Today’s guest post comes from Scottsdale-based physical therapist Dan Swinscoe. He’s been a great resource (and friend) to me over the years, and this post will show you yet another reason why that’s the case. Enjoy! – EC

Ever hear of the café wall illusion?  It’s pictured below. It is an optical illusion in which the straight lines between staggered rows with alternating dark and light rectangles appear to be sloped, but they’re not.  They’re actually straight.

What does this have to do with baseball?  It’s meant to illustrate the point that things aren’t always as they appear.

Specifically, I’m referring an article published in the Journal of Shoulder and Elbow Surgery in August 2022. Haeberle et al. performed an analysis on pectoralis injuries that occurred in major and minor league baseball between 2011 and 2017.

They found that most of the injuries were: a) non-contact, b) mostly in pitchers, c) and mostly in the throwing arm – and level of play did not seem to be a factor. In the article, the authors inferred that pec tightness was the problem.  This, of course, then also implied stretching must be the solution. Right?

Even though I understand the logic, to me, making that conclusion is the café wall all over again: it isn’t what it appears to be. Looking at the café wall with different colors – a fresh perspective – it becomes more obvious the rows of rectangles are, in fact, straight:

To me, stretching the pecs of a pitcher who strained his pec is like stretching the fabric of your seatbelt because it’s uncomfortable when you slam on the brakes. In both instances, you’re likely to derive short term comfort, but be set up for potentially worse consequences later when you need those fibers to be taut instead of stretched out. If a pitcher is getting symptoms of a pec strain, I’m immediately looking for reasons WHY that tissue is being tensioned enough to break down and become painful and inflamed.

The first thing I suspect is a lack of thoracic (upper back) rotation. The thoracic spine “delivers” the scapula so the throwing arm can be placed into position to throw. If this movement is lacking, a typical compensation would be for the humeral head to translate forward in the socket, which would then place stress on the pec and give opportunity for pain and a sensation of tightness.

How do you know if a player has enough thoracic rotation? I like to use the Seated Trunk Rotation Test as taught by OnBase University. We are looking for a minimum standard of 45 degrees. Many professional players are well beyond that, so if a player is dealing with a pec strain, check to make sure that the TS mobility is 45+ to the throwing side. If the pitchers’ individual style of throwing has his lead leg striding across to the arm side (“closed off” delivery), that means he needs even more thoracic rotation to safely accommodate the motion.

Watch this link to see how we use the Seated Trunk Rotation Test:

[Note from EC: at the end of this article, you’ll see an opt-in box to get free access to a presentation I did that focuses heavily on thoracic spine rotation in throwers.]

To be successful pitching at the professional level, so much shoulder external rotation is required that it would be uncommon for for an elite level pitcher to lack pectoralis maor mobility. But, it IS common for them to FEEL LIKE they do.

The feeling of tightness is often a protective mechanism in the body when a movement isn’t controlled as well as needed. With respect to the shoulder, you can use the 90/90 test to learn a lot about how your player controls his arm in a way that mimics the layback position with throwing.

Use this link to learn the test and see how a player might compensate. The compensatory actions are the source of the complaint, but the root cause for the compensation would be decreased ability to keep the ball centered in the socket against the forces created when pitching.

Although less common, it’s very rewarding to find that when a player complains of feeling tightness in the front of the shoulder, the root cause is actually hip flexor mobility. It’s further down the kinetic chain, but when the player strides toward the target, the throwing side leg is behind the body in an extended position. If full hip extension is lacking, that leg will essentially pull the spine towards flexion at a time when the arm needs the spine to extend. This can lead to stress in the throwing pec area also. Imagine the difference between reaching overhead with a shirt tucked in tightly vs a loose untucked shirt. All the sitting involved with prolonged travel can cause hip flexors to tighten up. Keep this in mind with players on long road trips.

In summary, with pitchers (especially elite ones), if they feel pec tightness, assume the pec tightness is a sensation informing you of a problem somewhere. Treat it like a check engine light or canary in the coal mine because things are seldomly as they appear. Assess the entire kinetic chain and remember that protective muscle guarding makes normal muscles feel tight and stretching them provides only a temporary short-term fix.  To quote neurologist Karel Lewit, “He who treats the site of pain is often lost.”

About the Author

Dan Swinscoe, MPT, CSCS is a physical therapist and strength coach in Scottsdale, AZ with over 30 years experience helping athletes move, feel and play better. His clinic is Train2Win Rehab and Performance. (www.T2WClinic.com), and you can contact him at dan@t2wclinic.com. His online resources can also be found at www.FixYourFunction.com.