Biomechanics and injury risk of a headbutt.

Headbutt is a relevant type of a criminal assault that can result in injuries. The aim of this study was to collect basic biomechanical data and assess the injury risk associated with a headbutt. Series of measurements were carried out with volunteers with and without relevant soccer heading experience, and the impact velocity of the striking head was measured. A soccer ball was used as a surrogate of the stationary victim's head. Two scenarios were considered: one corresponding to the typical headbutt situation, i.e. short movement of the assailant's head without backswing, and one representing the worst case, i.e. the most severe head impact without time or space constraints for the assailant. The results as well as epidemiological data from court cases and a large Munich's university clinic show that a typical headbutt is not likely to lead to life-threatening injuries, but bony injuries of the face can easily occur. Under certain circumstances (support of the victim's head, secondary impact on the ground etc.), severe injuries with potentially lethal outcomes are possible. A thorough analysis of each case is thus an imperative. The (soccer) heading experience does not influence the velocity of the headbutt.