Sometimes you do everything right, and it still comes out wrong. You give it your best, but you fail.

In my case, it is my body that has failed. Specifically, my knees are so bad that they require surgery. And I can honestly say that in the past 46 years, I've done everything I could to prevent such an outcome -- by which I mean that I've done almost nothing at all.

Why run when you can walk? Why stand when you can sit? Why fidget and putter around when you can remain motionless for hours, except to turn the pages of your book?

This has been my lifelong style. Over the years, I have rigorously refrained from vigorous activity. When other girls were taking up jogging and tennis, I sat down at the piano and stayed there.

Don't get me wrong: You can work up quite a sweat playing Chopin ballades and Prokofiev sonatas for four hours a day.

But running up and down the ivories is not the same as running up and down a basketball court. I tried the latter for several weeks in ninth grade. A couple of jammed fingers forced me to choose playing arpeggios over playing forward, but that was a convenient excuse: What I really didn't like was all that moving about.

Some might call it laziness. In retrospect, at least, I consider it smart.

You see, it's the excessive pursuit of sports that is causing an alarming rise in serious injuries among teenage girls. Well, "excessive" is my term, but the experts are realizing that female physiology cannot easily weather the nearly year-round beating it's taking on the court, on the field and at the track.

Girls experience markedly higher rates of concussions in sports that both sexes play, such as soccer, but the greatest disparity lies in the number of injuries to the anterior cruciate ligament -- the rubber band-like fiber that attaches the upper leg to the lower and stabilizes the knee.

Women's high levels of hormones such as estrogen and their tendency to land with straightened rather than bent knees are factors that contribute to teenage girls sustaining ACL injuries five to eight times as often as boys in the same sports.

My doctor explained all this to me a few weeks ago, so I hastened to assure him I've been admirably sedentary for years.

I like to think I was listening to my body and doing what was best for it. Even in my teens, my body was mostly saying, "Snap-Crackle-Pop." My sister and I have always joked about our "Rice Krispie" knees.

Sports aside -- far aside -- it turns out there's still a physiological reason for my amusing personal sound effects.

After easily ruling out a sports-related injury, my doctor mused on the problems created by women's wider hips and "knock-kneed" stance. It puts greater stress on the outside of the knees and over time can produce outward growth of the knee -- bone spurs.

In addition, the way women's thigh muscles interact with our knees often prevents the kneecap from moving correctly over the joint.

I have both of those problems, plus a tear in the meniscus, another piece of cartilage that cushions the bones. Surgery not only can address most of these issues, my doctor said, but it could also soon return me to all my previous activities.

Hmmm.

Confession: I may have been exaggerating a bit when I described my sloth. While eschewing the vigorous gym workouts that would make my Scots-Irish complexion look like a stroke was imminent, I did a few years of weight training. I figured out my muscles should be doing work that I was ill-advisedly letting my joints handle.

And I quickly dropped 10 pounds last year, thinking my knees wouldn't hurt so much if they didn't have so much to haul around.

But I didn't drop the "extreme gardening" I like to indulge in -- the kind where I decide five years after planting the Japanese maple that it would look better over there and decide to move it without waiting for help.

That may be how I tore my meniscus.

All in all, though, my body's defensive move has been motionlessness. I stand, or sit, by my strategy. Even though now I need surgery, I figure it could have been necessary many years earlier, and the damage could've been much worse.

I'll be away from these pages for a while this summer, but you can rest assured I won't be going anywhere. As I always have, I'm staying put.