He participated in the 1986 Soviet Spartakiad, winning a gold medal in the 4 × 400 m relay and a silver in the decathlon competitions.

[4] On 7 September 2016, as a member of the country's Ministry of Sport, he protested the ban of the Russian team from the Paralympic Games over the doping scandal during the entry of Belarus at the 2016 Summer Paralympics opening ceremony's parade of nations by holding a Russian flag as a display of solidarity to its neighbour.

The Russian flag was quickly confiscated by officials and security, and after he was identified, Fomochkin's accreditation was cancelled by the IPC for violating policies which forbid political protests and gestures.

The IPC also warned that it would closely monitor medal presentations involving Belarusian athletes to ensure they do not display political gestures.

[5][6] Fomochkin's actions were praised by Belarusians (including President Alexander Lukashenko), as well as Maria Zakharova, a member of Russia's Ministry of Foreign Affairs; she stated to a news agency that Fomochkin had "[shown] solidarity with people who were disgracefully treated in an inhumane way in not being allowed to compete at the Paralympics".