"It's your ball," he said.

My opponent, a well-practiced basketball player in his twenties, passed to me across the university gym. I took the ball, drove up the front court, wheeled to take the shot . . . and realized I was behind the basket. It was a clumsy move, but I was playing one-on-one for the first time in my life.

At 45, I am getting a taste for a new game. It is a reminder that my graying hair is matched by creaking bones and stiff muscles. It is also my latest victory in getting over a lifelong insecurity: As a child, I had never played any ballgame well. By trying again, starting several years ago when my children were young, I began to understand the simple satisfaction of second chances. Not that the lesson comes easy; I never would have picked up a ball again had I not wanted to teach my children how to play.

The basketball court and the baseball diamond, those happy hunting grounds of American childhood memories, had been fields of fire for me. When I picked up those sports again in my forties, it was, to be sure, one of those midlife course corrections, a quest to fix the small things that have bedeviled us since childhood, so that the big issues that play across the stage of life's second act could somehow fall into place. Redeem the child and you free the man, I thought.

Yet the past is dangerous territory, and I resisted revisiting. Finally, because I did not want my kids to feel the slings and arrows of the sandlot as I once had, I took the risk of feeling their sting and embarrassment again. And, for me, that went deeply against the grain.

I first said hello to ballgames as a child of 8. But after two seasons of Little League, I said goodbye. I was a strikeout king at the plate, a poor glove handler in the field and, as for throwing, that was the real humiliation: I was told that I threw like a girl. Frustrated, angry and often bored, I gave up on baseball. I liked sports but I didn't like losing. So I made a simple rule: no balls.

It wasn't that I avoided exercise entirely. Eventually, I became a sports dabbler. A weekend athlete all through my teens, twenties and thirties, I happily ran, biked, swam, did martial arts and even lifted weights. At 40, I learned to row in a single scull. Sculling is a grueling sport, but that did not scare me. I took up the challenge and, to my surprise, I did well.

And that, I thought in passing, was that. I had proven to myself that I could succeed at sports. Sure, one speck of doubt remained, one shred of failure that said "the kid can't play ball." That wound, I thought, was best left unlicked.

But I hadn't reckoned on my kids.

Four years ago, when my daughter was 5, my son, 2, I surprised myself one day by admitting that it would be good for them to play baseball. "You're going over to the enemy!" the voice inside me cried. No, I thought. I was simply declaring victory and bringing the troops home. I didn't want the kids growing up avoiding ballgames, as I had. So the old rule went out the window: It would be yes, balls now.

My wife, a hockey-fanatic Canadian, wouldn't have known a ground ball from a grand slam, which left it up to me to play the traditional role. I bought a couple of gloves, cadged lessons from friends ("How can you not know how to throw a baseball?" "Never mind."), borrowed a hand-me-down bat and tee-ball mount, and took Mike and Sylvie out to teach them baseball.

Now Sylvie has finished a season in a girls' softball league. Mike plays tee ball, soccer and basketball as well. Each kid attended clinics beforehand. And, yes, that was me on the sidelines, taking notes.

There were some bumps along the road. There was the time I was asked to coach first base during one of my daughter's games and I panicked. "Now what do I do?" I thought. Luckily, the kids seemed to know on their own just when to run. There's a lesson in that, I think: You're not really a Little League Dad until you learn how wise the kids are. I suppose it means I have arrived.

Now I spend evenings in the backyard, playing catch with my kids. My son calls for a grounder, my daughter asks for a high pop-up. It's all so easy and natural that I can hardly understand anymore what all the fuss was about. I can't imagine why I nursed my ball phobia for 35 years instead of retiring it with fears of the dark and things that go bump in the night. What I do know is why I finally moved on.

We carry around can't-do stories that hold us back like ankle weights. We can rewrite the story: The hard part is wanting to. That is what my kids taught me--in all their eagerness, in all their unstudied movement from awkwardness to ease, in all their confidence--a ball is just a ball.

Which is why I found myself on the basketball court that day earlier this summer. I had walked through the gymnasium and was on my way to the weight room when I met the student who challenged me to a game of one-on-one. About to invoke the old "no balls" rule and beg off, I said, on second thought, "Sure, let's play."

I wanted to see how far the new me could go.

Not far enough to beat someone with a big advantage in age and experience, but I did score. As the ball rang against the hoop and brushed the net, it sounded like a hosanna. I might have been standing in the winner's circle, all smiles and high-fives, the cameras flashing.

So it truly is my ball, at last.

Barry Strauss, a historian and director of the peace studies program at Cornell University, is author of the recently published "Rowing Against the Current: On Learning to Scull at Forty" (Scribner).