“The overhead press is dangerous.” “Don’t do any exercises with your arms over your head.” These are the words that are being spread around fitness and bodybuilding gyms with increasing frequency. They come not only from coaches and trainers but also from physical therapists. The main reason for saying that overhead exercises are dangerous is that some athletes experience pain during execution.
However, to make a blanket statement that the overhead press or overhead exercises are dangerous is not only incorrect but it can lead to the abandonment of some of the best exercises to fully develop the deltoid, especially the middle head and to maintain a safe shoulder!. Thus before you omit overhead exercises, it is important to understand why or how such exercises may be dangerous. Then you can determine for yourself if the exercises are truly dangerous.
Before going into a separate analysis of the three basic overhead lifts, it is important to understand the joint and muscular actions involved when raising the arm overhead in a sideward (lateral) and front-back (anterior-posterior) plane. Equally important is to determine if it is these actions that create shoulder problems or if there are predisposing factors that cause pain when doing an overhead strength exercise.
For example, the arm does not function by itself in the shoulder joint. It works in close coordination with the shoulder girdle, i.e., movements of the clavicle and especially the scapula. As you raise the arm upward, the scapula rotates approximately one degree for every two degrees of arm movement. The exact amount may vary somewhat.
The key point here is that specific muscles are used to raise the arm and other specific muscles are used to rotate the scapula. Their work must be closely coordinated in order to allow for a full range of motion and to keep the movement safe. If there is a major muscle imbalance or if some of the muscles are not strong enough to rotate the scapula as the arm is being raised, problems such as shoulder impingement may appear.
The major muscles involved in the shoulder joint when raising the arm sideward (shoulder joint abduction) as in the overhead press, or with the elbows out to the sides, are the middle deltoid and the supraspinatus, a relatively small rotator cuff muscle. The main action of the supraspinatus is to raise the arm from alongside the body to the level and above level position.
In addition, this muscle is active in pulling the arm bone (humerus) up into the shoulder joint. If the supraspinatus muscle is weak, the humerus may become depressed, especially if the pull of the latissimus dorsi is very strong, which pulls the arm downward. Also, when the humerus is not fully rotated in the shoulder joint, it can create problems when raising the arm.
As the supraspinatus and deltoid contract to raise the arm, the scapula undergoes upward rotation via contraction of the upper and lower portions of the trapezius and the serratus anterior. The serratus anterior pulls the lower outer border of the scapula forward (sliding it around the rib cage out to the sides). The upper trapezius pulls the top of the scapula inward toward the spine and the lower trapezius pulls the inner border of the scapula downward. As a result of these three forces, the scapula rotates around an axis through its center.
Synchronization of these muscles in rotating the scapula together with synchronized action of the deltoid and supraspinatus in raising the arm is very important for safe movements in the shoulder. These integrated actions are critical for safe, full-range movement. Any mis-timing of the muscular contractions or if one or more of the muscles are either too strong or not strong enough in performing its function, or if one of the muscles does not come into play as needed, it can seriously interfere with effective and safe movement of the arm in the shoulder joint.
When the arm and scapula movements are well synchronized there is little if any, chance of injury in the shoulder joint. This is why we can see so many athletes such as volleyball and basketball players constantly raising their arms overhead to execute the movements needed in the sport and not receiving any injuries. The key to prevention is to maintain the flexibility needed in the shoulder joint and doing unweighted, or even some weighted exercises moving the arms completely overhead.
For more information on shoulder joint safety and exercises specific to the shoulder joint, see Biomechanics and Kinesiogy of Exercise