An athletic trainer once told me that the rigidity of the modern football helmet reduces neck injuries. After I broke three fingers one season, I inquired about why helmets had to be so hard. He explained that softer, externally padded helmets have the tendency to "stick" to one another, albeit briefly, when a collision happens. The increased "stickiness", of helmets colliding at full speed, leads to much more frequent and much worse neck injuries, as heads get twisted more vigorously. Rigid, slick helmets deflect off each other and reduce the chance that players' heads will get twisted during high speed collisions. It sucks that the rigid properties of current helmets reduce neck injuries, but promote concussions. Pick your poison I guess.
I did not make this headline up