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Written by Stephen E. Alway, PhD, FACSM
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Tuesday, 24 April 2007 |
Shoulder injuries can be career ending for a bodybuilder. They can
arise during the last reps of a heavy set just about as easily as
during a warm-up set with a light weight. Most shoulder injuries are
not the result of strained deltoids, but rather because the deep
muscles of the shoulder have rotated or twisted beyond what they could
handle. This is because the shoulder is the single most complex joint
in the human body. It is literally held in place by muscles and
tendons. Thus, it's not surprising that the shoulder is vulnerable to
injury and it's not uncommon to find many shoulder-related injuries in
the gym each year. Shoulder injury can be avoided, however, if the soft
tissue structures that support the joint are strong and not overly
stretched (i.e., torn).
Shoulder injuries can be career ending for a bodybuilder. They can arise during the last reps of a heavy set just about as easily as during a warm-up set with a light weight. Most shoulder injuries are not the result of strained deltoids, but rather because the deep muscles of the shoulder have rotated or twisted beyond what they could handle. This is because the shoulder is the single most complex joint in the human body. It is literally held in place by muscles and tendons. Thus, it's not surprising that the shoulder is vulnerable to injury and it's not uncommon to find many shoulder-related injuries in the gym each year. Shoulder injury can be avoided, however, if the soft tissue structures that support the joint are strong and not overly stretched (i.e., torn).
This month's column will stress the anterior muscles and medial rotators of the shoulder. For a review of the muscles on the posterior (back) side of the shoulder, get a copy of last month's column. This area is frequently damaged when the arm is rotated medially (toward the mid-line of the body), or when something is done that's as straightforward as throwing a baseball. If injured, this muscle will pretty much shut down most of your upper body exercises, including most dumbbell and cable work. The major muscle responsible for medial rotation of the shoulder, and therefore the one most frequently injured, is the subscapularis muscle.
Anterior Shoulder and Rotator Cuff Muscles
Movements at the shoulder are very complex relative to other joints (e.g., the hinge joints of the knee or elbow). The glenohumeral (shoulder) joint is made of the circular head of the humerus bone of the upper arm, which, sits in a very small indentation in the scapular bone (shoulder blade) called the glenoid fossa. This ball and socket joint is constructed so that the ball is too big to fit into this socket joint. This results in a very unstable joint. By contrast, the hip joint is a very deep and stable joint, even though it is also a ball and socket joint. In the shoulder, ligaments and the tendons of the rotator cuff muscles largely hold the bones together. Without intact and strong rotator cuff muscles, the shoulder joint would be unstable and dislocated with only small movements.
The deltoid is a thick, powerful, muscle that caps the other muscles of the shoulder joint and it covers the bony connections that Make Up the shoulder joint. The anterior fibers of the deltoid begin along the lateral part of the clavicle (collarbone). The posterior fibers attach along the spine of the scapula (shoulder blade), which is located on the upper and posterior side of the scapula. The medial fibers begin in regions between the previous two sites on the acromion of the scapula. All the fibers from the deltoid converge halfway between the shoulder and the elbow on the lateral aspect of the humerus bone of the upper arm. The medial fibers of the deltoid abduct the arm (raise it to the side). The anterior fibers raise the arm to the front of the body (anterior shoulder flexion), while the posterior fibers move the arm posteriorly. In addition, the anterior fibers can assist in medial rotation of the shoulder joint.
Though we don't normally think much about the rotator cuff musculature, it will be something that you will be forced to think about, either now to prevent injury, or later, when you are in rehab to recover from the shoulder injury. Four scapular muscles (subscapularis, supraspinatus, infraspinatus and teres minor) form the rotator cuff muscles. The infraspinatus muscle is located in the infraspinatus fossa of the scapula bone. It attaches between this fossa and the greater tubercle on the head of the humerus bone at the shoulder. The teres minor muscle attaches between the superior (upper) lateral border of the scapula and the greater tubercle of the humerus. The infraspinatus and teres minor muscles rotate the humerus laterally at the shoulder joint and help stabilize the shoulder joint by holding the head of the humerus in the glenoid fossa. The supraspinatus is a rounded muscle that lies in the supraspinatus fossa at the top and posterior side of the scapula. It begins near the medial side of the scapula (close to the vertebrae and the center of the body) and runs over to the superior part of the head of the humerus. The supraspinatus muscle abducts the humerus by raising the arm out to the side of the body, so the hand moves in a lateral movement upward.
In contrast to the other muscles of the rotator cuff, the bulk of the fibers of the subscapularis muscle are located on the front or anterior side of the scapula bone. The muscle fibers cross the anterior part of the shoulder joint and attach on the humerus bone near the shoulder. This muscle is a strong medial rotator of the humerus by moving the medial side of the arm toward the center of the body. The subscapularis also holds the head of the humerus bone into the glenoid cavity of the scapula.
Cable Rotational Raises (vertical to horizontal)
Rotational raises from vertical to horizontal are somewhat similar to a front dumbbell lateral raise, but it emphasizes loading the rotator cuff muscles.
1. This can be done with one arm at a time, or both arms simultaneously, but the one-arm version will be described here. Start with a light weight on a high pulley station. Place your feet about shoulder-width apart. Take the high pulley handle in your right hand (assuming this is the first arm to be exercised). Start with the arm vertical over your right shoulder. Your elbow should be just short of being fully straight. Keep your elbow locked in this position throughout the exercise. Lock your wrist so that all the rotation movement occurs at the shoulder joint. If you allow your wrists to rotate, this will drastically decrease the effectiveness of the exercise for the anterior deltoid and subscapularis muscles.
2. Your palm should be facing toward the center of your body (semi-pronated grip) when your arm is in the vertical position. Pull the cable handle downward in a line directly in front of your shoulder and chest, toward your right thigh. Stop when your arm reaches a position that's horizontal to the floor. As you are pulling your arm downward, turn the palm of your hand (by rotating your shoulder and arm medially) so the palm faces the floor at the position where the arm becomes parallel to the floor. It's important that you rotate your shoulder to turn your hand because this will activate the medial rotator functions of the deep and anterior shoulder muscles.
3. Hold the final position (horizontal arm position) for a count of three before returning to the starting position. Next, raise the weight back to the top vertical position, where the arm, cable and shoulder are in the same vertical line. As your arm moves upward, rotate the cable handles slowly in a lateral direction. Resist the weight returning to the top position so your palms face toward the center of your body again. Pause for a count of one, then repeat the lift downward to the horizontal position as you rotate your shoulders medially.
Important Tips
The subscapularis muscles will be most strongly activated as your arm is pulled downward and your shoulder is rotated medially. The anterior deltoid will assist the subscapularis in this action. The teres minor and infraspinatus muscles help assist resisting the weight as your arm is raised back to the starting position.
Do not rotate your shoulder in a jerky or ballistic manner, especially when your arm is on the way down and when you are medially rotating your arm at the shoulder joint. Jerky movements could result in micro-tears in the subscapularis muscle and sooner or later, you will experience significant and prolonged shoulder pain.
Warming up any joint with light weights and stretching are part of any good training program for any joint, but nowhere is this more important than in the shoulders. Remember that the shoulder joint is literally held together by its muscle attachments, not other bones. Thus, stronger and thicker shoulder muscles mean greater shoulder stability and reduced risk of injury. You should also allow sufficient time to recover after hard anterior deltoid days, particularly if you're also planning a subsequent heavy chest day (which will also activate those anterior deltoid fibers).
Finally, your goal for injury-free, strong and thick shoulder muscles can become a reality, but only if you treat your shoulder joints with respect and pay close attention to your exercise mechanics ("form"). With good training habits and effective rotatator cuff and shoulder exercises, you'll increase the likelihood of maintaining shoulders that are healthy and free of injury. The shoulder is one of the few areas where no pain equals much gain, so gain a lot and have a productive bodybuilding experience!
References
Basmajian, J.V. Recent advances in the functional anatomy of the upper limb. Am J Phys Med 48:165, 1969.
Basmajian, J.V., and C.J. Deluca. Muscles Alive. 5th Edition. Baltimore, Williams and Wilkins, pp. 220-224, 1985.
Burke WS, Vangsness CT and Powers CM. Strengthening the supraspinatus: a clinical and biomechanical review. Clin Orthop 292-298, 2002.
Codine P. Bernard PL. Pocholle M. Benaim C. Brun V. Influence of sports discipline on shoulder rotator cuff balance. Medicine & Science in Sports & Exercise. 29(11):1400-5, 1997
Desmeules F, Cote CH and Fremont P. Therapeutic exercise and orthopedic manual therapy for impingement syndrome: a systematic review. Clin J Sport Med 13: 176-182, 2003.
Hirano M, Ide J and Takagi K. Acromial shapes and extension of rotator cuff tears: magnetic resonance imaging evaluation. J Shoulder Elbow Surg 11: 576-578, 2002.
Kibler WB, McMullen J and Uhl T. Shoulder rehabilitation strategies, guidelines, and practice. Orthop Clin North Am 32: 527-538, 2001.
Kuechle DK. Newman SR. Itoi E. Morrey BF. An KN. Shoulder muscle moment arms during horizontal flexion and elevation. Journal of Shoulder & Elbow Surgery. 6(5):429-39, 1997.
Moncrief SA, Lau JD, Gale JR and Scott SA. Effect of rotator cuff exercise on humeral rotationtorque in healthy individuals. J Strength Cond Res 16: 262-270, 2002.
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