UCL Pronator Strain

RapidForce Reverse L - Muscle Support Shape

RapidForce® Shapes stabilize and support the muscles, tendons, and ligaments in the elbow. The L Shape is designed to reduce swelling by gently lifting the skin above the pain point, which can help circulate blood, oxygen, fluids, and nutrients to an injury site.

The ulnar collateral ligament (UCL) connects the elbow joint to the arm bones, enabling arm movements and providing stability. Pronation refers to the twisting motion that allows an upward-facing palm to be turned downwards. (Supination, pronation’s counterpart, refers to the act of twisting a downward-facing palm so it faces upwards.)

Thus, a UCL pronator strain refers to an injury that occurs after the arm is moved from the upward-facing position to the downward-facing position, such as those made when throwing, hitting, swinging, lifting, or making overhead motions. UCL strains are usually a result of overuse and gradual wear and tear, but it’s possible to strain it after an impact to the elbow as well. Volleyball, baseball, and tennis players are particularity susceptible to UCL pronator strains, as are those who participate in golf, gymnastics, weightlifting, javelin throwing, and other sports that require repetitive overhead arm movements.

Pain from a UCL strain will be located on inside (medial side) of the elbow. Symptoms of UCL injuries include pain when flexing, closing, or clenching the fist as well as tingling, numbness, swelling, a slight loss of motion, and decreased power when pronating the arm. Feeling a popping sensation immediately after a UCL injury occurs is also fairly common.

The L Shape (inner right arm) and Reverse L Shape (inner left arm) is designed to reduce UCL pain, particularly pain resulting from overuse or over-pronation. The L Shape’s central core is bonded to the skin directly above the inner edge of the elbow bone, supporting and stabilizing the injury. Two arms—one shorter and one longer—are stretched outwards, creating additional structural support along the bend of the elbow. The Shape is also intended to provide some mechanical lift, which gently lifts the upper layers of the skin, creating more space for blood, oxygen, nutrients, and fluids to reach the injury site more efficiently.

RapidForce® Shapes are unlike any other pain-relief product on the market today. Each Shape’s patented design was carefully developed and perfected by a team of physical therapists, athletic trainers, engineers, and an ultrasound technician who sought to create a product that supports the muscles and helps relieve pain caused by muscle, tendon, joint, and ligament injuries. RapidForce® Shapes are used by athletes at all levels, including professional athletes, semi-pro athletes, and people who lead or want to lead an active lifestyle.


If you'd like assistance choosing the best RapidForce® Shape for your needs, please email us at advice@rapidforceshapes.com..

Disclaimer: Please see your medical professional with any kind of pain. Pain could be an indication of a serious condition. RapidForce® Shapes are not meant to replace professional medical advice, professional treatment, or a professional treatment plan.

RapidForce Shapes for Elbow Pain Relief

Application Instructions

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Time it Right

While RapidForce® Shapes can be applied at any time, they should be applied 1–2 hours before beginning strenuous physical activity. The Shapes can start working is as little as two hours, but some applications take up to four hours.

Prep Skin Thoroughly

Wash and dry the skin to remove oils, moisture, and dirt. Trim or shave body hair; this helps create a more secure bond and more comfortable removal. Apply the provided Skin Tac liquid adhesive wipe. Allow 30 seconds for it to dry.

Customize Stretch

Secure the Shape’s central core to the most painful spot. For daily wear or moderate-to-light athletics, a mild stretch of 1/2” is ideal. Application instructions vary based on Shape, so read and follow the instructions mailed with your shape(s).

Secure Bond

With both the Shape and the skin at room temperature, carefully begin applying the shape. Once the shape is secure, rub it vigorously to maximize adhesive bond to skin.

  1. 1. With your elbow bent approximately 90 degrees, locate the bone on the inner edge of the elbow

    1. With your elbow bent approximately 90 degrees, locate the bone on the inner edge of the elbow

  2. 1. With your elbow bent approximately 90 degrees, locate the bone on the inner edge of the elbow

    2. Apply the center of the L Shape

    Peel off the backing of the center of the L Shape and place directly over the bone. Press to secure the bond.

  3. 1. With your elbow bent approximately 90 degrees, locate the bone on the inner edge of the elbow

    3. Apply the shorter arm - 1/2” Stretch

    Peel off the middle backing of the shorter arm, leaving the end tab in place. While stabilizing the central core with one hand, customize stretch based on the intensity of activity and place parallel to the bone of the upper arm. Smooth the fabric onto the skin, moving from the center of the L Shape outwards. Remove the backing from the end tab and place on the skin. Do not stretch this small piece. Press over the entire arm of the Shape for about 10 seconds to secure the bond.

  4. 1. With your elbow bent approximately 90 degrees, locate the bone on the inner edge of the elbow

    4. Apply the long arm - 1/2" Stretch

    With arm still bent, place the long arm of the L Shape along the forearm. Apply using the same application method as described in Step 3.

  5. 1. With your elbow bent approximately 90 degrees, locate the bone on the inner edge of the elbow

    5. Feel Relief and Remove

    You may begin feeling relief within a few hours. However, it could take up to 24 hours. RapidForce shapes can provide pain relief and muscle support for up to five days but can be removed at any time. To remove, pull from the end of the arms to the center. If hair is present, pull in the direction of the hair’s growth to reduce discomfort. For easier removal, use mild warm water in the shower and then remove the shape slowly.