New York Jets cornerback Darrelle Revis is carted off the field after tearing his ACL at Sun Life Stadium on September 23, 2012 in Miami Gardens, Florida.
In recent years Dr. Daniel Herman, a sports medicine fellow at the University of Florida — he will start an assistant professorship at the University’s Department of Orthopedics and Rehabilitation in July — has started a personal parlor game. He’ll hear about an athlete sustaining a concussion, then track that athlete’s subsequent injury history. “It’s become a hobby of mine,” Herman says.
Too often, a concussion would be followed by some kind of knee or ankle ailment. Recent examples include New York Jets cornerback Darrelle Revis, who was just traded to the Tampa Bay Buccaneers. Revis missed Week 2 of this season because of a concussion, then returned to the field in Week 3; in that game, he tore his ACL, and missed the rest of the year. New Orleans Hornets rookie Anthony Davis had a concussion in November, and missed 11 games. He later sprained an ankle in January, and in April, Davis sprained his MCL and suffered a bone bruise in his left knee.
Then there’s RG3. Washington Redskins quarterback Robert Griffin III tore his ACL during a playoff game in January. Yes, RG3 has had a history of knee injuries; he tore his ACL while at Baylor, and hurt his knee in December. But it’s still worth noting that he got a concussion in October. “It makes you wonder,” says Herman.
(MORE: Even Football Players Without Concussions Show Signs of Brain Injury)
Herman set out to answer that nagging question: does a concussion leave an athlete more susceptible to a lower extremity injury? His research suggests that it does. Last week, Herman presented a new study at the American Medical Society for Sports Medicine conference in San Diego. Herman and his co-authors examined University of Florida football and women’s basketball, soccer, and lacrosse players from 2006-2011. They found that athletes who suffered a concussion were 3.79 times more likely to get a muscle or ligament injury — within 90-days of the concussion — than non-concussed teammates (the severity of the injuries were not statistically different between the concussed and non-concussed groups). Herman acknowledges that his study involves a relatively small sample of athletes, and that broader followups are necessary. Still, he says, “we’re pretty confident that there’s an association.”
Even if athletes are asymptomatic after a concussion, says Herman, their cognition could be altered; changes in reaction times and decision-making could lead to further injury. Herman has also studied recreational athletes at the University of Virginia, and found that the worse students score on neurocognitive tests, the worse they tend to perform on movement tasks. So when concussed athletes are ready to play again, they may want to focus on “dynamic” stretches involving resistance, plus do squats, hops, and jumps in warmup. Studies suggest that such plyometric exercises — which improve strength, agility and balance — can reduce ACL injury risk. Also, Herman says coaches could limit the playing time of concussed athletes when they return to play. “Fatigue may have an outsized effect for people coming back from a concussions,” says Herman. Keeping players off the field now can help keep them on the field later.
(MORE: Neck Strength Predicts Concussion Risk, Study Says)