Armstrong was taken to a hospital for X-rays after crash with Chechu Rubiera in mile five of Thursday's leg of the race, the Amgen Tour of California tweeted. Team spokesman Philippe Maertens said Armstrong got stitches in his left elbow and under his left eye, the Associated Press reported.
“It’s our word against his word,” Armstrong said of former teammate's charge. “I like our word. We like our credibility.”
Landis, the only Tour de France winner to ever be stripped of his title, admitted in an interview to using performance-enhancing drugs and blood doping techniques over the course of his cycling career.
In an interview with ESPN.com and in emails obtained by the The Wall Street Journal, Landis also claimed that several other cyclists, including Armstrong, took substances such as human growth hormone and steroids to improve their performance.
Armstrong has been accused of doping on several occasions throughout his years in the sport, but has always denied the charges and has never been sanctioned.
With his longtime coach Johan Bruyneel standing next to him, Armstrong told The Associated Press Landis seems to be pointing fingers at everyone still involved in the sport.
“We have nothing to hide,” Armstrong said. “We have nothing to run from.”
But Landis claimed that Armstrong not only cheated, but taught him how the various drugs and techniques worked.
"He and I had lengthy discussions about it on our training rides during which time he also explained to me the evolution of EPO testing and how transfusions were now necessary due to the inconvenience of the new test," Landis wrote in an e-mail published by the Journal.