The popular and extreme workout CrossFit is drawing fire after a Denver physical therapist claimed it's dangerous and even deadly.
Eric Robertson, an assistant professor of physical therapy at Regis University in Denver, wrote in an article that the CrossFit culture pushes people beyond their limits and common sense.
Westbound CrossFit owner Angel Cardenas in West Sacramento doesn't buy into that.
He said it's often the group setting that draws people to the extreme workout.
"Because you get results, you're working out in this group environment, you've got the music going and that's one of the reasons why people really push," said Cardenas.
But does that "peer pressure" push people too far?
Cardenas says trained coaches start beginners out slow and get their bodies conditioned before they're transitioned into tough, more intense workouts.
But UC Davis Medical Center sports medicine specialist Dr. Dan Parker argued that in some cases, it can be dangerous.
"If you get enough excitement in a group, like CrossFit, you can push yourself beyond the normal natural limits and cause massive injuries to your cells."
He was referring to a rare condition called rhabdomyolisis or "rhabdo".
It's nothing new to the sports world. Parker said athletes get it from working out too hard, too soon.
"Usually the bicep or tricep muscles become very big or swollen. They'll begin to notice they have "Popeye" muscles, excessively sore and sometimes dark urine," explained Parker.
In simple terms, athletes push their bodies beyond their limits and end up killing their muscle cells.
Parker said it's something their kidneys can't handle.
"You can die from exercise-induced rahbdo ... You'll lose your kidneys first so you'll be on chronic dialysis for the rest of your life."
But Cardenas said in certified CrossFit gyms, trainers know what to watch for.
"An experienced coach will see when an athlete may be suffering from muscle fatigue during a workout, and you know when to tell that athlete to chill out, slow down."
Cardenas does not know of any athletes who have developed rhabdomyolisis and Parker said he has never had to treat anyone in the Sacramento area for the condition.
In fact, Parker said the odds of getting it are "too small to estimate".
But both agree while rare, it is important for people to be aware of it and know when to stop the workout.
Courtney Carlmark, CCarlmark@news10.net