This is a common condition seen in both athletes and non-athletes as these muscles tend to be weak, overstretched, and prone to injury.  It is a common early season condition seen in baseball players, especially pitchers.  Throwing a ball at 100 mph involves powerful muscles such as the pectoralis major, subscapularis, and deltoid.

The force of deceleration can be up to ten times greater than acceleration.  The motion must be decelerated and stopped by the small, typically weak and inhibited, infraspinatus and teres minor muscles, so when they repeatedly stop abruptly during deceleration they stress or strain the tendons of attachment in the back of the shoulder over time.

Treatment:

• Follow the basic shoulder protocol, as you must release the tight restricted anterior muscles first to allow the weak, inhibited, or overstretched infraspinatus and teres minor to relax. The most important muscle to release prior to treating these muscles is the subscapularis.
• Next perform the specific protocol for these muscles including myofascial work and cross-fiber gliding to bring the muscle back to their normal resting position, multi-directional friction, and eccentric (scar tissue) fiber realignment.
• Repeat the process until the client is pain-free. It is then imperative to strengthen these weak, inhibited, overstretched muscles.