Ski
From Wikipedia, the free encyclopedia
- This article is about the sporting device; for the related activity see Skiing. For other uses, see Ski (disambiguation)
A ski is a long flat device worn on the feet designed to help the wearer slide smoothly over snow. Originally intended as an aid to travel in snowy regions, they are now primarily used for recreational and sporting purposes. Also, a ski may denote a similar device used for other purposes than skiing, e.g., for steering snowmobiles.
Snow skis glide on snow because downward pressure, as well as heat from surface friction, melts the snow directly under the ski. This creates a very thin layer of water directly under the ski upon which the ski glides. This is why if there is freezing rain that freezes to the bottom of the ski perhaps when carrying the ski, the ski, when set down on the snow, won't glide until the ice wears off or is knocked off. Ski wax is used to decrease drag by increasing the water repellent properties of the base.
It was not until the early eighteenth century that skiing was transformed from a mode of transportation to a recreational sport. The people of Norway developed a new method of turning, known as “Christie,” which enabled skiers to go faster and jump, which was the first significant change in ski design. The next advancement of skiing as a sport came a century later when these Nordic people developed two categories of ski race, cross-county and jumping. One of the final, and most influential, advancement of skiing came when the sport spread from Scandinavia, and Northern Europe, to the rest of Europe in the early twentieth century. The next revolution in the sport would have to wait only a few more winters.
The very first winter Olympics, the nineteen twenty four Chamonix, France Winter Games, had only five events and two of them were skiing events. The two events, in this Olympics were the very same events that the Norwegians had developed two hundred year prior, ski jumping and Nordic racing. The sport grew again, at the nineteen thirty two winter Olympics in Lake Placid, when cross-country skiing was added to the list of Olympic sports. The original Nordic ski technology was improved during the early twentieth century in order so that skiers could make turns at higher speeds. New ski and binding deigns, coupled with the introduction of ski lifts to carry skiers high up on mountains, enabled the development of today’s most prominent category of the sport, alpine skiing. At the 1936 Olympics in Innsbruck, Austria Alpine skiing was officially accepted as a winter sport. From this point on, skiing has continued to reform itself. Within the sport, these four categories still exist, but they also contain subcategories. Alpine skiing, for example, now contains Giant Slalom, Downhill, and Super G as separate events within the category of Alpine skiing.
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[edit] Construction
Skis were originally wooden planks made from a single piece of wood. They are now usually made from a complex assembly of components including glass fiber, Kevlar, Titanium or composite materials, though many may still contain wooden cores.
Most skis are long and thin, pointed and curved upwards at the front to prevent the ski from digging into the snow. The user is attached by bindings which in turn hold the ski boots. Beginning in the early 2000's, many ski manufacturers began designing their skis and bindings together, creating an 'integrated binding system.' These systems serve two purposes. First, they often use a railroad track style design, to allow the toe and heel pieces to slide, which in turn allows the ski to flex deeply, without a flat-spot underfoot, caused by the presence of a binding. Second, it forces the consumer to purchase both skis and bindings from the same manufacturer, increasing profits.
[edit] Types of ski
Many types of skis exist, all designed for different situations, of which the following are a selection.
[edit] Downhill ski
Up until not too long ago, downhill skis were of very simple construction. They began as planks of wood. Later on metal edges were added to better grip the snow and ice of a ski trail. Through the 1970s and 1980s, with many composite synthetic materials becoming available, skis got stronger, lighter, and more supple (which enabled better turning). In the mid-1990s, manufacturers began producing "shaped" skis (when viewed from above or below, the center or "waist" is narrower than the tip or tail) for use by the mass market and by slalom competitors. Shaped skis are less efficient at straight travel (because they compress a wider track in the snow, compared to similar-length straight skis), but they are easier to turn. Direct downhill racers still use straight skis for speed.
By setting the ski at an angle so that the edge cuts into the snow, the ski will follow the arc and hence turn the skier, a practice known as carving a turn. Straight skis can be used to carve turns, using the flexibility of the ski to produce an arc, but it is easier with shaped skis. Influenced by snowboarding, during the 1990s this shaping of the ski became significantly more pronounced to make it both easier for skiers to carve turns, and to dramatically increase the turning sensation experienced. Such skis were once termed carving skis, or shaped skis or parabolic skis to differentiate them from the more traditional straighter skis, but nearly all modern recreational skis are produced with the curve.
- See also:
- For other turning techniques, see Skiing.
- A history of the modern shaped ski: http://skiinghistory.org/sidecut.html
The ski binding anchors the foot firmly to the ski at heel and toe. As a safety feature, it is spring-loaded, detaching the ski from the foot in case excessive force is applied. Modern bindings utilize a DIN spring system to minimize the amount of force applied to joints such as the knee during backward twisting falls. The ski is turned by applying a mixture of pressure, rotation and edge angle.
[edit] Twin-tip ski
Twin-tip skis, also known as "freestyle skis", are skis with turned-up ends at both the front and rear. Twin-tip skis make it easier to ski with one's back facing downhill, allowing reversed take-offs and landings when performing aerial maneuvers. The turned-up tail allows less application of aft pressure on the ski, causing it to release from a turn earlier than a non-twin-tip ski. Twin-tip skis are generally wider at the tip, tail, and underfoot and constructed of softer materials to cushion landings. Bindings are typically mounted closer to the center of the ski to facilitate the balance of fore and aft pressure, while skiing backwards or "switch", bindings are built lower to the ski for easy rail sliding. The popularity explosion of twin-tip skis created a push for the inclusion of more terrain park elements at ski areas across the globe. In the past five years twin tips have become popular among youth skiers, ages 14-21. Once considered a passing fad, twin-tip skis have become a staple ski in the product line of all major ski-producing companies worldwide, with a few specializing in only twin tips. Line Skis, started by Jason Levinthal, is the first company to market only twin-tip skis. The first twin-tip ski was the Olin Mark IV Comp introduced in 1974. The first company to successfully market a twin-tip ski was Salomon, with their 1080 ski.
[edit] Alpine touring ski
Alpine touring ski. This type of ski is usually a modified light-weight downhill ski with an alpine touring binding. Like the backcountry ski it is designed for unbroken snow. For climbing of steep slopes, skins (originally made from the fur of seals, but now made of synthetic materials) can be attached at the base of the ski and the binding opened at the heel. For skiing downhill the bindings are locked. The ski is used with alpine touring boots which are hard but lighter than downhill skiing boots.
[edit] Monoski
The monoski is a single, double-width ski that attaches by a common DIN binding interface to modern front entry boots. More common in use during a brief boom in the 80s, today the monoski is used by only a few thousand enthusiasts world-wide. The monoski is produced by only half a dozen companies world-wide in limited quantities. Due to its extra width and flotation in deep snow, enthusiasts claim it superior as a powder ski.
[edit] Telemark ski
Telemark ski. A downhill or touring ski, where the binding attaches only at the toe. The Telemark ski was the first ski with an inwards-turned waist which made it much easier for skiers to turn. It was pioneered by Sondre Norheim of Telemark, Norway. The fact that the foot is only attached to the ski at the toes, means that specialized more flexible ski boots are used, and a specific turning technique involving pushing one foot forward and lifting the heel of the other foot is used.
[edit] Cross-country ski
Cross-country skis are very light and narrow, and usually have quite straight edges, though some newer skis have slight sidecut. The boots attach to the bindings at the toes only. There are three binding systems currently used, Rottefella's NNN and Salomon's SNS profil and SNS pilot. The ski bases are waxed to reduce friction during forward motion, and kick wax can also be applied to get adhesion when going uphill. Some waxless models may have patterns on the bottom to increase the friction when the ski slides backward. There are two major techniques, classical (traditional striding) and freestyle or skating which was developed in the 1980s. Skating skis are shorter than classical skis and do not need grip wax. Skating is also the technique used in biathlons.
[edit] Backcountry ski
Skis for mountain/backcountry/cross-country free range skiing which are designed for skiing on unbroken snow, where an established track is lacking. These are characteristically quite wide, and with cable bindings to provide general sturdiness, and to better extract ones feet from deep snowbanks, in case it should be impossible to reach the bindings by hand. This is also the model used by military forces trained to fight in winter conditions, and the most closely related to the historical ski. The widest backcountry skis are often called 'Big Mountain' skis.
[edit] Mogul ski
These skis are specifically designed for Moguls. They are typically softer, less wide and less waisted compared to a common carving ski.
[edit] Ski jumping ski
Skis for ski jumping. Long and wide skis, with bindings attaching at the toe.
[edit] Skiboards and Bigfoots
Skiboards are built like tiny snowboards, typically 90-130cm in length, marketed originally as a more convenient method of skiing, but now for those who want extreme freestyle on the slope. True skiboard bindings are mounted in the center, are non-releasable, and require an ankle leash due to the absence of a braking system. Before this time period the Austrian ski company Kneissl produced a short, foot shaped ski called the Bigfoot. The Bigfoot was popular during the late 80s and early 90s. The Line ski company has manufactured skiboards since the mid 1990s and is credited with the creation of the first modern skiboard. Skiboards, when at going at high speed and on the flat bottom of the skiboard, tend to vibrate, and thus some people prefer to skiboard on the edge of the skiboard in order to decrease the vibration and have more control of the skiboard. Others, especially veterans, find the vibration to be a non issue. As with skis, the edges can still be used to decrease contact with the snow (and thus increase speed).
Due to their much shorter size, skiboards can be easier to learn on, and much more agile, than conventional skis. Compared with traditional skis, they can make blue trails as easy as green; make moguls a non-issue; facilitate uphill climbing; aid tricks (by being easier to turn in the air); and be carried and stored more easily.
[edit] See also
- Skiing and skiing topics – further details of skis related to particular variations of ski sport
- History of skiing – the ancient history of skis
- Roller skiing skis on wheels to enable skiing when snow is not available
- Snowboarding a newer way to ride on snow, on one large board rather than two skis
- Skiboarding very short, twintip skis
