The video demonstrated below, by an orthopedic surgeon, shows the mechanics of why shoulder impingement happens with the tendons.
See the small space between the ball acromium? That is where the impingement happens. Making sure the supraspinatus tendon, which pushes the ball down as the arm bone is lifted by the deltoid, is working well is a big part of the picture of shoulder healthy function. BUT….if you raise the shoulder blade UP by STRENGTHENING the muscles which lift it up, (such as serratus anterior) and STRETCH muscles which PULL it down (such as latissimus dorsi) you can gain more space, which puts less pressure and pinch on the supraspinatus tendon.
http://comstockpt.com/2011/11/22/neck-pain-stretches-out-olympia-wa/ This link will show you some latissimus stretches, and if you refer to Part 1 in this series of blog posts, with the man leaning against the wall you can see how to strengthen the serratus anterior
Do you have neck pain, especially from sitting for a long time? I recently took a long flight and after a while my neck and upper shoulders started to become stiff. What exercises help that?
Of course stretching your neck and shoulders helps like this:
BUT there is another tight muscle that strains your neck and it is, SURPRISE, the latissimus muscle! It is located below the shoulder blades and when tight, pulls the shoulder blades down straining the muscles on top of the shoulder blade which connect to the neck such as the upper trapezius, levator scapulae and rhomboids. Here is a picture:
Here it is: the fix for shoulder blade/scapular weakness on one side that makes progressing your P90X workout, or any upper body workout for that matter, harder.
If you follow the above links you will see how to strengthening one-sided shoulder girdle problems. When the shoulder girdle is weak, it can cause winging. If it is just a little weak, like it is with this lady, then you may have headaches, because of the stretch to the upper trapezius. You might also develop rotator cuff impingement due to this problem.
How do you develop shoulder blade weakness? Usually it hppens because you might have an arm injury, which can make your muscle weak as they try to protect you and stop you from using an injured body part. Other causes can be prolonged computer use in which your arms and shoulder are held in the shoulder forward position.