Isometrics for tendon pain, especially very painful tendons, can give immediate and sustained pain relief. The exact science behind why it works is still under research. However, they have shown that it works on the cortical representation via the brain, which helps change the view of what is and is not painful. If the isometrics do not work on decreasing the pain there is a high probability that the tendon is not the issue or the source of pain. Therefore, it is a great way to ensure that your symptoms are truly from the tendon.
Research has shown that when performing these isometric exercises that there is a pain relief window of up to 45 minutes to 8 hours following the exercise. As a result, this is a great option for those athletes who have pain and want to continue to play sports.