Leglock

[3][4][5] The technique has been seen across a wide range of different combat sports and is reportedly over 2,500 years old, having been seen in the lost art of Pankration in the original Olympic Games.

In training or sparring, leglocks are applied in a slow and controlled manner, and are often not hyperextended such as in the case of the comparatively dangerous heel hook.

In self-defense application, or when applied improperly or with excessive force, leglocks can cause muscle, tendon and ligament damage, even dislocation or bone fractures.

By leveraging the hips forward, the foot becomes forcefully plantar flexed, hence creating a potent joint lock on the ankle.

By controlling the opponent's body, and using the hands to plantar flex the foot either straight or slightly sideways, hence putting considerable torque on the ankle.

A heel hook is a leg lock affecting multiple joints, and is applied by transversely twisting the foot either medially or laterally.

Many practitioners considered the heel hook to be a dangerous leg lock, with a high rate of injury,[12] especially to ligaments in the knee.

[13] Despite being a very old technique,[14] the heel hook is illegal in many forms of competitive grappling and was at one point completely banned in Brazilian jiu-jitsu under IBJJF rules, but this was changed for advanced competitors as of 2021.

A kneebar is performed on the leg similarly to how the armbar is performed on the arm.
A figure-four toe hold.
The regular heel hook twists the ankle medially. The opponent's leg is entangled to prevent him from escaping the hold .