Shoulder pain is one of the most common injuries in the gym. Almost 40% of these shoulder injuries involve the shoulder joint. Most of these injuries can be prevented if more attention is paid to the smaller muscle groups in the shoulder joint, more especially the external rotators which are located in the back of the shoulder which include the Infraspinatus and the Teres minor. These types of injuries are commonly refereed to as subacromial impingement syndrome.

Kolber MJ, Cheatham SW, Salamh PA, Hanney WJ. Characteristics of Shoulder Impingement in the Recreational Weight-Training Population.
J Strength Cond Res. 2013 Sep 25. [Epub ahead of print]

Abstract

Despite reports implicating subacromial impingement syndrome (SIS) as an etiological source of shoulder pain among weight-training (WT) participants, a paucity of case-controlled evidence exists to support this premise. The purpose of this study was to determine if WT participants present with characteristics of SIS. Additionally, we investigated the role of exercise selection among those identified as having SIS. Seventy-seven (154 shoulders) men (mean age 28) were recruited, including 46 individuals who engaged in WT a minimum of 2 days per week; and 31 controls with no history of WT participation. Prior to testing, participants completed a questionnaire summarizing their training patterns. Upon completing questionnaire, two previously validated tests used to identify SIS were performed on both groups and included the painful arc sign and Hawkins-Kennedy test. When clustered, these tests have a positive likelihood ratio of 5.0 for identifying SIS when compared to diagnostic gold standards. Analysis identified significant between group differences in the combined presence of a positive painful arc and Hawkins-Kennedy (p < .001) test. A significant association existed between clinical characteristics of SIS (p ≤ .004) and both lateral deltoid raises and upright rows above 90°. Conversely, a significant inverse association was found between external rotator strengthening and characteristics of SIS. Results suggest that WT participants may be predisposed to SIS. Avoiding performance of lateral deltoid raises and upright rows beyond an angle of 90 degrees; as well as efforts to strengthen the external rotators may serve as a useful means to mitigate characteristics associated with SIS.

So what can be done to prevent impingement in the shoulder joint?

Of course this first thing to do is strengthen the Infraspinatus and the Teres minor by doing exercises that perform external rotation of the shoulder joint. Here is an example using rubber bands. The can also be done with cables or by laying on your side and using DB's.


The above study also show that we need to be very careful doing shoulder exercises like lateral raises or upright rows where you position your upper arms above the horizontal line or 90 degrees, which causes stress to the connective tissue in the shoulder joint. Trust me, I see more people than not doing both exercises seen below where the arms are above 90 degrees.