Mo Trafeh grinned at his metaphor, describing in primal terms the pursuit that will play out in Sunday's USA 10-mile championship.

"It's just like the lions chasing the gazelles,'' said Trafeh, the defending champion. "The gazelles might be faster, but the lions are stronger."

Last year, Trafeh played the part of the lion, with Janet Bawcom co-starring as the gazelle. The race -- which is the opening act for Sunday's Twin Cities Marathon -- gives the women a head start on the men, with an extra $10,000 in prize money going to the first runner across the finish line. Trafeh ran down Bawcom with a half-mile to go to earn the bonus in 2011, and both will run again Sunday as part of an accomplished field in a race that awards $12,000 to both the men's and women's winners.

The equalizer bonus proved so popular last year that race organizers will offer it again. The women will start shortly after 7:02 a.m., getting a head start of 6 minutes, 31 seconds on a men's field that will take off at 7:09.

Bawcom also ramped up the intrigue when she proved in March that the gazelle can prevail, beating Trafeh to the finish line after a seven-minute head start in the U.S. 15-kilometer championships.

A member of the 2012 U.S. Olympic team, Bawcom, 34, is the top seed in a women's field that includes fellow Olympians Kara Goucher and Julie Culley. Goucher, a Duluth native, is seeded second and won the U.S. half-marathon title in her hometown last June. Trafeh, 27, is the No. 1 seed among the men, with four-time Olympian Abdi Abdirahman seeded third.

More than 20,500 runners have entered Sunday's 10-mile and marathon, which follow a course through Minneapolis and St. Paul and end on the State Capitol grounds.

"I really like the equalizer," said Bawcom, who became an American citizen in 2010 and finished 12th at the London Olympics in the 10,000 meters. "It makes the race more exciting for everybody. We have a really good field, and we're going to work hard and do the best we can to see the women get the equalizer.''

The bonus was adopted as a way to lend more fun and excitement to the race, and as an added attraction to elite runners. The women got a seven-minute head start last year. Virginia Brophy Achman, executive director of race organizer Twin Cities in Motion, said the strength of the women's field was among the factors that led to reducing the advantage this year.

The race directors look at athletes' past performances, course records and times from other elite 10-mile races to determine how much of a jump the women should get. Brophy Achman said the women's field started at a slow pace last year, but with three Olympians competing, she anticipates they will push each other to a faster pace Sunday. That led race organizers to shave 29 seconds off the head start, in the hope of setting up a sprint to the finish between the male and female leaders.

Bawcom said she expected the men to catch up with the women at the 7- or 8-mile mark last year. She was crestfallen when she remained in front entering the final mile, only to be passed by Trafeh. He won the race in 46 minutes, 46 seconds, while Bawcom earned the women's title in 54:15.

Both said that with $10,000 at stake, the equalizer alters race strategy. Culley said the women, knowing the men will be gaining ground, must go out faster to create a gap too wide to overcome. Trafeh said the men will help each other, and they have a built-in advantage as the pursuers.

"[The women] might spend a lot of time looking back and wondering where we are,'' said Trafeh, winner of four U.S. distance titles in the past two years. "That might make them a little more nervous than we are. It's a lot of fun."

With so many top runners, it could be just as fun for the spectators. Abdirahman, who did not finish the Olympic marathon in London because of a tendon injury in a knee, said he is fit, healthy and motivated to win. Trafeh's time last year was the second-fastest in race history, trailing only Abdirahman's 46:35 in 2009. Bawcom has won the U.S. 15K and 25K titles this year; Goucher set the course record of 53:16 with her victory in 2008.

"It's going to be hard, and it's a great field," Bawcom said. "But I'll do anything to try and outrun the guys."