Do you remember the cartoon where Popeye, the sailor man, ate spinach to gain superhuman strength? He would flex his biceps, huge because of the spinach to show the villains he was ready to fight! That cartoon undoubtedly helped parents persuade kids that spinach was a superfood. The bulging biceps gesture continues to signify strength, confidence and power.
We understand the bulging biceps gesture universally, but we don’t entirely understand the muscle. The biceps muscle allows us to bring our hand to our mouth, carry things, and decelerate the arm at the elbow when throwing a ball. But what is its job at the shoulder? Some studies support its role as a stabilizer. Others conclude the muscle has little relevance at the shoulder. What we know is that when injured, the biceps tendon can be painful and debilitating.
The biceps brachii is one of three muscles on the front of the upper arm. “Biceps” means two heads, and “brachii” means upper arm. It is a two-joint muscle, meaning it crosses the shoulder and elbow joints. Both heads (long and short) of the muscle insert on the forearm just below the elbow joint.
The tendon of the long head of the biceps brachii (LHBT) fits in a groove on the front of the arm bone (humerus) as it works its way up to its insertion point on the scapula (wing bone). It has attachments to the tip of the scapula and to the cartilage inside the shoulder joint called the labrum. The LHBT is held in the groove by a group of ligaments, fibers from the rotator cuff muscles and the pectoralis major (chest) muscle. The proximal tendon is connected to the structures mentioned and highly innervated.
Injury to the biceps tendon
The LHBT is susceptible to injury when it is overused, overstretched or subjected to trauma.
Sports such as baseball and tennis require significant shoulder flexibility to wind up to throw or serve the ball at high speeds. The tension placed on the LHBT in the maximum stretched position can be extreme. Injury to the LHBT can also occur from the traction force when releasing a ball at high speeds.
The overhead throwing motion is a complex movement. We need a balance between strength, flexibility and motor control. If this balance is compromised, we risk injury. “A thrower’s shoulder must be loose enough to throw but stable enough to prevent symptoms” Wilk et al. Stability includes not just strength, but balanced strength which is difficult to achieve in a stretched position.
Anybody is at risk for injury. Gradual wear and tear of tendons weakens them. This degenerative process may happen without you realizing it (many small rotator cuffs are asymptomatic). As you lose strength, you lose stability. We strain the LHBT when our ball and socket joint becomes compromised. It may be LHBT irritation that brings you to your doctor rather than the underlying cause of your dysfunction.
As we age, our joint becomes less congruent due to arthritic changes. We also lose space within and above the joint making pinching more likely when we raise our arm. Weakness combined with poor posture, an aging body, tightness, and a sport or activity that requires overhead motion is the perfect recipe for injury.
Genetics and anatomical anomalies may be risk factors, but there is not much you can do about these. What you can do is be proactive about the factors you can control.
Keeping your shoulder strong and flexible will reduce your risk of injury. The best exercises are those that improve the balance of your rotator cuff muscles and improve posture. We tend to be weaker in the muscles behind the shoulder. These muscles deserve attention in any strengthening program. I have provided a link to a simple, effective shoulder program (here). If you are stiff or have discomfort, consider working with a professional. A physical therapist can take you through a screening process to determine what areas of your body need to be addressed for optimal shoulder function.
When exercise and stretching aren’t enough
If conservative therapy is unsuccessful, invasive procedures may be needed. A surgeon may be able to repair your damaged tendon. More drastic measures involve removing the LHBT and attaching it lower on the arm. Another surgical technique removes the LHBT entirely. A tenotomy will reduce pain and does not seem to jeopardize the overall function of the shoulder (so far). This approach has the benefit of less recovery time. A surgeon will choose one of these procedures depending on the degree of LHBT damage, your age and the overall health of your shoulder. LHBT pain may cause you more suffering and dysfunction down the road than the minor loss of strength from the tendon removal.
While it is true we can live and function without the long head of the biceps tendon, if given the choice, wouldn’t you prefer to keep it intact? Keeping your shoulder strong and healthy requires effort. And a little spinach won’t hurt.