, but also significantly stiffer. The plates are smaller and asymmetrically shaped so that the tip of the back-facing sticks is on the bottom.
See also
- Roller ski - a cross-country ski with rollers
- Ski wax
Individual evidence
- ↑ drawings of historical ski bindings ; accessed on January 29, 2015.
- ↑ Explanation of the bindings on www.nordicskisource.com ( Memento of the original dated February 6, 2012 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. .
- ↑ DWO , p. 70, no. 343.8.1
- ↑ Material behavior of cross-country poles. Retrieved July 8, 2019 (German).
