After all, most of us don't dress like Olympic runner Usain Bolt when we go for a walk.

WSJ: An Urban Cyclist's Criteria

To claim they're worth it, CEOs don't actually have to be all that much better than the runner-up for the job.

WSJ: In Defense of the CEO

"The size of your feet change, and shoes don't fit you right, " says Thom David, a barefoot runner from Oceanside, Calif.

WSJ: Barefoot Jocks Keep Gym Members on Their Toes

What Democrats likely don't need are rivals with little hope of winning tearing down the front-runner.

CNN: A debate for Democrats is when to fold cards

"Even if I knew for sure that running fast had an element of risk, I don't know that I would back down, " said Foiles, the 56-year-old runner who lives in a Kansas City suburb.

WSJ: Endurance Sports: Studies on Older Endurance Athletes Suggest the Fittest Reap Few Health Benefits