The handful of Islanders who ran the marathon this week were not the only ones who had trained for the big day.

Officer Jeff Trudel and Det. Michael Snowden of the Edgartown police department trained to be among 100 members of a special bicycle unit that patrolled the marathon route Monday.

After reporting for duty at 7 a.m. Monday morning, the two were stationed along the finish line while the elite athletes ran the final stretch.

Mr. Trudel stood near the site of the second of two pressure cooker bomb explosions which killed three people and injured more than 260 last year.

“It was an eerie feeling to be standing there at that time, imagining what it had been like,” he said.

Mr. Trudel and Mr. Snowden were part of a vast law enforcement presence which included agents from the state police, Federal Bureau of Investigation, and police departments across the commonwealth.

Onlookers were surprised to see Edgartown Police written on their backs, they said.

“On a couple of occasions, we’d hear, ‘Hey, Edgartown,” and turn around and there’d be three people taking pictures of the back of my shirt,” Mr. Snowden said. “They were impressed we were up there.”

When reached by telephone Tuesday, Mr. Snowden said he was sore; he had biked for most of the day and patrolled the area around Fenway Park where marathon and Red Sox crowds converged.

“I am proud of the guys we sent,” police chief Antone Bettencourt told the Gazette. “It shows what our department is all about . . . It is the least we can do for the city we use all the time.”

Bicycle training took place two weeks ago at the Fire Academy on Moon Island. Mr. Bettencourt said the crowd-control training will benefit the town of Edgartown, which plays host to the Fourth of July parade and fireworks display.

Islanders who ran the marathon this year included Jim Lanctot, Nedine Cunningham, Richard Koehler, Marylee Schroeder and Chantal Desgagne.