The elite women runners start the Boston Marathon in Hopkinton, Mass. (Stew Milne / AP)

The men’s field is particularly deep, with champions from marathons including Chicago, New York, Amsterdam, Paris and Houston. The defending Boston champion, Robert Kiprono Cheruiyot of Kenya, set a record with a time of 2 hours 5 minutes 52 seconds over 26.2 miles last year, but has not run particularly well since. He placed sixth in his only other marathon of 2010, last fall’s race in Chicago.

Geoffrey Mutai has the fastest qualifying time, a 2:04.55 in a second-place finish at Rotterdam. Ryan Hall is the American men’s favorite — the race hasn’t been won by an American male since 1983. Hall finished fourth last year in 2:49 and third in 2009.

In the women’s field, Teyba Erkesso beat Tatyana Pushkareva by three seconds and both are back in a field that includes 15 women with personal bests of 2:26:30 or better. The top American, Kara Goucher, finished third in 2009 by nine seconds and is running again after giving birth last September to a son.

“I have run that race again about 1,000 times in my head,” Goucher told the Associated Press. “I just want to win this thing.”