The Masters South Central Zone Swimming Championship is not under the umbrella of the US Anti-Doping Agency, which stripped the American cyclist of his seven Tour de France victories and banned him for life from its events, the Austin-American Statesman newspaper reported on Thursday.
Armstrong (41) will swim over the weekend in Austin, the Texas state capital, and compete against swimmers around his age.
"The purpose of our organisation is to encourage adults to swim," Rob Butcher, the executive director of masters swimming, told the newspaper. Organisers do not test the swimmers for performance enhancing drugs.
Butcher said no official complaints had been made about Armstrong's participation.
Armstrong has entered the event's three longest races: the 500, 1 000 and 1 650-yard freestyles.
He has not officially confirmed his participation in the event, but on March 23 posted the following message on his Twitter feed: "Great @MastersSwimming workout this morning at the [email protected] Thx Coach Hux for the punishment."
In October 2012, Armstrong was stripped of his Tour titles as well as all other results from August 1998, and was banned for life after the US Anti-Doping Agency determined he was the key figure in a sophisticated doping scam on his US Postal Service cycling team.
Armstrong finally made a belated admission of doping, after many denials, in a televised interview with Oprah Winfrey in January, in which he said he used a combination of blood-doping transfusions, blood-boosting EPO and testosterone throughout his career.
Not everyone is happy about competing against him.
Jamie Cleveland, a local triathlete set to swim against Armstrong, said he hoped his famous rival would drop out of the race.
"This whole masters swimming is him trying to sidestep his punishment," Cleveland told the newspaper. "I've been an endurance athlete all my life. I've taken great joy in discovering my limits; I've taken great joy in challenging my limits. It really irks me that Armstrong has admitted to doping and he's shown no remorse." – Sapa-AFP