By Jim Halley, USA TODAY

Oregon health officials have concluded that multiple factors led to similar injuries last month that hospitalized football players from McMinnville High.

"There is not one factor that we can pinpoint as the cause," said Katrina Hedberg, the Oregon state epidemiologist. "Rather, it appears that multiple factors including the type of exercise, the hot day and not enough water for some of the players contributed to their illnesses. Our goal is to prevent similar injuries in our state's young athletes."

Of the 43 McMinnville players involved in preseason workouts Aug. 15, three had surgery because of triceps compartment syndrome, which is a muscle injury involving swelling that can impede blood flow; five had rhabdomyolysis, a muscle injury that can lead to kidney failure, and high levels of creatine kinase, an enzyme that can show the presence of muscle injury; and 14 had muscle pain and above-average creatine kinase levels.

Blood tests for creatine levels were inconclusive, the report said, because they could not distinguish the presence of natural creatine from creatine that could have been the result of using supplements. Hedberg said steroid use did not seem to be a common factor either. "Can I absolutely rule the use of steroids out? No. But it did not seem to be as likely a common factor as other things," she said.

The report did not find any environmental factors such as toxins, poor water quality or carbon monoxide in the gym and wrestling room where the workouts took place that might have contributed to the players' conditions.

Health officials said they interviewed 40 of the 43 team members involved and met with coaches, school administrators, hospital administrators and physicians who treated the players. Health officials said they also reviewed the team's medical records and assessed symptoms and exposures.

The report recommended that players, coaches and officials recognize that intense, short-duration, repetitive resistance exercise involving a single muscle compartment can lead to serious health complications. It also suggested that coaches, trainers and school administrators routinely assess health and safety hazards at workouts and take effective countermeasures, such as adequate rest and hydration.

"We want to encourage everyone to be physically active," Hedberg said. "But if you're going to run a marathon, you should start out walking and then jogging. It makes sense to work your way up to any kind of intense exercise."

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