Chris sat down with Aaron to discuss all things shoulder. We dive into: Internal versus external impingement, why compression might be a better term over impingement, an objective assessment of the shoulder, validity and reliability (or lack thereof) of shoulder special tests, upper extremity plyometrics, distinguishing normal adaptations from pathological deficits, and much more. Aaron is currently a PhD student at the University of Minnesota, where he is focusing on shoulder biomechanics in overhead athletes, a full time faculty member and professor at the University of Minnesota in their PT department, and a part time sports medicine clinician at the Mayo Clinic in Minneapolis. We hope you all enjoy!