Thirteen University of Iowa football players remain hospitalized after becoming ill with what the university says is a little-known muscle syndrome called rhabdomyolysis. Rhabdomyolysis occurs when muscle is destroyed and the pigment in it that makes it red, called myoglobin, gets into the kidneys and can damage them.
At a press conference on Wednesday, a spokesman said it's unclear how the students developed the condition.
"The causes of rhabdomyolysis are extensive. There may be a hundred different causes for this problem," said Dr. John Stokes, director of Division of Nephrology at the University of Iowa. He is not involved in the care of the players. "When it occurs in young, otherwise healthy individuals, one of the common scenarios we look for is a recent exercise."
Stokes said that it's unusual for so many people with different body types and genetic predispositions to come down with rhabdomyolysis at once. Although it attacks the kidneys, the condition almost always goes away.
"It does appear to be a little unusual, but apparently the common denominator for each of these individuals had to do with the fact that they were undergoing a workout, a heavy exercise program, and heavy exercise is known to produce this syndrome," he said.
Paul Federici, the director of football operations at the University of Iowa, said at the press conference he didn't know the exact structure of players' workouts, but said there were breaks and also plenty of water available.
When asked whether players may have been taking dietary supplements, some of which can cause rhabdomyolysis, Federici said he didn't know if they were taking any, and if they were, they are only allowed to consume substances that meet NCAA compliance. Rhabdomyolysis can be also caused by certain medications, such as statins to lower cholesterol.
Biff Poggi, the father of one of the players, said his son experienced a lot of soreness, but is doing better. He said his son complained of pain on subsequent days after different workouts, at least one of which included a lot of squats. As a father, he said he's concerned about his son and his training, but he's also a football coach and said the workouts don't seem unusual to him.
"This time of year if you're a football player is the time where you're doing the most kind of strenuous work, kind of preparing for spring practice," Poggi said. "These kind of workouts would happen."
Experts say rhabdomyolysis can occur after extremely strenous exercise or after some sort of crushing injury that causes muscle to die.
"When you exercise, the muscles secrete potassium to help blood flow to those muscles to help get them the oxygen that you need," said Kate Mone, a sports nutritionist at the Cleveland Clinic. "Now, if you're doing continuous, repetitive bouts of exercise strenuously, your muscles are going to deplete that potassium. There won't be as much blood flow to those muscles and those muscles are going to begin to break down."
Although the myoglobin that's released after muscle death can cause kidney damage, rhabdomyolysis rarely leads to death or lifelong complications.