Armstrong, Lance,1971–, American cyclist, b. Dallas, Tex. He won (1991) the U.S. amateur cycling championship, turned professional (1992), and by the mid-1990s had won the Tour DuPont twice and was being hailed as the finest U.S. cyclist. In 1996, however, he was diagnosed with testicular cancer, which had spread extensively. After undergoing surgery and chemotherapy, he returned (1998) to cycling and reached the pinnacle of the sport with seven consecutive victories (1999–2005) in the Tour de France. He also won a bronze medal in the time trial at the 2000 Olympics. Armstrong retired in 2005, resumed his career in 2009, and retired again in 2011.
Accusations in 2005 that he had engaged in blood doping in 1999 were denied by Armstrong and disputed in 2006 by an International Cycling Union (ICU) investigation, which found no evidence to support the charges. Subsequently, additional accusations were made regarding Armstrong and his team, but he continued to deny the charges until 2013, when he finally admitted to doping. In 2012, after the U.S. Anti-Doping Agency (USADA) said it had clear evidence of doping and released a detailed and extensive report covering the years of his Tour de France victories, the ICU agreed with USADA's decision to strip Armstrong of his results since 1998 and bar him from the sport for life. In 2013 he was stripped of his Olympic medal, and in 2018 he agreed to pay $5 million to settle claims he had defrauded the United States Postal Service (his cycling team's sponsor).
See his memoirs (2000 and 2003); D. Coyles, Lance Armstrong's War (2005); J. Macur, Cycle of Lies (2014).