I never thought I'd see it happen. But there I was feeling as out of place as a sumo wrestler participating in a rhythmic gymnastics competition. Absent those little loin cloths.

I was clearly on unfamiliar turf as I was surrounded by the clang of metal, the whirling dervish of machinery, four giant television screens with closed captioning, and enough Lycra tights to clothe a small country. With extension cords run amuck, I carefully searched for a piece of wall, without a mirror, to lean against.

A lingering running injury was keeping me off the roads. For the first time, I was standing in the middle of a large room encircled by the most intimidating pieces of technological exercise equipment known to runners.

My injury had caused me to miss a couple of weeks of consistent running. I was actually proud that, absent from my daily dose of endorphins, I hadn't yet turned into a babbling, depressed, psychotic delinquent. But it was still early in the day. Who knew what missing another lunchtime run might bring?

I knew if I didn't soon find an alternative form of exercise I might engage in some regrettable behavior. Perhaps, in a fit of jealousy, volunteering at a race and purposefully calling out inaccurate split times. Instead, I figured I'd visit the local health club and find the latest way to kick my butt.

Treadmills I was familiar with, but my injury prevented that as an option. I quickly surmised that the popular elliptical machines would require having to place a reservation with the gym maitre de for a party of one, corner machine, a week from Tuesday. I didn't have the luxury of waiting.

I then saw a forlorn looking wallflower of a stair stepping machine, imploring me for a little action. It seemed perfect for my abilities, as I have absolutely no sense of rhythm. "He marches to the beat of his own drummer," is a kind reference to my only attempt at a dance aerobics class. It's more like, "He ain't got no beat, ain't that a bummer."

But I figured if this stair stepping machine could lead, I could follow. Heck, I'd been going up and down stairs since I was two years old! How hard could this be? Well, guess again, imbalanced one!

After spending forty-five minutes sorting out the instructions for getting started, I began the stepping up and down motion on the machine on the manual setting at a quick pace. I immediately discovered why handrails were provided as I picked myself up off my derriere. In examining the machine's electronic board I saw that I'd skillfully traveled a grand total of 3 steps before plummeting to the floor.

I got back aboard, held on for dear life, and was off into the world of speed stepping. Amazingly, I was enjoying it. My heart rate was way up there, the time seemed to be moving quickly, and I was cruising along and keeping in sync with the ever-changing climbing speed. It was then I glanced over at the timer. Big mistake. I'd been on board for a grand total of one minute and thirty seconds. Only fifty-eight minutes and thirty seconds to go, and my quadriceps were already into a full revolt.

But I got into a nice cadence, decreased the level and became enthralled as I stared intently at the electronic board. I glanced over at the flashing numbers signifying my calories burned per hour. Either it was inaccurate or I was about to burn off my entire food intake for the last three weeks. I calculated that, after a month of daily use of this machine, I'd weigh about 32 pounds unless I consumed seven cheesecakes and three apple pies per day.

I'd found a temporary replacement for running and loved it. But after a week of being together, things quickly changed. Arriving at the gym one morning I was mortified. Someone else was using my machine. Infidelity had stricken our mechanical relationship. My machine had strayed. Did one with better and gentler legs usurp me? Had I pushed our relationship too fast?

All I knew was, I was temporarily lost without my machine. I'd almost forgotten that I was a runner and my injury had pretty much healed. I regained my sanity and was back putting in the miles on the roads, with my stair stepper only a distant memory of a one-week fling.

But if I ever became an exercising bigamist, well, there's always the Empire State Building Run Up race. I could combine my loves of stair stepping and running. Just a thought if I should ever stray again.

Bob Schwartz has just published his new book, I Run, Therefore I Am Nuts! See Human Kinetics for ordering information. Editor