The first down line that football fans see on-screen hasn't always been there. Here's how the innovative technology made its debut.
Bone-jarring tackles almost always make the highlight reel in a National Football League game. And those tackles happen more than 100 times per game.
They may not always look pretty; a big linebacker engulfing a smaller running back. But the play is actually employing some pretty elegant physics, including p=m*v.
Even without concussions, youth football alters brain structure
December 6, 2016