The Armbar From Mount: S-Mount Setup & Finishing Details
What is an armbar in Jiu Jitsu? An armbar (or cross armlock) is a joint-lock submission that uses full-body leverage to hyperextend an opponent's elbow joint past its normal range of motion. By securing the opponent's wrist and isolating their arm between your thighs, you create a fulcrum against your hip bone to bend the elbow in the exact opposite direction it is meant to bend.
You can hit an armbar from almost anywhere—closed guard, turtle, side control. But the most dominant, effective way to hit it is from the mount position, where your knees are wrapped around their hips and your entire body weight pins them to the mat.
If you are working through our beginner BJJ techniques, mastering the mounted armbar is essential.
Want to drill these details in person? Use our BJJ Gym Directory to find an academy near you.
The Setup: Sliding into S-Mount
The biggest battle is getting the arm. From mount, opponents will glue their elbows to their ribs. The absolute best way to isolate the arm is by transitioning into S-mount.
In S-mount, you let your knees do all the work. Use your arms to isolate their arms above their head so they cannot push up. Then, slide one knee all the way up under their armpit to block the shoulder. Your other leg folds across so you are sitting heavily on their chest. This creates a tremendous amount of crushing force, pinning their shoulders flat to the mat.
Once your legs have isolated the shoulder, taking the arm becomes much easier. A great tip for keeping this isolation tight: take the arm you are using to secure their arm, and literally touch your hand to your opposite hip. This locks their limb against your body before you even throw your leg over their head.
Finishing the Armbar (And the "Hip Bone" Detail)
When you finally throw your leg over their head to secure the position, there are multiple ways to configure your legs. You can drape them straight over, cross your ankles, or tuck one leg under their head while the other blocks the body.
But here is where the mechanics matter. A massive mistake beginners make is trying to break the arm by wedging the opponent's elbow directly into their groin. Your groin is a soft target—it hurts you more than it hurts them.
Instead, pull their arm across and isolate their elbow directly over your hip bone. Your hip is a hard bone structure. Bridging into the elbow across your hip bone creates immediate, devastating breaking pressure.
The "Falling Back" Mistake
Another huge mistake white belts make is thinking an armbar means you have to fall flat on your back and stretch out. That is false.
Oftentimes, the armbar should be finished while you are still maintaining the top mount position. If you have a tight S-mount and proper hip isolation, you can get the tap without ever falling back. You only need to lean back if the person is violently exploding out of the position. Falling straight back immediately gives them unnecessary space.
Stop losing dominant position. Find a local coach in our Gym Directory to fix your armbar finishing mechanics.
Stopping the Escape (Thumb Direction & Chain Grappling)
The most common escape is when the opponent turns their thumb down toward the mat to relieve the pressure and spin out.
To shut this down, press your heels heavily down into their body to kill their mobility, and forcefully control their wrist so their thumb is pointing straight upward. If the thumb is up, they cannot spin.
However, keep in mind that Jiu Jitsu is not about hitting one move at a time. It is a system of positions. If you throw the armbar and they manage to roll or slip out, they are opening themselves up to other attacks. If they roll, transition straight back into top mount. If they turn the wrong way, immediately lock up a Triangle Choke.
Start looking for the next series of attacks as soon as they try to escape. The armbar is just one piece of the puzzle. Pair this with our guides on the Guillotine Choke to build a completely lethal submission game.
Ready to start chaining submissions together? Find a gym in our Local Gym Directory to get started.