Blame it on the absence of girls’ athletic programs for my generation.  Or on the feminine ideal of the era about what “young ladies” did and didn’t do.  Whatever the reason, my childhood friends and I created our own rules when it came to physical activity: never sweat and never get your hair wet. These standards put everything but walking, tetherball, badminton, and swimming (women had to wear bathing caps back then) on the no-try list. We broke the rules once and all signed up for ski lessons in junior high school. We persisted because of the good-looking instructor.

While rules — societal and self-inflicted — about physical activity for females of all ages have changed a lot in my lifetime, it’s still easy to fall back on them as we age.

These days, every time I read headlines such as, “Exercise May Protect Against Brain Shrinkage,” (Anahad O’Connor, New York Times, October 26, 2012) I regret the limitations I and others lived with in our youth. This particular article (like others of its ilk) says, “Remaining physically active as you age, a new study shows, may help protect parts of your brain from shrinking, a process that has been linked to declines in thinking and memory skills.” Now they tell us.

My early experiences have had an impact on my fitness level as an adult. Over the years I’ve gone through bouts of aerobics, modern dance, and belly dancing but never stuck with any of them. I go to the local Y to use the treadmill, elliptical machine and weight room, timing visits somewhere between often and sporadic. In good years I cross-country ski.

But with age comes injuries, joint pain, and muscle strains — we all  have them — that can lead us to narrow our list of acceptable activities even further. Which is why I cannot explain what motivated me to sign up for a class at the Y just because I saw a group of women my age lying upside down on the machines pictured above, who assured me they were having fun. I registered up for “Express Gravity.” We use the instruments of torture for a full-body workout — stretching, core work, and weights —  in only thirty minutes. (The photo doesn’t show it, but the slab at the bottom folds down into a surface for your feet to propel the rest of your body upward.)

I just finished my fourth class — the last of the first session. I am at least thirty years older than my three other classmates and the instructor. I have to make adjustments to the machine because I’m not as strong as the others. When the instructor says, “Ten seconds to go,” I hear that as a call to stop.  I modify the workout and still have to pant.  Yet this is the best class I’ve taken in years.  There’s something energizing about working hard and feeling tired as a result of activities more strenuous than keyboarding. I feel stronger, heartier, more fit — delusions maybe, but satisfying ones. Sure the same old pains are with me, but they’re not any worse than if I hadn’t taken the class. I’m registering for the next session. The fitness rules for “ladies” don’t apply any longer. Some of the ones for older adults don’t have to either.