She was one of the four superstar ballerinas of the Soviet Union along with Natalia Makarova, Alla Osipenko and Irina Kolpakova, as well as the preferred dance partner of Rudolf Nureyev before his defection.
[2] Among her classmates was Rudolf Nureyev, with whom she performed the Le Corsaire duet in a school graduation film, which attracted the attention of the Kirov Ballet.
Upon her return to the USSR, Sizova refused to condemn his actions, although she questioned why he would leave to perform in foreign ballets she considered inferior.
[4] The Kirov recognised her talent of musicality and vulnerability, and gave her the leading part in Igor Belsky's balletic setting of Shostakovich's Leningrad Symphony.
[3] After Nureyev's departure, Sizova continued her career with a new partner, Yuri Soloviev, with whom she performed roles of great sensitivity and demonstrated the highest achievement of the Kirov's training.
[5] Amongst other roles, Sizova received great acclaim as Princess Aurora in the 1964 Kirov production Tchaikovsky's The Sleeping Beauty opposite Yuri Soloviev.