Twelve players were diagnosed with rhabdomyolysis, a potentially life-threatening condition, after the workout, with five still in the hospital Saturday.

Five Tufts University men’s lacrosse players remain hospitalized following a recent workout led by a graduate of a Navy SEAL training program, according to a spokesman for the school.

A dozen players were diagnosed with rhabdomyolysis after a “voluntary [and] supervised” 45-minute workout held on Monday, a university spokesperson said. Seven players were treated in the emergency room and released from the hospital, he said.