Freestyle, originally a mixture of Alpine skiing and acrobatics, developed in the United States in the 1960s. The first official competition was held in Attitash, New Hampshire, in 1966. The International Ski Federation recognised the sport in 1979 and the following year a World Cup series was organised. The first world championships were held in Tignes, France, in 1986.
Three freestyle skiing disciplines -- moguls, aerials and ballet -- were included as demonstration events in the 1988 Calgary Olympics. Moguls became a medals sport at the 1992 Games and aerials achieved the same status in 1994 but ballet is not part of the Olympics. Ski-cross debuts as a medals sport in Vancouver.
Men and women compete in moguls, aerials and ski-cross.
In moguls, skiers race down a slope over large, uniform bumps called moguls, from an Austrian dialect word for mound. The length of the run is between 230 and 270 metres with moguls up to 1.2 metres high. The course also has two jumps and skiers must perform aerial manoeuvres which are judged for height, distance, landing, execution and degree of difficulty. Jumps have colourful names such as backscratcher, helicopter, daffy and mule kick.
Turns account for 50 percent of the marks, jumps for 25 percent. The remaining 25 percent is based on each skier's time. Moguls competitions are accompanied by loud music, usually chosen by the skier.
The 20 best competitors from an elimination round go into the final.
In aerials, competitors perform combinations of flips and twists off snow-packed jumps as high as four metres. Skiers often fly 18 metres above the ground. A panel of judges score the competitors for height and distance, worth 20 percent of the marks, execution and precision -- worth 50 percent -- and landing, worth 30 percent. The landing area is covered in soft snow to absorb the impact of dropping from a height equivalent to a three-storey building.
Sixteen competitors advance to the final after a two-jump elimination round. Each takes two jumps in the final. Scores from the elimination round are not carried forward to the final.
Ski-cross is the newest freestyle event to be included in the Games. Four skiers start off side-by-side and race down a course that includes turns, rolls and banks like those on a regular ski slope and structures such as jumps usually found in snowboard cross events. The event requires physical endurance and strength as skiers have to ski up to five runs lasting 60 seconds or longer to win.
A timed qualification run is used to seed skiers into different heats, each with four competitors. The first two competitors to cross the finish line in each round advance to the next stage.
Men's moguls: Dale Begg-Smith (Australia)
Men's aerials: Xiaopeng Han (China)
Women's moguls: Jennifer Heil (Canada)
Women's aerials: Evelyne Leu (Switzerland)
Cypress Mountain in West Vancouver. Venue capacity is 12,000 spectators. Unseasonably warm weather last month melted the snow at the venue and organisers have had to bring in snow from higher elevations to replace it.
Defending Olympic champion Jennifer Heil hopes for a repeat in Vancouver to erase the label the Canadians have of being the only host country never to have won an Olympic gold on home soil.
The debut of ski-cross should add even more excitement to freestyle skiing and attract an X Games crowd to watch the mass-start event that promises speed and potential for some spectacular crashes.