I have never considered myself a runner. Most likely this is because I do not run.

I have always been secretly jealous of them, though: ponytails swaying in rhythm behind them, iPods shuffling Journey, Queen and “Eye of the Tiger.”

So smitten with the idea of running have I been that I bought a pair of running shoes, three running skirts and four tank tops with built-in jog bras. A still shot taken of me at just the right angle might even fool nonrunners into thinking I am one.

But the truth is I just dress the part so I can run errands in comfortable shoes.

“Oh, I’m such a mess,” I tell people, “I’m on my way to work out.”

No one has to know “work out” is a euphemism for vacuum and read magazines.

This past spring, though, I decided the running skirt might fit better if I started using it for actual running. I had read (in a magazine) that a one-mile sprint a few times weekly would provide a significant cardiac health and metabolism boost that sitting would not.

So I laced up the shoes and faithfully, at least eight times over two months, jogged a 1.1-mile loop around our block. My ponytail swayed in rhythm while I gasped for air and cursed to the beat of “Survivor” as I worked my way to a 9-minute mile and a stabbing pain under my left kneecap.

I gave myself the summer off to heal, but the damage had been done. And the first week of school, I made an appointment with a sports medicine physician because that is who we athletes see when we are injured.

I detailed my workout regimen to the doctor as he rotated my legs around my hip socket and bent my legs like a frog, asking me over and over again if anything hurt. It reminded me of the game our son likes to play with his sisters, both trying to create pain, but only one of the two with the medical degree to justify it.

Finally he succeeded in recreating the sensation of a knife entering and exiting under the patella. A brief, but sick and twisted, smile flickered across his face as he watched me jump from the table to the ceiling in pain.

“You have runner’s knee,” he remarked triumphantly.

“Does this mean I am a runner?” I asked.

“It means that running has worn down the protective coating around the joint and caused you pain,” he clarified.

“So, would you agree then,” I began, drawing correlations based on the human biology degree I earned so very long ago, “that my sedentary lifestyle prolonged the life of my knee, allowing it to remain intact for 40 years?”

My doctor and I have differing theories about the contribution my sedentary lifestyle made to my joint health, but we are in agreement that I most definitely have a running injury, which, in my opinion, is just as much proof as a medal that I, now, am a runner.