The throwing shoulder of the baseball athlete is put through unnatural motions at high velocities in excessive repetitions. A predictable and often necessary adaptive response of the throwing shoulder is an increase in external rotation to accommodate for the throwing motion, a response attributable to the typical increase in throwing velocity. Likewise, in response to the increase of external rotation comes a decrease of internal rotation of the throwing shoulder. Sports Medicine and rehabilitation professionals initially focused on the difference of internal rotation between shoulders (throwing vs. non-throwing) and observed increased injury rates of the throwing shoulder in those athletes who possessed a difference greater than 10 degrees between sides (referred to as Glenohumeral Internal Rotational Deficit or GIRD).
Today, we look at the difference in total arc of motion between sides (5 degrees or less is acceptable) as more of a red flag of injury risk. This is due in large part, to the fact that with a sport-specific adaptation of increased external rotation, reduced internal rotation may be necessary or at least acceptable…So bottom line, while we still record and monitor GIRD, total arc of motion is considered a greater risk for potential shoulder and arm injury in the baseball athlete.
Another region of the body that has gained increased attention and shares some influence to overall shoulder health and function is the mobility of the thoracic spine. Gray Cook proposed a joint-by-joint approach to identifying potential drivers of dysfunction (it is important to understand that all joints require varying levels of both stability AND mobility as motion and stabilization occur by a means of 3-dimensional interactions). Cook has referred to the thoracic spine as “a region of tendency toward stiffness and therefore could benefit from greater amounts of mobility and flexibility.” He expands upon this thought of interconnectivity with “the tendency of the shoulder scapular region toward sloppiness and therefore could benefit from greater amounts of stability and motor control. Scapular substitution represents this problem and is a common theme in shoulder rehabilitation. The shoulder joint has a tendency toward stiffness and therefore could benefit from greater amounts of mobility and flexibility.” From an application standpoint, it may be difficult or counterintuitive to address issues (e.g. restriction, stiffness, pain) in the shoulder without at least considering the implications of a stiff, immobile thoracic spine.
Switching gears from rehabilitation to performance, Eric Cressey has stated “a lack of thoracic rotation may create an arm drag effect during the pitching delivery. Basically, if your thoracic rotation stinks, you will attempt to find more external rotation in the wrong places.” Cressey goes on to state “lacking thoracic extension will increase the demand for extension from the lumbar spine, leading to low back pain, hip issues and abdominal/oblique strains.”
Now that we know just how important a mobile and stabile thoracic spine is to shoulder health and pitching performance, let’s review a few quick and effective drills to improve your thoracic mobility before training or throwing:
4 Exercises to help with T-Spine Mobility
Kneeling T-Spine Rotation
Tall Kneeling Kettlebell Rotation
Stephen C Gamma, MS, ATC, CSCS holds a Master of Science in Athletic Training from the University of Idaho and is a Certified Strength and Conditioning Specialist (CSCS) with the National Strength and Conditioning Association. Stephen is a former Minor League Baseball Strength and Conditioning Coach and recipient of the 2010 Appalachian League Strength and Conditioning Coach of the Year award. Stephen is the Assistant Athletic Trainer at Mount Saint Mary College (NY) and Director of Sports Performance at Pro Prospects Training Center (NY). Stephen has presented research (poster) at the 2014 FWATA Annual Symposium and 2015 World Federation of Athletic Training and Therapy World Congress. Publications include the International Journal of Sports Physical Therapy, The Sports Digest, and Joeygreany.com