Sep 6, 2018Prepare for Impact
When athletes see a head impact coming, the response is often to tense up their neck muscles in preparation for the hit. A recently published study from Stanford University suggests that this might not help avoid concussion. Rather, head position might be a bigger determining factor.
According to ScienceDaily, the study used computer modeling to estimate higher-force impacts that could lead to concussion.
“We found it really interesting that your soft tissue — muscles, ligaments, and tendons — isn’t doing much to dictate how your head is rotating immediately after an impact,” Michael Fanton, PhD Candidate in Bioengineering at Stanford and the study’s lead author, said. “Whereas even a few degrees of change in your head-neck angle can really alter how much your head is rotated and therefore, probably, your risk of concussion.”
In an earlier study, research participants’ heads were tilted backward with miniature weights attached. Next, the participants’ head movements were monitored as they tensed or relaxed their necks. Those measurements were used to develop a computer model that illustrated how the head moves.
Then, the research team replicated low- and high-impact forces in the computer model. Although tense neck muscles were associated with a slight reduction in head acceleration in the low-impact forces, they didn’t seem to make a difference for higher-impact forces. In other words, when involved with a hard and fast impact, it didn’t seem to matter if neck muscles were tense.
“Originally, we thought your neck muscles could affect head acceleration and we wanted to figure out if that offered another strategy for reducing brain injury,” Fanton said. “It was surprising that in these shorter-duration impacts, the neck muscles are not doing a whole lot.”
The research team also analyzed front-to-back acceleration as it relates to head and neck positioning. The results showed that the head’s positioning can make a difference for concussion risk — with the area that is hit also affecting the head’s rotation.
The researchers expect this work may be helpful as new protective equipment is developed in a number of sports. Although head and neck positioning won’t be a simple solution to prevent injuries such as concussion, it may be helpful.
“Discovering how sensitive the head is to slight changes in positioning has implications on design of helmets and other protective equipment,” David Camarillo, PhD, Assistant Professor of Bioengineering and Mechanical Engineering at Stanford, said. “For example, could the facemask in football be offering a lever arm that adds to the rotation of the head and therefore risk of concussion? Are downhill mountain bike helmets protecting the chin at the cost of the brain? We hope to use this model we have developed to determine better design geometry of helmets and potentially for input to coaching on how to brace for impact.”