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Ahead of a vice presidential debate that could sap or seal Mitt Romney's polling momentum, fitness-obsessed Paul Ryan has been preparing with the P90X of debate workouts.

According to attorney Ted Olson, who played the role of Vice President Biden during practice, the Republican running mate has held a whopping nine 90-minute prep sessions. The sparring rounds were held across the country, from Wisconsin to Oregon to Virginia. And Olson says Ryan is ready.

President Obama, though, expressed confidence in his man ahead of Thursday night's faceoff in Kentucky.

"Joe just needs to be Joe," the president told ABC News. "Congressman Ryan is a smart effective speaker, but his ideas are the wrong ones."

Though vice presidential debates are typically a sort of intermission between the more closely watched presidential debates, the Biden-Ryan contest could have more of an impact, which could explain the intensive practice sessions. It comes as the polls in the race take a turn on the heels of Romney's dominating performance against Obama last week in Denver. The Republican nominee has closed Obama's lead in several swing states and in some polls has surpassed the president nationally.

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Romney is depending on Ryan to sustain the momentum going into the final two debates, while Obama is banking on Biden to blunt it.

As with the last round, each campaign is taunting the other.

Ryan noted Biden has been on stage "many times before," but said he's got an Achilles heel -- "President Obama's record."

The Obama campaign is continuing to hammer the message that the Romney campaign is playing fast and loose with the facts on the debate stage.

"We now know that Mitt Romney will say anything to win, even if it's not true," deputy campaign manager Stephanie Cutter said in a memo Thursday. "The question now is whether Ryan will adopt the same dishonest strategy or if he'll stand by the very extreme positions he's taken as the 'intellectual leader' of the Republican Party."

The 90-minute debate at Centre College, a liberal arts school with just 1,340 students in tiny Danville, is sure to draw a television audience of tens of millions. But it's unlikely to eclipse the 70 million who tuned in to watch Biden face off with Republican firebrand Sarah Palin four years ago.

Thursday was a rare day when the political activities of the running mates were taking center stage and those of Obama and Romney were seen as secondary. But with just 26 days left until the election and the race still tight, neither Obama nor Romney was completely ceding the spotlight. The president was hunting for votes in Florida while his GOP opponent devoted time to North Carolina, another battleground.

Thursday's debate, moderated by Martha Raddatz of ABC News, will cover both foreign and domestic topics. The debate is to be divided into nine 10-minute segments. At the outset, Raddatz will ask an opening question, and each candidate will have two minutes to respond.

"I think Paul Ryan will do great," Romney told supporters at a town hall meeting Wednesday in Mount Vernon, Ohio.

He said the debates offer people a rare chance to see the candidates directly, unfiltered by misleading and negative ads.

The GOP nominee said he'd seen some of the anti-Romney TV ads running in Ohio that morning, and added, "It's a good thing I don't do that very often because my blood pressure would be very high."

Obama, in a radio interview Wednesday with Tom Joyner, said he'd been "too polite" in his debate with Romney -- a sure sign that Biden won't be going easy on Ryan. And that Obama won't make the same mistake in the next two presidential debates, on Tuesday in Hempstead, N.Y., and Oct. 22 in Boca Raton, Fla.

"We've got four weeks left in the election, and we're going to take it to him," Obama said.

Later, in an interview with "ABC World News," Obama minimized the importance of his poor first debate performance, saying: "Gov. Romney had a good night. I had a bad night. It's not the first time I've had a bad night."

Fox News' Ed Henry and The Associated Press contributed to this report.