Washington DC - Marathon rehearsals, informal consultations, campaign rallies: Joe Biden and Donald Trump are each preparing in their own unique way for their televised debate next Thursday, the first in the 2024 race for the White House between the bitter rivals.

With a week to go, the Democratic president was set to head to Camp David, a mountainside retreat for US leaders close to the capital, Washington, to hone his attack lines and rebuttals.

Few details have been released about the 81-year-old Democrat's preparations, except that his former chief of staff Ron Klain will be involved and that one of Biden's aides will play the part of Trump in mock debates.

The Trump campaign has been downplaying the need for the formal dress rehearsals candidates usually plan, a change of tack from 2020 when the former president practiced with former New Jersey governor Chris Christie.

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"President Trump takes on numerous tough interviews every single week and delivers lengthy rally speeches while standing, demonstrating elite stamina," senior Trump advisor Jason Miller said in a statement.

"He does not need to be programmed by staff or shot up with chemicals like Joe Biden does."

In lieu of traditional training sessions, Trump has surrounded himself with influential senators and vice-presidential candidates to discuss issues likely to come up, from foreign policy to immigration, according to media reports.

The Republican, who was convicted of 34 felony charges of business fraud in New York in May, has also reportedly been crafting possible responses for when the debate inevitably turns to his legal troubles.

The showdown, scheduled for 9:00 PM in Atlanta, is the third between the two men.

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The last debates between the two men in 2020 were tension-filled affairs, with Biden at one point snapping, "Will you shut up, man?" as Trump repeatedly talked over him.

This time, moderators for host network CNN have more tools than usual to maintain decorum, with the microphones muted throughout, except for the candidate whose turn it is to speak.

Biden outlined his debate strategy in a recent interview with ABC: "Say what I think. Let him say what he thinks."

"The things he says are off the wall... I want to move in a direction where he talks about, you know, suspending the constitution," Biden said. "All I have to do is hear what he says – remind people what he says and what I believe, and what he believes. He's about him. I'm about the country."

Biden is also betting on a show of restraint to project stability in the face of Trump's drama and to press his message to voters that the twice-impeached Republican billionaire is a danger to democracy.

The president's camp pitched a much earlier debate than usual – these blockbuster encounters usually take place in autumn – in hopes that 90 minutes of unfiltered Trump would cement the Republican in voters' minds as the chaos candidate.

Biden campaign chairwoman Jen O'Malley Dillon said last month the president would go after Trump on abortion rights, threats to democracy, and his plans for "tax breaks to billionaires."

Biden has to convince his doubters on style as much as substance, however, and provide a robust response to attacks from the Trump campaign over his mental acuity.

It's been a long time since the president – whose stiff gait and sometimes slurred speech betray his age – appeared live, standing up, for 90 minutes.

His supporters are hoping to recapture the energy he managed to summon – and the praise he garnered – for his State of the Union address to Congress in March.

It was an uncharacteristically spirited performance for the octogenarian that clearly caught Trump off guard, prompting the Republican to insinuate without a shred of evidence that Biden might have been boosted by narcotics.

Trump, in fact, has repeatedly predicted ahead of speeches and debate performances that Biden would embarrass himself, a low bar that the president has invariably been able to clear comfortably.

Perhaps having learnt his lesson, Trump was anticipating a strong Biden debate performance as he suggested baselessly to rallygoers in Wisconsin on Tuesday that the president would likely be high on stimulants during the debate.

"He's going to be so pumped up!" Trump said.