Kelly Gneitling is a three-time United State's national champion in sumo wrestling and has the 405-pound frame one would expect of a man who holds those titles.

On Sunday, he'll run the Los Angeles Marathon in an an attempt to snag a Guinness World Record for the heaviest human to finish a 26.2 mile race.

Gneitling actually completed the L.A. Marathon in 2008, but he hadn't notified Guinness, so they weren't able to verify his weight.

His time in 2008 was a snail-like 12 hours, but Gneitling hadn't trained before that race, and has been training for the past few months for this one.

By finishing the race, and becoming a Guinness Book of Records holder, Gneitling hopes to prove that "big people can do the unimaginable."