Football Helmets Differ in Concussion Risk

Pauline Anderson

February 04, 2014

Not all football helmets are created equal, a new study suggests.

Researchers directly compared helmet design with another, with hits measured during real-play conditions, and found that the Riddell Revolution helmet reduced concussion risk by 54% compared with the Riddell VSR4 model, an advantage that is due to less head acceleration.

"The main purpose of the study was to illustrate the concept that there are differences in performance between different helmet designs," said study author Steven Rowson, PhD, assistant professor, School of Biomedical Engineering, Virginia Tech-Wake Forest University, Blacksburg.

Just because 2 helmets both pass national standards doesn't necessarily mean that they are equally protective against concussions, he added. Although scientists at Virginia Tech have been rating helmets in the laboratory for several years, this was the first study to compare helmet performance on the field, said Dr. Rowson.

The study was published online January 30 in the Journal of Neurosurgery.

Helmet-Mounted Arrays

From 2005 to 2010, a total of 1833 football players from 8 collegiate teams were fitted with helmet-mounted accelerometer arrays (HIT System, Simbex) that collected data on the severity, frequency, and location of impacts to the head during all games and practices.

Players wore a Riddell VSR4 or a Riddell Revolution helmet. These 2 helmets were chosen for comparison because they were the only helmets designed to fit the HIT system, said Dr. Rowson.

The study looked at the rate of concussions diagnosed by a certified athletic trainer or team physician at each institution.

Dr. Scott W. Powers

During the study period, there were 1,281,444 head impacts — 322,725 to players wearing the VSR4 helmet and 958,719 to those wearing the Revolution model.

After adjustment for head impact exposure of each player (a player in a position such as kicker might get only a few hits, while a running back may get hundreds during a season), the relative risk of sustaining a concussion in a Revolution compared with a VSR4 helmet was 46.1% (95% confidence interval, 28.1% - 75.8%).

More Impacts, Fewer Concussions

Although players in Revolution helmets experienced significantly more impacts than those wearing VSR4 helmets, they sustained fewer concussions (2.82% vs 4.47%).

The study results "spoke to the fact that the one helmet was better at reducing head acceleration than the other helmet," said Dr. Rowson. "This is true for all helmet types, in that those that reduce head acceleration will reduce risk of concussions."

The Riddell Revolution (left) and the Riddell VSR4 (right) helmets significantly differed in concussion risk. Courtesy of Dr. Rowson

A helmet modulates the energy transfer to the head during impact, which dictates the accelerations that the head will experience, according to the authors. These head accelerations result in transient intracranial pressure gradients and neural tissue strain responses and are correlated to risk for concussion.

The 2 helmets used in the study are actually very similar in design except that the Revolution has 40% thicker foam or padding, making it stiffer, Dr. Rowson said. To get a better response in terms of reduced head acceleration, "it's just a matter of optimizing those properties," he said.

Star System

Although this is the first on-field helmet comparison, Virginia Tech has been comparing football helmets in the lab since 2003 and releasing this information to the public. It rated the VSR4 with 1 star and the Revolution used in the study with 4 stars; the company took the VSR4 model off the market after the release of this rating, Dr. Rowson noted.

Currently, there are 4 top-rated 5-star football helmets, including the Riddell 360, Rawlings Quantum Plus, Xenith X2, and Riddell Revolution Speed. For more information, visit www.sbes.vt.edu/nid.

Dr. Rowson said he's often asked if a helmet can be designed that prevents all concussions, and his answer is always "no." "You will never be able to get a concussion-proof helmet," he said.

Concussion incidence can, however, be reduced through rule changes and use of proper tackling techniques. Some players may be more susceptible to head injuries and others may be more tolerant of them, said Dr. Rowson.

Although no data indicate how long a football helmet will last, the recommended life span is 10 years, said Dr. Rowson.

The study was supported in part by awards from the National Institutes of Health (NIH) and the Centers for Disease Control and Prevention. The HIT System technology was developed in part by assistance from the NIH. Dr. Rowson has disclosed no relevant financial relationship.

J Neurosurg. Published online January 31, 2014. Abstract

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