The NFL has recently taken a big hit (no pun intended) regarding player safety and the number of head injuries sustained by its players. As many of the readers are aware, there have been a number of changes made to both the rules of the game as well as the stricter enforcement of proper tackling mechanics. And though a lot of people have been following the law suit from the player’s union and the regular adjustments of the rules, there is one very under reported, yet incredibly promising way we can reduce the rate of concussions in football: the helmet.
When considering the biomechanics of football, thinking about the helmet certainly would be an important and very logical discussion to have. The purpose of a helmet is to protect the head during hits by facilitating the transfer of energy in such a way that accelerations experienced by the head will be reduced and therefore nervous tissue damage and pressure changes within one’s skull may be minimized. This is done through strategic placement of padding and appropriate selection of materials.
Before we take a specific look at the helmet studies, let’s just go over the facts surrounding concussions briefly (For even more information regarding concussions and diagnosis please check out a previous article). A concussion is defined as any change in an athlete’s cognitive function observed or perceived after receiving a rapid acceleration of the head. Symptoms of a concussion may include: nausea, headache, photophobia (light bothers their headache), loss of consciousness, transient amnesia, insomnia, irritability, and inability to focus. Each year anywhere from 1.6 to 3.8 million sports-related concussions are sustained in the United States alone with football ranking at the top of that list as the biggest culprit. Clearly this is a growing problem across all sports and more particularly all levels of football from Pop-Warner to the NFL.
So what kind of data do we have regarding helmets? Well, this has actually been a hot topic in sports medicine for a few years. There have been numerous studies looking at helmet design and how it may affect the impact experienced by the players. In fact researchers have looked at everything from the old “leatherhead” helmets of the past to the a comparison of a foamy exterior helmet with the newer Riddell helmets used in the NFL and by most college teams. The facts are pretty interesting and yet this continues to be such an under reported item by the more popular sports media sources.
The majority of studies that have been published are comparison studies. They typically compare the current helmets in use (made by Riddell) to other helmets by attaching o helmet to a pendulum like machine with small weights inside of the helmet to represent the weight of a head another helmet is commonly placed on the head of one of those MMA/Kick Boxing dummies to represent the most lifelike head and neck movement of a hit. The pendulum is then swung at different velocities to allow the helemts to collide and data is colleceted by a pretty cool product that was developed by Riddell several years ago called HITS (Head Impact Telemetry System) that allows for the location, magnitude and duration of a hit to be recorded for up to 250 separate impacts per session/use, which sends wireless data to a nearby computer.
These types of studies have been great to help us compare available helmets on the market and to provide safety recommendations for each type, but unfortunately do not provide much, “in game” data. The types of hits we are able to produce in the lab are quite controlled and though force and angles may be reproduced, clearly they are not the same as the force experienced during active play.
The HITS system has been used by a lot of college football teams as a way to monitor their players during the games. Some school will pull players when they experience hits above a certain threshold to do a quick neurologic exam on the sidelines before allowing them to take another snap.
It was until a recently published study in April 2014 in the Journal of Neurosurgery that we were able to retrospectively look at data from 2005 to 2010 from over 1800 collegiate football players and almost 1.3 million hits. Eight NCAA teams were a part of the study: Virginia Tech, University of North Carolina, University of Oklahoma, Dartmouth College, Brown University, University of Minnesota, Indiana University, and University of Illinois.
In this study players were equipped with either a Riddell VSR4 helmet or the newer Riddell Revolution model (40% thicker foam and greater offset). Each of the helmets also had a HITS accelerometer system in them as well. Throughout the duration of the study all of the concussions were diagnosed by a team physician or certified athletic trainer as they typically would be even if they had not been a part of the study.
Over the course of the study, 1,281,444 hits were recorded with 64 total concussions being diagnosed. Players wearing the VSR4 helmets sustained 8.37 concussions per 100,000 impacts versus the 3.86 concussions per 100,000 impacts observed in the Revolution group. In fact the players in the revolution group actually sustained significantly more impacts than the VSR4 group yet still displayed a lower percentage of concussions when the data was compared (2.82% of all Revolution players vs. 4.47% of VSR4 players).
The study even broke down data by position to provide the 99th percentile of head accelerations by position, as well as a graph of the top 5th percentile comparison of head accelerations recorded in the study. These measures provide us with good data to compare how much impact a player’s head sustained during contact.
This study provides us with the best comparison of two of the most popular available helmet models on the market with a highlight on how helmet designs should be optimized to reduce head acceleration over a large number of hits.
Though it did not look at players in the NFL, examining 8 NCAA Division I teams allows for us to not only have a large population to examine, but is likely data that can be carried over to the NFL for use in reducing the number of concussions. Their data expanded upon previous knowledge regarding the differences in helmet use and truly allows us to see that, though we can not eliminate concussions with the use and design of helmets, we can certainly reduce the incidence of this type of injury.
The discussion of concussions can often times provide a heated debate that delves into sport politics and rules of the game, but the most important thing we must realize is that with opinions and differences aside, it all comes down to keeping an athletes safe throughout their careers as well as throughout their lives after the sport.
As we move forward in football, there is without a doubt a need to examine concussions and do our best to prevent them from occurring. It’s important for us to examine all aspects of the game from mechanics to safety equipment. It seems like a “no-brainer” to put intense focus on the helmets we use, but unfortunately endorsement deals can sometimes hinder advancements and the availability of the safest equipment. Hopefully we continue to find new solutions and solidify data to help players to remain as safe as possible on the field while playing the sport that they love.
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