TIANJIN (REUTERS) - An exclusive bikini contest in China open only to those aged 55 and above.

The organisers call it the 'Grandbikini' event.

It kicked off on Saturday with more than 400 people showing off their figure at a local water park in Tianjin, including a handful of men eager to pose.

The contest is in its third year, organised by a senior citizens' committee to promote health and wellness.

A panel of judges rates participants on criteria such as stage presence, smiles and gestures, many of them already regulars to the contest.

They include the oldest participant, Ma Jing, a 78-year-old cancer survivor taking part in her blue bikini.

"I'm very honoured. If I can take part in a bikini contest at this age, for me, it means I'm mentally happy and physically healthy," she said.

By the time the event wound down, the jury handed out more than 100 awards.

But for many, it was more about confidence, encouraging a positive attitude towards growing older and perhaps trying to prove that age is just a number.