He did not give any names of athletes, and the BBC's Tom Burridge in Madrid says the trial is unlikely to shed light on doping beyond the world of cycling.

BBC: Spain 'doping doctor' Fuentes treated non-cyclists

Since 2004, when doping allegations against Armstrong first came to light in a book by French sports journalist Pierre Ballester, the foundation has experienced steady year-to-year revenue growth, according to financial records, with the exception of a dip from 2005 to 2006, the year Armstrong was cleared of allegations stemming from a 1999 drug test.

CNN: Livestrong likely to survive Armstrong doping admission