Opinion: The NFL’s Helmet Tests Are Brainless
Date Posted: October 17, 2019
Posted In: Discussion,
From Wired: Since 2012 the NFL has been running simulations to test helmets, which manufacturers submit to on a voluntary basis. Researchers on contract with the NFL mount the helmet to a dummy head (outfitted with an accelerometer to measure head movement at impact) and then strike it with a helmet-shaped dome at various speeds and locations, simulating helmet-to-helmet impacts. The problem: That’s all they test.
This testing condition is what disqualified wide receiver Antonio Brown’s desired helmet for 2019; the ensuing saga was national sports news. What wasn’t reported is that the NFL’s helmet testing and ranking system does not take into account helmet-to-ground and helmet-to-body impacts—scenarios that in the 2015 to 2017 NFL seasons accounted for 46 percent and 18 percent of concussions, respectively. Safety testing that ignores two-thirds of scenarios that cause injuries the equipment is designed to protect athletes from is suspect at best. By analogy, for a long time, corner impacts were not tested to rank car safety. As a result, drivers were being killed because cars were not engineered to protect from these impacts. What happened? Lab-based testing of corner impacts led to new rankings, and car manufacturers responded with new engineering.
One might argue that testing only 36 percent of impact scenarios could be sufficient if they were representative of all scenarios. Above all, testing must assess how helmets reduce linear and rotational forces to the brain. But we know that head-to-ground hits can cause higher levels of rotational acceleration, especially when they represent a “combined impact” scenario: a player is hit on the shoulder, say, causing a whiplash effect with rotational acceleration to the head, and then when the player hits the ground with increased momentum, that second contact imparts a force in the opposite direction. Studies show that combined impact carries higher rotational loading compared with isolated hits. Why is this important? Because the science is clear: Rotational loading on the brain is the principal driver of both clinically significant injury (i.e., concussion or mTBI) and clinically silent injury (subconcussive hits).
So it’s not surprising that the NFL’s helmet testing and ranking has had no discernable impact on the incidence of concussions (to say nothing of the incidence of clinically silent injury, which hasn’t been measured at all). Over the seven years the ranking has been in place, the number of concussions has fluctuated slightly but essentially remained the same, with an average of 244 cases per season. There are 256 games in an NFL season. (Some of the reported concussions are sustained during practice.)