It’s rare for Paul Nitz to do anything slowly. During a track career that has spanned five Paralympics, the Edina native has earned a reputation as one of the world’s speediest men on wheels, winning multiple gold medals and setting a world record in the 100 meters.

This year, though, Nitz has been in the unusual position of trying to make up for lost time. After two years away from elite competition, he didn’t decide until January that he wanted to train toward the 2016 Paralympics. That left him only 4½ months to prepare for this week’s U.S. Paralympics track and field championships in St. Paul, an early stepping-stone on the road to Rio.

At age 46, Nitz is a quarter-century older than young American star Ray Martin, who broke Nitz’s world record earlier this month. But after coming back from a near-fatal staph infection in 2003 — and taking the bronze medal at the 2012 Paralympics — he knows how to rally. With a wealth of experience, the support of his family and what he calls “an unhealthy amount of stubbornness,” Nitz is hoping to get back on a roll when the national meet begins Friday at Hamline University.

“I wasn’t quite sure I was going to make another run at it,” said Nitz, who moved back to Minnesota in 2013 after 21 years in Connecticut. “Each four years, you get four years older, and you lose a little bit of motivation. But being back around my family re-energized me, and my training started to show improvement.

“My procrastination in getting the ball rolling means I’m not as far along as I would have been if I had kept training after London. But I’ve given it my everything in every workout — and considering where and when I started, I’m as well prepared as I can be.”

Nitz lives in Minnetrista near the track at Mound Westonka High School, where he trains five to six days per week. He returned to his home state to be closer to his family, which will be at Hamline to see him compete in the 100, 200 and 400 meters.

Cathy Sellers, high-performance director for U.S. Paralympics track and field, said Nitz is among the greatest athletes of all time in the T52 classification for competitors who race in wheelchairs. He won a pair of gold medals — in the 100 and the 4x100 relay — in his Paralympic debut in 1992. Nitz defended his 100 title at the 1996 and 2000 Paralympics and raced in three events in the 2012 Paralympics, finishing sixth in the 200 and seventh in the 400 in addition to his bronze medal in the 100.

Three years ago, at age 43, Nitz recaptured the world record in the 100 with a time of 16.73 at a meet in Switzerland. Though his lengthy career isn’t unheard of for a wheelchair sprinter, Sellers said that setting a world record at that age is remarkable — and yet perfectly in character for a man who never stops pushing.

“Paul was a pioneer for that classification, and he’s been a catalyst for younger athletes,” Sellers said. “He set the bar high. And his attitude has always been, ‘Come on. Come and get me.’ ”

Nitz’s spinal cord was severed during his birth, leaving him without the use of his legs. As a kid, he participated in several of the sports programs offered at Courage Center — now Courage Kenny Rehabilitation Institute — and excelled at basketball, earning a place on the wheelchair team at Southwest Minnesota State.

Though he didn’t take up track until 1990, Nitz found his athletic calling in the sprints. His hopes for a fourth consecutive Paralympic gold in the 100 were ruined when a massive staph infection hospitalized him for three months in early 2004 and required multiple surgeries. He made the team for the 2004 Paralympics in Athens but did not medal; things got worse in 2008, when the lingering effects of that illness contributed to his failure to qualify for the Beijing Paralympics.

Nitz persisted despite more health issues in 2011, and he surprised even himself with the world record and Paralympic bronze in 2012. Given that comeback, he is optimistic that he will be in contention for a sixth Paralympic appearance.

This weekend, he will face Martin, 21, who won four golds at the 2012 Paralympics and broke Nitz’s world record two weeks ago with a time of 16.46. The national meet will determine the U.S. teams for October’s world championships in Qatar and the Parapan American Games in Toronto in August; ideally, Nitz said, he will race well enough to make one of those rosters.

If not, he plans to continue rolling toward Rio — knowing that the race goes not only to the swift, but to the stubborn.

“I’ll have to really step up my game, but I’m getting closer,” Nitz said. “Some people’s bodies might slow down at [age] 30. Mine has not.

“It will take a fair amount of work, more than it took when I was 26. But to be able to pull on the USA [jersey] again, that’s the ultimate goal.”