The armbar: how it works and how to do it
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By Scott Flear, founder of JitsAI.
An armbar is an elbow lock: you trap your opponent’s arm between your legs, line their elbow up against your hips and lift your hips while you hold the wrist, which straightens the elbow past the point it can go. Your hips are the pivot and their forearm is the lever, so a small lift puts a lot of force on the joint, fast. Tap early, and finish it slowly in training.
What is an armbar?
The armbar is one of the first submissions you learn in Brazilian jiu-jitsu, and you can hit it from mount, closed guard, the back and side control. In judo the classic version is juji gatame; in Brazil it’s the armlock or chave de braço. It doesn’t need the gi, so it works the same in no-gi.
It’s a joint lock, not a choke. The force goes into the elbow, which is built to bend one way only, and that’s why the armbar shows up so often in injury data: in one survey of 1,140 grapplers it caused more injuries to the person caught than any other submission (Hinz et al. 2021).
How does an armbar work?
Your elbow is a hinge. It bends and it straightens, and it doesn’t go backwards. The armbar makes it try.
- The bones stop, then the soft tissue takes over. Straighten the elbow fully and the bones at the back of the joint meet. Past that point, only ligaments and tendons are holding on. A 2026 review lists the back of the elbow, the collateral ligaments on both sides and the forearm tendons as the structures at risk (Hasegawa et al. 2026).
- Thumb up points the hinge at your hips. With their thumb pointing at the ceiling, the elbow faces your hips, so all of your hip lift goes into the joint. If the thumb turns sideways, the arm rolls and the pressure leaks out.
- Your hips are the pivot, their forearm the lever. Turning force is force times distance. Hold the wrist rather than near the elbow and the same hip lift does far more to the joint.
That’s why a smaller person can armbar a bigger one, and why the load comes on faster than people expect. Tap when the arm straightens, not when it hurts.
Two episodes from our Anatomy Series. Episode 1 is the physics: a long lever against a short one, with the armbar as the example. Episode 4 asks whether that would still work on a gorilla, and finds where leverage starts losing.
How do you do an armbar?
The armbar from mount is the version most people learn first. The same finish, thumb up and elbow on your hips, applies from guard and from the back.
- Step 1: Climb high in mount. Walk your knees up towards their armpits. Isolate one arm and pin it to your chest.
- Step 2: Swing your leg over the head. Put your weight on your hand on their chest, step your foot up by their head, and swing your other leg over their face as you sit back.
- Step 3: Sit back tight to the shoulder. Sit down with your hips right against their shoulder and your knees pinching the arm. A gap between your hips and their armpit lets the elbow slip out.
- Step 4: Thumb up, elbow past your hips. Hold their wrist to your chest with their thumb pointing at the ceiling, and line their elbow up just past your hips.
- Step 5: Lift your hips slowly. Squeeze your knees, keep the wrist on your chest and lift your hips a little. Go slowly, and let go the moment they tap.
Common armbar mistakes
- Sitting back away from the shoulder. If you land far from the shoulder, the elbow slides off your hips and they pull the arm out. Sit down tight to the shoulder.
- Thumb sideways. With the thumb pointing sideways, the elbow isn’t facing your hips and the pressure leaks out. Turn the thumb to the ceiling.
- Holding near the elbow. A grip close to the elbow is a short lever. Hold the wrist.
- Exploding into it. The force builds fast at the end of the movement. Sudden hip lifts are how elbows get hurt in training. Lift slowly and give your partner time to tap.
When they defend the arm, the triangle and the kimura are the classic switches. The kimura is the same lever idea aimed at the shoulder instead of the elbow.
What happens if you don’t tap to an armbar?
The elbow goes past its stop, and the ligaments and tendons take the load. They can stretch, and they can tear. A 2026 review of grappling submissions says most reported armbar injuries are on the inner side of the elbow, and that the defender flexing their biceps against the lock can injure the biceps tendon too (Hasegawa et al. 2026).
The armbar is the submission most often behind injuries in the data we have. In a survey of 1,140 grapplers from 62 countries, it caused 55 of the 246 injuries reported by people caught in a submission (22.4%), ahead of the kimura (31) and the heel hook (27). Most injuries in that survey, 77.6%, happened in sparring, not competition (Hinz et al. 2021).
Competition data points the same way. In a study of BJJ tournaments cited in the same review, the elbow was the most commonly injured joint and the armbar the most common cause (Scoggin et al. 2014, via Hasegawa et al. 2026).
How to train the armbar safely
- Tap early. Tap when the arm straightens and you can’t turn your thumb, not when it hurts.
- Finish slowly and let go on the tap. Lift your hips gradually so your partner has time to tap, and release the moment they do.
- Train under a qualified coach. Learn and drill joint locks in a class, with someone who can check your position.
- Get checked if something’s wrong. Seek medical care for elbow pain, swelling or weakness that doesn’t settle after an armbar.
Does your armbar land on everyone, or only on beginners?
Finishing a white belt and finishing a resisting blue belt are different results. JitsAI scores each technique against a nine-level ladder by partner size and experience, so you know who your armbar really works on.
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Video transcripts
Transcript: What happens if you don’t tap to an armbar
This is what happens when you don't tap in an armbar your elbow is a hint one way bends straightens That's it It does not go backwards Straighten it and the hook on your forearm bone slams in to a notch on your upper arm bone on bone Hard-stop pass that nothing left, but ligaments and tendons holding on thumb up pointing at the ceiling now The hinge faces their hips and every bit of that hip thrust goes straight into the joint Thumb turns sideways the arm rolls the pressure leaks out. That's your way out Their hips are the pivot your forearm is the lever long lever tiny hip lift massive load that comes on fast Faster than your ego hang on too long and something gives ligaments stretch They can tear then you're off the mats for weeks maybe months. So tap early tap often train tomorrow
Transcript: Leverage
Strength loses to physics, every time. A pivot, a load, a push. Push further from the pivot and you get more twist. That twist is torque, force times distance. Same push, three times further out, three times the twist. In an armbar, your hips are the fulcrum. Grip near the elbow, barely anything. Grip the wrist, five times the leverage. Their arm has a short lever, yours is long. Base, stay wide and low. You tip when your weight passes your base. Frames, stack your bones. Stop pushing, start framing. Smaller person, longer lever, physics wins, every time.
Transcript: Could you armbar a gorilla?
What if you locked an arm bar on a gorilla for 60 seconds? In episode 1, your hips beat their bicep with a long lever against a short one. That geometry still holds on a gorilla arm. What changes is the muscle. Humans keep about a fifth of their muscle on their arms. Male gorillas keep over a third in a body twice your weight. Rough maths puts that at three to four times a man's arm muscle. Nobody has measured gorilla strength properly, and the famous 10 times stronger claims don't come from proper tests. In the lab, chimp muscle came out about a third stronger than ours, size for size. Three to four times still eats your margin. Then there's the pin. Pins run on weight, and you weigh about half of this. It can stand up with you still attached. This is where leverage starts losing. In training, tap early. Next up, takedowns.
Armbar questions
Thumb up or thumb down in an armbar?
Thumb up, pointing at the ceiling. That faces their elbow straight into your hips, so your hip lift goes into the joint. If the thumb turns sideways, the arm rolls and the pressure leaks out, which is also how people escape.
Is the armbar dangerous?
It’s safe when people tap early and partners finish slowly, but in a survey of 1,140 grapplers it hurt more people than any other submission: 55 of 246 injuries to the person caught (Hinz et al. 2021). Tap before it hurts, and go slowly when you’re the one finishing.
How do you escape an armbar?
Early. Before it’s locked, keep your elbows tight and hold your own hands or collar so the arm can’t be straightened. Once it’s on, turn your thumb sideways so the elbow isn’t facing their hips, and work your elbow out past their hips. If the arm is already straight, tap.
Is the armbar legal for white belts and kids?
The armbar isn’t on the IBJJF’s table of illegal moves for any age group or belt (IBJJF Rule Book v6, 2024).
What’s the difference between an armbar and a kimura?
The armbar straightens the elbow; the kimura twists the shoulder. Both are levers, and you can switch between them when one is defended.
Does the armbar work in no-gi?
Yes. It doesn’t rely on the clothing, so it works the same in the gi and no-gi.
Sources
- Hinz et al. (2021), Orthopaedic Journal of Sports Medicine 9(12). Survey of 1,140 athletes in 62 countries: the armbar caused 55 of 246 (22.4%) injuries to the person being submitted, ahead of the kimura (31) and heel hook (27); 77.6% of all injuries happened in sparring.
- Hasegawa et al. (2026), Common grappling submissions, Hawaiʻi Journal of Health & Social Welfare 85(6): 132–141. Armbar: elbow hyperextension with the hips as the fulcrum; the olecranon, collateral ligaments and forearm tendons at risk; most reported injuries on the inner elbow; biceps tendon injury from resisting. Reports Scoggin et al. (2014): the elbow was the most injured joint in BJJ competition and the armbar the most common mechanism.
- IBJJF Rule Book v6 (June 2024), Technical fouls: illegal moves table, p. 29. The armbar is not on the illegal-moves table for any age or belt.
This page explains a sport technique. It isn’t medical advice.