People gather at the Boston Marathon finish line, Saturday, April 15, 2017, in Boston. The 121st running of the marathon takes place on Monday. (AP Photo/Michael Dwyer)
People gather at the Boston Marathon finish line, Saturday, April 15, 2017, in Boston. The 121st running of the marathon takes place on Monday. (AP Photo/Michael Dwyer) Credit: Michael Dwyer

The Boston Red Sox will host the Tampa Bay Rays at Fenway Park Monday morning, while at night the Bruins will battle the Senators in Game 3 of their first-round NHL playoff series at TD Garden.

Prior to those games, all eyes in Boston that day will be on the 121st Boston Marathon, the runners and the 26.2-mile course that makes its way from Hopkinton to Boylston Street in the heart of Boston.

Once a year, the city obsessed with its professional teams turns its attention to the worldโ€™s oldest marathon.

โ€œThe crowds are unbelievable,โ€ Amherst resident and Boston Marathon runner Bryn Geffert said. โ€œIt feels like the entire city turns out to watch.โ€

Geffert is one of about 90 runners from the Pioneer Valley who are registered to compete in the marathon.

Geffert, a librarian at Amherst College, did a lot of his training with a colleague during the afternoon. Some runners join groups, both official and unofficial, in order to train for the big race.

One local group that will be represented in Boston again this year is the Shutesbury Coffee Cake Club.

Named for its weekly Saturday morning runs that start at Amherst Coffee and Sunday morning runs that begin at Cushman Market & Cafe, the Coffee Cake Club includes frequent Boston Marathon runners like Amherst residents Tim Kliegl and Nick Hopley, in addition to less experienced runners.

The free-to-join, informal group runs various distances and at different paces in order to make all runners feel welcome, Kliegl said.

โ€œItโ€™s a social group and itโ€™s just a group of people who get along and enjoy running, and itโ€™s a very positive experience,โ€ said David Martula, 72, of Hadley. Martula will be running the Boston Marathon this year for the 14th time.

In addition to the weekend runs, the group trains together almost every morning during the week. The club provides a fun way to both socialize and exercise at a high level.

โ€œWell, they like to say that theyโ€™re sort of a social group that runs, but the truth is thereโ€™s a lot of really amazing, incredibly dedicated runners that are part of that group; of all backgrounds and ages and everything,โ€ Hopley said.

That mix of socializing and competition works well for the Boston Marathon. Monday is a fun day that boasts large crowds while the race is extremely competitive.

โ€œItโ€™s the most competitive of all marathons in terms of for the average amateur runner, you can be up against all the best other amateur runners in the country, and really the worldwide appeal of it,โ€ said Hopley, who will be running for the 24th time out of the last 26 years.

The marathon also includes a large group of runners raising money for charity.

Pelham resident Jim Duda will once again be running for Credit Unions Kids at Heart, which raise money for Boston Childrenโ€™s Hospital.

According to Duda, each runner in the group is paired with a patient partner from Boston Childrenโ€™s Hospital, and the families of children treated by the hospital volunteer to hand out water during the groupโ€™s training runs, helping to form this great charitable running community.

Duda said that the group of about 21 runners has raised close to $400,000 this year to donate to Boston Childrenโ€™s Hospital.

โ€œItโ€™s sort of this magical thing,โ€ Duda said. โ€œYou go out there and run, put one foot in front of the other, and thereโ€™s all these volunteers that are out there helping to make that happen and at the same time thereโ€™s all these other people that are donating considerable money for the kids. And if you think about it sort of rationally it doesnโ€™t make a whole lot of sense, but it does all come together.โ€