BEIJING (AFP) - US diplomatic biceps are mightier than China's financial muscle, if a press-up contest pitting outgoing ambassador Gary Locke against a line-up of businessmen in Beijing is anything to go by.

The 64-year-old, who had already earned quasi-celebrity status as the first ethnic Chinese in the post and a rare example of a humble dignitary, took on three tycoons including property billionaire Pan Shiyi at a farewell dinner on Thursday.

Pictures posted by Mr Pan's wife Zhang Xin on her verified social media account showed the four assuming the position in their business shirts on a lurid yellow and blue carpet, in what looked like a hotel function room.

They pumped away, a musclebound announcer standing over them, until only Mr Locke remained, 60 press-ups later.

"Ambassador Locke turned out to be everybody's model of health," wrote Ms Zhang.

"Now I feel embarrassed if I don't do 50 press-ups before dining," runner-up Pan posted on his own verified account on Sina Weibo, a Chinese equivalent of Twitter, where he has almost 17 million followers.

The couple are listed as China's 32nd richest people by wealth publisher the Hurun Report, which estimates their worth at US$3.7 billion (S$4.7 billion).

Mr Locke entered the spotlight the moment he took up his post in Beijing in August 2011. The grandson of an immigrant from the southern province of Guangdong, he was Washington's first ethnic Chinese ambassador to the country.

He soon earned a reputation as a low-maintenance dignitary - in contrast to many Chinese officials - after being seen buying his own coffee and carrying his own luggage.

The press-up contest was not the first fitness feat by Mr Locke, who featured in this month's edition of the Chinese version of specialist magazine Men's Health, which put him on the cover, his torso encased in a tight black T-shirt.

Earlier Thursday he told journalists at a farewell press conference that he could hold the excruciating plank position, an abdominal exercise that involves holding up one's body in a press-up-like position, for a punishing 51 minutes.

"On the plank, so much of it is all so mental," he said. "It is very tough and gruelling just to be in one position and how do you bide the time."