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Aperçu du corrigé : Skiing.

Publié le : 14/5/2013 -Format: Document en format HTML protégé




Skiing, winter sport in which people move across snow-covered terrain with long, narrow, specially designed boards called skis attached to their feet. Although people
have been skiing for about 5,000 years, the sport did not become a popular form of recreation until the 20th century. Millions of people worldwide enjoy skiing for its
exhilaration, sense of freedom, physical challenges, and fitness benefits.



There are two basic types of recreational skiing: Alpine, or downhill, and Nordic, or cross-country. The goal in recreational skiing is to ski competently on a variety of
terrain and under various conditions. Competitive skiers go one step further, pitting their skill against the clock or against the skill of others. Skiing carried to its
limits--on extremely difficult slopes or under extremely dangerous conditions--is known as extreme skiing.


Alpine Skiing

Alpine skiing derives its name from the mountain range the Alps in Europe, where the sport developed in the late 1800s as a means of moving down snow-covered
slopes. Skiing spread to other parts of the world and is now done primarily at ski resorts on specially cut trails. A variety of lifts carry skiers up the hill. The most
common lift in North America is the chairlift, which is a series of seats suspended from a motor-driven cable that pulls the seats up the mountain. Various surface lifts,
which pull skiers up the hill while they remain standing on skis, include rope tows, T-bars, J-bars, and poma lifts (also known as platter pulls). Many larger areas have
enclosed aerial lifts, such as gondolas or trams, which allow skiers to take off their skis and ride up the mountain inside specially designed cars suspended from cables.
In Europe, cog railways and funiculars (cable railways) are also used to carry skiers up a slope.
Almost all ski resorts have equipment to make snow artificially when there is not enough natural snow to support the sport. Snowmaking equipment combines air and
water with special additives and then sprays the mixture at very high pressure onto the slopes. Grooming machines smooth out the slopes and ensure that the snow
has a uniform consistency.


Nordic Skiing

Nordic skiing, also known as cross-country skiing, can be done on almost any terrain that has snow and is not too steep. Nordic skiing is often done at cross-country ski
centers, which have many kilometers of mostly flat trails prepared for skiers. Most have trails prepared for both the traditional diagonal stride and for the newer skating
technique (see Skiing Fundamentals section of this article). Traditional trail preparation involves flattening out two tracks in which skiers can slide their skis. Skating
trails are wider and smoothed out.
Telemark skiing is the downhill component of cross-country skiing, which incorporates some Alpine techniques. It is becoming increasingly popular among recreational
skiers. A few ski areas have small ski jumps for learning basic jumping skills, but ski jumping is limited almost entirely to competition.



The easiest and safest way to learn to ski is by taking lessons. Virtually every ski resort offers instruction. The American Teaching System, a synthesis of the best
techniques from several countries, is recognized worldwide as the leading teaching method and is the basis for all ski schools in the United States.


Alpine Techniques

The basic technique for beginning Alpine skiers is the snowplow, or wedge. The snowplow enables skiers to make turns, control their speed, and stop. It is done by
placing the tips of the skis together and the tails apart, creating a wedge shape, and then pushing down on the inside edges of the skis. To turn, the skier shifts body
weight from one ski to the other while keeping the skis in the wedge shape. Traveling across the width of a slope is called traversing. Beginning skiers learn how to turn,
then traverse, then turn the other direction. As they gain skill, they gradually bring the tails of their skis closer together until they are parallel, and they traverse a
narrower area and link their turns. Most advanced skiers hold their skis a few inches apart in a parallel position, giving them the flexibility to shift their weight quickly
from ski to ski.
Some other techniques used in Alpine skiing include stem turns (pushing one ski out to the side in a small wedge), step turns (stepping onto the turning ski), and
sideslipping (sliding down the mountain sideways). Up unweighting and down unweighting (lifting up and sinking down on the skis) are used to facilitate turns,
especially in deep or heavy snow. In their extreme form, these become jump turns: Skiers jump into the air, turn their skis, and then sink back down into the snow.
This advanced maneuver is often used on extremely steep, narrow terrain where no other technique will work. Some Alpine skiers engage in freestyle skiing. Freestyle
for recreational skiers generally involves jumps off of natural bumps on the hill, a motion called catching air, and skiing moguls. Moguls are the bumps that appear on a
slope after many skiers make turns, pushing the snow into mounds.


Nordic Techniques

The basic technique used in cross-country skiing is the diagonal stride, or classical technique, which is similar to walking on skis: Skiers slide one foot forward and then
the other. They use their poles to propel themselves forward, pushing with their right pole as they slide their left ski forward, and then pushing with their left pole as
they slide the right ski, gradually adding speed and gliding between steps. The skating stride or freestyle technique borrows the motions of speed skating. With the skis
held at an angle, tips pointed outward, the skier pushes forward off the inside of each ski edge in alternation, using both poles at once.
In climbing hills, a skier puts the skis in the position of the skating stride, but instead walks up the hill. This is called the herringbone for the pattern of tracks it leaves in
the snow. On steep hills, skiers can also sidestep, placing their skis perpendicular to the fall line (the quickest path down the hill) and stepping uphill.
Downhill turning techniques used in Nordic skiing include the snowplow, the step turn, and the parallel turn, executed in a similar manner to Alpine skiing. Cross-country
skiers can also use the telemark turn, in which the turning ski is placed slightly in front of the other ski and the opposite knee is bent deeply as the skier slides around
the turn.


Ski Safety

Safety is very important to all skiers, and all Alpine resorts have a ski patrol. The ski patrol's responsibility is to take care of injured skiers, to mark hazardous spots on
trails, to make sure that trails are in good condition before opening them, and, at times, to act as traffic police in congested areas. Skiers are also responsible for taking
their own safety into consideration, as well as that of others. Anyone who participates in the sport should be aware of the Skier's Responsibility Code, which outlines
rules of proper conduct and assures a high level of safety for everyone taking part in the sport. This code is posted at all ski resorts.
Another way that skiers can act responsibly is by understanding trail designations and staying on trails that suit their level of expertise. The signs most commonly used
to designate trail difficulty in the United States are green circles for easy slopes, blue squares for intermediate runs, and black diamonds for difficult trails. Double black
diamonds are sometimes used to designate especially difficult terrain.



Alpine skis vary in construction, but they all have a hard plastic top surface, a polyethylene running surface, and steel edges. They are composed of a core material,
either foam or wood, with layers of fiberglass and sometimes metal.
Ski length is determined by a number of variables, including a skier's height, weight, and ability. The taller and heavier the skier, the longer the ski. Beginners generally
use shorter skis for easier maneuvering. Ski lengths for adults range from about 150 to 210 cm (about 5 to 7 ft).
One of the newer innovations in Alpine ski design is the so-called shaped ski, also known as the cut, super sidecut, parabolic, or hourglass ski. The name comes from
the ski's shape: a wide tip, a narrow waist, and a wide tail. Whereas traditional skis are wide at the tip and tail and slightly narrower through their middle, shaped skis
have greater variation in width. These skis are specifically designed to make it easier to carve a turn. Although they were originally designed for beginning and
intermediate skiers, many advanced skiers and racers have begun using shaped skis as well. Shaped skis are typically 8 to 15 cm (3 to 6 in) shorter than traditional
There are several variations on Alpine ski equipment. One is the monoski, which is a single, wide board. Another popular piece of equipment is the skiboard, which is
also called the mini-ski. Skiboards are only about 60 cm (24 in) long. Because of their short length, they allow skiers great maneuverability on the slopes. A more recent
innovation is the ski bike, which combines cycling and skiing. The ski bike has handlebars and a seat, just like a bicycle, but it has boards instead of wheels. Riders wear
short skis on their feet to help steer. Snow scoots are similar to ski bikes, but they have no seat, and riders secure their feet in foo...

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