Ok - I'm not this bad, but there are times when its been tough..
Justin Gimelstob Likes Odds of Completing Marathon - Andy Roddick Does Not - NYTimes.com: "The highest tennis ranking he attained was No. 63 in 1999. Over his career, he has had 29 cortisone injections. He has a surgically implanted screw in his left foot and, as he explained, he sweats while brushing his teeth. Gimelstob is more likely to cramp up into the fetal position than run 26.2 miles in less than five hours, but those who saw him scratch his way through a 12-year tennis career say his determination will prevail."
I'm confident he can do it. If he's had the commitment to become a professional tennis player he's got to have some serious mental toughness.
Also I'm going to highlight this article next time my wife points out to the spin instructor at 24 Hour Fitness that "I'm a sweater" and asks that the fans be turned on.