On February 6, the NFL announced the next round in the HealthTECH Challenge series, which is a “series of innovation challenges intended to deepen understanding of and advance solutions in the areas of head protection, materials science, and kinematic measurement, among others.” The purpose of these challenges is to improve the design and safety of football helmets while competitors receive funding and support. Although concussions within the NFL have decreased by 35% since their peak in 2017, NFL data found that this past season, “44% of in-game concussions resulted from impact to the player’s facemask, up from 29% in 2015.”
Despite football’s long history, helmet innovation did not advance much until the early 2000s. The first hard-shell helmet was worn in 1939 and persisted until 1976. After 38 college and high school football players died of head injuries in 1968, the National Collegiate Athletic Association (NCAA) and other organizations created the National Operating Committee on Standards for Athletic Equipment (NOCSAE). NOCSAE developed a pass-fail test, implemented in 1973, requiring helmets to keep a severity index below a specified limit. This spurred helmetmakers to use foam padding in helmets to absorb energy and create larger helmets, giving the head more room to slow down since a hit can inflict an acceleration of up to 180 g.
Modern football helmets emphasize “controlled deformation,” meaning that they crumple upon impact. Without deformation, shock is transmitted to the brain within three milliseconds, but when the helmet crumples, that same impact is spread over 15 milliseconds, decreasing the instantaneous acceleration by a fifth. Helmet material has changed, previously being made from a hard polycarbonate shell and foam padding to now having a flexible nylon elastomer shell. This shell is able to flex and then return the helmet to its original shape. Liners have advanced by using 3D-printing to improve compression. For example, Kollide, winner of NFL’s 2019 Helmet Challenge, manufactures a liner with 18 cylindrical pads containing thin cones inside each pad. When constricted, these cones “fold progressively from their tips, increasing resistance. While regular foam compresses by only up to 50%, these 3D-printed pads can compress by 80-90%, extending the impact duration and absorbing energy.”
Continuing to test helmet designs remains a focus for the Virginia Tech Helmet Lab, which has its own rating system. This process involves placing a helmet on a NOCSAE head and releasing a pendulum with a 15.5 kg bob that hits the helmet. This is repeated to hit the helmet in four spots at three impact speeds of up to 6.4 meters per second. Concussion risk is calculated by recording the accelerations to the head and is scaled to estimate how many concussive blows a player wearing that helmet would endure in a season. These estimates are used to assign scores, with 0 to 10 concussive blows earning a five-star rating.
Biocore, a research institute funded by the NFL, has its own testing program that uses “video from the between 30 and 60 cameras that watch every NFL game and readings from radio tags that track each player’s location and speed.” Researchers use this data and computer modeling to “deduce the linear and angular accelerations that each head blow generates,” and researchers “even catapulted dummies outfitted with accelerometers into each other and filmed the collisions ” to study impacts in a game. These hits are then replicated in a manner similar to Virginia Tech researchers, but with harder strikes at higher speeds of up to 9.3 meters per second. Biocore’s testing protocol is public for helmet manufacturers to use as a guide.
The research of these institutions has had an impact. Since the NFL’s 2019 Helmet Challenge, the league has been banning helmets that perform poorly based on these tests, highlighting the importance of safety technologies to the league. To make the cut, the four helmet makers—LIGHT, Riddell, Schlutt Sports, and VICS—have been implementing changes in response to these tests.
As the NFL continues to challenge innovators to improve helmet safety, there continues to be an emphasis on data-driven design.
