Large-Scale Trends and the 2018 NFL Season (part 1): Revenge of the Ants

The 2018 NFL offseason saw some of the most impactful rules changes in recent memory. The new rules reversed years of NFL biomechanical trends. Scoring was vastly increased, while injuries decreased. In combination with other recent rules changes regarding tackling helpless receivers, certain types of players/ offenses benefited disproportionately from these changes, even as all offenses saw their production increase. From a biomechanical standpoint, 2018 saw the return to prominence of the anterior-dominant players- cheekily referred to here as the “Revenge of the Ants”.

Last offseason it was discussed how the NFL was rapidly trending towards becoming a posterior-dominant slugfest (if you haven’t already, you can read about it here). As NFL players divided ever more clearly into anterior dominant or posterior dominant (showing decreasing levels of efficiency in their non-dominant areas), the anterior dominant players were increasingly struggling to finish NFL seasons uninjured. Although the QB position was the only one specifically discussed, the trends were clear at every offensive position: anterior dominant players were increasingly becoming marginalized by season’s end.

However, the 2018 rules changes have at the very least slowed down this trend, and in some cases entirely reversed it. To understand why this is the case, one must examine the specific biomechanics in question.

Biomechanical efficiency is essentially a measure of the ability for area muscles to be able to fire and return to rest; efficient muscles remain slack until triggered and then immediately return to rest afterward, while inefficient muscles may be triggered indirectly by neighboring action and often remain partly contracted after firing. Blood/ lymph flows very quickly on demand to efficient tissue (since all biomechanical junctions remain clear), while blood/ lymph flow is generally slower/ less variable to inefficient tissue (with partly/ chronically-contracted muscle tissue demanding constant flow and thus keeping junctions occupied).

However, biomechanical efficiency is hardly fixed in place (even as large-scale development generally remains so); injuries can quickly sap the efficiency of an area since, like in a chronically- contracted muscle, there is a constant demand for blood/ bodily resources to injured tissue. It may seem obvious that a major injury such as a broken bone or torn ligament will cause an area to become inefficient, but so too can an accumulation of small injuries.

So how did the 2018 offseason changes help keep anterior- dominant players healthy/ performing well? By removing one of the most consistent sources of small injuries to anterior muscle tissue- the helmet tackle.

When a player is tackled via form tackle, there are two impacts- one to the chest/ waist, and then one to the backside as the player hits the ground. Both impacts are made via relatively soft and broad areas- the chest/ shoulder pads on one side, and the ground on the other. Neither side of the body should sustain bruising beyond the superficial layers of tissue, and whatever bruising occurs will likely heal in time for the next game.

However, when a player is tackled via the helmet (as was the case in dozens of tackles per game prior to 2018), the primary impact point on the anterior (front) side of the body is not made via relatively soft/ flexible/ broad chest/ shoulder pads but by the very hard helmet, with all force going through a very small area where the helmet collides. These hits are far more damaging individually, and over the course of practices/ training camp/ preseason accumulate into dozens of small injuries (which generally won’t have time to heal before the next trauma). As a result, these tackles measurably impact the efficiency of anterior areas, with a player’s system constantly sapping blood (and blocking biomechanical junctions) to heal areas that never fully recover. By the end of one NFL season, each offensive player likely endured a three-digit-count worth of damaging helmet tackles to their anterior areas.

In studying film of the 2018 season, the change brought by the removal of these tackles was immediate, obvious, and widespread- anterior dominant players began the season (and ended it) far healthier and more efficient than anytime since the division between anterior-dominant and posterior-dominant players became widely apparent. Without dozens of minor injuries all along their anterior areas, anterior-dominant players returned to full quickness and control. As a result, NFL offenses boomed, with far fewer players overtly injured, and with anterior-dominant ones (such as Emmanuel Sanders) playing at a far higher level.