Endurance is a leadership discipline: What 250 marathons teach us about sustained performance

A beginning rooted in loss.

When I sat down with Martin Parnell, I expected to hear an extraordinary story. After all, he ran 250 marathons (10,550 km in total) in one year. What I didn't expect was how much of that extraordinary journey began long before he ever laced up a pair of running shoes.

Everything changed after the death of his first wife, Wendy, in 2001. "My world just changed, just turned upside down," he said. "I was lost." What followed was not a search for athletic achievement, but for direction, purpose and forward motion. For leaders, this distinction matters. Endurance rarely begins with ambition; it begins with the need for meaning strong enough to sustain effort over time.

A year later, when his brother challenged him to run a marathon, Martin didn't weigh the pros and cons. "I just said yes," he told me. "I was looking for something different." That yes became the first step in a nine-year journey toward the most demanding year of his life.

Setting an impossible goal.

When Martin first imagined running a marathon every day for a year, he didn't frame it as extreme. It was simply the next challenge. After consulting his doctor, who advised him to build in a margin for injury or illness, he adjusted the goal to 250 marathons. "It just seemed a good number. Five a week for a year." With that came a clear commitment: raising $250,000 for Right to Play.

What stands out is not the audacity of the goal, but its precision. “I had a very specific goal…250 marathons to raise $250,000,” he said. That clarity matters. Psychologist Edwin A. Locke demonstrated exactly why. In his foundational 1968 research, originally published in Organizational Behavior and Human Performance, Locke showed that hard, specific goals consistently produce higher levels of performance than vague or easily attainable ones. Ambition alone doesn’t drive execution; definition does.

There was no motivational theatre in Martin’s approach, just commitment and what he called “stickability.” In leadership, goals that stretch capability while remaining unmistakably clear create focus, discipline, and momentum. When the objective is specific, effort has somewhere to land. When it isn’t, even the most ambitious intentions dissolve into motion without progress.

How consistency builds unbreakable momentum.

For Martin, consistency wasn't a slogan. It was his operating system. Every day began the same way: up at 5:30 a.m., bed made, breakfast eaten, rituals repeated. More important was how he managed the mental weight of the task. "I'd break everything down into 10-minute chunks," he explained. Forty-two kilometres was overwhelming. Ten minutes wasn't. And then another ten. And another.

This is where many leaders misjudge performance. Durable results are rarely the product of heroic effort. They are the outcome of small, repeatable actions executed with discipline. Research supports this: The Power of Small Wins, a 2011 Harvard Business Review article, found that tracking daily progress, even minor achievements, is the most potent way to boost motivation, positive emotions, and performance, far more than major, infrequent milestones. Consistency, not intensity, is what compounds.

When the body breaks, adaptation becomes vital.

At marathon number 30, Martin felt a sharp pain in his leg. He was told it might be a stress fracture. "I thought, Martin, you're an idiot. You've told the world. This is fate." He believed it was over.

It wasn't. The diagnosis turned out to be a repetitive strain injury. The prescription: two weeks off, then walking. And so, in February's brutal cold, he walked eight marathons. "Walking a marathon takes eight hours and fifteen minutes," he said. "For some reason, I'm very good at doing long, slow, boring things."

Few entrepreneurs embody this same capacity to adapt without abandoning the mission

like James Dyson. For fifteen years, Dyson worked on a single idea: a vacuum cleaner that wouldn't lose suction. He built 5,126 prototypes before finally perfecting the Dual Cyclone vacuum. Progress didn't come from stubbornly forcing the first design to work, but from repeatedly changing the approach while holding the goal constant.

This is not grit for its own sake. It is intelligent endurance. High performers protect the mission by changing the method. Leaders who endure well don't push blindly through constraints; they adapt early, iterate relentlessly, and keep moving forward.

The support system behind every step.

Martin is clear that he didn't do this alone. "I'm a planner," he said. "I like to give myself the greatest chance of success." He assembled a multidisciplinary team: a doctor, a physiotherapist, a chiropractor, a nutritionist, and a sports psychologist. Every Friday, without fail, they met. He even monitored bone density through testing at the University of Calgary.

This wasn't over‑preparation. It was risk management. Collaboration was not a sign of weakness, but a strategic asset. "I don't mind asking for help… "It's critical," he said. In leadership, resilience is rarely about personal toughness. It is about building systems that sustain decision quality under pressure.

Purpose, making the impossible possible.

When I asked what got him out of bed on the hardest mornings, Martin didn't talk about grit. "If I were doing this just for myself, I probably could have found a reason to stop," he said. Each marathon funded a child's year-long play program. He had seen firsthand what that meant. "This was close to my heart. I'd committed to these kids."

Purpose did more than motivate him. It simplified decisions when fatigue set in. That same dynamic plays out in organizations. EY's joint research with Saïd Business School at the University of Oxford shows that organizations anchored in a clear, shared purpose are significantly more likely to succeed in transformation, innovation, and long‑term value creation. The research demonstrates that purpose acts as a performance multiplier, aligning strategy, leadership and culture in ways that make organizations more resilient, more adaptive, and up to 2.6 times more likely to deliver successful business outcomes.

By year's end, Martin was running faster than when he began. Fundraising surged, surpassing the original target. On December 31st, 2010, he finished his final marathon quietly. He had done what he said he would do.

What I learned from Martin.

As we wrapped up, Martin shared a phrase he now uses in his talks: "Endurance‑fuelled purpose." It captures the essence of his year.

Success that endures is rarely dramatic. It is built through routine, clarity, adaptation, and commitment to something bigger than oneself. Not every day needs to be extraordinary. But every day requires a next step.

Martin showed me that the finish line isn't a moment. It's a mindset. A discipline of showing up, especially when no one is watching, and trusting that ordinary actions, repeated with purpose, can create extraordinary outcomes.

Dr. Lance Mortlock is the author of Outside In, Inside Out – Unleashing the Power of Business Strategy in Times of Market Uncertainty, EY Canada Managing Partner, Industrials & Energy, Strategist & Adjunct Associate Professor.