[6][7] His first individual medal followed at the 2004 World Junior Championships in Athletics, where he edged compatriot Vladimir Kanaykin to win the 10,000 m track walk title.

[10] At the 2008 national championships he competed over the novel 35 km distance and managed third place in a race won by world record holder Vladimir Kanaykin.

[10] A senior title came at the end-of-season IAAF Race Walking Challenge Final, where he was victorious over the shorter 10 km distance ahead of both Stanislav Emelyanov and Eder Sánchez.

Working under coach Viktor Chegin,[10] his form turned around in the 2012 season as he opened with a personal best of 1:17:45 hours to win the 20 km title at the Russian Winter Walking Championships.

[16] At the 2013 Russian winter championships Ruzavin was second to Pyotr Trofimov, but gained selection for the 2013 European Race Walking Cup and shared in the team title with winner Denis Strelkov and Aleksandr Ivanov.

[17] He led from the start at the 2013 Universiade, held in Kazan, but fell back to fourth place while fellow Russian Andrey Krivov won the title.

[23] His suspension marked a continuation of a series of doping bans emerging from Viktor Chegin's Mordovia walking school, the most prominent being Olympic champion and world record breaker Elena Lashmanova.