The cross-training program urges exercisers to go harder and faster, all while pushing through their limits. But going too far with these strenuous drills could cause a condition called rhabdomyolysis. (Via ABC)
"Rhabdo," for short, causes muscle cells to literally explode, flooding blood vessels with their contents and in extreme cases, causing kidney failure. One woman said it was more painful than childbirth. (Via WebMD)
"I've had two babies...and I'd have 5 more before I ever had to go through this again."
And Dr. Ron Goldin says only experienced trainers should try CrossFit.
"If you haven't worked out for a while, don't jump into it, trying to keep up with the rest of the class and don't try to do the hardest workout you've ever done." (Via WPTV)
The condition is on the rise as CrossFit grows increasingly popular, with over 6,000 affiliated gyms in the United States. That's up from only 50 in 2005. (Via The New York Times)
But the regimen has its fair share of critics. A columnist for The Huffington Post scolds the CrossFit culture as "one of pushing your body to the point of near exhaustion. It is a system of punishing exercises built on a platform of peer pressure."
Even converts admit the gym climate can be a bit much.
"Some people refer to folks doing CrossFit as crazy and some people even call it a cult." (Via WTTG)
Critics have even tried advancing their cause by creating "Uncle Rhabdo," a clown mascot suffering from the muscle disease. (Via Breaking Muscle)
But other Crossfit trainers say rhabdo is just the result of irresponsible workouts. According to one participant, the disease is "an extreme condition thwarted upon oneself... It's not the sport, the organization or even the coaches. It's your own fault."
Overall, doctors agree that the intensive workouts are healthy... in moderation. It's key to listen to your body and avoid pushing too hard.