Hi Yarok
Interesting........I'd be keen to see if anyone else agrees with you or if you are alone with this theory. I can't quite see how a pec muscle which is overstretched can pull a humeral head forward?? I do however agree that the "rear part" is stiff but it isn't usually the muscular component causing the stiffness but the intervertebral and costovertebral joints causing the stiffness so some mobilisation here would help. The original question was about complaints of shoulder instability which is why I mentioned strengthening the scapular stabilisers.....of coarse this has to be done in conjunction withrotator cuff at a later stage but I believe working on the scapula initially to provide a stable base and then bringing in the dynamic stabilisers of the rotator cuff later is a better approach. I'd be interested to hear more about your theory.