Right on a street corner in downtown Flint, Mich., Bobby Crim drops his backside to the wet sidewalk, spreads his legs wide… wider… ouch… and slowly lowers his head, that famously clever head that masterminded Michigan state politics for two decades, until his forehead touches the pavement. Mission accomplished, he pops to his feet like he was fired from a toaster.

Bobby Crim, by the way, is 85 years old.

“Ready for a run?” he asks.

Joining us are a pack of guys who, like Bobby, are never not ready. For 40 years, most of them have joined Bobby every single August for his namesake race, the Crim 10-Miler. But as streaks go, this is one case where the run is even more impressive than the runners. Few American cities have survived the string of calamities that Flint has endured: auto plant shutdowns, poisoned drinking water, a three-time F.B.I. ranking as the most dangerous city its size in the country. Yet somehow the race that Bobby began in 1977 remains as festive and unbreakable as Bobby himself.

So what is Bobby’s secret? How can a man born during the Hoover administration not only keep running three races in one weekend (after finishing the 5K and 10-miler, Bobby hustles back to the starting line to join his two great-granddaughters for the Teddy Bear Trot), but make it such a blast that thousands of people want to join him? Bobby must be a master of both persuasion and human performance, and that’s why I’ve come to Flint: to see if Bobby can help me, a man in his mid-50s, prepare both myself and a donkey to run a long-distance race together through the Rockies.

“You’re not going to believe this,” Bobby says as we begin our jog with three locals including Ryan McLincha, who’s not only run every Crim but is currently kayaking from Flint to the Statue of Liberty. “But one of the best years we ever had was after news about the water crisis broke.” More than 15,000 runners showed up for the Crim last August, the second largest field in the race’s history.

Bobby began his career as a schoolteacher who fought an underdog’s battle into politics to advocate for kids, but despite the millions he’s raised for the Special Olympics and the eight years he’s spent as a state House speaker, few things have ever moved him like last year’s race.

“At our worst moment, when all you saw on TV was how Flint was this horrible hellhole, people turned out like never before,” Bobby says.

And why? Because of an insane idea that never should have worked: They made the Crim less spectacular, instead of more.

“It’s a prescription that’s applicable everywhere,” he says, even to the problems I’m having running with my donkey. Bobby is no burro racer himself, but as a Democratic state representative who became known for his unlikely friendship with the Republican governor William Milliken, to him the solution seems obvious. “You’ve got to prove you care.”

Years ago, superstar runners put the race on the map, building it from a local fun run into a showcase for legends like Bill Rodgers, Uta Pippig and Catherine Ndereba and the Olympians Ed Eyestone, Dathan Ritzenhein and Molly Huddle. It takes big money to lure that kind of talent, and the Crim stepped up: $40,000 was earmarked for podium prizes, meaning top pros pocketed five figures for less than an hour’s run. Race management follows a simple rule that hasn’t changed since Nike R&D was done with a waffle iron: fast runners means publicity, which means big-time sponsors.

But when you’re suddenly the most toxic city in America, all rules are off. “I was afraid no one was going to show up at all,” says the race director, Andrew Younger, who’s joining us for the run. He thought back to the early days of the Crim, when recreational running was just taking hold and 10 miles was still a scary challenge, and it gave him an idea: Why not use the prize money for non-runners, for people afraid to sign up because they don’t think they can handle the distance? Flint needs a reason to feel proud, and no one feels better about themselves — and their city — than neighbors who cross a finish line together. Instead of spending money on big names, he proposed, the Crim could use the $40,000 to attract lower-income Flint residents and start them on a lifetime of running.

Bobby adored the idea. So did Dr. Mona Hanna-Attisha, the crusading Flint pediatrician who first fought city officials to prove that lead levels in Flint were dangerously high. “There’s no magic pill for lead exposure,” Dr. Mona, as she is known in Flint, told me. “It’s an irreversible neurotoxin. But the Crim had a fantastic approach: Instead of worrying about a cure, just focus on the effects. And guess what helps all of them? Exercise.”

It sounds too easy, but that’s why Dr. Mona believes it can work. Children exposed to lead are also prone to attention deficiency, lower I.Q., learning disorders and criminal involvement. As of yet there’s no definitive proof that lead causes those behavioral problems but to Dr. Mona, that’s the beauty of the Crim’s solution. Get those same children involved in regular exercise, she explains, and you’ll see test scores rise, disciplinary problems drop, decision-making and self-esteem improve.

“Resilience is the treatment for adversity,” she explains. “Our kids are hearing on TV that they’ll have brain damage, A.D.H.D., lower I.Q., and we’re showing them they’re brave, resilient and strong. They can go outside and run 10 miles down the main street of their own hometown. The world says they’re damaged, but they’re learning they’re beautiful and unbreakable.”

And that’s been Bobby’s secret for 40 years. “It’s not easy for an 85-year-old to suddenly change, but when Andy wanted to do something new with the Crim, I said ‘Sure,’” he explains, as we slow to a walk at the end of our three-mile run. “It’s like my stretches. Once you make a commitment, you do what you have to every day so everyone else will keep turning up.”