Why? I am saying when we apply load in a dysfunctional environment hence the dip…we create disproportionate forces across joints in a high risk fashion. The shoulder joint was not meant to be wrenched back concentrically to an excessive range with your body weight..let alone plate loaded (old school) The shoulder joint extends the humerus to about 45-50 degrees…we take that to 80-90 with load. Unlike the hip joint, the shoulder joint is not a true ball-and-socket joint; in fact, it is more analogous to a golf ball sitting upon a golf tee. It is highly mobile, this joint generally lacks the stability offered by the surrounding bones and relies more upon the active structures (muscles) and passive structures (joint capsule, ligaments, etc.) for stability… thus rendering it more prone to injury. Exercises like the chair dip. bench dips and dips, create compression within the joint capsule, increasing shear forces and impingement of nerve endings. HERE IS THE PART TO UNDERSTAND… Dips also push the glenohumeral joint beyond the normal anatomical range of shoulder extension, stretching the joint capsule and reducing its ability stabilize and produce force, again rendering it more prone to injury. Additionally, as the humerus extends during the lowering phase of the exercise it internally rotates, adding to the potential for impingement, while also forcing a rounding of the shoulders that compromises stability within the entire scapulothoracic region.
Dave Parise CPT MES FPTA
