What a Pro Boxer Taught Me About Mental Toughness

There’s a powerful concept that shapes your entire life, yet most of us never think about it: your self-story. It’s the internal narrative you write about who you are, and it quietly determines your success. The good news is, you hold the pen. You can write a better story for yourself—one that helps you achieve your biggest ambitions.

I was thinking about this when I sat down with Chris Eubank Jr., a championship boxer and son of a boxing legend. He leaned forward in his chair and told me something that stuck.

“A lot of people don’t know this,” he said, “but 80 percent of being a fighter is mental. The guts and the grit you need just to walk through a crowd of thousands, knowing that when you get in that ring, you’re going to fight. You’re going to get hurt, and you’re going to have to hurt someone, with millions of people watching. Just that walk… most people on the planet can’t do it.”

When I asked if that kind of mental strength could be trained, he didn’t hesitate. “I think you can; I’ve seen fighters develop it. You need it. Because there will be times when you’re hurt and questioning everything. Every fighter has that moment.”

He then told me about his moment.

The Story That Forged a Fighter

Before turning pro, Eubank Jr. went to Cuba to train. “Out there,” he said, “the guys are animals. They’re monsters.” He was in the ring for what he thought was a casual sparring session when the Cuban Olympic heavyweight representative—a man three times his size—climbed through the ropes. They told him they were sparring.

“The bell goes, and this guy sprints over and just starts laying into me,” Eubank Jr. recalled. “The biggest shots I’ve ever taken. I’m running around the ring, and I can’t get this guy off me. Bang, bang, bang. He knocks me out of the ring!”

It was a four-foot drop onto solid concrete. His knee slammed into the ground, and his leg went completely dead. As he looked up, the Cuban heavyweight was leaning over the ropes, looking down at him.

“I’m at a mental crossroads,” he explained. “Do I say, ‘Listen, my knee’s bad. You’re too big’? Or do I get back in? Everyone’s looking at me, my dad is there. I made a decision. I was like, you know what, let’s fucking go.”

He got back in and took a beating for two more painful rounds. The only thing he could think was that he had to finish what he started. “I’m not leaving this gym with everybody knowing that I quit. I can’t go to sleep knowing that another man made me quit. So I got back into that ring and I took my beating like a man.”

From that day on, he was never scared again. It was the worst experience of his life, but it was also the best. He now knew what he was capable of. “If he can’t make me quit, who’s going to make me quit? Nobody. And that belief stayed with me for the rest of my career.”

This is the self-story in action. It’s the narrative you write for yourself, about yourself, and it dictates how you’ll behave in the future. He applies the same logic on the treadmill. If he gets a cramp with eight minutes left, he’ll limp on one leg to finish. Because if the treadmill can make him quit, a man in the ring can, too. It’s about teaching yourself that you’re the type of person who finds a way, especially when no one is watching. This is the mindset you need when you —those quiet moments of struggle define your long-term success.

Your Grit is More Important Than Your Talent

The U.S. military’s academy at West Point is known for its grueling initiation, a series of challenges called “Beast Barracks.” Researchers studying the program assumed that the cadets with the most intelligence, physical strength, and natural leadership ability would be the most successful.

But Angela Duckworth, a researcher at the University of Pennsylvania, found something surprising. She tracked nearly 2,500 cadets and compared their SAT scores, physical aptitude, and high school rank against a metric called the Grit Scale, which measures perseverance.

It turned out that physical strength and intelligence weren’t the best predictors of who would make it through. It was mental toughness. Cadets who scored just one standard deviation higher on the Grit Scale were 60 percent more likely to complete Beast Barracks. Perseverance was everything.

This is great news, because while you can’t change your innate abilities, you can absolutely develop your self-story. The challenge is that our stories aren't just built on our own experiences; they're also shaped by the stereotypes around us.

When I was eight years old, a classmate casually told me, “Did you know Black people can’t swim?” I’m of English and African heritage, and in that moment, my excitement for my first swimming lesson vanished. That lesson did not go well, and it took me 18 years to finally learn.

This “stereotype threat” is real. A 1995 study gave students a difficult vocabulary test. Before it began, some of the Black students were asked questions about their race. Those students performed worse than both the white students and the Black students who hadn't been questioned. The simple reminder of a stereotype was enough to impact their performance.

Another study tested the myth that women are worse at math than men. When female participants were told that men typically scored higher on the test they were about to take, their performance dropped significantly. But when they were told men and women scored equally, their performance was on par with the men’s.

One researcher took it a step further. What if you could escape your identity? Female students were asked to take a math test under an alias—some male, some female. Astoundingly, the women who used an alias performed just as well as the men, outscoring the women who used their real names. By disconnecting from their identity, they disarmed the negative stereotype.

How to Build a Stronger Self-Story

Scientists call the self-story your “self-concept.” It’s your personal belief about who you are and what you’re capable of. A positive self-concept is directly linked to resilience. People who believe in themselves are more optimistic, persevere longer, and handle stress better. This is fundamental whether you're an athlete or building a from the ground up.

So, how do you build a better one?

It comes down to what you do when nobody is watching. Every choice you make, big or small, provides evidence about who you are. This first-party evidence—what you observe yourself doing—is the most powerful tool for changing your beliefs.

Think about being in the gym alone. You’re on your last set and need ten reps. At rep nine, your muscles are burning. What you do next might seem small, but it’s a critical moment. If you stop, you write a line in your self-story that says, “When it gets hard, I quit.” If you push through and do the tenth rep, you write, “When it gets hard, I keep going.”

That evidence doesn't stay in the gym. It follows you into every area of your life. It whispers to you when things get difficult, shaping your response to adversity. This is especially true for anyone , where countless unobserved moments test your resolve. Your ability to push through is what eventually turns a .

To create new evidence, you have to change your actions.

• Choose to do the tenth rep.
• Choose to have the difficult conversation.
• Choose to ask the extra question.

Prove to yourself, in a thousand tiny ways, that you have what it takes. Because only then will you truly believe it. Your mental toughness is built from the evidence of your own choices. Be mindful of the story you’re writing every day—it’s the most important one you’ll ever tell.