When the Oregon football team hired Willie Taggart to take over as head coach after a losing season, school officials wanted him to hit the ground running and get the program turnaround started right away.

This likely isn’t what they meant.

At least three Oregon football players, including offensive linemen Doug Brenner and Sam Poutasi and tight end Cam McCormick, were hospitalized following an intense set of workouts in early January, according to The Oregonian. The players were put through “military” style workouts, which included “up to an hour of continuous push-ups and up-downs,” according to the paper’s reports.

Poutasi’s mother told The Oregonian that her son had been diagnosed with rhabdomyolysis after he complained about sore arms following the workouts. The players have been in the hospital for several days, and are in fair condition, a hospital spokeswoman told The Oregonian.

The Oregonian described the workouts “as akin to military basic training,” including “up to an hour of continuous push-ups and up-downs,” citing sources familiar with the workouts. Some players “passed out,” and other players “later complained of discolored urine, which is a common symptom of rhabdomyolysis,” the sources also said. Furthermore, The Oregonian reported, After testing, others were found to have highly elevated levels of creatine kinase, an indicator of the syndrome.”

Rhabdomyolysis can happen when the intensity of a workout spikes and when athlete’s overexert themselves during a workout. It can cause the “body’s muscles break down to such an extent that their cells flood in the bloodstream and can lead to kidney failure,” Michele Olson, Ph.D., professor at Auburn University Montgomery, told Men’s Fitness. Rhabdomyolysis can also result when an athlete is severely dehydrated and working out under hot conditions, according to the Mayo Clinic.

“The safety and welfare of all of our student-athletes is paramount in all that we do,” University of Oregon officials said in a statement. “While we cannot comment on the health of our individual students, we have implemented modifications as we transition back into full training to prevent further occurrences. We thank our medical staff and trainers for their continued monitoring of the students and we will continue to support our young men as they recover.”

As for the regular gym-going Joe: Rhabdo is an exceptionally rare condition, and as long as you’re properly hydrated and not working out in unduly extreme circumstances, you should be fine. And if you’re feeling weirdly awful after a workout, always give a doctor a call—even if it’s not rhabdo, taking care of yourself will ensure you’re back in the gym the next day and not, say, in the hospital.