Washing Donald Trump's hair and Bloomberg's meatballs: Offbeat moments in US election campaign

Donald Trump's fixation on water pressure, the bizarre tweets of Michael Bloomberg, a candidate who does push-ups at campaign gatherings, and another who can recite state capitals at lightning speed: AFP is starting its weekly list of the offbeat highlights from the run-up to the US presidential election.

In a country where the age of several front-runners in the race for the White House has raised concerns, 38-year-old Army veteran Tulsi Gabbard, a Democrat from Hawaii, performed a set of push-ups wearing high heels at a campaign stop in New Hampshire on Thursday.

Her show of force came after the Democratic frontrunner, 77-year-old Joe Biden, challenged Trump to a push-up contest after the president questioned his fitness.

During a campaign rally in Wisconsin on Tuesday Trump -- a notorious climate-change denier -- slammed the water-saving standards introduced by his predecessor Barack Obama, which he said affected the performance of toilets, sinks and showers.

"Sinks, toilets and showers - you don't get any water," Trump said. "They put restrictors on them, and now they've made them permanent."

"You go into a shower, and I have this beautiful head of hair. I need a lot of water," the president said to laughter, playing on longstanding speculation about him having hair implants.

Having missed the last Democratic debate, billionaire candidate Bloomberg had his campaign team send out a series of quirky tweets under the hashtag #BloombergFacts.

"Mike can telepathically communicate with dolphins," one said.

"Last year alone, Mike spent over $200 million dollars on scratch-off lottery cards," read another.

Another showed a plate of meatballs -- one with an image of Bloomberg superimposed -- and asked puzzled followers to decide which one looked most like the former New York City mayor.

Many US school kids are tasked with memorizing all 50 states in the union, but can they recite them in just 30 seconds? That was the challenge taken up by Democratic candidate Amy Klobuchar, a senator from Minnesota.

Hailing the fact that several Republican-led states now have Democratic governors -- Kentucky, Louisiana and Virginia -- she began to rattle off an alphabetic list of all the states in the union, cheered on by her supporters. "Alaska, Alabama, Arizona, Arkansas ... " she said, with barely a pause to draw breath. When she got to Wisconsin she proudly asked if any other candidate in the field could match her.