Narrative review: Assessing the incidence of head trauma in Australian mixed martial arts

Why this study matters

Mixed martial arts (MMA) allows strikes to the head. The authors note that knockouts and technical knockouts are common in the sport, and that medical associations have raised concerns about the brain health of its athletes. Earlier studies of how MMA bouts end mostly involved professional fighters. The authors state that, to their knowledge, no study had looked at fight outcomes in Australian MMA. They add that little was known about how amateur bouts end for men and for women.

What the researchers did

The two authors studied MMA events held in Australia from 1 July 2020 to 31 July 2023. Only events run by Australian-based organizations were included. They identified 194 events and had video for 143 of them (74%). Events without video were left out. In total they reviewed 1473 bouts involving 1476 athletes. Male divisions made up 92.3% of the bouts (1359), and professional bouts made up 24.2%. Amateur bouts have added restrictions, such as no elbow strikes, and shorter rounds.

Fight details came from two public websites, and both authors reviewed the videos to verify them. A knockout (KO) was recorded when a fighter could not defend, usually because of lost consciousness or disorientation. A technical knockout (TKO) is declared when the referee, physician or coach believes a fighter has stopped defending intelligently. The authors used the video to identify TKOs that followed strikes to the head. A KO has been accepted in earlier studies as meeting the criteria for concussion, and the authors used a TKO after head strikes as a stand-in for one. Rates are given per 100 athlete-exposures, with each bout counting as two exposures.

What they found

Across all bouts, the rate of KO or TKO after head strikes was 16.7 per 100 athlete-exposures. These outcomes ended 34% of male bouts and 23% of female bouts, a statistically significant difference (P = 0.01). In men, the rate was 16.6 per 100 athlete-exposures in amateur bouts and 18.7 in professional bouts. In women, it was 12.6 in amateur bouts and 7.4 in professional bouts. Within each sex, the share of bouts ending this way did not differ significantly between amateur and professional level. A judges’ decision was the most common result: 38% of male bouts and 58% of female bouts.

In men, weight class was associated with the outcome. Heavyweight bouts ended in a KO or TKO after head strikes most often (58%), followed by light heavyweight bouts (50%). Flyweight (24%) and bantamweight (26%) bouts did so least often. Compared with lightweights, the odds were higher for amateur light heavyweights (odds ratio 2.22), amateur heavyweights (2.70) and professional heavyweights (5.00). An odds ratio above 1 means the outcome was more likely than in the comparison group. Women were grouped into lighter and heavier classes because female bouts were few, and the two groups did not differ significantly.

Submissions ended 24.0% of male bouts and 18% of female bouts. Most submissions in men were chokes.

Strengths and limits

The study spans just over three years and includes amateur and professional bouts in male and female divisions. Results were verified on video.

The authors list several limits. A TKO after head strikes suggests a possible concussion but is not definitive evidence of one. Only the way each bout ended was counted, so concussions in winning fighters were likely missed and the true number is probably underestimated. Events without video were left out, which may bias the sample. Judging an outcome from video depends on the reviewer. Without medical records from after the bouts, the severity of injuries is unknown.

Female bouts were a small part of the sample (114 of 1473), which limits what the findings show about women. Amateur bouts fought under two different rule classes were not analysed separately. The authors add that the findings may not apply to other combat sports or to MMA elsewhere.

What it adds to research on fighter health

The study provides rates of fight-ending head trauma for Australian MMA, at amateur and professional level, for men and for women. The authors report that the male rates slightly exceed figures published for professional MMA, which ranged from 15.4 to 15.9 per 100 athlete-exposures. They note that the Association of Ringside Physicians recommends a medical suspension of at least 30 days after a loss by KO or TKO. They also describe a loophole: a fighter may compete for another organization or in another combat sport before recovery. The authors suggest shared medical records across combat sports, such as a “concussion passport”, and a national policy that collates KOs, TKOs and medical suspensions. The study did not test these measures.