Jan 28 (Reuters) - Factbox on freestyle skiing at the Sochi Olympics.
The competition: There are ten events in total (five for men and five for women) offering a total of 30 medals. Competitions take place from February 6 to February 21.
Moguls - Scores awarded for speed (according to a special formula) and style, both when negotiating the course and performing two jumps. Best performers in the qualifying round advance to the final round.
Aerials - Like gymnastics on skis, athletes are assessed on two jumps each in the qualifying round, and those with the highest combined score advance to the final round. Points are awarded for jump, takeoff, form and landing.
Half-pipe - Athletes have two runs each on the half-pipe slope (234 meters long, with walls 6.8 meters high on each side), where they perform tricks, turns and flips to impress the judges. The best run counts and the top 12 skiers progress to the final round to battle it out for the medals.
Ski Cross - Competitors ski a qualifying run and are then put into groups of four, where they race against each other down a twisting course full of jumps, with the two top skiers making it to the next round. The final race decides the medals.
Slopestyle - Athletes have two chances to negotiate a slope littered with rails, ledges and jumps as they try to impress the judges with their speed, skill and technique. The event follows an elimination format, with semi-finals and finals. Skiers are scored based on execution and degree of difficulty of their tricks but can pretty much do what they want.
History: Made its debut as a demonstration sport in 1988 with moguls gaining medal status in 1992.
The U.S. (14 Olympic medals, 6 gold), Canada and Australia are the traditional powers in freestyle skiing, with China a growing force. Norway, France and Switzerland also strong in the various disciplines.
Along with their snowboarding equivalents, the freestyle skiing events tend to be among the most breathtaking of the games, as speed and skill combine with spectacular wipeouts.
Venue: The Rosa Khutor Extreme Park some 70 km from the city of Sochi.
The contenders to watch: Alex Bilodeau (Canada, men's moguls), Hannah Kearney (U.S, women's moguls), Li Nina (China, women's aerials), Liu Zhongqing (China, men's aerials), Tom Wallisch (U.S., men's slopestyle), Lisa Zimmerman (Germany, women's slopestyle), Justin Dorey (Canada, men's half-pipe), Devin Logan (USA, women's half-pipe), David Duncan (Canada, men's ski cross), Marielle Thomson (Canada, women's ski cross) (Compiled by Philip O'Connor; editing by Martyn Herman)