Ryazanov competed at the 2008 Summer Olympics in Beijing, China,[3] placing 17th in the qualifications for the individual all-around, but did not advance to the final due to the two per country rule.

Ryazanov placed third on parallel bars at the 2008 Moscow World Cup and 8th on rings at the 2008 European Men's Artistic Gymnastics Championships in Lausanne, Switzerland.

He won the silver medals on rings and high bar, and placed 4th with his team at the 2008 Pacific Rim Championships in San Jose, California.

He then won the bronze medal in the all-around at the 2008 Russian Cup in Lobnya, behind Maxim Devyatovsky and Sergei Khorokhordin; all three earned automatic berths onto the Olympic team.

In April, he won the bronze medal in the all-around at the 2009 European Artistic Gymnastics Championships in Milan, Italy behind Fabian Hambüchen of Germany and Daniel Keatings of Great Britain.

He died in a car crash in the village Vorsha in the Sobinsko Region, about 125 miles east of Moscow, on October 20, 2009, just two days after the World Championships had concluded.