Kneebar

The leg armbar

The kneebar is a leg-lock submission that hyperextends the opponent's knee joint. The mechanic is similar to an armbar applied to the leg — the attacker isolates the leg between their thighs, grips the foot or shin, and elevates their hips to hyperextend the knee.

The technique is less injury-aggressive than the heel hook but produces similar structural damage if held past the tap.

Mechanics

From a 50/50 guard or ashi garami position:

• Establish leg entanglement: trap the opponent's leg between yours.
• Pin the foot to your chest or armpit: control the opponent's foot to prevent rotation.
• Bridge the hips: lift your hips toward the ceiling to apply pressure on the knee joint.
• Maintain control: keep the opponent's foot pinned and the leg straight.
• Finish: the hyperextension at the knee produces the tap.

Setup positions

• 50/50 guard: both fighters have a leg pinned. The most common kneebar entry in modern MMA.
• Ashi garami / single-leg-X guard: a leg-entanglement position with both legs around the opponent's trapped leg.
• From top mount: attacking the opponent's leg as they defend.
• From north-south: rotating to the leg as the position allows.
• Imanari roll: a rolling entry to leg-lock positions, named after Masakazu Imanari.

Common errors

• Knee not centered: the attacked knee needs to be centered against the attacker's groin; off-center positioning reduces the lever.
• Leg not straight: the opponent's leg needs to be extended for the hyperextension to apply.
• Hand position on the foot: gripping high on the leg vs the foot changes the lever — the foot grip provides the cleanest lock.
• Loss of foot control: if the opponent rotates the foot, the lock comes apart.

Defense

• Hide the foot: pointing the foot inward (toward the attacker) makes rotation impossible.
• Hand fight on the wrist: gripping the attacker's wrist to prevent the foot lock.
• Spin out: rotating away from the lock direction.
• Counter-attack: from the same position, attacking the opponent's leg with your own technique.

Variations

• 50/50 kneebar: the canonical entry from 50/50 guard.
• Belly-down kneebar: applying from a face-down position.
• Standing kneebar: rare but possible from clinch range against an overextended leg.

Exemplified by

• Rousimar Palhares: kneebar finishes alongside his heel-hook game.
• Frank Mir: the kneebar finish of Brock Lesnar at UFC 81 (Mir's UFC heavyweight title-eliminator bout — Lesnar's MMA debut).
• Ryan Hall: integrated kneebars into the broader leg-attack system.
• Imanari: the namesake of the rolling-leg-attack entry technique.

Drills

• Position drill: from 50/50 guard, drill the kneebar entry and finish.
• Imanari roll drill: practice the rolling entry from standing or kneeling positions.
• Defense drill: partner attacks the kneebar; you practice hiding the foot and spinning out.
• Live leg-attack sparring: rounds where leg attacks are the primary target.