It is fairly common for a Boxing or MMA match to end in a knockout. Some knockouts don’t look too bad, maybe the guy has a flash of unconsciousness and the fight ends. But some knockouts can be very bad, and last up to several minutes with the fighter unconscious.
So in this post, I wanted to answer this question and details relating to it. So, how long does a knockout last?
In most cases, a knockout lasts less than 10 seconds, after which the person regains consciousness. However, a bad knockout can last longer than a minute and even several minutes. The length of the knockout depends on the severity of the concussion and whether or not the brainstem was damaged.
A person who’s been knocked unconscious usually doesn’t ‘come to’ until hours later, despite regaining consciousness much earlier. People who have been knocked out usually do not recollect anything from when they were knocked out to when they ‘came to’, leaving a gap in their memory.
Why Are Some Knockouts Longer?
Typically, the length of a knockout directly correlates to the amount of force that the fighter was hit with. For example, a knockout from a punch usually lasts less than a knockout via flying knee.
Ben Askren (black trunks) was unconscious for several minutes after Jorge Masvidal (red) knocked him out with a flying knee.
The difference here is the force of the blunt trauma. As the brain tries to heal itself from trauma due to punches, a fighter gets wobbly and may start losing control of his body. However, a much stronger strike can cause immediate loss of consciousness, especially one on the chin.
First, let’s look at a knockout due to an accumulation of strikes. A memorable case was when Michael Bisping became UFC Middleweight Champion by knocking out the then-champion Luke Rockhold.
Bisping hit Rockhold with a left hook that clipped Rockhold on the chin, causing him to wobble. Rockhold falls to the ground, but quickly gets up to his feet, attempting to clinch with Bisping. Bisping avoids the clinch and lands another left hook, which drops Rockhold against the cage. Bisping knocks Rockhold out with three punches before the ref steps in.
This image is just seconds after Bisping knocks out Rockhold. You can see Rockhold on the ground, after quickly regaining consciousness.
This knockout was not instant, and the reason why is because of the force in the punches. Yes, the punches were very strong, strong enough to eventually render Rockhold unconscious. However, they were not enough to cause an instant knockout, with Rockhold regaining cosciousness almost immedieatly after Bisping was pulled off of him.
In contrast, a very hard strike can cause instant knockout, possibly due to damage in the midbrain, which is located inside the brainstem. The brainstem is a very sensitive part of the brain, and injuring it has severe consequences.
This results in a harsh knockout that can last several minutes. This is also the reason punches to the back of the head are illegal in MMA and Boxing.
Let’s talk about a knockout so strong, that it possibly caused loss of consciousness through damage to the midbrain. An example of this is when Marlon Moraes knocked out Aljamain Sterling with a knee to Sterling’s head.
Marlon Moraes (right) lands a hard knee on Aljamain Sterling, just as Sterling went for a takedown.
During their fight, they had a brief scramble after which the ref gave Aljamain time to get up to his feet. Once the fight was restarted, Moraes immediately threw a switch kick with his left foot. Almost simultaneously, Sterling dived in for a takedown on Moraes.
The combined downward force of Sterling’s takedown with the upward force of Moraes’ knee caused Sterling to lose consciousness almost immediately. Sterling remained unconscious for several minutes and was carried out of the arena on a stretcher.
However, this type of knockout is very different from the one of Rockhold mentioned earlier. The knockout was caused by significant damage to the brainstem. There is clear evidence of the severity of Sterling’s concussion just from looking at his body’s reaction to the knockout.
The first sign of moderate to severe concussion was the loss of consciousness. But the second sign is much more telling in terms of the severity of the injury. The second sign of severe concussion was the abnormal posturing of Sterling’s body after being knocked unconscious.
As soon as Moraes hit Sterling, Sterling’s body became stiff, a reaction known as the ‘fencing response’.
Usually when someone is knocked out due to punches, their body goes limp, and they receive a mild concussion. In Sterling’s case, the strike caused damage to his brainstem, which also activates what is known as the Lateral Vestibular Nucleus (LVN).
When the LVN is activated, it also activates the muscles related to flexion in one arm, and extension in the other, resulting in a position similar to that used by fencers, hence the name Fencing Response.
Thus, a strike that has enough force in it can damage the brainstem, which is evidenced by the Fencing Response. Damage to the brainstem results in a moderate to severe concussion which can leave the fighter unconscious for several minutes.
I should note that the force doesn’t necessarily need to be a hard one to result in the Fencing Response, as a moderate force to the brainstem in particular will end with the same result.
Jaylen Brown suffered a concussion resulting in Fencing Response when he fell onto the back of his head during a game.
So let’s sum up the original question, which was ‘Why are some knockouts longer?’ Well in short, a knockout can be longer if the strikes causing the knockout resulted in damage to the brainstem, which results in knockouts that last a few minutes. A shorter knockout is usually caused by weaker strikes that diffuse the damage to the brain, causing the brain to fill with blood and the person to lose their balance and eventually their consciousness.
What Happens During A Knockout?
So we know that knockouts are caused by hard strikes to the head. We also know that strikes to the chin are more likely to cause a knockout, which is why the first rule of boxing is to keep your hands up. But we have yet to understand why and how a knockout actually occurs.
So let’s start from the beginning. When a fighter receives a strike to the head, it causes a rapid acceleration to the skull. This acceleration causes the brain to slam against the walls of the skull.
As the brain continues to receive trauma, the body will send an excess supply of blood to it in order to repair itself. The loss of consciousness occurs when the brain requires more blood than the body can supply.
This explains brain trauma in which the fighter loses only some of his senses, such as in the case of UFC fighter Kevin Lee when Edson Barboza hit him with a kick.
This image is just after Kevin Lee (right) was hit by a hard kick. You can see that he’s clearly lost his balance, and perhaps his proprioception as well.
Had Kevin Lee received more strikes just after getting hit with the kick, he easily could have ended up unconscious due to the accumulation of blood in his brain. Fortunately for him, he managed to threaten a takedown against Barboza and recover, with Lee eventually winning the fight.
But now let’s talk about someone being knocked unconscious, as in, ‘knocked-out cold’. As mentioned before, this usually occurs from a hard strike to the chin. But why is the chin an area prone to cause a knockout?
The brain is susceptible to rotational acceleration, and the chin is prone to rotational acceleration when hit. It is very easy for the chin to spin the brain, versus a straight punch to the face for example.
When the chin gets hit, the rotational acceleration is felt more intensely by the midbrain and diencephalon. This is according to UK neurologist J.M.S. Pearce, in this article on concussions. In it, he states:
Current opinion is that concussion results from the disruption of the electrophysiological and subcellular activities of the neurons of the reticular activating system situated in the midbrain and diencephalon, where maximal rotational forces are exerted.
J.M.S. Pearce, ‘Observations on Concussion’
The main part of the quote you should focus on is the Reticular Activating System, because the disruption of said system is what produces the loss of consciousness recognized as a knockout.
In conclusion, most knockouts result in mild concussion, meaning the fighter only goes unconscious for a few seconds. The severity of the concussion directly correlates to how long the knockout lasts.
Another big factor is whether or not the brainstem received damage from the knockout strike. Knockouts that are several minutes long result from damage to the brainstem, evidenced by the Fencing Response on the unconscious fighter’s body.
I hope this helped you learn something about knockouts and the implications of receiving one. If you want to learn more about brain injuries in combat sports, check out a post I made on How Often You Should Spar, where I cover the dangers of fighting.
Also, check out the Training Tips page for questions you might have when training. Train hard and stay safe. Thanks for reading!