How to Knock Someone out with the Sleeper Hold
A Simple Hold, With Devastating Consequences
Anyone that's studied a martial art that includes a form of grappling has learned about pressure points, and the weaknesses that every human body shares. When it comes to quick knock outs, though, there are only three things that you can do; great harm to the head, interrupt the flow of oxygen to the brain, or cut off the supply of blood to that same, very-necessary organ. All of these are risky moves, but when they work, they are fight enders. The infamous Sleeper Hold uses the third strategy, and once you know that, it's a fairly simple thing to execute.
You've seen the Sleeper Hold in dozens of action films, and it's been used as a gimmick by dozens of professional wrestlers over the years. However, it requires careful practice and skill to get it just right.
Step One: Get Into Position
The first thing you need to do is get behind your opponent. Whether you're sneaking up out of the shadows Rambo-style, or you just get them turned around in an ongoing scrap doesn't matter, as long as they have their back to you.
As Wonder How To points out, you want to bring your dominant arm (left or right, whichever is more comfortable for you) around your opponent's throat. Ideally the crook of your elbow should be sitting right against the Adam's apple or the trachea. Rest the elbow of your other arm against your opponent's opposite shoulder, and using your dominant hand, grab your opposite bicep. You now have a hard, firm grip on your opponent, and the sides of his neck should be pressing against the bicep and forearm of the arm you have around his throat.
Step Two: Apply Pressure
Once you've got your hold in place, the next step is to reach down with your non-dominant hand and push the back of your opponent's head down into your arm. Lastly, and here's where the tricky part comes in, flex the forearm and the bicep of your dominant arm so that you're squeezing the sides of your opponent's neck. If you did this right, they'll pass out in less than a minute, and probably closer to 15 seconds. 10 seconds if you're lucky and they're particularly winded.
Also, if you have problems getting into position (usually because your opponent is taller than you are) then kick the back of their leg to bring them down to one knee, or hit them hard in the lower back so that they arch up. This will give you a great opportunity to get a better hold.
How This Hold Knocks Someone Out
Why does the Sleeper Hold work? That's a good question, and astute readers (or those that paid attention in biology) already know.
The simple explanation is that when you squeeze your arm against the sides of your opponent's neck, you are cutting off blood to the brain by clamping down on the major arteries. Without a steady flow of blood to the brain, your opponent begins to pass out; and within less than half a minute, they go down, no muss, no fuss. Of course, if you get the timing wrong, of if you maintain the hold past the point of unconsciousness, it's entirely possible to kill someone. This is why whenever you perform the Sleeper Hold you should be very careful and, if possible, have supervision from someone with experience in this and other, similar martial arts techniques.