Tygart insists Lance doped during comeback

United States Anti-Doping Agency head Travis Tygart has claimed Lance Armstrong is still lying about the full extent of his doping past.

Tygart, the USADA chief executive who was one of the key figures in exposing the disgraced cyclist, insisted there was scientific proof that Armstrong did use performance-enhancing drugs on his comeback to the sport, in 2009 and 2010.