How high should you raise your arms when doing front or lateral arm raises? If you're like the majority of bodybuilders and athletes who do these exercises, you'll probably answer, "To the level position," that is, where the arms are parallel to the floor.
The reason for such execution is based on the supposed prevention of shoulder impingement, which is usually characterized by pain in the shoulder when the upper-arm bone (humerus) jams in the shoulder joint and pinches a nerve. However shoulder impingement can occur only when a malfunction of the muscles or some other problem already exists in the shoulder joint. The mere act of raising your arms from directly up in front of or from the side of the body to a completely overhead position does not by itself cause shoulder impingement.
In fact, if you closely examine the muscle involvement in these exercises, you'll find that moving from the level to the overhead position offers the most productive range of motion. This is the best range of motion for maximum involvement of not only the deltoids, but also the upper and lower trapezius muscles and serratus anterior. Stopping at the level position eliminates most of the deltoid involvement and only partially utilizes the trapezius and serratus muscles.
When the muscles that move the scapulae are well-developed, they move and rotate the scapulae in synchronization with arm movement so that the shoulder joint turns and opens up in the direction of the movement. Synchronized rotation, abduction (sliding to the sides of the ribcage) and elevation of the scapulae are crucial in preventing shoulder impingement.
Aggravating the Problem
If the muscles aren't sufficiently developed or if you have a problem with the rotation, abduction or elevation of the scapulae, then the chances of shoulder impingement are increased. In such cases, it isn't the exercise that causes shoulder impingement, but a pre-existing problem that's Aggravated by the exercise. A physician should evaluate the condition to determine the cause and a plan to correct it.
Rehabilitation of the joint and its surrounding muscles will most likely be needed. During this period, to allow for full healing, the patient may have to curtail range of motion in the shoulder and possibly eliminate certain exercises. This might mean performing front and lateral raises, but only to the level position. After the joint is healed, which may take 4-12 weeks, you should begin doing full-range arm raises without weights until you can raise your arms with no discomfort. Then begin using very light weights and very gradually (over weeks and months) begin to use heavier weights.
To further substantiate the need for a full range of motion when doing front and lateral arm raises, we can take a look at overhead press exercises. When the overhead press from behind or in front of the neck is executed, the elbows are well below the level of the shoulder in the initial position. Because of this, the arms travel from approximately 30-45 degrees below shoulder level to the 180-degree full overhead position a range of 135-150 degrees. This is why overhead presses are so effective for development of the deltoids and the other muscles.
Even if prevention of shoulder impingement isn't the main reason for limited-range movements, many bodybuilders and athletes stop at level because of the excessively heavy weights that they use. Very heavy weights, however, aren't needed when doing front or lateral arm raises with extended arms, since a small weight at the end of a long lever (your arm is acting like a lever in this exercise) can be quite heavy. Moving from the level to the directly overhead position involves maximal contraction of the muscles. Using heavy weights that you can handle only up to the level position doesn't produce maximum muscle gains or definition.
When using very heavy weights, to move them from thigh height to the level position, you must vigorously contract the muscles and literally swing the weights up so that they ride out and up on their own momentum. If a vigorous swing isn't executed, then you must severely bend the elbow to decrease the effective resistance in order to raise the arms high enough. But with severely bent elbows, you change the positioning of the elbow so that you don't truly isolate the deltoid or the other muscles involved.
Stopping at the level position plays an effective role in total muscle development when you want to work some muscles with greater isolation. For example, when doing lateral arm raises, the supraspinatus does the bulk of the work from 0-90 degrees. In front-arm raises, the upper pectoralis major, together with the coracobrachialis, undergo the strongest contractions to get the arms to the level position. When above level, however, the deltoid and trapezius become the predominant muscles. Thus, doing limited-range arm raises should be included in the repertoire of exercises for bodybuilders and athletes alike.
Strengthening the supraspinatus is extremely important for prevention of shoulder impingement, since this muscle plays a key role in holding the humerus in the shoulder joint. Overdeveloping the latissimus dorsi and lower peetoralis major muscles, however, can depress the arm sufficiently to cause problems in the joint. But when the supraspinatus is strong, it helps counteract the downward pull of the lats and lower pecs.