Joint Injury
When the normal physiologic range of motion is slightly exceeded, pain develops around the joint. Damage occurs to the joint with both slow and violent forces bending the joint past its normal range if the forces are sufficient. Such injuries included broken bones, torn ligaments, torn joint capsules, broken joint cartilage and even disruption of the skin, all associated with severe pain and swelling. Locking a joint refers to placing a joint in a position where all the slack is taken up and no further normal motion occurs. The student at Christopher N. Geary's Shaolin Kempo is taught how to apply joint locking techniques in a manner used to produce pain sufficient to control an opponent, but joint damage is avoided during practice.

Types of Joints
The 3 types of joints most commonly used for locking techniques are:

Hinge joints: These are the simplest joints and act like a hinge, allowing angular bending and extension (only to a certain degree). Examples are fingers, elbows and knees.
Ball and socket joints: These act like a ball fitted within a socket where the rounded end of one bone fits into the cavity of another bone and allow more range of motion than a hinge joint. Examples are shoulders and hips.
Gliding joints: Motion is produced by allowing bones to slide over one another. An example would be the facet joints of the spine.

Types of Joint Locks
Areas used for joint locks include fingers, thumbs, wrists, elbows, shoulders, knees and feet, but any joint can be used. Most joint locking techniques try to put the joint into a painful extension, but there are techniques (especially the wrists) where hyperflexion is used to produce control. At Christopher N. Geary's Shaolin Kempo, it is recognized that professional training is required because of the potential for permanent injury. The information presented here is to give the martial arts student a background of joint locking techniques to be studied only under qualified instructors.