All nine members of the Tufts University men’s lacrosse team who were hospitalized this month with the rare muscle injury rhabdomyolysis have been discharged, and the university says it has hired experts to investigate what led to so many serious injuries after a training session.

All of the Tufts lacrosse players have been released from the hospital after 12 were diagnosed with a life-threatening muscle condition, rhabdomyolysis, after participating in a Navy SEAL-type workout.

Last week, nine lacrosse players at Tufts University were hospitalized with a rare—and potentially deadly—muscle condition called rhabdomyolysis.Rhabdomyolysis, or rhabdo for short, stems from a breakdown in damaged muscle and is usually caused by strenuous exercise.