Knee injuries may start with strain on the brain, not the muscles (w/ Podcast)

Jul 24, 2009

New research shows that training your brain may be just as effective as training your muscles in preventing ACL knee injuries, and suggests a shift from performance-based to prevention-based athletic training programs.

The ACL, or anterior cruciate ligament, is one of the four major ligaments of the knee, and ACL injuries pose a rising public health problem as well as an economic strain on the medical system.

University of Michigan researchers studying ACL injuries had subjects perform one-legged squats to fatigue, then tested the reactions to various jumping and movement commands. Researchers found that both legs---not just the fatigued leg---showed equally dangerous and potentially injurious responses, said Scott McLean, assistant professor with the U-M School of Kinesiology. The fatigued subjects showed significant potentially harmful changes in lower body movements that, when preformed improperly, can cause ACL tears.

This video is not supported by your browser at this time.
Professor Scott McLean discusses how sports injury prevention training programs could differ in the future.

"These findings suggest that training the central control process---the brain and reflexive responses---may be necessary to counter the fatigue induced ACL injury risk," said McLean, who also has an appointment with the U-M Bone & Joint Injury Prevention Center.

McLean says that most research and prevention of ACL injuries focuses below the waist in a controlled lab setting, but the U-M approach looks a bit north and attempts to untangle the brain's role in movements in a random, realistic and complex sports environments.

The findings could have big implications for training programs, McLean said. Mental imagery or virtual reality technology can immerse athletes to very complex athletic scenarios, thus teaching rapid decision making. It might also be possible to train "hard wired" spinal control mechanisms to combat fatigue fallout.

In a related paper, McLean's group again tested the single leg landings of 13 men and 13 women after working the legs to fatigue. While both men and women suffer an epidemic of ACL injuries, women are two to eight times likelier to tear this ligament than men while playing the same sport. However, the study showed that men and women showed significant changes in lower limb mechanics during unanticipated single leg landings. Again, the findings point to the brain, McLean says.

During testing, a flashing light cued the subjects to jump in a certain direction, and the more fatigued the subjects became, the less likely they were able to react quickly and safely to the unexpected command.

The research suggests that training the brain to respond to unexpected stimuli, thus sharpening their anticipatory skills when faced with unexpected scenarios, may be more beneficial than performing rote training exercises in a controlled lab setting, which is much less random than a true competitive scenario. In this case, expanding the anticipated training to include shorter stimulus-response times could improve reaction time in random sports settings.

"If you expose them to more scenarios, and train the brain to respond more rapidly, you can decrease the likelihood of a dangerous response," he said. It's analogous to how a seasoned stick shift driver versus a novice learner might both respond to a sudden stall. The inexperienced driver might make a slow or even incorrect decision.

More information:

The paper, "Fatigue Induced ACL Injury Risk Stems from a Degradation in Central Control," will appear in Medicine and Science in Sports and Exercise in August 2009.

"Difference between Sexes and Limbs in Hip and Knee Kinematics and Kinetics During Anticipated and Unanticipated Jump Landings: Implications for ACL Injury," appears online at the British Journal of Sports Medicine: bjsm.bmj.com/cgi/content/abstr… rcetype=HWCIT,HWELTR

Source: University of Michigan (news : web)

Explore further: 'Ice Bucket Challenge' passes $100 mn mark

add to favorites email to friend print save as pdf

Related Stories

Motion analysis helps soccer players get their kicks

Jul 09, 2009

As soccer continues to grow in popularity, injuries to soccer players are likely to increase as well. Certain injuries fall into gender-based patterns and new research at Hospital for Special Surgery suggests some underlying ...

Researchers identify technique that improves ACL surgery

Jul 09, 2009

Surgeons from Hospital for Special Surgery in New York have identified a drilling technique that improves the outcome of surgery to reconstruct the anterior cruciate ligament (ACL). The news will be presented during the annual ...

Recommended for you

Cold cash just keeps washing in from ALS challenge

Aug 28, 2014

In the couple of hours it took an official from the ALS Association to return a reporter's call for comment, the group's ubiquitous "ice bucket challenge" had brought in a few million more dollars.

Medtronic spends $350M on another European deal

Aug 27, 2014

U.S. medical device maker Medtronic is building stronger ties to Europe, a couple months after announcing a $42.9 billion acquisition that involves moving its main executive offices across the Atlantic, where it can get a ...

Mind over matter for people with disabilities

Aug 26, 2014

People with serious physical disabilities are unable to do the everyday things that most of us take for granted despite having the will – and the brainpower – to do so. This is changing thanks to European ...

User comments : 0