The Violence of the Pass

Football is going to change. That much is clear. The correlation between the impacts sustained on the football field and the brain damage of players is no longer just a correlation: it’s starting to look like a tragic cause.

But how is the sport going to change? There will be better helmets, of course, and stricter rules about helmet-to-helmet contact, and more accurate monitoring of head trauma.  We’ll start tracking the linear acceleration (g) of skulls as carefully as we track the stats of quarterbacks.

However, it’s also worth considering the ways in which the concussion crisis will interact with pre-existing football trends. Over the last decade, the single most notable shift within the sport has been the rise of the passing offense, with the amount of passing yards increasing by roughly twenty percent. In 2003, as Ty Schalter notes, only Indianapolis used the shotgun offense more than 30 percent of the time. (Three teams never used the shotgun at all.) By 2012, most teams were approaching a shotgun usage rate of 40 percent or higher.

At first glance, this shift towards passing might seem like an effective response to the concussion crisis. Studies relying on head telemetry data – they use special helmets outfitted with a network of sensors – show that linemen and linebackers sustain, by far, the most sub-concussive hits over the course of a game. (Running backs take the hardest hits.) Less running plays, then, should translate to less wear and tear on the brains of those players brawling at the line of scrimmage. (Pass routes are the only part of the game in which, after five yards, no meaningful contact is allowed; it’s football pretending to be basketball.) When a pass dominant offense takes the field, the game is still violent, but the violence seems contained. More spread equals less smash mouth.  

Alas, a new paper by Douglas Martini, James Eckner, Jeffrey Kutcher and Steven Broglio at the University of Michigan, Ann Arbor, suggests that the rise of the passing offense will do little to quell the concussion crisis. In fact, it might even be making the problem worse. In their study, Martini et. al. tracked 83 high school football athletes using the HITS head impact telemetry system. While most public attention has focused on the brains of NFL players, these highly paid athletes actually represent a very small sliver of those at risk. There are, give or take, a few thousand players on NFL payrolls. There are approximately 68,000 football players at the college level. And there are 1.2 million football players at the high-school level.

The question investigated by these researchers was whether or not offensive style influenced the amount and distribution of head impacts. One team utilized a run-first offense (RFO); the other used a pass-first offense (PFO). The RFO team passed, on average, 8.8 times a game and ran the ball 32.9 times, while the PFO passed 25.6 times and ran 26.3 times. 

So what did they find? The first thing to state is the obvious: football is a contact sport. These 83 teenagers endured 35,681 head impacts over the course of the season; at least six of these impacts resulted in serious concussions. 

What’s more, the different offensive styles resulted in significantly different patterns of impact. The running offense generated about 1.5 times as many total head blows as the passing offense – many of these occurred during practice – while the passing offense generated bigger average blows, especially during the games. This was true across every measure of head impact, from linear acceleration (g) to the overall hit severity profile (HITsp). In short, when teams throw the ball in the air, there are fewer total hits, but each hit is harder, especially for skill position players, such as running backs and wide-receivers. The scientists speculate that the root cause of these differences is simple physics, as players in the pass offense are “able to reach higher running velocities before contacting an opponent than the equivalent RFO athletes… As such, the PFO athletes would have larger initial velocities that resulted in greater deceleration values following impact.” And it’s the deceleration that’s dangerous, as the soft brain lurches into the hard bones of the skull. This helps explain why, in 2012 and 2013, receivers and cornerbacks sustained more concussions than any other positions in the NFL. Their speed across the field more than makes up for their lack of mass.

The larger lesson is that there appears to be a fundamental tradeoff between the frequency of hits in a football game and their magnitude. (More research on this subject is desperately needed - the NFL should install head telemetry units in every helmet.) The passing attack might look less aggressive, but appearances can be deceiving; the elegant throws still end with a cloud of dust. If nothing else, this study is yet another reminder that head violence is an intrinsic part of football, and not a by-product of a particular style of play.  

Martini, Douglas, et al. "Subconcussive head impact biomechanics: comparing differing offensive schemes." Medicine and science in sports and exercise 45.4 (2013): 755-761.