The Shoulder Joint
The bench press causes the majority of shoulder joint injuries. In order to have a strong shoulder joint and avoid injury, it is important to understand this complex joint. It is also important to learn about the rotator cuff and scapula in order to perform the appropriate exercises to strengthen and increase the range of motion for these structures.
Many people are familiar with the shoulder muscles. The primary muscles in the shoulder are known as “deltoids”. There are several deltoid “heads”, including the anterior (front), lateral (side), and posterior (rear). Certain exercises such as side raises or front raises isolate the various “faces” of the deltoid muscle. Compound movements like the clean and press, Arnold press, and military press are compound movements that involve the majority of the deltoid muscles.
Other upper body exercises involve the shoulder joint as well. The bench press places tension on the shoulder joint. When the bench is performed on an incline, more tension is shifted to the shoulder joint. When the flat bench is performed through an exaggerated range of motion, such that the elbows drop below the same plane as the shoulder joint (so the upper arms go below parallel with the ground) the shoulder joint is forced to rotate slightly in order to accommodate the range.
One critical component of the shoulder joint is the rotator cuff. The rotator cuff is a group of four muscles that attach to the scapula (shoulder blade). The ends of these muscles attach to tendons that in turn attach to the arm bone (the humerus). The rotator cuff is what allows the shoulder joint to move in multiple directions - unlike the elbow joint, which is restrict to flexion within a specific plane, the shoulder joint is a rotary joint that may move in multiple directions. Any joint such as the hip joint or the shoulder joint that can move in multiple planes (rotate) sacrifices stability for increased movement, and therefore becomes more susceptible to injury.
One of the first ways to prevent shoulder joint injuries is to prepare the shoulder joint for stress. This means training the shoulder joint with resistance. While many people incorporate shoulder exercises into their training program, they fail to properly balance the movements or prioritize based on relative strength. As an example, the shoulder joint helps control the descent of a pull-up - the shoulder group as a vertical pushing mechanism is antagonist to the upper back group as a vertical pulling mechanism. Therefore, training between the two should be balanced, so that the volume of pull-up or pull-down movements matches the volume and intensity of shoulder pressing movements within a training cycle.