Shelby Houlihan, who holds the U.S. record in the 1,500 and 5,000 meters, revealed Monday she was banned for four years after testing positive for a banned substance she says was tainted pork in a burrito.

Shelby Houlihan, who holds the U.S. record in the 1,500 and 5,000 meters, revealed Monday she was banned for four years after testing positive for a banned substance she says was tainted pork in a burrito.