IT TOOK AWHILE TO SINK IN. BUT finally I'm beginning to realize it. I'm a bit of a survivalist.

A fitness survivalist.

You see, I have this nagging feeling that I should be able to lift my own weight.

I'm not talking about bench-pressing or dead-lifting the equivalent of my weight in iron. I mean literally lifting my weight. Like in walking. Running. Step-ups. Jumping rope. Sit-ups. Push-ups. Dips.

And, the clincher, chin-ups.

What draws me to such thoughts?

Partly it's self-sufficiency. I like the idea of being able to carry my weight, literally as well as figuratively.

Partly it's practicality. I can get in a few of these exercises anytime, anywhere: at work, in a hotel, at home when I'm too slug-like to get to the club.

Partly, I confess, it's some unfounded anxiety about falling off a cliff, catching hold of a protruding branch and just hanging there: Could I pull myself up?

Of course, lifting one's weight is the oldest exercise around. With limited new fitness ideas each year, the dusty ones are bound to pop up again, often with new labels. In this case, it's "functional strength," the ability to control one's body.

The way to develop some of these exercises is simply to do them. To become a stronger walker, walk more. Same with running and step-ups.

With jumping rope, however, I bear in mind a friend who started an exercise program with hundreds of jumps. She couldn't walk for three days. So when I haven't jumped much rope, I proceed with caution.

Some exercises have modified versions for the not-yet-strong-enough. Dips on the floor, for example, or off a low stool, or at the corner of the kitchen counter.

For push-ups, one can start out doing them against a wall. Progress to knees on the ground, then full push-ups. I've read that Mary Joe Fernandez, the pro-tennis player, was well-ensconced in the Top 10 before she mastered her first full push-up. She considered it one of her greatest triumphs.

The experts have actually made sit-ups easier by determining that one should rise up only far enough that the shoulder blades are off the ground.

Chin-ups, however, are on another planet altogether. (Right there with rope-climbing, which is also on my fantasy to-do list.) If I can't do one chin-up, how can I work on them? Some traditional ways help, such as exercises that strengthen the back, shoulders and arms. And negative chin-ups, using some assistance (a jump, a friend, a stepladder) to get to the up position, and then letting myself down, slowly. After six or eight months of this, I might work up to that one chin-up. Then it gets easier, I hear.

(Maybe all this wouldn't be such an issue for a guy. You guys out there, you can all do 20 or 30 push-ups and sit-ups and chin-ups. Right?)

But I tried a machine the other day that puts chin-ups and dips within reach for almost everyone. It's called the Gravitron. It's made by Stairmaster, the Kirkland company.

If you belong to a fitness club, you may have seen a Gravitron, or something like it. Cybex, Taurus and Levitron are some other brands in clubs. A quick check found one of those at about 20 of 66 local clubs. (Strangely, not at any of the women-only clubs.)

My club doesn't have one. I'd only heard of it through friends. Until I got a one-day pass at Sound Mind & Body on Madison.

I stepped onto a square platform, which put me inside a scaffold-like structure. I punched in my weight and level of difficulty desired. As I started the chin-ups, the platform rose with me, relieving a percentage of my weight from my arms. A readout showed the weight I was actually lifting.

I could do 10, 15 chin-ups, no problem.

It was the most fun I think I'd ever had in a health club.

I'm not quite sure why I liked it so much. Because I could actually see over the bar? Because I could imagine what it would be like to do chin-ups on the moon? Or maybe because because I felt what it was like to weigh 54 pounds again?

A few days later, I was trying to explain my fitness-survivalist tendencies to a couple of friends: Say I fall off a cliff...

"What about that superhuman strength you're supposed to get in emergencies?" one of them asked. "Wouldn't that be enough to pull yourself up?"

Maybe so.

But what would I do for fun in the meantime?

Molly Martin is assistant editor of Pacific.