Career Highlights: At age 36 - he'll be 37 while in London - Keflezighi became the oldest man ever to win the U.S. Olympic Marathon Trials by posting a personal-best time of 2:09:08 in Houston. The surprising 2004 silver medalist in the Athens marathon returns to the Olympics after missing the 2008 Beijing Games, struggling during those trials with illness and injury. Born in the African nation of Eritrea, Keflezighi came to the United States in 1987, went to high school in San Diego and attended UCLA, winning NCAA titles in four different events in 1997. The next year, he became a U.S. citizen, and he's gone on to set the pace for American distance running. His medal in Athens was the first for an American man in an Olympic marathon since Frank Shorter in 1976, and in 2009 he became the first U.S. man to win the New York City Marathon since Alberto Salazar in 1982. Keflezighi once held the American record in the 10,000m (27:13.98), having won the U.S. Olympic Trials in that event in 2000 and 2004. He finished 12th in the 10,000m race in Sydney. Keflezighi currently trains above 7,000 feet in Mammoth Lakes, Calif.