Russia's Viktoria Komova, a two-time world champion and twice Olympic silver medalist, is retiring from gymnastics because of health problems at just 21, a national team coach said Friday.

Komova, who had hoped to compete at the Rio Olympic Games in August, has issues with her spine that make her unable to follow her training regimen, Valentina Rodionenko said.

"Komova has stopped competing, her health doesn't allow her to," Rodionenko told R-Sport news agency.

"She is ending her career."

Komova won silver in London in the individual all-around and was also on the Russian squad that took a team silver in the same 2012 Games.

She said last year that she intended to carry on for at least one year after the Rio Olympic Games.