Associations such as the National Football League (NFL), and the National Federation of State High School Associations (NFSHSA) made it illegal to perform any kind of spearing or head down contact to another player.
The National Collegiate Athletic Association only made "intentional" spearing illegal.
This is mainly due to the severe injuries players would sustain upon using the spearing technique.
Although this ban might have decreased the number of head injuries, players' use of spearing still persists.
[1] Within the sport of gridiron football, the spearing technique was responsible for most of the catastrophic cervical spinal cord injuries and concussions, which is a result of axial loading.