With todays equipment it doesn't take much. The elbow pads are not like back in my day. They're more like weapons now and even the slightest impact at the speed those guys are going at will ring your bell. As for it looking like Cooke barely touched him, the camera can be deceiving and again it is often those innocent looking hits that are actually very serious. My worst concussion (in my second year and I missed the last half of the season) happened on a play that nobody even saw what happened to me. Watching game film later, the other player's knee seemed to just graze my helmet as I was going down but believe me, the impact was tremendous.
We all think concussions only occur after a hit where the guy is knocked cold at that moment. In actual fact, most of the concussions hockey and football players suffer don't manifest until later that day or the next.
I had 3 when playing college football and with all 3 I felt a bit woozy for a few minutes but cleared up and finished the game. It was only later or the next day that the headaches and the dizzyness set in.
