I heard it on an ordinary eight-mile run: "You're an inspiration," she screamed as I ran past. I half-turned my head, waved politely, smiled and thought, "Yeah, it isn't easy being out here."

Sure, it's a stretch to think a mere runner can inspire like Martin Luther King, Jr., Gandhi or even Mark Fitzgerald, my neighbor, who always gets his trash out on time. But I guess some non-runners see our quirky dedication as deserving of an enviable-yet-masochistic badge of honor; a recognition of sort - like the bewildered acknowledgment your kid's teacher gives you after volunteering for a middle school field trip. It's just not something everyone would do.

As I continued running that day I replayed the inspired women's words and got thinking, Who's my inspiration? Why am I here? And better yet, why will I be here again tomorrow and the next and the next with a few guilty days off in between?

I first thought of the rewards: a marathon finish, a great 5K race, guilt- free carbs. But those weren't it. Sure those things are great reasons for running, but they don't inspire me (although guilt-free carbs are great in restaurants. I love stunning the waiter when I ask for the high-carb menu). But true inspiration requires a more-rigorous litmus test, something grander.

Six months later I found my answer, the source of my inspiration. It came from a pair of shoes that weren't even mine.

To be honest, I didn't actively search for this inspiration. Immediately after the inspired-women run I was more concerned with the stomach discomfort (actually a little south of the stomach) attributable to the 10 ounces of Gatorade and two bites (OK, four) of my daughter's ice cream sundae. I just went on with my days of running and sweating and cramping and sprinting; went on with the tempo runs and morning runs and morning runs in rain and evening runs in stronger rain, all without the need for inspiration. So I thought.

Then one day my 11-year-old son came home from school. Our conversation began with the usual clockwork precision - Me: "How was your day?" Him: "OK." But then it took an unexpected turn: My son told me he was the second-fastest kid in school. And, here's the best part, not in the wimpy field-day 40-yard dash. He, my son, is the second- fastest in his school in the mile.

During the next few months I took my son, my second-fastest-in-his- school son, on an occasional run. At first it was once a week, then once a month, then once in a while. As time went on, his running passion from the second-place finish (did I mention second in the school?) waned. The running phase appeared over, much like the Pokemon phase and the Lego phase.

But then it happened. During one of my many visits to the local running store I found a pair of running shoes in my son's size; same brand as mine (until then my son had been running in his everyday/basketball/ tag/church shoes). I brought the shoes home and dropped the bag in front of my son, in front of the TV. He opened the bag and pulled out the shoes.

"They're just like yours," he said with a look in his eyes I will never forget. "Thanks, dad. Can we go running?"

Now, the way I look at it, I have about five years before my son's steady increase meets my unfortunate and just as steady decline in this sport I love. OK, maybe three years.

But until then, I better get moving - 'cause now I am inspired. MR