Newly published research in The American Journal of Sports Medicine finds high rates of traumatic brain injury (TBI) in UFC fighters relative to other contact sports. To be exact, it finds that 31.9 percent of UFC fights end with one fighter suffering a TBI, and that TBI rates in MMA are twice as high as football, three times higher than boxing and eight times higher than kickboxing and hockey. These all seem like huge numbers, don’t they? What are we to do, ban MMA? Require head gear? Like all statistical analyses, the devil is in the details. So today I’ll take you through the key points of the study, share my thoughts and let you decide where you stand at the end. This one’s for the fight nerds! Wait…all my articles are for fight nerds.
What we have is a statistical study based solely on the official fight outcomes and video review of numbered events UFC 66 – UFC 146. The authors didn’t medically examine fighters either before or after their bouts. While physical examinations would be ideal, they’re often cost prohibitive for university researchers so the idea is to see what can be learned from the data and video. In and of itself, this is not a major problem. It just means we have to exercise caution before using their results to make decisions or advocate policy. A study on brain trauma without actual confirmation of trauma and some type of treatment/control design can still be valuable if the results are taken the right way.
Two types of analyses are performed. The first basically provides descriptive statistics couched in the form of a regression. It tells us that older fighters, heavyweights, and those who have been knocked out a lot in the past are more likely to get knocked out today. It also shows that the highest likelihood of a KO or TKO occurs in the first minute of a round and first round of a bout. The specific quote is:
Our study found that fighters were at the greatest risk of sustaining KOs or TKOs from repetitive strikes during the first minute of a round, and in the first round of a fight, the risk of these outcomes decreases with each subsequent round or minute within a round.
These findings are described as novel, but I think they’re somewhat mis-characterized. What they’re likely capturing is one fighter’s skill over the other in the knockout department. Suppose I’ve got much more skill than you so your risk of getting knocked out each minute is 50 percent. If we fight every day, we’ll end up seeing that roughly half my knockouts come in the first minute, one quarter in the second minute, one eighth in the third minute and so on. You aren’t at greater risk of getting knocked out early, it’s the same 50 percent each minute of the fight. The data is documenting my skill advantage and the fact that the first minute always comes…well…first.
The authors briefly mention differences in fighter skills but instead focus on fatigue, believing that being less fatigued early-on leads to higher-velocity head strikes. This is a tough one because it also leads to better defense. I’d actually argue that if fatigue were the dominant factor over fighter skill, it would make later knockouts more likely when breathing gets harder, defense gets worse, hands start dropping and one fighter probably has a cardio advantage over the other. Either way, this analysis isn’t critical to the key points of the paper. It was likely included to provide additional descriptive information about knockouts.
The second analysis is where this paper makes a valuable contribution. They examine the videotape of 142 bouts which were finished by strikes and document whether the losing fighter was KO’d with a loss of consciousness or TKO’d with repeated strikes and a lack of intelligent defense. They show that an average of 3.5 seconds pass from when a fighter gets KO’d and when the referee stops the fight. During that time, the knocked out fighter absorbs 2.6 additional shots to the head. This is information that every athletic commission should know, try to monitor and improve upon.
They also diagram where on the head the knockout blow tends to land. I’d imagine this has value in the medical community, and athletic commissions will be relieved that only 1.5 percent land to the back of the head (yet publicly say that the number is too high). They also examine TKOs and find that the losing fighter absorbs an average of 18.5 shots (mostly to the head) in the 30 seconds before their fight is stopped.
The latter part of the paper focuses on the incidence of head trauma per 100 exposures. An exposure occurs every time an athlete plays one game or fights one fight. They find a KO rate of 6.4 per 100 exposures and TKO rate of 9.5. They assume all KOs are traumatic brain injuries while “the classification of a technical knockout is less clear.” I’m pretty sure Urijah Faber would argue that he didn’t receive a TBI from his TKO loss to Renan Barao at UFC 169. But, at the end of the day, they use “a liberal estimate” and define a TBI to be any KO or TKO finish.
Next, they compare the estimated TBI rate of MMA (15.9 percent), to medically documented concussion rates in Australian boxing and kickboxing bouts (4.9 and 1.9 percent, respectively). They state that concussions are not certain in the MMA cases examined, but argue anyway that KOs and TKOs are “of considerable concern for the safety of fighters.” They also compare the TBI rate for MMA to those estimated for professional football (8.08 percent) and junior ice hockey (2.2 percent), revealing how much higher the MMA rate is.
Towards the end, all this information comes together to “strongly argue for banning the sport in youth” and to institute preventative strategies for professional fighters such as a 10-second count following a knockdown – head gear is mentioned in a subtle way earlier in the paper. This is where I start to have a bit of a problem. It’s one thing to perform a study and let the results speak for themselves. It’s quite another to talk about how the results strongly argue for policy when they’re based on limited information.
Here are some of my general concerns:
(1) The study doesn’t medically examine fighters before and after competition, in training and out of training. This would be ideal although it’s understandably impractical. Our best shot at something approaching this structure seems to be the Cleveland Clinic’s Professional Fighter Brain Health Study. Let’s hope as many fighters as possible go the Aaron Riley route and choose to participate in their free medical services.
(2) The study only examines knockouts in competition. It doesn’t account for head trauma that may or may not occur in practice or the effect of repeated, non-knockout shots to the head and compare these with other sports. This isn’t necessarily a flaw in design – it’s just outside the scope of the paper – but it’s a wee bit important to consider before supporting policy action.
(3) A TBI is essentially assumed for all cases in which a fight is finished by strikes. This is definitely liberal, but we’ll go with it for now.
(4) They compare TBI rates instead of the number of TBI occurrences over a given time frame. Let’s assume their football and hockey TBI rates apply to the NFL and NHL and see what happens over the course of a year. This is what we get:
NFL and NHL players may have lower TBI rates but they have many more exposures (games) throughout the year, not even including the playoffs. Compare that to the average number of TBIs for an MMA fighter competing 1-4 times per year. Since 2009, the average UFC fighter competes 1.77 times per year with 42.8 percent competing once, 38.8 competing twice, 16.8 competing three times and 1.6 percent competing four times – Donald Cerrone is the only fighter to compete five times in one year, accomplishing the feat in 2011. If traumatic brain injury were your only concern, according to these numbers would you rather be an NFL/NHL player or a mixed martial artist? And don’t tell me you’d rather be Buffer, Rogan or Goldy because they have the coolest jobs in the world and don’t get any brain injuries. Work with me people!
Let’s look at it another way. Suppose a super-secret Kumite is held once every five years in a foreign land. Suppose 60 percent of the participating fighters get concussed…and none dies at the hands of Chong Li. Is this a major medical concern because 60 percent is a big number? It’s a matter of opinion, but my answer is no because frequency matters. I’d be much more concerned about football and hockey players getting concussed more than once a year than a few people getting concussed once every five years. Is it great if we can bring head trauma rates down? Absolutely. But with head gear and 10-second counts? What’s happening to my beloved sport?
The study concludes with:
Public health authorities and physicians should be cognizant of the high rates of head trauma associated with participation in MMA, in addition to the risk of brain injuries associated with KOs and TKOs from repetitive strikes, and manage and counsel patients and other stakeholders appropriately.
Manage and counsel stakeholders appropriately? I couldn’t agree more.
None of this is suggesting that there might not be a real issue with brain trauma in MMA. It’s cage fighting for god’s sake. While this isn’t the study to rigorously document the effect of MMA on the brain, it does add value in the lessons learned from the video analysis.
What are your thoughts on the study? Do you agree or disagree with my assessments? Sound off in the comments.
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