NFL approves new QB helmet, but research shows only marginal concussion risk reduction

New helmet approved for NFL quarterbacks, but laboratory testing shows it reduces concussion risk by only 7% compared to most popular models last season
Quarterbacks won't be required to wear new helmet, leaving its real-world impact unclear
Helmet designed to absorb impact energy in any location, but brain still vulnerable to moving inside skull
Advocates hope new helmet drives innovation, but warn against overpromising on concussion prevention until more research is done