At age 51, Dave Voss doesn't talk about himself as a master triathlete. More like a conscientious worker: "I'm pretty good, but I love it, I work at it, and I just never quit."

"Some people think I'm nuts," he added. "Look at my face at Mile 22, say, and maybe all you see is the pain and the strain. But I'm on such a high. Even if I'm not doing well, I'm figuring out how to get on track."

Voss has been active all his life -- a little soccer, baseball, jogging, biking, chasing after bad guys as a Minneapolis cop. But not until age 40 did he run his first marathon, and at 46 took on grueling triathlons -- at maximum "ironman" distance, that includes swimming 2.2 miles, biking 112 miles and running 26.2 miles over 12 to 14 hours.

"Winning is great. Completing is important. But I love just doing it," he said. "Competing or training, it's almost the same thing."

Married to a Minneapolis police lieutenant, Voss is a sergeant who has worked assaults for six years and homicides for a decade before that. He grew up in the Chicago area and was a police officer in California before Minnesota.

In front of his wall of medals and plaques, he talked about mastery and why it matters.

What is mastery? "It's experience plus will power. Mastery is knowing I can pace myself, but still push a little farther, a little faster, a little smarter, even if I'm exhausted. It's not being better than anybody else, but being the best I can be. I'm still the student but I'm the teacher, too, helping rookie athletes or rookie cops."

How did you start? "After my first marathon, I was on a hotel bed in Duluth with ice packs on my legs and I'd had it. No more. Until I woke up from a nap and thought, gee, I should be able to do better than 3:57 [Last year, he ran that marathon at 3:02.] The triathlon seemed like a good challenge. After my first triathlon, I was hooked for life. Now I use marathons to train for triathlons."

What is training like? "I'm up at 4:30 most mornings to run or bike for an hour or so. When I'm in full training, most of the year, I'll work out again at night for a couple hours, then three to five hours on weekend days. At the peak, I train about 20 hours a week. And I pay attention to my food."

What's the sacrifice? "I couldn't do this without support from work and my family. The department gives me flex time so I can train and compete. When I started, I joined triathlete coach Matt Haugen and his Performance Power team for three years. Erik's Bike Shop is my major sponsor, so I get to ride a $4,000 bike I could not afford. But without my wife, I couldn't do this. Right now, I'm training light, so we can do more together, like go to church. Church is important to me, but I think God understands triathletes."

Does mastery help other parts of life? "I'm a better cop. I'm more fit mentally and physically than ever before. As a detective I don't usually run after people, but once I was chasing a guy and hollered out, 'I can run to White Bear Lake. How far can you go?' The guy just gave up." [He credits Minneapolis policeman and runner Jim Heimerl with first use of that line.]

What's your ultimate goal? "My dream is to compete at Kona, the Hawaiian Ironman Triathlon, the world championship. I'd have to come in near the top in my age class at one of the qualifying triathlons. And I want to live in Florida and be the 85-year-old runner passing all those 55-year-olds."

Warren Wolfe • 612-673-7253