In collegiate American football, specific actions by players against opponents are prohibited to enhance player safety. These actions involve forceful contact against an opponent with the crown of the helmet, forcible contact to the head or neck area of a defenseless player, or leading with the helmet, shoulder, forearm, fist, hand, or elbow to attack with an intent to injure. For example, a defender launching himself headfirst into a receiver who is already in the process of making a catch would likely be penalized.
This player safety legislation aims to reduce the incidence of concussions and other head injuries. It has evolved over time in response to growing awareness of the long-term effects of such injuries. The impetus for this protective measure stems from medical research linking repeated head trauma to serious neurological conditions. The consequences of infractions can include ejection from the game, suspension for subsequent games, and significant impact on game outcomes.