The last time Joan Benoit Samuelson and Michael Westphal ran together was for part of Mile 10 of the 1979 Boston Marathon.

They were both college students from Maine, and talked about Westphal’s sister (also named Joan), a former running rival of Samuelson and the only girl who ever beat her in a high school race.

On Sunday, they’ll continue their conversation at the Sugarloaf Marathon & 15K to celebrate their recent 60th birthdays and to raise money for the Michael J. Fox Foundation.

Samuelson will run the marathon, her first on Maine soil, and Westphal, who returned to running a few years ago as a way to deal with the effects of his Parkinson’s disease, will join her for the final 15 kilometers. Pelvic stress fractures prevented him from running Sunday’s full marathon as originally planned, when Samuelson greeted him at the finish line of the 2016 Boston Marathon – his first attempt at Boston in 30 years.

“It just happened spontaneously,” Samuelson said. “I said, ‘Michael, I’ve never run a marathon in Maine. When I do, it’s going to be with you.’ ”

The 35th running of the Sugarloaf Marathon is scheduled to begin in Eustis at 7 a.m. The 15K is scheduled to start at 7:30 in Carrabassett Valley, but Westphal plans to wait there until Samuelson arrives, probably around 9, and accompany her to the finish line in Kingfield.

“We were playing with different scenarios but that was the best plan,” Westphal said. “We decided (Friday) morning. She and I really want to run together.”

Westphal said he learned about the stress fractures in early February but didn’t get X-rays until a few weeks ago when the problem flared up again. When, unknowingly, he ran the MDI Marathon with a similar ailment two years ago, “I was crippled for about a month afterward,” he said. “So I decided I’m doing the 15K.”

Back in ’79, Westphal was a student at the University of Maine and Samuelson at Bowdoin College. He grew up in Minnesota but moved to Great Cranberry Island when he was 13. Samuelson grew up in Cape Elizabeth and settled in Freeport.

“I ran with her about a half-mile, from 9 to 9.5,” Westphal said. “Then I left her and kept going.”

Westphal reached the finish line on Boylston Street in 2 hours, 30 minutes, 26 seconds – good for 301st place overall. Samuelson, then known as Joan Benoit, set a course and American record of 2:35:15 and endeared herself to fans lining the course by wearing a Bowdoin singlet and a Red Sox hat, slightly askew.

She went on to set a world record in Boston in 1983 and made history in 1984 as winner of the inaugural women’s Olympic Marathon in Los Angeles. After graduating from Maine in 1979, Westphal won the 1980 Paul Bunyan Marathon (2:29:32), but family and his carpentry and caretaking business soon took precedence over competitive running. Until last spring, his most recent attempt at Boston had been in 1993 – and that run ended in Mile 9 with a knotted calf muscle.

A formal diagnosis of Parkinson’s came in 2006, about three years after symptoms first appeared. Others in his family also have suffered from the chronic and progressive movement disorder, which affects a half-million Americans. There is no known cure but the National Institute of Health supported $161 million in research in fiscal year 2016.

Rolf Westphal, Michael’s brother, said they don’t know whether the stress fractures are related to Parkinson’s disease.

“They’re doing more tests,” he said. “They want to check his bone density.”

Samuelson, meanwhile, has had a busy spring. She was in Los Angeles as part of a bid to host the 2024 Olympics and in Italy for a Nike-engineered assault on the 2-hour marathon barrier with three runners, one of whom, Eliud Kipchoge of Kenya, finished in 2:00:25.

Samuelson has another barrier in mind. No woman age 60 or older has run a marathon in under three hours. She plans to give it a shot in Chicago in October, even though the Sugarloaf course is known for fast times.

“I would like to go under three, but the intention is to try to do that this fall,” she said. “This (weekend) was all about Michael and it’s still all about Michael.”

A special joint fund-raising page for Samuelson and Westphal – dubbed Running Beyond 60 – has been set up on the Fox Foundation website. Their goal is $60,000. As of Friday, pledges were just shy of $17,000.

“It’s a celebration of sport and life and passion,” Samuelson said. “We’ve enjoyed the sport since we were high school athletes. The fact that we’re still in the sport and still passionate about it, and the inspiration that Michael shares with others in his quest to continue, that’s motivation for everybody, including myself.”

Five days after the Sugarloaf race, Samuelson will be honored with a tribute night at historic Hayward Field in Oregon to kick off the Prefontaine Classic.