The request came last winter from a friend who also would be celebrating her 60th birthday in 2017: Let’s do a triathlon together. And not just any tri, but the Ironman 70.3 Maine in Old Orchard Beach.

“I hemmed and hawed for about a month,” said Jade Doyle of Falmouth, who has run only one half marathon, and never immediately after swimming 1.2 miles and biking 56 miles.

Doyle eventually agreed and will be on the beach Sunday morning with her friend, Kate Kelly, also 60, of Cumberland, preparing to head into the water south of the Old Orchard Beach pier along with more than 2,000 other triathletes.

This marks the sixth consecutive year of an August triathlon in Old Orchard Beach, an event formerly known as the Rev3 Triathlon. This year’s race marks the first as part of the Ironman 70.3 series, which includes more than 100 similar events around the world.

Because of Ironman’s name recognition and popularity, the field more than doubled from last year’s race, whose organizer, Revolution3, will be back to coordinate the event.

“We have 2,300 athletes who are registered to race,” said Tracy Bryant, the volunteer director. “In the past, we’ve had around 1,000 athletes combined (for the Olympic distance and the 70.3-mile distance).”

Before the Ironman branding, Old Orchard Beach offered Olympic distance (1.5K swim, 40K bike, 10K run) as well as the 70.3-mile race. Aquabike, which consists of the first two legs, remains an option.

“It doesn’t matter to me at all,” Doyle said of the rebranding. “I didn’t sign up because it’s now the Ironman. I’m doing it because someone asked me to join them and maybe I have a little bit of an adventurous spirit.”

Mike Booth, 47, of Scarborough is a veteran of Old Orchard Beach triathlons.

“I have to be honest,” he said. “This is the first Ironman in Maine, so I want to do it. I live right off Pine Point Road in Scarborough, so it’s pretty unusual to do an Ironman event where you can sleep at home.”

Zev Myerowitz, 33, of Cape Elizabeth is the defending champion at the 70.3 distance, completing the 2016 race in 4 hours, 12 minutes, 40.22 seconds. He’s also gearing up for the full 140.6-mile Ironman world championships in October in Kona, Hawaii.

Bryant said the Old Orchard event requires roughly 1,000 volunteers.

“We have a lot more athletes who will be out there for a lot longer during the day, so we’ll need more people to support that,” she said. “We are well on our way. We’ve got a whole lot of new groups who are participating.”

State Sen. Justin Chenette of Saco is a longtime volunteer who said it’s a great fundraising tool for nonprofit organizations because the race pays $15 per volunteer per shift, which usually lasts three to four hours. Cheerleaders, wrestlers and student council members from local high schools will volunteer to raise money for their programs.

“It’s kind of a neat experience,” Chenette said, “and all the athletes are so appreciative of us being there.”

Activities get under way at noon Friday with the opening of the Athlete Village in Memorial Park. Briefings, bike check-ins and tech services also are available Saturday, and plenty of gear is for sale both days.

The race begins at 6:20 a.m. Sunday. An awards ceremony is scheduled for 3 p.m.

Thirty age-group qualifying slots for next year’s Ironman 70.3 world championships in South Africa are available for the winners of each men’s and women’s age division.

Athletes begin with a 1.2-mile point-to-point swim starting just south of the pier and heading north, entering the water two at a time at two-second intervals to avoid congestion.

Next up is a 56-mile bike ride that winds through Saco, Dayton, Lyman, Waterboro and Hollis before returning to Old Orchard Beach. Drafting is not allowed, nor is riding side-by-side.

The race ends with a 13.1-mile run to Scarborough and back, including a long stretch on the Eastern Trail.

All athletes are expected to finish within 8 hours, 30 minutes of the final swimmer entering the water.

“I’ll finish, I know that,” Doyle said. “It’s just a matter of how quick or how slow I am.”

Glenn Jordan can be contacted at 791-6425 or:

[email protected]

Twitter: GlennJordanPPH