The NFL says the number of concussions in practices and games in the preseason and regular season dropped 13 percent from 2012 to 2013.
Using information collected from team doctors, the league also says there was a 23 percent decrease over the past two seasons in the number of concussions caused by helmet-to-helmet contact.
Speaking at a pre-Super Bowl news conference Thursday, Jeff Miller, the league's senior VP of health and safety policy, calls the data "positive trends."
Some players have expressed concern that the NFL's emphasis on decreasing hits to the head could lead to more low hits and more knee injuries. But Miller says there has not been an overall increase in damaged knee ligaments.
NFL  wrote: