There is currently a major buzz going on in the strength and conditioning field centering on the concept of thoracic spine mobility. Coaches are actively seeking ways to build mobility in this anatomic region in order to reduce lumbar rotation and enhance scapular stability. The idea revolves around the concept of Kinetic Linkage where each joint is affected by the integrity of the joint above or below. The T-Spine is extremely important. A proximal to distal linkage of the thoracic spine, scapula and GH joint is critical in long-term shoulder health (as is ankle and hip mobility). The thoracic spine needs to be mobile to allow adequate translation of the scapula over its surface. This enhances the GH joint and prevents anterior/superior humeral head migration, which leads to impingement. Take a look at the picture below.