Question: Why the big concern over upper back mobility in regard to building heathly shoulders?
Answer: Poor mobility of the thoracic spine (upper back) is often associated with a slouched, or more specifically, a kyphotic posture. This altered spinal alignment prevents the scapulae (the shoulder blades) from tilting backward as you raise your arms. This lack of tilt narrows the space in the shoulder joint that the rotator cuff runs through (the subacromial space) and makes it more likely that your rotator cuff will get pinched, called impingement. Over time, if you impinge frequently, you’ll most likely end up with some form of rotator cuff injury.
The mobility of the thoracic spine also directly affects the strength of the lower trapezius which is an upward rotator of the scapulae. If the thoracic spine lacks mobility the lower trapezius will test weak, thus limiting upward rotation. A lack of scapular upward rotation also narrows the subacromial space making impingement more likely.
There’s actually more to it, but you can see in just these two instances why thoracic spine mobility is so important. That’s why Mike Robertson and I included exercises specifically designed to improve throacic spine mobility in our Inside-Out: The Ultimate Upper Body Warm-up.
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