quote:
Originally posted by thepainguy:
Here's an e-mail I recently received discussing the Inverted W and my theory of Hyperabduction...
Chris I am an orthopedic surgeon, and would like to offer you a theory on why the inverted W is bad to the long term health of the shoulder.
In the position of hyper abduction, elevation and extension of the distal humerus above the shoulder (inverted W) the inferior glenohumeral ligament is placed on stretch. The humeral head must lever against it to advance the arm forward. This ligament is the primary anterior stabilizer of the glenohumeral joint with the arm elevated (i,e. pitching). In other words, this position places this ligament under tension, then it is levered against in order to throw. This eventually will either loosen the shoulder, or tear the anterior labrum. It should be recognized this ligament is under stress during the "normal" delivery. If you traumatically dislocate your shoulder, this ligament is a key part of the pathology. Shoulder instability in turn leads to impingement, and other problems. Conversely, when the elbow is below the shoulder, this ligament would not be as stressed.
Also, the specific use and timing of the muscles about the shoulder is critical. They have done muscle activity studies during throwing, and there are distinct differences between amateurs and professionals. There is also evidence for muscle use differences in the healthy shoulders, and the ones that aren't.
I am not a shoulder guru, certainly not a pitching guru, but am interested in pitching mechanics. Like you, I learned from others while coaching little league/AAU, and agree there is a lot of misinformation out there.
Chris. Was this ortho aware of what I've pointed out many times to you? What I mean is that this position of "hyperabduction" in the M or inverted W happens for only a brief moment in the delivery and that any forward motion of the humerus or any external rotation of the humerus is very, very small while the arm is in that position. Any forward motion of the humerus or significant external rotation happens AFTER the humerus has already dropped to shoulder height, or lower, in some instances.
