A growing number of concussion experts  (Meehan, 2011), strength and conditioning trainers (Cohen, 2012), and physical therapists , believe that one important way to reduce the risk of sport-related concussion is by strengthening the neck, the theory being that stronger neck muscles will help cushion against and lessen the linear and rotational forces that cause concussion.
Now, for the first time, there is research to back up the theory.
Using a newly developed cost-effective, hand-held tension scale device to measure neck strength, researchers at Nationwide Children's Hospital in Columbus, Ohio and the Colorado School of Public Health (Collins, 2014) found that neck strength was a significant predictor of concussion, with the odds of concussion falling by 5% for every one pound increase in aggregate neck strength.
The data also showed that the quarter of the subject group of more than six thousand high school athletes playing boys' and girls' soccer, basketball, and lacrosse with the weakest necks suffered the greatest number of concussions, while the quartile with the strongest necks suffered the fewest.
Researchers also identified differences between anthropometric measurements and concussion by gender and sport. Among boys, smaller mean neck to head circumference ratio and smaller mean overall neck strength were both significantly associated with concussion.
Among girls, smaller mean overall neck strength was only marginally associated with concussion, and mean neck to head circumference ratio was not associated, although the researchers said it was unclear what relative roles biophysiology, anthropomology and sociocultural constructs (such as the theory advanced by some that girls have higher concussion rates because they are more willing to honestly self-report experiencing concussion symptoms) may play in these differences.
Previous studies have found that rates and patterns of concussion in gender-comparable sports differ, with females sustaining significantly more concussions than males, reporting different symptoms, and having worse overall outcomes (Broshek et al, 2005; Dick, 2009; Field, Collins, Lovell & Maroon, 2003; Frommer, et al, 2011; Gessel et al, 2007; McClincy, Lovell, Pardini, Collins, & Spore, 2006).
The study reported that smaller mean neck strength was significantly associated with concussion in basketball and lacrosse, but that there was only a marginal association in soccer. While it has long been believed that a long neck paired with a large head placed football players at an increased risk of concussion, the researchers found that the ratio between neck length and head circumference was not a significant predictor of concussion among the study population of basketball, soccer, and lacrosse players.
"Given the recent growing concern regarding sports-related concussions and limited availability of primary prevention techniques, this finding is important," writes lead author Christy Collins of the Center for Injury Research and Policy of the Research Institute at Nationwide Children's. "Identifying differences in ... neck strength may drive development of screening tools that could identify athletes at elevated risk of concussion. Once identified, these athletes could be targeted for concussion prevention interventions, such as neck strengthening programs, tailored to their specific risk factors."
"The evidence [suggests] that neck strengthening programs may be an effective primary concussion prevention mechanism that is inexpensive, easy to adopt, widely available, and fully within the athlete's control," says R. Dawn Comstock, PhD. associate professor in the Department of Epidemiology at the Colorado School of Public Health and principal investigator for the High School RIO TM (an internet-based data collection tool used in the National High School Sports-Related Injury Surveillance Study) from which the study results were drawn. The study, published online in the Journal of Primary Prevention in June 2014, was first presented by Comstock at the 4th Annual National Youth Sports Safety Summit in Washington, D.C. in February 2013.
"We focus so much on how to properly diagnose concussions," Comstock told Time's Sean Gregory after her summit presentation. That's obviously important, but preventing concussions is a much better outcome. We're not saying you won't get a concussion if your neck is stronger. But the data shows that neck strengthening has strong potential as a key concussion prevention tool."
"The results are promising and support what those of us caring for athletes believed to be true, based on our observations, who see strengthening the neck musculature as a means of reducing the risk of sport-related concussion," said William P. Meehan, III,  M.D., Director of the Sports Concussion Clinic and the Micheli Center for Sports Injury Prevention in the Division of Sports Medicine at Children's Hospital Boston, and a MomsTEAM concussion expert.
Previous studies have found that stronger necks decrease head acceleration, rapid change in velocity, and displacement after a collision, which in turn may reduce the risk of sports-related concussion, with one finding that even a small decrease in velocity may result in a significant reduction in concussion risk.
Other studies have found that neck strengthening programs are effective in increasing neck strength among athletes.
A 2013 study (Dezman, et al, 2013) found that balanced neck strength may reduce the acceleration of the head during the act of heading a soccer ball, thus reducing the risk of brain injury from such low grade hits.
Because hand-held dynanometers, currently the gold standard for measuring neck strength, are too costly for many high school sports programs, the researchers developed as the first step in their study a cost-effective hand-held tension scale device attached to a a Velcro adjustable head strap with a D ring to measure neck strength (in pounds). They found that measurements taken with the device correlated highly with measurements with the handl-held dynanometer. In addition, athletic trainers reported being able to measure neck strength in a high school setting, suggesting that neck strength measurements of high school athletes obtained by ATs using the tool, which costs about $10 (compared to a hand-held dynanometer that can cost up to $750-$1,000 each), could predict which athletes may be at increased risk of concussions.
Neck strengthening exercises are easy to do and don't require a huge investment in equipment.
Here are some simple strengthening exercises Dr. Meehan says athletes can add to their current resistance training:
In order to perform lateral resistance exercises, an athlete places their right hand on the right side of their head. The muscles of the neck are flexed so that the right ear attempts to move downward towards the right shoulder, but, because the athlete is resisting that action, the head doesn't actually move. The athlete should hold this position in active resistance for about 5 to 10 seconds. The exercise can then be performed on the left side of the head, front of the head, and back of the head.
The rotational resistance exercises are similar: the athlete places their hand against the side of the forehead and then attempts to rotate the head towards the right or the left while nodding "no." This motion is resisted by the hand so there is no actual movement of the head. Again, the athlete should hold the position in active resistance for about 5 to 10 second and then repeat in the opposite direction.
As with all resistance training, particularly in younger athletes, the emphasis should be on proper and safe technique. Younger athletes who are unfamiliar with resistance training should be coached and supervised by an adult with expertise in resistance training of the pediatric athlete. The descriptions outlined above are for descriptive purposes only; anyone planning on engaging in them should consult a proper manual or seek professional assistance.
For more on neck strengthening advice from MomsTEAM's expert physical therapist, Keith Cronin, DPT, click here .
Editor's Note: Doctors Meehan and Cronin are featured in MomsTEAM's PBS documentary,"The Smartest Team: Making High School Football Safer " discussing neck strengthening as a way to reduce the risk of concussion.
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Originally posted February 22, 2013; updated February 25, 2013 to include Dr. Meehan's comments; substantially updated and revised July 12, 2014 to report on the published study.