Реферат на тему Cross Country Skiing Essay Research Paper CrossCountry
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Cross Country Skiing Essay, Research Paper
Cross-Country skiing is a sport and technique of traveling over
snow-covered surfaces with the feet attached to long, narrow
runners known as skis. The skis distribute the skier’s weight
over a larger area, preventing the skier from sinking into the
snow. Three kinds of skiing have developed: Alpine, Nordic,
and Freestyle. Alpine, or downhill, skiing is movement down
steep slopes; in races, victory is decided by elapsed time.
Nordic, or Cross-Country, skiing, is movement over relatively
level surfaces; racing involves covering short and long,
prearranged courses in the shortest time. An important
subcategory of Nordic ski races is ski jumping, movement
down a vertical surface (called a ski jump); the distance
jumped and the skier’s flight are evaluated. Since the 1980s
freestyle skiing, for fun and in competition, has become
popular.
Equipment
The basic equipment, although varies somewhat, is essentially
similar for all types of skiing. Skis are made of strips of
shaped wood, metal, or synthetic material that can be attached
to a specially designed ski boot; the hard resistant surface of
the skis, maintained by application of special ski waxes,
produces high speed in moving over packed snow. Skis vary in
length according to the skier’s height and can reach 1.8 to
2.1 m (6 to 7 ft) long. Ski width also varies, from 7 to 10 cm
(3 to 4 in) in the front, tapering slightly inward in the middle
and widening at the rear; the front tip of the ski curves upward.
Downhill skis are shorter and wider than cross-country skis.
Flat-soled, ankle-high boots are an important item of equipment;
rigid leather and plastic boots are used for downhill skiing
and lighter, more flexible boots, with nylon or leather uppers,
for cross-country. The downhill boot is attached to the ski by a
binding that clips at the heel and toe and affords flexibility
and safety in the event of a fall. The cross-country boot
attaches to the ski by a toe binding, leaving the heel free
to flex up and down for the kickoff step. Ski poles,
commonly 1.2 to 1.5 m (4 to 5 ft) in length, are used for
balance and for movement; they are made of light metal tubing,
with handgrips, straps and a small disk at the bottom that
allows a firm hold in the snow.
Cross-Country Skiing
Cross-country (Nordic) skiing places greater emphasis on
endurance and strength, with less of an emphasis on speed.
Although, in competitions, the average time for a 15-km
(9-mi) race is about 50 minutes; for the longer course of
48 km (30 mi) or so, a time of 2 hours, 45 minutes is
regularly achieved. Conventional distances to be covered
vary from 5 to 50 km (3 to 30 mi) or more in length. Courses
are distinguished with colored markers, so that competitors
can follow the same approximate route. Altitude variations
are modest because the essential movement is horizontal
and not vertical.
Historically, cross-country racing developed out of the need
for a mode of transportation. In its non-competitive aspects,
it is a sport in which old and young alike may participate.
Although not well adapted to heavily wooded areas, cross-
country is practicable throughout the world and, unlike
alpine skiing, does not depend on special slopes,
mechanical ski tows, and the use of artificial snow. The
fundamental cross-country stride combines a kickoff step with
one foot and a gliding step with the other. These steps
alternate smoothly and rapidly; the ski pole in one hand is
planted down as the opposite leg begins its kickoff. Several
variations to this basic stride allow for upward and downward
movement and necessary maneuverability and provide for some
degree of rest from continuous exertion. In the skating
technique, developed in the 1980s, a skier moves in a
side-to-side motion, pushing off on the inside of the ski.
Waxing
To ensure easy movement over the snow, skier’s rub an
application of special non-friction ski waxes. This allows
them to slide easily and effortlessly over the snow. Without
wax skiing would be difficult and tedious, and only slow
speeds could be obtained during perfect weather conditions.
Waxes for Cross-Country skiing are designed for different
temperatures, and weather conditions. For example a wax
could be designed for: Temperatures below -20, from -10 to
-20, or above -10; Warm and slushie conditions, or cold and
icy conditions.
To apply ski wax, you find the desired wax according to
weather conditions. You then rub the wax on the bottom
side of the ski, making sure to cover all of it. Then to
smooth the wax to on the ski you rub the surface with a
wooden cork-like material. going over everywhere you
waxed.
History of Skiing
The use of some kind of equipment for travel over snow
is ancient. Greek historians mention skins, sliders,
or shoes used for this purpose, and similar references
occur in Norse myths. The earliest skis of which any
record exists were found in bogs in Sweden and Finland.
They are thought to be between 4000 and 5000 years
old and consist of elongated curved frames covered
with leather.