During an ideal week of training, Matt Payne logs 250 miles on his bicycle, 40 miles on the running trails and 15,000 yards in the swimming pool. But with most of his time already spoken for — by his wife and two young children, and a career as a mechanical engineer — Payne usually doesn’t have the luxury of devoting that many hours to preparing for triathlons and duathlons.

So the Columbia Heights resident does much of his training in a most practical manner: by riding his bike to work and to the swimming pool, and running during his lunch break. That routine has built Payne, 38, into a national champion. Saturday, he will return to Harriet Island in downtown St. Paul to defend the title he won last year at USA Triathlon’s duathlon national championships.

In duathlon, competitors begin with a run, followed by a bike race and another run. More than 500 men and women will compete for titles at the standard distance (5-kilometer run, 34.5k bike, 5k run) and sprint distance (2.5k run, 23k bike, 2.5k run). The event also is a qualifier for the 2016 world championships in Aviles, Spain.

“I get out for longer rides and runs on weekends when I’m not competing,” said Payne, who was USA Triathlon’s 2014 male duathlete of the year. “But I roll a lot of my training into the workday. If I ride to the pool to swim, then ride to work and ride home, that’s 2½ hours on the bike. And I can still have dinner on the stove by the time my wife and kids get home.”

A former marathon runner, Payne turned to triathlon when he began biking and swimming while recovering from running injuries. Though he didn’t start racing until he was 29, he has improved with age. Payne won a national age-group title in sprint-distance triathlon last year, and USA Triathlon named him honorable mention men’s age-group triathlete of the year.

Payne said many of the same people compete in duathlons and triathlons. He does about 12 races per year, and he credited Minnesota’s circuit of high-quality events for developing a number of athletes who will be chasing titles Saturday. Ashley Heinlein of Stillwater, who finished second in the women’s 20-24 age group in the sprint division at the 2014 nationals, said duathlon is popular in Minnesota because athletes can still run and bike when the lakes are frozen.

“More people are becoming familiar with it,” said Heinlein, 23, who has raced in three world duathlon championships. “The sport is expanding, which is fun to see.”

Heinlein and Payne agreed that the race layout on Harriet Island is good for athletes and spectators. The three-lap bike course includes a climb up a steep hill on Ohio Street, while the two-lap run course is flat and fast.

There is no prize money for winning the national duathlon title, Payne said, but he got loads of free merchandise — and the satisfaction of reaching a personal goal in his home state, in front of friends and family.

“This is the only hobby I have,” he said. “When you go out and race, you want to win. And it’s really cool when you actually do.”