A kneebar (also known as legbar, kneelock or hiza-juji-gatame) is a leglock that can hyperextend the knee. The basic kneebar technique is similar to that of an armbar. The practitioner will trap the opponent’s leg in between their legs and secure the leg with their arms so the opponent’s kneecappoints towards the body.
The practitioner then applies pressure with their hips, forcing the opponent’s leg to straighten, hyperextending the knee joint. A variation of the kneebar is similarly accomplished, but instead of holding the leg with the hands, the practitioner will trap the opponent’s foot behind one armpit.
The practitioner will then apply pressure using their upper body as well and their hips, yielding a greater amount of force applied to the knee, therefore rendering the lock much more difficult to escape before tissue or ligament damage occurs.
In this video, leg lock master Karen Darabedyan explains the different grip variations that can be used to apply the knee bar submission:
