After 10 miles I still had a big smile on my face. I felt smooth and comfortable. I had found my rhythm among the more than fifteen thousand other runners in South Africa’s famous Comrades Marathon. Good thing. There were 46 miles left—twenty more than I had ever run before. And I had no inkling that I was about to learn one of the most important running lessons of my life.

I had been dreaming about getting to Comrades for thirty years, from the first time I read about it in the mid-1960s. No other race could match its history and unique traditions. For one, the course changes direction every year—one year it follows an uphill route from Durban to Pietermaritzburg, the next it reverses direction and drops downward from P’burg to Durban. (Like the downhill Boston Marathon, both routes are hilly. Both test one’s mental and physical powers.)

The first Comrades took place in 1921 as a tribute to South African World War I veterans. The very name refers to their unshakable support for each other. One South African soldier, Vic Clapham, marched in a sweltering 1,600-mile pursuit of the German forces in East Africa. He organized the annual Comrades to honor his fellow soldiers and their endurance.

In just a few years, Comrades became the most famous sporting event in a sports-mad country. Runners don’t enter to run as fast as they can but rather to finish within the twelve-hour time limit. This earns them a bronze finisher’s medal. After collecting ten bronzes, you qualify for a highly prized green number. This number doesn’t just get you an admiring look from other participants. It is yours in perpetuity. Literally. You own it. No one else will ever be given the same number in the Comrades Marathon. This is, in my mind, the grandest tradition in all of running.

Elite runners might one day win an Olympic gold medal. But merely determined runners can win an absolutely unique Comrades green number for all time. They simply have to put in the sweat, toil, and tears required to finish ten Comrades. This requires no special talent, but a world of endurance.

Given that I had to fly 8,000 miles to reach the 1994 Comrades start line, I knew I would never earn a green number. But I wanted that bronze finisher’s medal. And things were going very well.

Until I hit the first hill at 10 miles on the way to Umlaas Road. Suddenly I faced a total gridlock of bodies in front of me. Everyone had stopped running. They were all walking. I wanted none of this. I was a proud Boston Marathon winner. I had traveled to South Africa to run Comrades, not to walk it.

I darted to my right and squeezed through an opening. I zigged left to find another, then zagged back to the right, turned sideways to make myself as thin as possible, and gently pushed myself forward between two big-chested runners. In a matter of minutes, I passed several hundred, but the effort was stupid.

I still had 46 miles to go. Minutes before, I had been flowing along almost effortlessly. Now I felt myself huffing and puffing, as if I were running frenzied intervals. Everyone else was strolling along happy as could be. I asked myself: What’s wrong with this picture?

Fortunately, I came to my senses. The walkers all around me knew exactly what they were doing. They had finished many previous Comrades—and many wore a green number to prove it—with the simple strategy of walking the steepest uphills to save their legs and lungs for the flats and downhills. There were a lot of miles to come, and it was more important to conserve oneself for the last half dozen of those miles than to scurry uphill now.

The Comrades runners were geniuses. And I—the first-timer—was an idiot not to have comprehended their method. I let my hubris get in the way of clear thinking.

I jammed on the brakes and joined the happy throng walking to the top of Umlaas Road. When my comrades started running again, I followed suit. When they walked at the next significant hill, I did the same. It was blissful.

The internet hadn’t reached its full flowering in 1994, and I didn’t yet know the term crowdsourcing, which I also refer to as collective wisdom. But I experienced it full force at the 10-mile mark of that year’s Comrades Marathon. The crowd around me—a large group with many years of experience—knew exactly what it was doing.

I had some credentials too. I was a Boston Marathon winner, after all, and could probably run a faster 26-mile race than most of the Comrades crew. I was the editor of Runner’s World, which meant I had access to advice from famous runners, coaches, and sports scientists. I had read many magazine articles and several books about Comrades, so I was well versed in the race history.

Yet I knew almost nothing about how to actually run the 56 miles between P’burg and Durban. I was a complete rookie. The crowd around me all held PhDs. They had earned them the hard way—by trial and error through a handful, a dozen, or even several dozen prior Comrades. These weren’t quitters. They were students, and finishers.

Collective wisdom plays an important role in many other areas of running, and I’ve included some of the best examples in Run Forever. There’s no mathematical proof to the 10 percent rule. It’s just a great rule of thumb. Similarly, no one knows for certain that beginners should follow the run-walk method, or that marathoners need to cover 20 miles in training. But these tried-and-true techniques have worked in countless cases. We should never disregard the collective wisdom. It’s a great and handy guide.

One thing I’m sure of: I never ran smarter than the day I followed the collective wisdom of thousands of Comrades runners. Once I saw what they were doing and how, I stuck with them all the way. My Boston Marathon winner’s medal could do me no good on the road to Durban. My South African comrades showed the way. They got me to the finish line inside the Durban Cricket Stadium more than an hour ahead of the cutoff time. And I’ve got the Vic Clapham bronze medal to prove it.