At some point anyone who trains regularly will have an incident of shoulder pain. While looking to maintain healthy shoulders it is important to maintain good tissue quality in and around the shoulder.
The musculature of the posterior shoulder plays a direct role of how your shoulder posture positions itself. To the back of the arm pit you have two muscles that play a large role in shoulder position and generally stabilizing the shoulder joint. However stability and stiffness isn’t all that great if you don’t have enough mobility and stability as you raise your arms. This can commonly be seen in individuals who through training (the chest usually) or by their posture (usually desk based) can’t put their hands above their heads without moving their torso forwards. In fact the two pictures of an overhead squat highlight this quite well as someone with good range and someone with poor range.
The musculature that can help release the shoulder is located just under the arm pit. The teres major has a tendon, at its insertion that lies behind that of the lats (the big prime muscle down your sides which form your “bat wings”…. If you are a guy) from which it is separated by a bursa or fatty pad that acts as a shock absorber, the two tendons unite along their lower borders for a short distance.
The teres major is not part of the rotator cuff but it does play a role in humerus position in line with the lats. The lats when trained obviously recruit the teres major. As the lat are connected to the spine tightness or restriction in movement of the lats will not only cause back pain but also shoulder pain. The lats also act as internal rotators of the arm- just as the pectoralis major does. Typically in the situation I have seen a lot of aggressive chest stretches to try and create mobility here. Simply the pecs may not be an issue but the posterior shoulder may be causing the mobility issues.
The exercises that tend to be effected are any that necessitate barbells being placed on the shoulders and being stabilized by the hands such as barbell back squat as well as any overhead exercise. What you will typically see on a shoulder press is extension from the back- this effectively means that you perform a back extension as there is not enough space in the shoulder joint for the movement to clear without a bit of friction in the joint.
The following exercise is a great way of removing posterior shoulder stiffness- typically we have seen some people achieve a better hand position with a barbell on the shoulders as well as improvement in range of movement in overhead work.