Are head injuries in MMA common?

When knockouts and technical knockouts are combined in mixed martial arts (MMA), match-ending head trauma occurs in 31.9% of matches. 90% of technical knockouts are the result of repetitive strikes to the head, often with the losing competitor sustaining a flurry of blows to the head that increase in frequency. The incidence of head trauma in MMA (15.9 per 100 athlete-exposures) is higher than the reported incidence of concussions in professional football (8.08 per 100 game positions), boxing (4.9 per 100 AEs), and ice hockey (2.2 per 100 AEs).

Head injuries in MMA

Source: American Journal of Sports Medicine, Published online before print March 21, 2014