It can be quite a challenge to decrease pain at the level of the patellar tendon. Eccentric exercises have been proposed yet they can be painful.
A recent study (http://bjsm.bmj.com/content/49/19/1277.long) investigated the effects of isometric and isotonic muscle contractions on pain during the single leg decline squat. This study also addressed quadriceps strength on maximal voluntary contraction.
Isotonic exercises can be defined as heavy, slow, concentric and eccentric resistance training. These have been shown to be as effective as eccentric exercises for patello-femoral (PT) pain and activity participation.
Isometric muscle contractions have been shown to reduce pressure pain thresholds in normal participants. The pain inhibition following a local isometric contraction, demonstrated in previous studies of normal participants, is widespread. This indicated CNS involvement.
Six male volleyball athletes were studied. Three had unilateral pain and three had bilateral patellar tendon pain. All athletes were playing once per week and training twice per week.
Tendon pain and quadriceps strength were tested at baseline. The intervention consisted of isotonic and isometric exercises. A re-test was performed 4-5 minutes after training and 45 minutes post intervention.
The results: isometric exercise immediately reduced patellar tendon pain with the effect sustained for at least 45 minutes. There was a smaller magnitude immediate effect for isotonic exercise that was not sustained.
The take home message: isometric exercises may be used as analgesia! It could be that isometric exercises can be used to reduce pain and change inhibition without a reduction in muscle strength.
If it’s true that, in the context of Posturology, the aim is not to decrease pain directly, I can see how adding isometric exercises can provide relied while investigating potential root causes as to why we even need to proceed with the isometric exercises.