The International Association of Red Sports and Gymnastics Associations, commonly known as Red Sport International (RSI) or Sportintern was a Comintern-supported international sports organization established in July 1921. The RSI was established in an effort to form a rival organization to already existing "bourgeois" and social democratic international sporting groups. The RSI was part of a physical culture movement in Soviet Russia linked to the physical training of young people prior to their enlistment in the military. The RSI held 3 summer games and 1 winter games called "Spartakiad" in competition with the Olympic games of the International Olympic Committee before being dissolved in 1937.
The notion of a separate working class national athletic federation emerged first in Germany during the decade of the 1890s, when a Workers Gymnastics Association was established by activists in the socialist movement in opposition to the nationalist German Gymnastics Society (Turnen). Other "proletarian" sports organizations emerged soon thereafter in that country, including the Solidarity Worker Cycling Club, the Friends of Nature Rambling Association, the Worker Swimming Association, the Free Sailing Association, and the Worker Track and Field Athletics Association, among others. By the time of World War I, the German proletarian sports movement included more than 350,000 participants.
Following the bloodbath of World War I, the German workers' sports movement began to reemerge, with a new competitive orientation beginning to take the place of individualistic club activities. The international social democratic movement also experienced a rebirth after its connections had been severed by war. In 1920 the social democrats established an International Association for Sports and Physical Culture, echoing its efforts in the pre-war period. This organization was rechristened as the Socialist Workers' Sport International (SWSI) in 1925.