Four months after clinching a record eight gold medals at the Beijing Olympics, US swimmer Michael Phelps is set to return to training braced for pain but eager to douse any thoughts of retirement.

"My shape is non-existent right now," the 23-year-old said after emerging from the pool at Beijing's Olympic water polo venue, the Yingdong Natatorium.

"I'm far from being in shape, but I talked to my coach today, and Tuesday is the official day I start," said Phelps, who has set his sights on more glory at the London Olympics, four long, gruelling years down the line.

"Four months has been the longest time I've been away from the pool ... I know it will be a lot of pain for the first few months," he said.

On Jan. 11, American swimmer Michael Phelps displays the Chinese character "niu" he writes with a writing brush to wish Chinese netizens a happy Spring Festival.(Xinhua Photo)

Phelps returned to Beijing this week to shoot a television advertisement for Mazda, the latest in a string of commercial endorsements he has signed since breaking fellow American Mark Spitz's record seven-gold haul at the 1972 Munich Games.

The shoot, part of a seven-figure deal which Phelps' representatives said was "the biggest for a Western celebrity" in China, saw the 14-time Olympic champion struggle after swimming butterfly for the first time in months.

But it also allowed a quick stop at the National "Water Cube" Aquatics Center in Beijing's Olympic Green, giving the American a chance to soak up the memories of what could turn out to be an unsurpassable feat.

"It was pretty cool, a pretty special feeling. I'm glad to have the opportunity to relive some of he moments that I had four months ago," Phelps said.

The long layoff, punctured by television appearances and charity events in between relaxing with friends and family, had not sapped the swimmer's motivation, nor had it completely banished thoughts of retirement.

"It's been fun but I really want to get back into a normal regime and get some kind of structure back into my life," Phelps said.

"There are times where I will wake up and say to myself 'I don't want to do this anymore.' But there are so many goals and times that I want to hit in events.

"I'm not going to retire until those are accomplished," he added.

He was cagey about the new goals, saying he was still working out a plan with his coach Bob Bowman, but he dashed any notions of striving to match or better his record Beijing haul.

"These four years are going to be much more relaxed than the last four years ... there will definitely be a lighter programme than what I did in Beijing," said Phelps, who is aiming to be fit for the world championships in Rome in July.

"I think some backstroke is definitely in the mix, hopefully I can master the 100 free. I'm gonna try a few different events I haven't tried before," he said.

(Agencies via Shanghai Daily January 14, 2009)