Tour de France legend Lance Armstrong says he is "buzzing" ahead of his New York Marathon debut on Sunday.
Armstrong won his record seventh Tour de France title in July 2005
Armstrong, 35, has not raced, on a bike or otherwise, since winning a record seventh Tour de France in July 2005.
The former cancer sufferer is eyeing a sub-three-hour time and will be paced by greats Alberto Salazar, Joan Benoit Samuelson and Hicham El Guerrouj.
"I haven't felt this kind of buzz since I raced," he said on Friday. "And I've never been passed in Central Park."
Armstrong, who was diagnosed with testicular cancer in 1996, competed in triathlons as a teenager but admitted he was not a natural runner.
I'll be OK from a fuel and energy standpoint - from a pain standpoint, I can deal with it
"I wasn't born to be a runner. I was born to be other things," said Armstrong, who spends his time raising money and awareness for cancer research.
"It would be foolish for me to say I've done workouts. I simply run. I don't do intervals. I just go every day and run, there's no science behind it.
"It's not about being competitive or winning, it's a personal goal. I needed something to keep me going.
"I don't want to say there's no question I'll finish, but I can always crawl.
"If I start smart and conservatively, I'll be OK from a fuel and energy standpoint. From a pain standpoint, I can deal with it."
One target for Armstrong might be the time of 2:55.39 recorded by former Tour de France star Laurent Jalabert in 2005.
The defending champion is Peter Tergat of Kenya, while last year's women's winner Jelena Prokopcuka of Latvia will also be back in an elite field that includes five Olympic medalists and 10 major marathon winners.