Lance bemoans doping record

Adelaide - Seven-time Tour de France winner Lance Armstrong says cycling's reputation for doping only arises because the sport is more strenuous than others in its efforts to crack down on drug cheats.

Armstrong acknowledged on Thursday that too many cyclists had tested positive for banned substances but other sports would have similar records if their athletes were monitored as closely.

The 38-year-old American has been linked to a US government investigation into drug use by cyclists, prompted by allegations from his disgraced former teammate Floyd Landis.

Armstrong said he was not concerned personally at being mentioned in doping investigations but regretted the blemish upon cycling.

"I can't say no, you would have to say yes," Armstrong said. "But to me that is really a byproduct of the sport trying harder than any other sport.

"I know if you laid those controls over any other world sport, especially one as demanding as cycling, you would have as many, if not more, positives."

Armstrong made the comments at a news conference at Rowland Flat in South Australia's Barossa Valley wine region, shortly after his arrival to contest the Tour Down Under race which starts on Sunday.

The six-day tour will Armstrong's final professional race outside the United States, but he said he had no feelings of regret or nostalgia.

"I have never been one to sit around and reminisce much," he said. "It would be a mistake for me to think back on the stuff that I did on the bike when I have things in front of me that are much bigger than that."

Armstrong understood how his unrivaled record in the Tour de France had prompted suspicion of drug use given so many other successful cyclists had subsequently been found to have used performance-enhancing substances.

"I won the Tour de France seven times and I won it because we changed the way people in cycling do business," he said. "And I'm not going to dance around the fact there has been plenty of questions about that.

However Armstrong attributed his success to the pioneering of "a whole new approach to the sport.

"We revolutionized the way people train, the way they build morale in the team, the way they preview the courses, the way they race, the way they sell the sport, the way they tell that story around the world," Armstrong said.

"I leave knowing that I did my best and I don't need somebody to give me a plaque or give me a statue, it has been very good to me on a lot of levels, it has been a good ride."