Seven-time Tour de France winner Lance Armstrong announced he has decided not to continue his fight against the US Anti-Doping Agency\'s claims that he used performance-enhancing drugs. Armstrong, while still maintaining his innocence, said in a statement on his website that he had made his decision after a US federal court dismissed his lawsuit against USADA, paving the way for the agency to continue its probe into the retired American cyclist. \"Today I turn the page. I will no longer address this issue, regardless of the circumstances,\" Armstrong wrote. \"I will commit myself to the work I began before ever winning a single Tour de France title: serving people and families affected by cancer, especially those in underserved communities.\" USADA chief Travis Tygart said Armstrong will be stripped of his seven Tour de France titles and banned from cycling for life,. Tygart told AFP that Armstrong would be stripped of all his results dating back to August 1, 1998. He called the move a \"sad day\" for the sporting world but expressed hope that it would help create a \"level playing field\" for future athletes. \"It is a sad day for all of us who love sport and our athletic heroes,\" Tygart said in a separate written statement. \"This is a heartbreaking example of how the win-at-all-costs culture of sport, if left unchecked, will overtake fair, safe and honest competition, but for clean athletes, it is a reassuring reminder that there is hope for future generations to compete on a level playing field without the use of performance-enhancing drugs.\" Tygart said USADA planned to hold a news conference on Friday to provide more details on the case.