BOSTON (AP) -- Hundreds of runners dressed like superheroes raced down the final 18 miles of the Boston Marathon course Saturday, training for the world's oldest marathon a year after twin explosions killed three people and wounded more than 260 others.
On Saturday, the 300 runners included 26 members of Team MR8, who are raising money in honor of Martin Richard, the 8-year-old Dorchester boy killed near the finish line at last year's marathon.
About 350 applied to the Martin W. Richard Charitable Foundation for one of the 75 spots on Team MR8. Each runner committed to raise $7,500 for the foundation.
Those chosen to run for Team MR8 include former Massachusetts State Police Sgt. Sean Murphy, who was disciplined after leaking dramatic photos of bloodied bombing suspect Dzhokhar Tsarnaev during his capture.
''At the first meeting, we were all given a picture of Martin and having his image burned into my mind is enough to run 26 miles,'' Murphy said.
He said the most he had run before submitting his application was 5 miles, but that he felt compelled to run for MR8 because of Martin's tragic story.
''The Richard family was doing what any American family could have been doing at that time: They were out enjoying the day, watching the marathon, and they had their world rocked,'' Murphy said.
Team MR8 is the first fundraising initiative from the Martin Richard Foundation, a nonprofit dedicated to peace through community and education.
After the marathon, a photo surfaced of Martin holding a sign that read ''No more hurting people. Peace.'' The photo went viral, touching many around the world, including President Barack Obama, who quoted Martin's message in a speech after the bombings.
The money raised by Team MR8 will be allocated for projects that the foundation's board members are starting to plan now, according to Larry Marchese, a spokesman for the Richard family.
''Just like everyone else, we are showing that you can't use terror to change the way we live,'' Marchese said. ''It's solidarity with all of Boston and the rest of the country, and the other part of it is these runners are raising the seed money for this foundation.''
The superhero run was hosted by the North Andover-based nonprofit Charity Teams, and included 20 other fundraising groups.
Most MR8 members, who range in age from 20 to 60, are from the Boston area, but notable runners include Arizona U.S. Rep. Kyrsten Sinema, and Amby Burfoot, the winner of the 1968 Boston Marathon and editor-at-large of Runner's World magazine.
''To carry on the legacy of a little boy who loved to be a peacemaker in his community and he loved to run, this is just one way to give back to his family,'' said MR8 runner Tina Cassidy. ''There's great motivation to do well for this team, not just on race day, but promoting peace and hope and all the things Martin cared about.''