Mexico's German Silva might have lost because he went for a drink of water. For seven-time women's wheelchair champion Jean Driscoll, it was a trolley track.

The Boston Marathon course has other pitfalls, from the ear-splitting cheers at Wellesley to notorious Heartbreak Hill. Fatuma Roba and Lameck Aguta eluded them all."I am told there is a hill," Roba joked after winning a laurel wreath to go with her women's Olympic gold medal. "But I didn't find it."

Aguta was more familiar with the course, having finished fourth the previous two years as he and his fellow Kenyans stretched their men's winning streak here to six in a row.

He made it seven - and the third different Kenyan to win in as many years - despite running 24 seconds slower than he did in 1996, finishing in two hours, 10 minutes and 34 seconds to beat countryman Joseph Kamau by 12 seconds.

"From Kenya, you work hard as a group and everybody can push for himself," he said of the new challenged posed by the Mexicans, who finished third and fourth with Dionicio Ceron and Silva. ". . . You have to fight for your country."

Last year was the big one for Boston - the 100th edition of the longest-running marathon in the world. Nearly 38,000 participants signed up to be a part of history, and they saw Moses Tanui end Cosmas Ndeti's three-year reign as champion.Roba ran steadily for the entire race, barely huffing, her arms barely moving as her legs pulled her along. She was among the leaders the entire way, pulling away from South Africans Elana Meyer and Colleen De Reuck to win by 45 seconds in 2:26:23.

Not bad for someone who had never seen the course before.

"This is quite challenging because Atlanta has less hills than Boston," said Roba, a 26-year-old Ethiopian who is the first Olympic champion, man or woman, to win the next Boston race. "I had friends who competed in previous years. They already told me, so I was quite ready."

That's what others have thought.

As far back as the 1907 race - its 10th anniversary - when a misdirected train blocked the way for all but the six leading runners, the Marathon course has posed an unusual set of problems for the competitors.

Ibrahim Hussein, who had already won twice by 1992, had to cover his ears when he ran through the "scream tunnel," the high-decibel welcome the runners get when they pass by Wellesley College. This year, one contestant was even bitten by a squirrel.

And the number of runners whose hearts were broken by the course's aptly named hills is too numerous to count.

Silva was the leader of a Mexican contingent set to break the Kenyan stranglehold on the men's division. But his hopes seemed dashed just after the five kilometer mark, when he was tripped up by another runner who, surprised by a traffic island, cut him off coming back to the course.

He angrily waved his arms to protest, but was back among the leaders by the five-mile mark.

Driscoll, of Champaign, Ill., had won every women's wheelchair race since 1990, tying Clarence DeMar's record of seven Boston titles. She was battling for the lead with Australia's Jean Sauvage as they came down Chestnut Hill Ave., ready to take the turn onto the last long straightaway into Kenmore Square.

But Driscoll's wheel found the rut of a trolley track, knocking her asunder and separating the tire from its rim. After a failed attempt to fix it, she wheeled the last four miles with a flat, finishing second to Sauvage.

Aguta and Roba each earned $75,000 from the purse of $500,000. Aguta's winning time was the slowest since Hussein's 2:11:06 in 1992, but the runners were plagued by a headwind that grew stiffer as the runners neared the Back Bay finish line.

Danny Gonzalez of Rancho Santa Margarita, Calif., was the top American finisher, coming in 19th. Kim Jones of Spokane, Wash., was the first U.S. woman, finishing ninth.