It has been increasingly clear to me that those Junior aged hockey players who possess less than ideal "Shoulder Mobility" screen scores seem to be the same individuals who may be at an increased risk of suffering traumatic acromioclavicular joint separations.
Over the last couple of years, I have utilized the FMS to screen each of my players prior to the commencement of the season. Having both tracked and treated their injuries year-long, it looks like one of the seven screens may be a powerful predictor of AC joint separations. Traditionally thought of as an injury that occurs due to the physical nature of the sport, AC separations are one of the most common injuries in ice hockey. In fact, shoulder injuries in general consistently rank quite high in epidemiological studies (see studies by Benson and Emery).
As per the FMS manual, "The shoulder mobility screen assesses bilateral shoulder range of motion, combining internal rotation with adduction and extension, and external rotation with abduction and flexion. It also requires normal scapular mobility and thoracic spine extension." A loss of such normal scapular mobility and thoracic spine extension often results in any of the following presentations: sick scapula, upper crossed syndrome, scapular protraction, etc. And as a result, a shoulder girdle that may be more prone to injury.
When thinking about AC joint separations, it is important to note that often it is the acromion that translates in a downward fashion rather than the clavicle moving superiorly. In each of the above faulty presentations, it is not uncommon for the acromion to already be trending toward an anterior-inferior position. Now when presented with trauma such as a seemingly benign body check, a protracted shoulder may indeed not be able to "cushion the blow" as well as one that is retracted, and may sustain an AC injury.
At least this is my take on it.
But what can we do to "better position" our players for increased resiliency?
Personally, I prefer dynamic and loaded correctives over manual stretching and therapy. Indeed soft tissue work may be necessary, but experience has demonstrated to me that the following correctives give me a bigger bang for my buck.