By Mark Laurensse

November 15, 2025

If you are not stretching your fingers (finger extensors) when you treat tennis elbow, you are missing out on 45% of the muscle tissue involved in tennis elbow. The next paragraph is very anatomical. It is a difficult read. Feel free to skip it and go to the next paragraph.

The ArmLock brace applies tension to all the tissues on the dorsal forearm. Prior teachings suggested overuse of the wrist extensor, specifically Extensor Carpi Radialis Brevis (ECRB), as the primary culprit of tennis elbow. Anatomical dissection has found that both the wrist extensor, specifically Extensor Carpi Radialis Brevis (ECRB), and the finger extensors, Extensor Digitorum Communis (EDC), converge to form a common tendon that attaches to the lateral elbow bone, the lateral epicondyle. Therefore, a contraction of either muscle group, wrist extensor or finger extensor, independent of the other, or shortening in response to repetitive work, would increase tension on the common extensor tendon, and in the case of tennis elbow, elicit pain. A study of tennis elbow patients looked at pain on resisted extension of the middle finger (Maudsley’s test), which was found to be positive in a significant portion of the subjects with tennis elbow. Their conclusion was that the finger extensors may play a greater role in tennis elbow than previously appreciated.

When treating tennis elbow, it becomes clear how pertinent it is to incorporate the finger extensors in treatment. The ArmLock brace is a gentle stretch that is controlled by you, the patient. This level of tension is at the toe region of the stress-strain curve where physical micro-trauma is not expected to occur. The duration of the treatment is the key, not the level of tension. We recommend holding the stretch for half an hour. 

After a few minutes, the crimp within the tendon (the waviness of the tendon fibers) slowly gets pulled out. As well, the muscles start to be forced to stretch out, relieving stuck tension, pulling apart actin-myosin bonds. And then… well, it is not too bad. You are now able to relax, read a book, or watch TV and essentially forget about your arm.