I was a block away from the final turn toward the finish line when, at last, I veered off course.

“Sprint until the end,” I told my older brother, Senter, just two feet toward my left. “And I’ll meet you at the line.”

I stuttered my step and dipped hard toward his right, disappearing down a street that paralleled the one he’d take to the end of his first half-marathon. For the previous thirteen miles, I’d followed his track throughout downtown Raleigh, out along Hillsborough Street and back, through the campus of Dorothea Dix, and into downtown Raleigh again. He’d slowed toward the middle of the longest run of his life, the culmination of an inspiring year of aggressive dieting, nutritional consultations, and daily exercise. But less than a thousand feet of Fayetteville Street from the finish line, he was now on target to beat his two-hour goal by a considerable margin. I knew he needed no more motivation.

Early that morning, after Senter had completed the first two turns of Raleigh’s third Rock ‘n’ Roll Half Marathon, I drifted into his little pack and matched his pace. A few days earlier, we’d decided I would run alongside him for a few minutes and then zoom ahead, getting in a long practice run thanks to the closed streets of a race for which I hadn’t registered. I’d wait for him at the finish line, we’d determined, and we’d have lunch.

For as long as I can remember, I’ve been too competitivenot necessarily with others, but certainly with myself. In school, I was always the one to read ahead because I took it on faith that there was more to learn. When I started running three years and eighty pounds ago, I could barely make it three miles without huffing, puffing, and eventually resting with my hands on my knees. Now, though, after every marathon I finish, I start to analyze my failures, not my success, wondering how to shave more minutes off my time.

But sometime around the four-mile mark, as Senter and I passed through my neighborhood, I decided to stay with him and cruise, to take as long as needed to make sure he achieved his aim. I realizedlamentably, I must admit at the age of thirty-two, for one of the first timesthat my own ambition could wait another day. As we climbed the final major hill, a real bear of vertical pitch, his steps were slowing, his lungs fighting. I told him that, only two years earlier, this had been the final hill of my first race, too, and I’d walked to the top. He laughed, then dropped his hands and powered on.

We didn’t speak again for the next mile, until I split to his right. “OK,” he said simply, staring straight to his own victory.