by Noel Shafi
April 2019
Abstract
This paper examines the physiological basis of Hadaka-jime, also known as the rear naked choke. The author will explore the Judo origins of Hadaka-jime, the execution of this technique, outcomes, and the neurovascular basis of this commonly used chokehold.
Introduction
In Judo, Shime-waza refers to a group of strangulation techniques where the hands, arms, or legs are used to apply pressure to the opponent’s neck (Kano, 1986). Shime refers to choking and waza refers to technique. Some of the strangulation techniques from this category are commonly known as air-chokes, while others are known as blood-chokes. Choking the opponent ultimately causes ochi or unconsciousness (Koiwai, 1987). However, this state of unconsciousness is usually temporary once the hold is released, and no choke-related deaths have been reported in Judo competition since the inception of the sport in 1882 (Koiwai, 1987).
Hadaka-jime, also known as the rear naked choke, is a blood-choke technique commonly taught in Judo and the martial arts community (see Figure 1). This choke is an effective way of controlling or rendering the opponent unconscious. It is also considered to be one of the most successful submission maneuvers in mixed martial arts competition according to a recent sports analysis (Hackett and Storey, 2017). In the law enforcement community, it is known as a vascular neck restraint or the carotid artery control hold, which may be employed by police officers to control combative suspects (Mitchell et al., 2012).
Technique
Hadaka-jime is applied by positioning yourself behind the opponent, placing one of your inner arms around his throat with the crook of your arm tightly against the front part of his throat, pushing his head forward with your other hand, and pulling back with your applied arm (Kano, 1986). Maximum pressure should be exerted to the region of the neck known as the superior carotid triangle (see Figure 2). This region contains important structures, including the carotid body, carotid arteries, internal jugular vein, vagus nerve (10th cranial nerve), and other nerves and branches. It takes about 250 mmHg or 5 kg or 11 lbs of rope pressure in order to occlude the carotid arteries and cause a loss of consciousness (Koiwai, 1987).
Outcome
Hadaka-jime ultimately causes the opponent to experience a loss of consciousness, assuming the technique is applied effectively, and assuming the opponent does not escape or offer submission. Unconsciousness will typically occur within 5-11 seconds. After the opponent is unconscious and the hold is released, he makes a full recovery within 10-20 seconds.
Neurovascular Physiology
The attacker applies pressure to either side of the opponent’s neck, which creates lateral compression to various neck structures, including vascular, muscular, and neural structures (Mitchell et al., 2012). Vascular structures of the side of the neck include the carotid arteries. Muscular structures on the side of the neck include the platysma and sternocleidomastoid muscles. Neural structures on the side of the neck include the vagus nerve.
Recent studies looked at measurements of mean middle cerebral artery flow velocity (MCAVmean) using transcranial Doppler ultrasound during applications of rear naked chokes on experimental subjects, and found that these subjects were rendered unconscious after an 80-83% reduction in MCAVmean bilaterally, or on both sides of the neck (Mitchell et al., 2012). Previous research found that there should be a minimum of 50% reduction in the MCAVmean bilaterally in order to render the subject unconscious (Njemanze, 1992). In other words, pressure must be exerted on both sides of the neck while meeting a critical lower limit on either side in order to cause a loss of unconsciousness.
As such, the compression of vascular structures appears to be the most important factor in rear naked chokes. The lateral compression of the common carotid artery in particular causes decreased blood flow to the brain. This condition is known as acute cerebral ischemia. As this situation is prolonged, there is reduced supply of oxygen to the brain. This condition is known as cerebral hypoxia. As this situation is prolonged, the opponent loses consciousness.
Summary
In summary, the neurovascular stages of Hadaka-jime are (1) lateral compression of common carotid artery, (2) acute cerebral ischemia, (3) cerebral hypoxia, and (4) unconsciousness. Exerting sufficient pressure on the superior carotid triangle and compressing vascular structures in this region bilaterally is the most important factor in properly executing the rear naked choke.
References
Hackett, S. R., & Storey, J. D. (2017, March). Mixed membership martial arts: Data-driven analysis of winning martial arts styles. In Sports Analytic Conference (pp. 3-4). Boston, MA: MIT Sloan.
Kano, J. (1986). Kodokan Judo. New York, New York: Kodansha.
Koiwai, E. K. (1987). Deaths allegedly caused by the use of “choke holds”(shime-waza). Journal of Forensic Science, 32(2), 419-432.
Mitchell, J. R., Roach, D. E., Tyberg, J. V., Belenkie, I., & Sheldon, R. S. (2012). Mechanism of loss of consciousness during vascular neck restraint. American Journal of Physiology-Heart and Circulatory Physiology.
Njemanze, P. C. (1992). Critical limits of pressure-flow relation in the human brain. Stroke, 23(12), 1743-1747.