When I started running, I got faster almost every day. Since my beginner’s pace was just a few strides beyond a walk and I was completely out of shape, I had nowhere to go but up–and up I went. The faster I raced, the more I wanted to run. The more I ran, the faster I got. For two years, each race I ran yielded a new PR for me.

And then one day, it didn’t. I had reached my natural limit. Now physically fit and in the best shape of my life, I no longer enjoy the results of a natural performance improvement. Although I knew that day would come, the first race I ran where my pace was slower than the last left me completely deflated.

I’ve gotten over that initial shock, but I still get mad at myself when I don’t beat my standing best. I think I should have worked harder, trained more, shed those extra five pounds, kicked it in at the end. Even though I can’t get better every time anymore–math friends, is this the law of diminishing returns?–I still want to.

I have reached the line between hobbyist and athlete, between talent and skill. I can still get better, but now it won’t be by accident. I have to be deliberate about training. I have to tackle the speed work that I loathe. I have to commit to running on the days I just don’t feel like it. I have to set a goal and work toward it. I have to live the discipline. I can still shave off some seconds or tackle a new distance if I really want to, but now I have to work for it, and it won’t happen at every race.

That’s the dividing line between the amateur and the professional, the B-student and the A-student, the person who sings in the choir and the person who cuts records. You have to be willing to keep going when your talent runs out.