There is some research to support the hypothesis that helmets change the way linemen tackle. http://www.unh.edu/unhtoday/2014/11/keeping-their-heads-out-game h

There is some research to support the hypothesis that helmets change the way linemen tackle. http://www.unh.edu/unhtoday/2014/11/keeping-their-heads-out-game http://www.unh.edu/unhtoday/2014/11/keeping-their-heads-out-...