By Tod Leonard

The San Diego Union-Tribune

SAN DIEGO — On her darkest days, Kathleen McCartney couldn’t fathom ever competing in the Ironman World Championship triathlon again.

The La Jollan had won the competition on Hawaii’s Big Island in 1982, famously passing a stricken Julie Moss in the final yards. Deeply in love with the sport, McCartney raced a handful more times after that.

In 2007, the mother of four was suffering debilitating back pain from a ruptured herniated disk.

“I was starting to lose leg function. I couldn’t walk properly. I was stumbling around,” McCartney recalled. “I had three kids who I was driving all over. I would somehow crumple myself into the car, take them to school, get through the day, cook dinner, and be on the couch with a heating pad.”

The 59-year-old competed in her 12th Ironman World Championship recently, amid a celebration of the 40th edition of the race. She finished the race in 15 hours, 52 minutes and 28 seconds. It has been 11 years since she underwent successful back surgery.

McCartney said the surgery saved her life and still didn’t put her on track for the Ironman.

“I decided to take a very, very conservative route,” she said. “I made the decision to never run again, to never do a triathlon.”

Another kind of pain flipped her thinking. In 2010, McCartney went through divorce after 25 years of marriage and felt as if she’d lost the essence of herself in the process.

“I needed to get my power and strength back,” she said. “Where am I going to find that? Of course, it was Ironman that makes me feel like a champion again.”

Having worked diligently to strengthen her core to avoid further back injury, McCartney resumed training again and did the 2012 Ironman, and she’s rarely slowed down since.

For the Ironman race that requires its participants to swim 2.4 miles, bike 112 miles and run a 26.2-mile marathon, McCartney no longer runs in training. In a normal week she puts in 160 miles on her bike, swims 90 minutes and walks about 12 miles.

Twice a week from her home in La Jolla, California, she rides the coast highway for 25 miles north to Carlsbad, where she serves as a patient liaison at the Tri-City Wellness and Fitness Center.

The commute includes the steep grade near the University of California, San Diego. On weekends, McCartney does one 60-mile roundtrip speed ride from her home to Oceanside harbor with a friend, Max Affarano, whom she drafts behind. They average 20 to 25 mph, though there is a coffee break that comes in each direction.

“You’ve got to have some fun, right?” McCartney said with a laugh.

And let’s remember: She is 59.

For McCartney, it’s never been about her age, because competing in Ironman is mental.

From the time she first watched the finish of the Ironman in Kailua-Kona in 1981, she believed it was something she was destined to do, no matter how audacious, considering she’d never extensively worked at any of the three disciplines.

“I had a dream. I believed I could do it,” McCartney said. “Once I believe I can do something and am committed, quitting isn’t an option. I don’t mean this to sound cocky, but Ironman gave me the belief that anything is possible. I believe that so deeply.

“Every single day since I did my first Ironman, I’ve believed that if someone came up to me and said, ‘Kathleen, can you do the Ironman tomorrow?’ I would have said yes. That’s the gift the Ironman has given me. It’s given me that strength, mentally and physically.”

In preparing for last year’s race, McCartney had a singular focus.

She wanted to cross the finish line with Mike Levine, a Stage 4 pancreatic cancer patient whom she was mentoring. Levine’s body, wracked by chemotherapy treatments, held up through the swim and 53 miles of the bike ride until he and McCartney had to stop.

“Mike wanted me to go on and finish,” McCartney recalled. “I said, ‘We’re here together. I don’t need another medal.’ We decided to stay together, and it was actually beautiful. It was as deeply moving and as rich an experience as any finish, I’ve ever had.”

Levine began training for this year’s Ironman, but his limited lung capacity didn’t allow him to continue, McCartney said.

She dedicated this year’s effort to Paul Smith, a cancer patient with whom she worked through her “Ironman in Minutes” program at Tri-City. Smith died in July.

Another patient in the program who is an inspiration is Katie Gutzwiller.

“I’m racing it for them,” McCartney said before the race. “And also just for life. This gives me life. It breathes life back into me every day.”