Freestyle skiing is a skiing discipline comprising aerials, moguls, cross, half-pipe, slopestyle and big air as part of the Winter Olympics. It can consist of a skier performing aerial flips and spins and can include skiers sliding rails and boxes on their skis. Known as "hot-dogging" in the early 1970s, it is also commonly referred to as freeskiing, jibbing, as well as many other names, around the world. History Ski acrobatics have been practiced since the 1930s. Aerial skiing was popularized in the 1950s by Olympic gold medalist Stein Eriksen. Early US competitions were held in the mid-1960s. In 1969, Waterville Valley Ski Area in New Hampshire, formed the first freestyle instruction program, making the resort the birthplace of freestyle skiing. The following year, Corcoran and Doug Pfeiffer, organized the first National Open Championships of Freestyle Skiing on the Sunnyside trails. In 1971, Waterville Valley Hosted the first Professional Freestyle Skiing Competition, which attracted freestyle skiing legends to Waterville Valley. Some of these competitors, such as Wayne Wong, Floyd Wilkie, and George Askevold, stayed at Waterville Valley as coaches of the first Freestyle Ski Team. International Ski Federation (FIS) recognized freestyle skiing as a sport in 1979 and brought in new regulations regarding certification of athletes and jump techniques in an effort to curb the dangerous elements of the competitions. The first FIS Freestyle Skiing World Cup was staged in 1980 and the first FIS Freestyle World Ski Championships took place in 1986 in Tignes, France. Freestyle skiing was a demonstration event at the 1988 Winter Olympics in Calgary. Mogul skiing was added as an official medal event at the 1992 Winter Olympics in Albertville, and the aerials event was added for the 1994 Winter Olympics in Lillehammer. In 2011, the International Olympic Committee (IOC) approved both halfpipe and slopestyle freeskiing events to be added to the 2014 Winter Olympics in Sochi, Russia. Forms of freestyle skiing Aerial skiing Aerialists ski off 2-4 meter jumps, that propel them up to 6 meters in the air (which can be up to 20 meters above the landing height, given the landing slope). Once in the air, aerialists perform multiple flips and twists before landing on a 34 to 39-degree inclined landing hill about 30 meters in length. The top male aerialists can currently perform triple back flips with up to four or five twists. Aerial skiing is a judged sport, and competitors