CrossFit is an extreme workout and now it's being linked to a potentially fatal condition that occurs when people push their bodies so hard that their muscle cells actually burst. It's a rare condition called Rhabdomyolysis, or Rhabdo.
"You can die from exercise-induced Rahbdo. More importantly, you'll lose your kidneys first so you'll be on chronic dialysis for the rest of your life," said Dan Parker, M.D., from the U.C. Davis Sports Medicine program.
Symptoms include pain, swollen biceps or triceps and dark urine. CrossFit tells us their trainers are experienced and know what to look for with athletes.