Ready for Labour and Defence of the USSR (Russian: «Готов к труду и обороне СССР» Gotov k trudu i oborone SSSR), abbreviated as GTO (Russian: ГТО) was the All-Union physical culture training programme, introduced in the USSR on March 11, 1931 on the initiative of the Komsomol. It was a complement to the Unified Sports Classification System of the USSR. While the latter provided Soviet physical education system requirements only for athletes, GTO was a programme for all Soviet people of almost all ages. By the year 1976, 220 million people were awarded GTO badges, while in 1986 the tests were passed by 33.9 million people.
Initially the GTO had one level with three age groups. To earn the GTO badge, an individual needed pass 21 tests, of which 13 had concrete norms. Sports in the country were only beginning to develop; there were a few physical culture collectives by enterprises and organizations, that could organize physical training, and the GTO provided the unique possibility to involve people into sports activities, hence the variety of tests. On December 7, 1932, the second level was introduced for the same three age groups. This was done to stimulate the improvement of skills of those who passed the first level. The second level had 24 tests, 19 of them had concrete norms. Each test result could be one of two: "passed" and "not passed".
The next change followed in 1934, when the third level had been introduced, with two age groups: for children 13-14 and 15–16 years of age. This level had a separate name - "Be Ready for Labour and Defence of the USSR" (Russian: "Будь готов к труду и обороне СССР"), abbreviated as "BGTO". This defined the structure of the GTO for many years: it had "BGTO", "GTO 1st level" and "GTO 2nd level" stages until 1972. After the structure of the GTO programme was established, next revisions dealt with the system of tests, applicable to evaluate physical conditions of different age groups of the population; improvements in norm requirements; specifying age limits of levels.
In 1939 the tense international situation caused the inclusion of tests, necessary to prepare young people for service in the Red Army, and to prepare all the population for the possible war. Such disciplines as "crawling over", "speedy foot march", "throwing a bunch of grenades", "rope (also pole and tree) climbing", "carrying over a cartridge box", various martial arts were introduced. Most of them were removed in post-World War II revisions. Only "throwing a grenade" and "50 m small bore rifle shooting" (men only) remained.