(CNN) -- Former pro cyclist Lance Armstrong will step down as chairman of the Livestrong cancer charity he founded in 1997 after recovering from the disease, organization spokeswoman Katherine McLane said Wednesday.

　　step down：卸任

　　The move comes the same day that Nike, a key Armstrong sponsor, announced it was ending its contract with Armstrong amid "seemingly insurmountable evidence" that he participating in doping.

　　participate in doping.：服用违禁药物

　　Armstrong said his decision was made to "spare the foundation any negative effects as a result of controversy surrounding my cycling career," according to a statement posted to the group's website.

　　Last week, the U.S. Anti-Doping Agency said it had uncovered overwhelming evidence of Armstrong's involvement in a sophisticated doping program while a professional cyclist. Armstrong has consistently denied the claims.

　　U.S. Anti-Doping Agency：美国反兴奋剂组织

　　Nike said it would continue to support Livestrong initiatives.

　　Founding chairman Jeff Garvey will take over for Armstrong, the Texas-based organization said.

　　take over：接任

　　Armstrong said that he and his family would "continue our service to the foundation and the cancer community," but didn't specify in what role.

　　Armstrong founded the charity after his own treatment for testicular cancer that had spread to his brain and lungs. He came back from the disease seemingly stronger than ever, winning the first of his seven Tour de France titles three years after he was diagnosed with cancer.

　　be diagnosed with：诊断为

　　His success became an inspiration for cancer patients worldwide, spreading his reach far beyond the insular world of cycling and cementing a place in celebrity culture, dating a rock star and appearing in movies. The bright yellow "LIVESTRONG" wristbands distribute by his charity became a potent symbol for perseverance in the face of adversity.

　　People should look to that legacy in assessing Armstrong, Livestrong President Doug Ulman said in praising the charity's founder.

　　"Lance's devotion to serving others whose lives were irrevocably changed by cancer, as his was, is unsurpassable," he said in the statement. "We are incredibly proud of his record as an advocate and philanthropist and are deeply grateful that Lance and his family will continue to be actively involved with the Foundation's advocacy and service work."

　　In its report, the anti-doping agency made public testimony from Armstrong's teammates and others involved in the U.S. Postal Service- and Discovery-sponsored cycling teams who said the seven-time Tour de France winner was among team members who used banned performance-enhancing substances and tried to hide it from testing officials.

　　Tour de France：环法自行车赛

　　Armstrong has said he never has failed a drug test and has consistently denied participating in any banned practices. Armstrong's lawyer, Tim Herman, called the report last week a "one-sided hatchet job" and a "government-funded witch hunt."

　　fail a drug test：未通过兴奋剂检测

　　hatchet job：恶意诽谤

　　witch hunt：政治迫害