In the year following a concussion, college athletes are almost twice as likely to suffer serious lower body injuries like ankle sprains compared to the year before their head injury, according to a new study. 

“Our data show increased rates of musculoskeletal injuries following concussion, but do not point to the exact cause of the increased rates,” said lead author Robert C. Lynall of the exercise and sports science department at the University of North Carolina, Chapel Hill.

Concussions may cause lingering changes to balance or gait, or may slightly slow the pathways in the brain related to muscular reaction time, according to some theories, Lynall told Reuters Health by email.

“We suggest it is possible these adaptations may be more pronounced in the dynamic and challenging athletic environment,” he said.

The researchers studied 44 Division I college athletes who sustained a doctor-diagnosed concussion and 58 similar college athletes who did not suffer a concussion. They included male and female athletes from a range of sports, including football, lacrosse, soccer, cross country running and wrestling.

The researchers extracted data on acute lower extremity injuries, like ligament sprains, muscle strains, contusions and fractures, during sport play for the year before and the year after the concussion occurred from electronic medical records input by collegiate athletics staff.

The concussed group were almost 100 percent more likely to suffer one of these injuries in the year after a concussion than the year before it, and were 64 percent more likely to have an injury than the group who had never experienced a concussion, as reported in Medicine and Science in Sports & Exercise.

Many studies have reported balance returning to normal levels within five days after concussion, Lynall said.

“A couple of studies, using more advanced techniques, have shown balance deficits may linger beyond return to play after the concussion,” he said. “More research needs to be done to really understand long-term effects of concussion on coordination and balance.”

They cannot say if the results would have been similar among athletes of different ages or skill levels, he said.

“It looks like there is an increased risk of, to be honest, probably many injuries, including lower extremity injuries,” said Dr. Christina L. Master of The Children's Hospital of Philadelphia (CHOP), a concussion researcher who was not part of the new study.

Current balance assessments performed during post-concussion evaluations may not be fine-tuned enough to sense the changes that are happening, especially for athletes who have excellent balance to begin with, she told Reuters Health.

Concussion can have wide-ranging effects on mental and physical health, Master said.

“No matter where you were before concussion, after is probably worse,” she said.

Further studies should focus on quantifying these changes, which can vary greatly by individual, and determining how long they last, and if they ever return to pre-concussion levels, she said. At least a year after concussion, the risk of musculoskeletal injury was still increased in this study.

Learning more about concussion recovery may change the way athletes at all levels return to play after a head injury, Master said.