The first thing you learn at Overload is that everything you know about fitness is wrong. Well, just about everything.

Calories still matter, but in the opinion of Overload founder Joshua Trentine, common terms such as cardio, reps and toning are worthless, and traditional weight lifting is a waste.

Some of Trentine's ideas are tough for a runner like me to swallow. But having given Overload a try, I concur he's got something people should consider.

As the name suggests, Overload takes you to your limits. You perform a small set of tasks slowly, with control, for a short time, until your arms or legs simply fail.

The reasoning is that most people spend their fitness time inefficiently, knocking out endless repetitions with too much assistance from momentum. Seeing little benefit, they either give up or keep on trying in vain. Alternatively, Overload trainers cut right to the chase, taxing large muscle groups with concentrated efforts lasting roughly 20 minutes. These, in turn, build more muscle by stimulating key hormonal reactions. Hence the slogan, "Maximum Fitness, Minimum Time."

Overload's facilities in Westlake, Beachwood and Columbus are like monasteries of fitness. Members sign contracts promising to give their all, and the heavily cooled workout rooms are distraction-free, with dim lights and no music or mirrors.

Also missing: free-weights. Instead, trainers employ machines, calibrating each to the individual. Some you might see in a gym. Others look like something out of a lab.

But if there isn't much to look at, it's for good reason. When you're there, you're supposed to be working, focused on your breathing and keeping a loose, unclenched face. They even ask you not to talk too much.

True to the formula, my workout was short. Trentine used five machines on me, and I'm pretty sure I spent no more than two or three minutes on each, not counting what it took to assume proper form and learn the instructions.

Each time, whether on the rower, lumbar device, or the leg, chest or overhead presses, Trentine set loads I consider easy, amounts I'd probably double on my own. In every case, though, moving so slowly, the burden came to feel like a ton of bricks.

Watching Trentine work out this way was like witnessing someone speak in tongues. It almost looked fake, or at least melodramatic. After just four or five repetitions, he'd be trembling, sweating and breathing rapidly.

But I can testify his struggle was real. After five rounds of Overload, using weights far lighter than Trentine's, I was exhausted, destined for soreness, my legs quivering and my arms like rubber. It felt as if I'd spent all afternoon lifting weights.

Happily, Trentine said I'd only need to put myself through this once or twice a week. That's all. If I weren't involved in endurance sports, there'd be no need for so-called "cardio" activities like running, cycling and swimming. Overload alone would keep me trim and strong, he said.

I suppose that's a good thing, given Overload's price tag. Individual sessions cost $70, while buying 96 sessions for 12 months sets you back $4,300.

But at 20 minutes a pop, Overload is certainly attractive, the closest thing to fitness in a bottle. At the very least, I'll keep in mind the principles when I'm at my loud, bright gym, doing my less-than-perfect thing.