“I found at 68 I couldn’t jump as high as I could at 64,” he told Sky News on Saturday.
“I hit the platform on the side rather than on top and fell backwards, hit my head, was knocked unconscious for 20 seconds.”
Mr Palmer said “everything was fine” when he woke up but the people around him urged him to get checked out.
“I went and got a brain scan, which was very reassuring and found that I had a brain but that it wasn’t damaged,” he said.
“So I’m okay, everything’s fine.”
It was the big-spending mining magnate’s second stumble in recent weeks, having tripped as he left the stage following his National Press Club address on April 7.
Despite the stumble, he still managed to kick off the $70 million campaign today under a huge tent at his Coolum golf resort.
Hundreds of yellow-shirt-clad supporters gathered to hear from Mr Palmer and UAP leader Craig Kelly, who said the party would push for the enactment of a bill of rights.
“Save Australia, we must. Save Australia, we will,” Mr Palmer said.
He is running for the Senate this year, having failed to return to Parliament in 2019 despite his party spending more than $80 million on its campaign, most of which came from Mr Palmer’s Mineralogy company.
The massive political spending, vastly outstripping even the major parties, has drawn criticism from some corners.