The NFL and the NFL Players Association (NFLPA) announced the results of the annual laboratory study which assesses the performance of helmets worn by NFL players.
Previously, players could choose any helmet they wanted to wear that passed National Operating Committee on Standards for Athletic Equipment certification standards.
The NFL banned helmet models including Tom Brady's Riddell VSR-4 helmet.
Of the 10 prohibited models, six are no longer being manufactured and thus are banned immediately.
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"This is the first time we will be prohibiting helmets", Jeff Miller, the NFL's executive vice president of health and safety, said in a conference call with reporters.
Brady switched over to Ridell's Speed model for two games during the 2012 season before returning to his original helmet.
'Over the last few years, we've seen some dynamic changes in the helmet industry, ' Miller said, as quoted by ESPN.
'We think that is an important move, and we think that will improve player health and safety. Other manufacturers have advised players to use newer models of helmets that perform better in testing, according to the league.
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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. And the objective of continuing to rank the helmets, and the goal of the joint decision to prohibit certain helmets this year, is to increase that continued movement into better-performing helmets'. The NFL warns that the results of this test should not extend to lower levels of play like collegiate or high school football.
Thirty-four helmets were tested for the 2018 rankings.
League owners agreed in March to a significant rule change that will threaten immediate ejections anytime a player lowers his helmet and initiates contact with another player.
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