Biomechanics: Chokes / Strangles

Physiology of Strangulations

One of the most powerful techniques in jiu jitsu is the ability to render an opponent unconscious. A strangulation is defined “as the condition in which circulation of blood to a part of the body is cut off by constriction” while a choke is defined as “the condition in which there is severe difficulty in breathing because of a constricted/obstructed throat or a lack of air.” In jiu jitsu often when someone uses the term ‘choke’ they really mean ‘strangle’.

How do strangulations work? A study examined the physiology of strangles. The vascular structures targeted by the technique are the internal carotid artery (ICA) and the carotid sinus. The carotid sinus has pressure receptors that maintain blood pressure and when there is an external compression the response of the body is to reduce blood flow. For loss of consciousness to occur the structure need to be compressed enough to decrease cerebral blood flow. Cerebral hypoxia or ‘going to sleep’ occurs when the cerebral blood flow velocity dropped below 50% from baseline on both the right and left carotid artery.

The compression force required to compress the carotid arteries was at least 100 mmHg. An important note is that more than 100 mmHg did not cause a faster response in which the subject was rendered unconscious. The average time for unconsciousness following the vascular constraint was held for 9-10 seconds (9.5 +/- 0.4 seconds).

Conclusion: When applying a strangulation make sure that you are compressing both sides of the neck and gradually increasing the force of the squeeze so that you can maintain for longer then 10 seconds.

Reference:
Mitchell JR, Roach DR, et al. Mechanism of loss of consciousness during vascular neck restraint. J Appl Physiol. 2012 Feb;112(3):396-402.

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