Lance Armstrong has come clean to Oprah, but if he wants to compete again, he'll have to do more talking.

World Anti-Doping Agency Director General David Howman said in a statement, "Only when Mr. Armstrong makes a full confession under oath -- and tells the anti-doping authorities all he knows about doping activities -- can any legal and proper process for him to seek any reopening or reconsideration of his lifetime ban commence."

Armstrong's much-talked-about interview with Oprah will air on the Oprah Winfrey Network on Thursday and Friday.

Source: Bloomberg