As long as I keep moving, I can fight the effects of aging.

After each run I finish or game I win, I feel powerful, even invincible.

Because I've played sports since I can walk, they keep me feeling young and remind me I've got some good years ahead of me.

From football to soccer to softball and whatever other leagues I can find, you can find me on a field one or two days of the week.

If not, I'm running or speed walking around the neighborhood.

It's all about keeping my thighs at bay and not giving up on being an athlete.

But after three knee surgeries for a twice-torn ACL, I probably should cut back. I should ease up to avoid the inevitable aches and pains that follow me through the day.

I can't.

If I am less active, I am even further from the athlete I used to be. And therefore -- in my twisted logic -- I'll be old and not quite myself.

My 86-year-old grandfather still lifts weights and swims. Why should a lack of cartilage slow me down?

There are women who run up until the final days of their pregnancy. Who am I to fret?

I've heard the warnings that I'll eventually need knee replacements and should rest. But I'm not even 30, despite what my nagging knees say.

Last week, those misconfigured joints were warning me not to push it, but I had a race to prepare for -- I had signed up for a 5k run with a few friends.

I used to run in these events fairly regularly, but this time around I was really nervous. Since my running isn't what it used to be and my knees were pulsating, I told myself, "I just have to finish the race."

Considering I've had aspirations of running a half-marathon, trying to get through a mere 5k sounds pathetic.

That was the goal, however pitiful it may be.

The night before, I went to bed early and woke up early on race day to make time for extra stretching. I felt sick to my stomach thinking that I wouldn't be able to finish.

By the time the start horn went off, I had no more time to be nervous, just time to think about finishing.

I relied on my friend Jackie to set a reasonable pace and relaxed into my gait. I didn't focus on my left knee wanting to let my right leg do all the work or the cramp in my back.

At mile two I started to ask, "Is this thing over yet?" Then I strode past an elderly woman who was plodding along with two knee braces and her back at an odd angle.

There I was complaining, while she was running on knees twice my age.

Maybe all is not lost, no matter how achy I feel.

Like those stupid bulges that keep me working out even when I don't want to, perhaps there is a reason I was given bum knees.

For one thing, I can predict the weather. A very handy party trick, indeed.

I also have these complicated scars that are definitely conversation starters.

"What happened to you? Were you in an accident?" I'll hear now and then.

But what will my fitness future hold?

Will I be able to maintain the level of fitness I'd like to? Will I have to give up on the idea of running and invest in some walking shoes?

Let me get back to you on that one. I have to think it over on my next training run.

Laura Lewis is an adventurous newlywed who has loved, lost and doesn't mind sharing. Her column appears every other Thursday.