NFL bans 10 helmet models after 2018, including Brady's

In a move to combat concussions after concerns for years that not enough was being done to protect players, the league and the NFL Players Association released laboratory performance test results on helmet brands.

They announced 10 models would be prohibited, although players who used four of them in the 2017 season could have one final campaign with them in 2018.

The banned after 2018 models included Brady's Riddell VSR-4 helmet, although the 40-year-old winner of five Super Bowls has the opportunity to test other helmets under game conditions this season also.

The tests were developed by biomechanical engineering experts to provide more information for players making helmet choices, although factors such as fit, comfort and durability were also given as considerations in helmet selection.

In prior seasons, NFL players could choose any helmet as long as it passed National Operating Committee on Standards for Athletic Equipment (NOCSAE) certification standards.

The prohibited helmets that performed poorly in testing are discontinued versions by helmet manufacturers or produced by companies that no longer make American football helmets.

Results were shared with NFL players, equipment managers, coaches and medical staffs as the study examined which helmets reduced the severity of head impacts.

Laboratory conditions simulated concussion-causing hits suffered by NFL players during games.

In all, 34 helmet models were tested, including the brands used by 98 percent of NFL players.

Testing was conducted in Canada with independent lab Biokinetics Inc. of Ottawa used. Canadian football uses rules similar to American football.

The league and union said results of the study should not be considered viable for youth, high school or college levels of American football.

Safest helmet types under the study were the VICIS Zero, Riddell Speedflex Precision, Schutt Air XP Pro VTD and Xenith Epic-Plus.

Worst performers in the study were Schutt Air XP, Rawlings brands, SG 2.0 and Brady's Riddell VSR-4. DM