Alpine skiing

[3] The ancient origins of skiing can be traced back to prehistoric times in Russia, Finland, Sweden and Norway where varying sizes and shapes of wooden planks were found preserved in peat bogs.

The Norwegian army held skill competitions involving skiing down slopes, around trees and obstacles while shooting.

[4] Norwegian legend Sondre Norheim first began the trend of skis with curved sides, and bindings with stiff heel bands made of willow.

[7] Norheim was the champion of the first downhill skiing competition, reportedly held in Oslo, Norway in 1868.

[8][9][10][11] The term "slalom" is from Norwegian dialects slalåm meaning a trail (låm) on a slope (sla).

Some races were on "bumpy courses" (kneikelåm) and sometimes included "steep jumps" (sprøytehopp) for difficulty.

[8] Husebyrennet from 1886 included svingrenn (turning competition on hills), the term slalåm had not been introduced at that time.

A skier with skis pointed perpendicular to the fall line, across the hill instead of down it, will accelerate more slowly.

In doing so, the snow resists passage of the stemmed ski, creating a force that retards downhill speed and sustains a turn in the opposite direction.

Alternating right and left allows the skis to remain parallel and point ahead without turning.

[15] Modern alpine skis are shaped to enable carve turning, and have evolved significantly since the 1980s.

The leather ski boots started off as low-cut, but gradually became taller, allowing for more ankle support, as injuries became more common .

This allowed the bindings to be more closely matched to the fit of the boot, and offer improved performance.

The triple crown of alpine skiing consists of winning all three World Cup titles in one season or all three Gold medals at the Winter Olympic Games in Slalom, Giant slalom, and Downhill skiing events.

Only two people have ever accomplished the feat: In most ski resorts, the runs are graded according to comparative difficulty so that skiers can select appropriate routes.

[citation needed] In the United States and Canada, there are four rating symbols: Easy (green circle), Intermediate (blue square), and Difficult (black diamond), and Experts Only (double black diamond) Ski trail difficulty is measured by percent slope, not degree angle.

Although slope gradient is the primary consideration in assigning a trail difficulty rating, other factors come into play.

[citation needed] In 2014, there were more than 114,000 alpine skiing-related injuries treated in hospitals, doctor's offices, and emergency rooms.

[21] The most common types of ski injuries are those of the knee, head, neck and shoulder area, hands and back.

Head injuries caused in skiing can lead to death or permanent brain damage.

[21] According to a 2004 Harvard Medical School study, alpine skiing burns between 360 and 532 calories per hour.

[23] Winter season lengths are projected to decline at ski areas across North America and Europe due to the effects of global warming.

[25] In Europe, half of the glacial ice in the Alps has melted and the European Geosciences Union projects snowpack in the mountains could decline 70 percent by 2100 (however, if humans manage to keep global warming below 2 °C, the snow-cover reduction would be limited to 30 percent by 2100).