I was discussing the issue of concussion with my personal trainer last week and he told me that in boxing, brain injuries occur when the glove comes in contact with the head as a 'soft' collision. The boxing glove was introduced in boxing to lengthen the fights, as bare knuckle fights were usually over quickly and were more 'bloody, as one can understand. He was comparing boxing with cage fighting where the knuckle is protected by a wad, but the hits are harder and therefore the damage is bone on bone. Nice. Anyway, in American football, with the head supposedly protected by the carsh helmet, the brain sloshes around in the cranial space (ala boxing) more often than when a League player is tackled, because of the head/helmet contact in most tackles and when players pile onto players. Make of that what you like.