Issue 026

June 2007

The knockout is perhaps the most dramatic and controversial aspect of MMA. It is hard to find a more devastating and convincing method of winning in any other sport. It adds excitement for the spectators, and for the fighters it ‘keeps it real’: it is a vivid reminder that there is more at stake than just trophies and titles. On the other hand, it is seized on by opponents of both boxing and MMA as proof of the barbaric, and dangerous nature of what we do. 

In this article, we’ll look at what actually happens when a fighter is knocked out; the dangers, after-effects and why some fighters are more prone to it than others. 

The most puzzling thing about a knockout is how a person can lose consciousness so completely and suddenly, and yet typically recover quickly and spontaneously, usually without appearing to suffer any serious long term effects. Some experiments have shown that unconsciousness can occur even without there being any visible damage to the brain itself. 

A knockout is a form of concussion, or shaking of the brain. The term concussion refers to a change in mental function following an impact, jarring or shaking injury to the brain. It can also refer to milder head injury where there is confusion but no loss of consciousness.

Inside the skull, the brain is cushioned by a layer of fluid. This helps to absorb shock and to cushion the brain from the impact of a blow to the head. When the head is hit, the skull changes direction of movement suddely, but because of its momentum, the brain continues to move (briefly) in the old direction. This causes the brain to bang against the inside of the skull, causing damage or disruption. 

A strike is much more likely to result in unconsciousness if the head is free to move than if it is fixed in place. Concussion also results much more easily from impacts that rotate the head than linear ones. Punches that connect with the jaw tend to rotate the head in this way, which is why it is such a vulnerable point for KOs. 

The mechanisms of how concussion actually results in unconsciousness are still not completely understood. Currently, the theory that appears to provide the best explanation is the convulsive hypothesis. In simple terms this argues that concussion works in a similar way to an epileptic seizure. The mechanical forces that act on the brain when the head is struck or jolted cause many brain cells to fire at the same time, and as a result important signals don’t get through. 

One of the most common features of concussion is amnesia (memory loss). This can be of two different kinds. Retrograde (or pre-traumatic) amnesia is the loss of memory of things that happened before the knockout: for example, the fight itself, or the day before the fight. Anterograde (or post-traumatic) amnesia refers to memory loss of things that happened after the person regained consciousness. For example, a fighter may later find they don’t remember the medical checks that happened or how they got back to their hotel after the fight. Some experts believe that the greater the amount of post-traumatic amnesia, the more severe the concussion and the more likely it is that there will be lasting problems.

There are conflicting views about the likelihood of suffering from long term problems following a knockout. A fighter may suffer from a collection of common symptoms known as post-concussion syndrome, which may occur following a minor head injury. These include headache, nausea, dizziness, tiredness, irritability, anxiety, aggression, insomnia and depression. He or she may also suffer from a temporary loss of concentration and mental processing speed. This can last for weeks, months or occasionally even years after a concussion. Some recent reports have suggested that the risk of suffering long term problems from a concussive head injury rises sharply at the age of around 40. 

Frequent repeated head trauma, such as experienced by professional boxers, is associated with dementia pugilistica, (otherwise known as punch-drunk syndrome), andcan lead to an eventual loss of mental ability and sometimes tremors and lack of coordination.

Amateur boxing appears to be much safer from this point of view than professional boxing. Many participants claim that MMA is safer than boxing, because participants take fewer solid blows to the head in training and competition. This seems plausible, but at the moment there is no research evidence one way or the other. 

Once a fighter has been knocked out, they are significantly more likely to be knocked out again in the future, and the post-concussive problems are likely to become worse each time. The reasons for this aren’t entirely clear, but a fighter is particularly vulnerable if he doesn’t allow enough time for the brain to properly recover before going back to training or fighting. 

If a fighter suffers from a second significant head impact in the days or weeks following a knockout, there is a risk of a serious condition called

second impact syndrome. In this situation, the brain can swell dangerously, raising the pressure inside the skull. It can be fatal, or cause severe brain damage. Because of this, governing bodies for boxing and MMA usually stipulate a mandatory no-contact ban, typically a period of 4 weeks before the fighter can spar following a knockout, and sometimes a further period before he or she can fight again. This is sometimes ignored by fighters who don’t understand the reasons behind it and are keen to get back to training as soon as possible, but it is vitally important to allow the brain this time to recover. 

Some fighters are known to have a better chin, or ability to take a punch, than others. What is it that gives one fighter a glass jaw while another is much harder to knock out? Looking at the science behind the knockout, there are a few possibilities. Firstly, the strength of the fighter’s neck counts for a great deal. Remember that it is the movement of the head, not the actual impact itself, that usually causes the knockout. A stronger neck can reduce the amount of movement, and therefore the jarring of the brain. Another possibility is the actual shape of the skull itself. The brain sits on top of a series of hollows inside the skull, and these will naturally vary in shape from person to person. If they are smoother and flatter, it allows the brain to rotate more when the head is hit, causing more damage and making it more likely that the person will lose consciousness. Interestingly, I have seen it suggested that people who make more use of their brain – increasing the growth and connections between the neurons – may be less susceptible 

to being knocked out because the greater number of connections helps protect the brain from the rotational forces in the same way that a rope made from many strands is stronger and harder to break than one made from fewer. This is mostly speculation, but if true could have some intersting implications.