What's Really Causing Knee Injuries in Football?

NFL players are more worried about knee injuries than concussions, and recent data suggests that their concerns may not be unfounded.

NFL players are more worried about knee injuries than concussions, and recent data suggests that their concerns may not be unfounded.

An infographic by Simple Therapy via the Huffington Post details every injury reported this season up to Jan. 14. The knee was the most common culprit of the more than 1,300 injuries, consisting of 22.4 percent with 294 reported cases. Ankle injuries were next, with 201 reports, or 15.3 percent. 93 head injuries were reported, making up 7.1 percent.

While the impact of brain trauma cannot be overstated, the frequency and severity of knee injuries should worry players. SimpleTherapy states:

Many of these injuries involve the ligaments in the knee, most often the MCL, PCL and ACL (medial cruciate ligament, posterior cruciate ligament and anterior cruciate ligament respectively). These ligaments contribute to the four-bar linkage of the knee and make possible the pivoting and starting/stopping that every football player does constantly. Consequently, tears to these ligaments can be severe and have serious consequences for players, including surgery to reconstruct the ligament and long courses of physical therapy and conditioning to return to play.

Indeed, the consequences of knee injuries are not lost on players. A USA TODAY Sports survey of 293 NFLers found that nearly half were most concerned with their knees or other parts of their legs, while almost a quarter were worried about head and neck injuries.

There's been much talk this season about the possible cause of the rise in knee injuries, which have increased 11 percent from 2012 and 34 percent from 2011. After high-profile injuries to New England Patriots tight end Rob Gronkowski and Miami Dolphins tight end Dustin Keller, players admitted that the new penalties and fines against hits to the head designed to avoid concussions cause them to intentionally hit low. But as ESPN pointed out back in December, that doesn't explain the rise in ACL tears caused by no contact. Theories have blamed artificial turf and shoes that sacrifice stability for speed -- an explanation offered by NFL Commissioner Roger Goodell himself -- but a potential cause gaining traction is the reduction of offseason workouts mandated by the 2011 collective bargaining agreement.

If that's the case, it would be good news for the NFL. Player conditioning is a problem that can be solved with more rigorous pregame warm-ups without trying to change the inherently violent nature of football. As Seattle Seahawks cornerback Walter Thurmond said, "You can't make a vicious game safe at the end of the day," but you can take steps to better prepare players for the battlefield.

(Kavitha A. Davidson is a Bloomberg View columnist who writes about sports. Follow her on Twitter at @kavithadavidson.)

This column does not necessarily reflect the opinion of Bloomberg View's editorial board or Bloomberg LP, its owners and investors.