World super middleweight champion Felix Sturm announced Saturday he failed a doping test following his win over Russia's Fedor Chudinov last February.

Sturm, 37, tested positive for anabolic steroid Hydro-XY Stanozolol in his A sample after he beat Chudinov on majority decision in Oberhausen on February 20 for the WBA super middleweight belt.

The five-time world champion German said he was shocked by his doping result and denied any wrongdoing.