Sam Thompson has run the entire length of the Appalachian Trail. He’s finished dozens of marathons and even a few ultramarathons. A few weeks ago, he ran a 50-mile race just to get in shape.

Even his closest friends, however, are shaking their head in disbelief at Thompson’s next challenge.

Fifty-one marathons. In 50 states. In 50 days.

&#8220‘You’re nuts’ is the general reaction,” Thompson said with a laugh. &#8220But after I talk to somebody for five minutes they understand why I’m doing it.”

The idea had been bouncing around Thompson’s head for a few years before Hurricane Katrina gave the 25-year-old former Vicksburg resident the spark to try it.

Thompson went to the Mississippi Gulf Coast immediately after the storm to help with cleanup efforts, and has been there since. Most days, he supervises a crew of about 100 volunteers from the First Presbyterian Church in Bay St. Louis. As the work slowly progressed, Thompson thought the &#822050 in 50 in 50” idea – he’ll also run in Washington, D.C., upping the total to 51 marathons – would provide a good fundraiser for relief efforts.

Setting up a fundraising organization proved too difficult to do, however, so Thompson is running the marathons to raise awareness for Katrina victims.

&#8220Like somebody told me, I had the idea and now I had the cause, so I better get busy,” he said. &#8220It was too hard to get everything in place (for fundraising). I am officially raising awareness for the Mississippi Coast. People need to realize things are not fixed down there.”

Thompson added that, as demanding as the 51-marathon challenge will be, it will give him a break from the mental stress of the cleanup efforts.

&#8220I’m really just excited to take a break from down here. As long as I’m on the Coast, I’m working every hour I’m awake,” he said. &#8220It’s great to help people, but at the same time it does break you down.”

Thompson’s quest will begin with a marathon in Leadville, Colo., this morning and end with a run in Bay St. Louis on Aug. 19. In between, he’ll run nearly as much to catch rides and planes as he will on the ground.

He’ll also cheat a little.

The official marathon schedule is pretty light during the summer months, and finding 50 marathons in 50 days in 50 states is literally impossible. So to keep his plan alive, Thompson will run certified 26.2-mile marathon courses on his own time. Only five of his marathons will be run on actual racedays, but local running clubs and media will help certify his runs.

While that may make it easier to squeeze in a brisk 26.2-mile jaunt, it does nothing to ease the demands of travel and the havoc they can wreak on the schedule. To make it to Cordova, Alaska, for example, he’ll run through California’s Napa Valley in the middle of the night.

&#8220I’ve got some weird runs. Just to be able to make the flight to Alaska I’ve got to run the Napa Valley course in California at 2 a.m.,” he said. &#8220I don’t think most doctors would recommend it.”

The King Salmon Marathon on July 8 in Cordova – a town in southern Alaska accessible only by boat or plane – is part of the grueling western swing of the trip. It is the eighth marathon on his list, and will be followed by a run on the Seattle Marathon course the next day. From there, Thompson will go to Boise, Idaho and Phoenix, Ariz., before hopping a plane to Honolulu.

Thompson will run through a course there, then get on the plane and return to the mainland for a jaunt through Albuquerque, N.M., on July 13.

A support staff will travel with him and help with some of the driving, giving Thompson much-needed rest. Still, the combination of desert heat, mountain air and jet lag could become Thompson’s biggest challenge. He’s hoping the routine of running will carry him through it.

&#8220I really think by that point it’ll become second nature. My body will become accustomed to it,” he said. &#8220I’m hoping by that point it will become the normal thing to do. You get up, you run a marathon.”

That’s nothing new for Thompson, whose earlier exploits include a 100-mile race in Texas in 2005 and running the length of the 2,175-mile Appalachian Trail in 2004. Those were different types of challenges, though. The Texas race was a one-day event, while the Trail run allowed him to take a few rest days here and there.

The 50 in 50 in 50 challenge offers none of those safeguards.

&#8220It’s definitely comparable (to the Trail run), but in a lot of ways this is tougher. There’s essentially no rest time. If I’m not running, I’m driving,” Thompson said.

Thompson jokingly added that he did have one insurance policy if the physical demands become too much for his body to take.

&#8220My brother is an orthopedic surgeon. He said that whatever I break, he’ll fix,” Thompson said with a laugh.