(1) Teddy, though outwardly somewhat portly, was an endurance outside explorer. He was also tough as nails and a competitor. You want runners like that on your team. He'd make my top five.
JFK - more just an image of an athlete but really hobbled by addison's. (Also could be a distraction with all the partying and hot chicks that gravitate around him to the other team members)
(2) GWB - good runner, I'd keep an eye on the drinking and partying, but he makes the team.
(3)Carter - he's on team, I wouldn't make him captain, he'd be writing out everyone's eating, sleeping, and social schedules to the minute.
(4) Thomas Jefferson - he looks fast, and every team needs that one nerdy asperger's guy.
(5) Obama - no explaination needed, I'll really have to make sure he doesn't smoke, ever.
(Alternate) Nixon - you need the runner on the team with the killer instinct, who will do what ever he needs to do to win.