Figure skating jumps are an element of three competitive figure skating disciplines: men's singles, women's singles, and pair skatingbut not ice dancing. Jumping in figure skating is "relatively recent". They were originally individual compulsory figures, and sometimes special figures; many jumps were named after the skaters who invented them or from the figures from which they were developed. It was not until the early part of the 20th century, well after the establishment of organized skating competitions, when jumps with the potential of being completed with multiple revolutions were invented and when jumps were formally categorized. In the 1920s Austrian skaters began to perform the first double jumps in practice. Skaters experimented with jumps, and by the end of the period, the modern repertoire of jumps had been developed. Jumps did not have a major role in free skating programs during international competitions until the 1930s. During the post-war period and into the 1950s and early 1960s, triple jumps became more common for both male and female skaters, and a full repertoire of two-revolution jumps had been fully developed. In the 1980s men were expected to complete four or five difficult triple jumps, and women had to perform the easier triples. By the 1990s, after compulsory figures were removed from competitions, multi-revolution jumps became more important in figure skating. The six most common jumps can be divided into two groups: toe jumps (the toe loop, the flip, and the Lutz) and edge jumps (the Salchow, the loop, and the Axel). The Euler jump, which was known as a half-loop before 2018, is an edge jump. Jumps are also classified by the number of revolutions. Pair skaters perform two types of jumps: side-by-side jumps, in which jumps are accomplished side by side and in unison, and throw jumps, in which the woman performs the jump when assisted and propelled by her partner. According to the International Skating Union (ISU), jumps must have the following characteristics to earn the most points: they must have "very good height and very good length"; they must be executed effortlessly, including the rhythm demonstrated during jump combinations; and they must have good takeoffs and landings. The following are not required, but also taken into consideration: there must be steps executed before the beginning of the jump, or it must have either a creative or unexpected entry; the jump must match the music; and the skater must