Jan 28 (Reuters) - Factbox on snowboarding at the Sochi Winter Olympics:
Halfpipe - Competitors perform a series of tricks while going down from one side to the other on a semi-circular ramp. Judges give marks based on the variety of tricks, the difficulty and the execution.
Slopestyle - A new Olympic event. One of the most popular events at the X Games, it tests the competitors' ability to handle rails, hips and tabletops while performing tricks. Competitors are judged on creativity, execution and the difficulty of line and landing.
Parallel slalom and giant slalom - Riders race head to head, while in snowboard cross, four riders start simultenaously from the top of a twisty course, producing plenty of thrills and spills.
History: Snowboarding made its first Olympic appearance at the 1998 Games in Nagano, Japan. It has grown streadily since then and now features 10 events after slopestyle (men/women), parallel slalom (men/women) and snowboard cross (men/women) were added to the original events: halfpipe (men/women) and giant slalom (men/women).
The United States, where the sport was born in the 1960s, is the dominant nation, collecting 19 of the 60 medals awarded.
American Shaun White, one of three double gold medallists in the sport, is arguably the biggest star in the sport and heads into the Sochi Games as one of the men to beat in the halfpipe and slopestyle.
The venue: The events will be held at the Rosa Khutor Extreme Park in two different stadiums. The first one, called PSX (for parallel slalom, snowboard cross, parallel giant slalom, slopestyle) has a capacity of 6,250. The second one, HAM stadium (halfpipe), has a capacity of 4,000.
Rosa Khutor Extreme Park, which is about 70 km from Sochi, will also host the freestyle skiing competitions.
The U.S. are expected to take two of the four titles in halfpipe and slopestyle with White (men's halfpipe) and Jamie Anderson (women's slopetyle).
Torah Bright of Australia is the women's halfpipe favourite while Canadian Mark McMorris could be the man to beat in the men's slopestyle.
Watch out for Australian Alex Pullin (men's snowboard cross), Slovenian Rock Margus (parallel slalom), Benjamin Karl of Austria (parallel giant slalom).
Expect a tough battle between fellow Canadians Dominique Maltais and Maelle Ricker in the women's snowboard cross. (Reporting by Julien Pretot; Editing by Martyn Herman)