Michigan Concussion Center Associate Director of Research Dr. JT Eckner has spent much of his career studying the effects of neck strengthening as a concussion prevention strategy.
For over a decade he has worked with Mechanical Engineering research professor Dr. James Ashton-Miller, director of University of Michigan’s Biomechanics Research Laboratory and Concussion Center faculty member, to develop research methodology to study the head’s response to standardized forces and the relationship with neck size and strength.
Eckner’s and Ashton-Miller’s research shows neck strength can reduce head acceleration following impact in a lab, suggesting that neck strengthening exercises may be a good strategy for concussion prevention. “We have seen that our research participants with stronger necks experience smaller head acceleration responses, so we think that if an athlete does exercise to strengthen their neck it should reduce their concussion risk,” Eckner said.
Despite the promising findings, there is still much to be learned. Eckner and his team are now taking his research a step further with a large scale study involving male and female high school soccer players to better understand how neck strengthening exercise affects an athlete’s risk for concussion. “Our goal is to set up a really well-controlled study to lay this question to rest in terms of what it means if you do a neck strengthening intervention with respect to your risk of concussion, based on what we can measure in the lab,” he said.
“We think the high school age range is a sweet spot for this study because high school athletes are mature enough to be doing resistance exercise as part of their training regimens, and getting good benefit from it, but they are new enough to this sort of exercise that there is still a lot of room left for improvement,” he explained.
All of the study participants will complete exercises targeting muscles below the neck, but those assigned to the intervention groups will also do high-volume or low-volume manual resistance neck-strengthening exercises. Athletes will be assessed in the lab four times over the three-month study. An MRI of the athlete’s neck will be taken at the beginning and end of the study to measure overall growth, and each lab session will use ultrasound to assess the athlete’s overall neck circumference and cross-sectional areas of a few key muscles. In addition, Eckner will track how much force the neck muscles generate in each direction of motion (forward, backward, sideways, and in rotation) and muscle activation patterns using a technique called surface electromyography.
“We expect the neck muscles will get stronger before they get bigger due to improved efficiency of muscle fiber recruitment as participants train their necks,” he said. “As the muscles start to get stronger, and eventually bigger, we expect to see head accelerations begin to decrease during our standardized tests in the lab.”
During the lab sessions, participants will wear headgear with an attached cable that can apply standardized “tugs” to simulate both anticipated and unexpected impacts. To simulate more real-life scenarios, the athletes will use their shoulder to block a swinging punching bag and will also head a soccer ball lobbed to them from a machine. Eckner will assess head movement during each task.
“We know that bigger head accelerations are associated with a higher risk of concussion, and smaller head accelerations are associated with lower risk,” he said. “We think we will see that the neck strengthening exercises are going to reduce head accelerations. We think that we will see some benefit as soon as the muscles start to get stronger, and then even more benefit after muscle hypertrophy, or growth in muscle size, occurs. We also think that neck strength and neck muscle size may have slightly different effects when a test impact is anticipated and the athlete braces for it, versus when we simulate an unanticipated blind-side impact they don’t brace for ahead of time.”
Eckner is hoping to address two main questions: How much time and what volume of training exercise does it take before head accelerations begin to change? And how important is increasing just neck strength through more efficient muscle activation, versus also increasing the size of the neck muscles, in terms of affecting head acceleration? He adds that it is also important to assess whether the answers to these questions differ between males and females.
If the results of this study turn out as Eckner expects, the strengthening exercises he is studying will be easy to replicate in gyms across the country since the program doesn’t require any specialized equipment. “In our study the participants will all be exercising with a professional strength coach, but the program is something that could be widely translated into high school gyms and weight rooms across the country,” he said. “There is no reason coaches and athletes couldn’t learn to apply this intervention with one another.”