A punch or kick to the head seems like a logical way to obtain a quick knockout, but a liver shot can drop an opponent to the canvas just as fast. The liver is a strangely powerful organ and direct trauma can have a lasting effect..
Liver and The Nervous System
The capsule that surrounds the liver contains a multitude of nerve fibers, which link it directly to the autonomic nervous system. This is the part of the nervous system that controls involuntary actions such as heartbeat, the widening or narrowing of blood vessels and breathing. This system also reacts in “fight or flight” situations and regulates the internal organs including stomach, intestines, kidneys, bladder, lungs, pupils, heart, glands and the liver.
Play-by-Play of the Collapse
When there is a sudden impact to the liver itself the organ stretches, which causes a pressure change. The events that follow are operated through the autonomic nervous system, meaning that they are involuntary and thus unstoppable.
1 Nerves signal a sudden dilation of blood vessels all over the body, with the exception of the brain.
2 Heart rate drops suddenly
3 Blood pressure dramatically plummets
When blood pressure is decreasing the body tries to take control. It is the combination of the open blood vessels and decreased heart rate that causes the drop. When the two issues cannot be resolved, emergency actions are taken and the body fights to maintain flow to the brain by putting the body in a flat or recumbent position. This survival tactic is the reason for the collapse.
Liver Knock Out
If the sudden trauma to the liver is severe enough the fighter could lose consciousness. The set up is the same for the general collapse, but in this situation there is also a constriction of blood vessels in the brain. If blood pressure drops suddenly enough the brain thinks it is not receiving enough blood pressure and further restricts the flow as a precaution, causing loss of consciousness. Some fighters have reported that after a liver shot, their mind is clear, but their body is non-functional.
Why the Liver?
This phenomenon can occur with any of the organs, but the liver happens to be the most exposed. It slightly protrudes under the rib cage, which leaves it vulnerable. This protrusion has been attributed by some to the relatively recent evolution of the human body. The theory is that the liver has increased in size to meet our demand for its services, while our rib cages have not.
Notable Liver Shot Victories:
- Ronda Rousey knocked Sara McMann down with a knee to the liver in February 2014.
- Amir Khan knocked Marcos Maidana down in the first round of their 2010 fight with a liver shot.
- Lyoto Machida knocked down C.B. Dollaway with a liver kick in December 2014.
- Alistair Overeem knocked down Brock Lesnar with a liver kick in December 2011.
- Bernard Hopkins knocked Oscar De La Hoya out with a liver shot in 2004.
- Bas Rutten repeatedly knocked down Jason DeLucia with liver punches during their 1996 Pancrase fight, rupturing DeLucia’s liver and earning a TKO victory