Physical fitness surely is a good thing. Every study ever performed has shown that the fit and lean outlive the dumpy and diffident every time. But there is a problem: Unlike most things in America—real estate, gold, cars in the garage—which hew to the premise that more is better and super-more is super-better, physical fitness has a limit, at least for most people.

Sure, some triathletes and ultra-marathoners seem impervious to these facts of life, but in the real world peopled by the 99-percenters, it turns out we can only buff and pump and tone our gorgeous muscles into so much gorgeousness. After a certain point, the muscles break down. It’s called rhabdomyolysis and increasingly, workout enthusiasts, as well as hapless college football players, are developing this extremely serious medical condition.

It is hardly a surprise: Our muscles are pretty basic contraptions. The goal of every muscle is to move a bone. Straighten your arm. Go ahead try it—I promise this is not like asking you to sing along with a lame folk song. OK, here’s what happened. Your triceps muscle, stationed on the underside of your upper arm, shortened. That’s all a muscle knows how to do—shorten. And when the muscle shortens, the attached bone moves. Simple physics.

For the up-close microscopic view, imagine two flat hair-combs lying on the desk with the teeth facing each other. These are like our muscle fibers. When we flex, the teeth from comb A (which is facing right) slide into the thin gaps between the teeth from comb B (which is facing left) and this shortens the muscle. And our bones move. And our arm straightens.

The problem is that some people do this way too much. Sure, some become governor of California after a recall election and others go to weight-lifter conventions (and most get bored after a month and resume their previous immobility). But some, the ones with real stick-to-it-iveness, join a gym and start a program like CrossFit. CrossFit “starts with a belief in fitness” to “forge elite fitness” and wants to “prepare trainees for any physical contingency”; their secret is that their “specialty is not specializing.”

In other words, their workouts are for those too frightened to join the Marines but looking for high-voltage exertion designed to push every muscle to the edge; too often, it seems, they can push a person well beyond. Some CrossFit adherents have had a problem with muscle overuse and development of rhabdomyolysis, at least since 2005, when a U.S. Navy technician named Makimba Mimms won a lawsuit after claiming he had become disabled from rhabdomyolysis related to following a CrossFit program.

The typical biologic sequence is that the muscle fibers can deteriorate from extreme overuse and spill their cellular insides into the bloodstream. Among the products that begin to float around is a molecule called myoglobin, which damages the kidney directly; molecules precipitate in some of the delicate drainage tubules, disrupting normal flow. The result can be total kidney failure and the need for dialysis; for some people, the kidney failure is permanent. Rhabdomyolysis also can cause other problems related to muscle inflammation itself, such as nerve damage, permanent weakness—an entire textbook of physical maladies.

There have been other reports since then, including one picked up by the New York Post. Each tells the same tale: an enthusiast who wants to look good and feel better decides to push past the pain just a little too much then ends up for a week or two in a local hospital.

Of course, CrossFit is in no way the only exercise program or health product that may cause health problems. A report this week from the Centers for Disease Control describes liver failure among persons taking a fitness and weight-loss dietary supplement. Yet CrossFit does seem unique in its response to the rhabdomyolysis problem. Rather than dispatch a team of slick lawyers with leather briefcases, they seemingly adopted a cartoon character, Uncle Rhabdo. He’s a droopy aging Bozo with organs (kidney? intestines?) and arms aflop. The message is derisive—rhabdomyolysis and whatever else might happen to certain people is really for wimps and buffoons only. Not manly men. Real men, Governor Arnold sorts of men, can do CrossFit programs and keep on ticking.

But that is not the end of it. CrossFit also has repurposed the name of the Navy technician who won the lawsuit by naming a workout—a children’s workout—after him: the Makimba.

Get it? He’s a guy who couldn’t even get past the kindergarten program.

This sort of apparently overt corporate hostility toward the underclass surely is new, yet it’s a business plan that seems to be working. Just wander by your local health and fitness center—there are many—and peer in. Fitness, good looks, longevity all now are considered a zero-sum game: If a few guys can‘t cut the mustard, well, that can only mean I am even more of a hunk than even I imagined.

We have seen this before, the mean-spirited ridicule of those who can’t keep up, though we had hoped and assumed it was over when we left high school: the cool guy dismissing the laggard with cruelty and contempt. It’s called bullying and finally is recognized as psychopathology.

The odd fact about CrossFit though is that it is both the bully and the bullied—the 99-pound weakling with an eyeful of sand seeking salvation at the gym and the tormentor, the muscle-bound brute flashing handsome teeth. Without any particular intent, CrossFit may have stumbled upon something even more compelling than the promise of health and fitness: the perpetual motion created by the never-ending cycle of self-hatred alternating with self-adoration.