For you, Sept. 20 probably was just another Sunday. For me, it was my debut, the first race I had ever trained for: the D.C. Road Runners/Moving Comfort Women's 10K.

I am in my mid-30s. I began running five or six years ago, when it seemed everybody else did. I wanted to treat my mild high blood pressure and also keep in shape. Contrary to the experiences of many, it took me a year or two to stop thinking of running as pain and relax and enjoy it. But eventually even I became addicted.

About a year ago, I noticed a change. I was getting up every morning, doing my three miles and becoming bored. I started to fantasize about racquetball, tennis or even an early morning midwinter swim at the local pool. I tried to vary my running route, but it didn't seem to help much.

About that time, a good friend -- a woman runner in her mid-60s -- somehow talked me into signing up for a race to benefit the National Symphony, a worthy cause since we were both piano teachers. There were two races, a 10-kilometer and a two-miler; natually, we signed up for the shorter one. Somehow, my friend managed to get me downtown from the suburbs at 8 a.m. for the race. I was shocked to find hundreds of runners waiting for the start of the 10K.

After it began, we lined up for the two-miler, a motley group of senior citizens, women, overweight men and children. So there I was in my new National Symphony T-Shirt when Rostropovich himself, dog under arm, pulled the trigger for the start of the race. We were off and I was transformed.

I ran hard for 1 1/2 miles before looking over my shoulder and noticing everyone behind me. In the last 20 feet, another woman shot by me. I could have committed murder.

So I started training a little harder and began showing up for races sponsored by local running groups. The distances ranged from two to eight miles, and I never seemed to repeat my spectacular early performance, usually finishing in the bottom 20 percent.

But an amazing thing happened: I began to talk with other women runners at the races, trading information about running clothes or particular courses we enjoyed. During the races, we would encourage and pace one another. I realized that this was the first time I had known what must be a common experience for men: camaraderie in sports, the pleasure of taking part and having friendships arise from that experience.

I continued racing without much success. Then a running friend named Larry asked me to cheer him at the finish line of a marathon in Cleveland, a race for which he had trained hard.

The day of the race was too hot for good running and Larry didn't do as well as he had hoped. Through his disappointment, he described his training. Unlike me, he varied his running, making one fairly slow, long run a week for endurance and one or two fast but short runs for speed. He also took one day off a week.

I decided to adapt the training to myself for running 10K races. Such a plan would vary my routine, reduce my boredom and perhaps improve my performances.

But I needed a goal. So last June, I picked the D.C. Road Runners/Moving Comfort Women's 10K Sept. 20 for my debut, hoping to avoid the summer's worst heat. The first 500 finishers would win running apparel, and I was determined to be among those 500.

Despite a month-long vacation that included only sporadic jogging, I increased my distance to 12 miles on long weekend runs and did a fast run once a week. I felt I was running faster and better than ever. As the race approached, I began to feel smug.

The big day dawned cool and brisk, perfect for running. Sign-in was 7:30 a.m. at Hains Point and hundreds of women were there. At the starting line, I nervously took my place toward the rear of the pack, knowing I wasn't competing to win. My number was 345 and I made a silent promise to come in ahead of my number. To my left was a 10-year-old, racing her first 10K with her mother. To my right, was a 10K veteran looking forward to a pleasant morning run. Everywhere women were stretching and jogging in place. The competition looked tough.

Just before the race began, Larry and his dog showed up to be my cheering section. Then we were off with Larry's last words ringing in my ears: "Don't go out too fast." Which is exactly what I did. I hit the one-mile mark in eight minutes, too fast a pace for me, and slowed down.

The race consisted of two 5K loops, and there was lots of chatter on the first. I picked my way through the bodies, always chugging ahead. I concentrated intensely, telling myself to keep pushing but not to push beyond my ability.

At the end of the loop, a runner beside me quipped, "Not bad for two old ladies."

"Old ladies, hell," I shot back.

The second loop was quieter. The pain in my chest was growing. Larry and George paced me the last mile, Larry shouting encouragement to everyone. I hit the finish line in 53:20, seven minutes faster than my last 10K. I was number 333.

Perhaps I was not God's gift to running, but I had improved. I immediately picked up my hard-won prize -- a pair of running shorts.

"So," I said to Larry afterward, "when do I start training for my first marathon?"