Seven-time Tour de France winner Lance Armstrong (C) reacts as he hears the sound of a bike crash behind him, during a ride with local cyclists in Los Angeles' Griffith Park on September 10, 2009. Armstrong used his Twitter account to invite local rides to join him for a morning ride. Getty Images logo Getty Images 2 months ago

Seven-time Tour de France winner Lance Armstrong (C) reacts as he hears the sound of a bike crash behind him, during a ride with local cyclists in Los Angeles' Griffith Park on September 10, 2009. Armstrong used his Twitter account to invite local rides to join him for a morning ride.