The wristlock is a joint lock submission targeting the wrist (radiocarpal joint) by twisting or bending the hand beyond its natural range of motion. Historically prominent in traditional martial arts such as jujutsu, Aikido, and Hapkido, wristlocks have long been valued for their effectiveness in self-defense scenarios. In Brazilian Jiu-Jitsu (BJJ), the wristlock is commonly known in Portuguese as "mão de vaca" (cow's hand). Although historically perceived with some stigma as a sneaky or cheap submission, wristlocks have gained broader acceptance in modern BJJ, paralleling the rise in popularity of leglocks.

Wristlocks primarily target the radiocarpal joint, where the distal radius and ulna articulate with the carpal bones of the hand. Effective wristlocks involve applying leverage to hyperextend, hyperflex, or rotate the wrist beyond its anatomical limits. Proper execution requires isolating the wrist joint by controlling adjacent joints—particularly the elbow and shoulder—to prevent the opponent from relieving pressure. Ligaments such as the radial and ulnar collateral ligaments, along with the dorsal and palmar radiocarpal ligaments, become overstretched under applied force. Additionally, tendons controlling wrist movement experience significant tension, making wristlocks potent submissions when executed precisely.

Wristlocks frequently arise opportunistically from various positions and submission attempts. Common setups include:

• Wristlock from the Triangle Choke (bottom position), exploiting the immobilized arm.
• Wristlock following an Omoplata sweep, capitalizing on the opponent's trapped arm position.
• Wristlock from a Kimura grip in side control, taking advantage of the opponent's defensive posture.
• Opportunistic wristlocks when opponents defend submissions like the Armbar by clasping their hands, inadvertently exposing their wrists.

Detailed Execution: Wristlock from Triangle Choke

To execute a wristlock from the Triangle Choke, the attacker first secures the opponent's arm and shoulder tightly using their legs. With the opponent's elbow immobilized against the thigh and shoulder pinned, the attacker employs a two-on-one grip to control the opponent's hand. By applying forward pressure (palmar flexion), the attacker forces the wrist into hyperflexion, resulting in submission. Maintaining tight control over the elbow and shoulder ensures the wrist joint absorbs maximum leverage.

Detailed Execution: Wristlock from Mount Position

From the mount position, the attacker isolates the opponent's elbow by pinning it with their knee and body weight. Using both hands, the attacker firmly grips the opponent's hand, controlling the palm and knuckles securely. Applying downward pressure, the attacker folds the wrist inward toward the forearm. This wristlock is particularly effective when the opponent defensively places their hands on the attacker's chest or collar, inadvertently exposing their wrist.

Practitioners often encounter several common errors when applying wristlocks:

• Attempting wristlocks without first isolating the opponent's elbow and shoulder, allowing easy escapes.
• Relying solely on arm strength rather than integrating core, chest, or leg leverage.
• Incorrect grip placement, such as gripping too close to the fingers, resulting in ineffective or illegal small-joint manipulation.
• Telegraphing wristlock attempts, giving opponents time to react and defend.
• Lack of controlled, gradual pressure application, increasing injury risk and loss of control.

Effective wristlock defense begins with preventative measures, such as maintaining proper hand positioning and wrist stabilization. If caught in a wristlock, practitioners should immediately align and mobilize their arm to relieve pressure, often by straightening or rotating the wrist and arm. Engaging larger joints, such as the elbow and shoulder, can create space and reduce leverage. Hand-fighting techniques, like peeling the opponent's grip or bracing the trapped hand, can neutralize the submission. Additionally, postural adjustments and body rotations can alter the angle of attack, diminishing the wristlock's effectiveness.

Wristlocks are most effective when applied opportunistically, capitalizing on opponents' defensive reactions or errors in hand placement. They serve as excellent secondary submission options when primary attacks like the Armbar, Kimura, or Omoplata stall or fail. Common strategic scenarios include exploiting an opponent's hand posted on the mat or chest, or attacking from closed guard and dominant top positions such as mount and side control. The element of surprise and rapid onset make wristlocks valuable tools in a grappler's arsenal.

Under IBJJF (International Brazilian Jiu-Jitsu Federation) rules, wristlocks are permitted for adult competitors at blue belt level and above. However, they remain prohibited for white belt adults and all juvenile divisions due to safety concerns. Wristlocks can cause rapid injury due to the delicate nature of wrist ligaments and bones, necessitating controlled application in training and competition. Despite historical stigma, wristlocks have become increasingly accepted in competitive BJJ environments, recognized for their effectiveness and versatility when applied responsibly.