As a health practitioner, the two most common injuries I see are shoulder and low back injuries. Here is my advice for how to handle and heal from these common athletic injuries.
Shoulder Impingement Syndrome occurs when the subacromial space lesses due to misalignment, abnormal bone growths, thickening of the tendon, or swelling in the bursa.
Most rotator cuff injuries heal with conservative treatment; however, a transcutaneous electric nerve stimulator (TENS) may help speed up this process. http://painrelieftens.com/blog/24-how-to-use-a-tens-machine-on-rotator-cuff-injuries
Motions Of The Glenohumeral Joint | Good to note: beyond 90 degrees flexion belongs to the scapulothoracic joint, not G/H jt. So if the client is unable to flex their arm beyond 90 degrees, look to dysfunction in the S/T joint.