BILLERICA -- On a snowy day in February of last year, Dr. Bryan Lyons, a Billerica dentist, sat quietly doing paperwork inside his Boston Road office. Business was slow on this day, with the messy weather keeping clients home.

Then came a phone call that left Lyons at a loss for words.

"I remember it like it was yesterday," said Lyons. "Dick Hoyt called me -- he was on a layover in Texas. He said, 'as you know, (2014) will be our last Boston Marathon.' I said, 'yeah, it's going to be exciting.' Then Dick says, 'but Rick (Dick's son) would like to continue to run. And we want to know if you'd run with him?' I was just speechless.

Then Dick says, 'are you there, Bryan?' It was such an honor."

If you were to ask a random person on the street to play word association with the Boston Marathon, there's a strong chance he or she would respond with "Hoyt."

The father-son duo of Dick and Rick Hoyt, from Holland, Mass., are synonymous with The Hub's iconic 26.2-mile race. The 74-year-old Dick and 53-year-old Rick completed 32 Boston Marathons together. Rick was born a spastic quadriplegic with cerebral palsy, unable to walk or talk, so Dick runs races while pushing Rick in a custom-racing wheelchair.

Team Hoyt first took shape in the spring of 1977 when Rick told his father that he wanted to participate in a five-mile benefit run for a lacrosse player who had been paralyzed in an accident.

Dick agreed to push Rick in his wheelchair and they finished all five miles, coming in next to last. The pair has since completed over 1,100 races, including six Ironman competitions. They also biked and ran across the U.S. over a 45-day span in 1992. Their well-documented story is both legendary and inspirational to people all over the world. (The foundation, formed in 1989, aspires to build the individual character, self-confidence and self-esteem of America's disabled young people through inclusion in all facets of daily life.)

The years of competition and travel certainly took a toll on Dick's body. Due in large part to his increasing back pain, he decided 2014 would be his last marathon pushing Rick. That opened the door for Lyons, a close family friend and member of The Hoyt Foundation marathon team since 2008.

"World-class athletes, professional triathletes had said to Dick, 'hey, when you're done, I'd love to take over and push Rick,' " said Lyons, a Methuen resident who has had his dental practice in Billerica since 1996. "But it was always no. If you read any of Dick's books, neither was going to continue without the other. It was sort of shocking for him to ask me.

"My friends told me (the Hoyts) don't want the big name, they want the big heart.

If that's the least that I can provide, I'm happy."

Lyons is also a very accomplished triathlete and runner. April 20 will mark his seventh Boston Marathon. Dick, who will serve as grand marshal of this year's marathon, still plans to participate with Rick in shorter races. But for the marathon, Rick's favorite race, Lyons was an easy choice to fill the void.

"I think we got the right guy," Dick said. "It's just Bryan's personality and everything. He's an awesome guy and the right guy to do what we're doing. You know, he's not going to go out and run a 2:05 marathon. But he's a great human being who enjoys running and pushing Rick, and we've been great friends."

Lyons and Rick have been hard at work training since the start of the new year, participating in several local races. When Rick is not available to train, Lyons pushes the wheelchair loaded with two 60-pound sand bags to simulate Rick's weight.

Lyons grew up in Nashua before attending the University of New Hampshire followed by Tufts Dental School. He was always active, but running was a secondary source of fitness to him, behind soccer and skiing.

In college, and soon thereafter, he treated running as a way to maintain fitness, but slowly developed a deeper appreciation for it. He ran his first marathon in 2000 in Myrtle Beach, S.C.

One year later, things changed.

On the night of Feb. 6, 2001, Lyons was driving home from work when his vehicle was struck by a drunk driver in Billerica. He didn't suffer any life-threatening injuries, but the physical and emotional damage was still palpable.

"It was a long, arduous road to recovery," Lyons said. "It took me until July 17 to be able to sleep through one night without waking up with back pain. I literally had to sleep sitting up. It took me 11 months to run one mile without back pain, and almost five years to run five miles."

Lyons ran his first half marathon -- post-car accident -- in January 2006. His time was a half-hour slower than before the accident.

"I was pretty discouraged," he remembered.

A friend recommended triathlons to Lyons, thinking that the variety (swimming, biking and running) would reinvigorate him. He completed his first triathlon in the fall of 2006, and fell in love with it.

Lyons signed up for a local triathlon club called TriFury. Dick's brother, Jason, is also a member of TriFury and he sent out an email in the fall of 2008 saying that Team Hoyt was looking for runners for the marathon team.

"To be able to run Boston with Team Hoyt was, to me, the best," said Lyons. "Within minutes of getting that application, I contacted Team Hoyt and told them I want in."

The original plan was for the 2013 Boston Marathon to be Dick and Rick's last together, but they were not able to finish the race due to the bombings. They then decided to come back again in 2014 to complete the course one final time.

The torch has now been passed to Lyons. When he talks about the opportunity to push Rick, the expression on his face tells the story. He is clearly honored, a stray tear welling in the corner of his eye.

"Bryan will be out there, and he'll do his best, we know that," said Dick. "He's a great athlete, a great person, and the type of person that we want to be pushing Rick. And Rick wants Bryan to be the one to do it."

Follow Matt Langone on Twitter and Tout @MattLangone.