The NFL and NFL Players Association have approved a position-specific helmet design for the first time since they began regulating equipment for players, representatives for both groups confirmed Tuesday.

The helmet, known as the VICIS ZERO2-R TRENCH, was built for offensive and defensive linemen and is ranked No. 2 on the league's 2021 safety rankings. The helmets are equipped with bumpers on their front and upper sides, where NFL engineering studies showed are a common point of contact for linemen who absorb concussion-causing contact, according to Dr. Ann Good, a senior engineer at BioCore and a consultant to the NFL.

The league and union have been ranking helmets based on proprietary safety data since 2015, using lab tests designed by BioCore, and began banning the lowest-performing helmets in 2019. The primary goal was to drive down reported concussion totals among players, which peaked at 281 during the 2017 season. The 2021 ratings, distributed to teams Tuesday, added three models to the prohibited list and six to a category called "not recommended."

Approximately 18% of players finished the 2020 season using one of those nine helmet models. But Dr. Kristy Arbogast, an engineering consultant for the NFLPA, said her expectation is that almost all of them will move to a better-performing helmet in 2021. In each of the past two seasons, 99% of NFL players have used a helmet recommended by the NFL/NFLPA ratings.

The NFL hasn't publicized its complete concussion data from last season. But Jennifer Langton, the league's senior vice president of health and safety innovation, said that reported concussion rates over the past three seasons (2018-20) are 25% lower than in the previous three seasons (2015-17).

"With these results," Arbogast said, "we were able to demonstrate [to players] that the use of a lab test in ranking helmets and prohibiting helmets were relevant to [players'] game experience. We showed that by moving up the [ranking], players could really take an active role in their safety."

It remains to be seen how many linemen will switch to the model built for them this season, but it is the first step in the NFL's goal of spurring manufacturers to produce models for each position group. Dr. Jeff Crandall, the chair of the NFL engineering committee and the co-founder of BioCore, said there has been some "baseline testing" of models designed for quarterbacks. A model is likely to be finalized for future seasons, possibly in 2022, once an analysis is done of new technology the NFL is adopting for coach-to-quarterback communications.