Sports equipment designed to make football safer encouraged more reckless moves and ended up making the sport more dangerous than unpadded, unhelmeted rugby.

• 美式橄榄球的护具本在保护球员，现在反而鼓励球员更不顾后果横冲直撞，结果使得美式橄榄球比起不用护垫与头盔的英式橄榄球更危险。