Jack Hayes (not his real name) was proud of the fact that after more than 30 years of continuous weight training, he’d never experienced a significant training injury. Jack attributed his injury-free history to a variety of commonsense training principles. He always warmed up with lighter weights before attempting any heavy lifting, kept himself flexible by performing a stretch routine after each workout and was a stickler for perfect form. No swinging the weights or dropping them too fast. He refused to use weights that he couldn’t completely control with proper form.
So when the incident occurred, Jack was taken by surprise. He’d begun his chest workout in the usual manner, by performing a warmup set of incline dumbbell presses with weights well below his primary workout poundage. Jack had done the same warmup uneventfully countless times before, but this time it was different. On the eighth rep he felt a pop in his shoulder, near where the biceps converges with the shoulder. His arm suddenly went dead; all strength disappeared in an instant.
A visit to an orthopedic specialist revealed that Jack had experienced a rotator cuff tear. How could it be? Despite doing everything right, he’d still gotten the injury’seemingly from out of nowhere.
In truth, Jack’s experience was hardly unique. Getting some type of tendon injury appears to be an occupational hazard with continued weight training, and you’d be hard pressed to find a bodybuilder who’s never experienced the inflammation of a tendon, commonly called tendinitis, or some type of tendon injury. The injuries manifest themselves as chronic pain in the shoulders, elbows, knees, wrists or whatever area of the body is affected. Are tendon injuries inevitable for those who lift weights? Let’s start with some background on what causes the various types of tendon problems.
Tendon Facts
Tendons are a type of tissue that connects muscle to bone. They transmit the force of exercise placed on muscle, which allows joints to move. The structural capabilities of tendons are considerable; they are the strongest link in a bone-muscle-tendon unit, with a tensile strength half that of stainless steel. Tendons fail, however, when applied force exceeds their biomechanical limits.
Tendons are primarily composed of two proteins that give them flexibility and strength’collagen and elastin. Specifically, they contain 70 percent collagen, 2 to 5 percent elastin, glycoproteins (proteins linked to sugars) and 1 to 3 percent cells, with a water content of 65 to 70 percent, including the water that’s in the other elements.
The collagen gives a tendon its strength. About 13 different types of collagen exist in the human body, but tendons contain mainly type-1 collagen. That’s an important point because when a tendon is repaired after an injury, the body uses mainly type-3 collagen to form a type of scar tissue. The problem is that type-3 collagen isn’t as strong as type-1, which leads to a recurrence or chronic tendinitis if the area is not cared for correctly. The body synthesizes collagen from the amino acids glycine, proline and lysine. Other nutrients, such as iron, copper and vitamin C, must be present as well. The first sign of a deficiency of vitamin C is often a weakness in connective tissue, including tendons, because collagen cannot be synthesized without it.
The process of synthesizing connective tissue slows with age. Tendons and other connective tissues in the body begin to dry out and lose water’recognizable as a feeling of stiffness throughout the body. The stiffness results from relatively dehydrated connective tissue as well as structural changes in the collagen and elastin. The less active a person is with age, the more apparent that effect becomes. Like muscle, tendons thrive on activity.
The water loss, which predisposes a person to injury, may be caused by a lowered level of proteoglycans, substances existing in tendon and other connective tissues that retain water. Without them the tissue dries out. Supplements containing glucosamine and chondroitin may be helpful in that instance, since they supply the raw material from which proteoglycans are made in the body. Regular use of glucosamine and chondroitin may hydrate tendons and help prevent injury.
Tendon injuries take far longer to heal than soft-tissue injuries, such as muscle sprains or strains. The difference in healing rates is related to the difference in blood supply. Muscle is richly supplied with blood, which aids and speeds healing, while tendons have a lower blood circulation’and a longer healing process. ALL Why would tendons have such a relatively poor blood circulation? They must remain under considerable tension from forces placed on muscle for an extended time. Under such high tension the structure of tendons actually changes, stretching to accommodate the even application of force. If there were plenty of blood circulating to the tendon, the stretching would lead to a squeezing effect on the blood vessels, which in turn would cut off blood flow’and oxygen’to tendon tissues, possibly leading to tissue death. The poor blood supply overcomes the problem, but it also delays the healing process.
An interesting aspect of tendon physiology is that tendons that are stiffer are stronger and show a superior level of energy-storing capacity. Stretching a tendon before you lift, however, reduces its energy-absorbing capacity’and adding more load to the tendon could result in a rupture. That’s apparent in the common injury scenarios experienced by bodybuilding trainees. A perfect example occurs during pec tears. Stretching the pectoral area just prior to attempting a heavy bench press can reduce the energy-absorbing capacity of the tendons. The force applied during a heavy bench press can exceed the capacity of the tendon to transmit the force, resulting in a pec tear, or, more precisely, a rupture of the pectoral tendon attachment.
The lesson here is that stretching a muscle before you perform heavy lifts is no way to prevent injuries. It not only weakens the target muscle but also opens up the possibility of a tendon rupture. That’s most likely to happen during the eccentric phase of a rep’or the lowering of the weight’since that’s where the most tension is placed on both muscles and tendons.
The good news is that tendons, like muscles, respond to exercise by getting thicker and stronger. Exercise promotes increased collagen synthesis in tendon, creating collagen fibers that are thicker and more efficient. Inactivity brings the reverse. Tendons show reduced collagen synthesis, with disordered and thinner collagen fibers as well as other negative structural characteristics. As with all other tissues in the body, tendons adhere to the use it or lose it principle.
Not all injuries to tendons result in an outright rupture. If the applied force exceeds the ability of a tendon to handle it, the result may be small tears. Microtears, as they’re known, are recognizable as the chronic pain of tendinitis. They can be caused by using poor biomechanical angles during an exercise or poor form. Continuing to exercise the painful area in a misguided effort to work through the pain only makes it worse and delays healing. Eventually, the inflamed area can become weak enough to rupture.
The healing response of an injured tendon involves three phases. The first is inflammation, in which inflammatory prostaglandins enter the area, along with other substances linked to pain and various types of immune cells.
People frequently respond to the pain by taking pain relievers, such as nonsteroidal anti-inflammatory drugs. At this phase of the healing process, however, that would be a mistake. Recent studies show that using pain relievers during the initial inflammatory stage of a tendon injury delays healing because the inflammatory process is required for optimal healing.1 It’s a different story at a later stage of the process, called the remodeling phase, when the body produces the various proteins that make up tendon structure.
The best treatment for the initial stage of a tendon injury is to apply ice to the area, resting the area, elevating it and applying compression. After about a week try limited movement, since that also promotes blood flow and healing. Tendon injuries can take as long as a year to heal fully, and training the area intensely before that occurs will likely lead to a recurrence of the injury.
Several recent studies have found practical solutions for some aspects of tendon injury. For example, during a tendon injury the body produces excessive amounts of free radicals, those destructive by-products of oxygen metabolism you’ve read so much about, in the injured area.2 So maintaining a high level of antioxidant protection through regular exercise and the use of dietary antioxidants that fight free radicals, such as vitamins C, E and others, may help minimize the effects of a tendon injury.
Since the initial phase of a tendon injury can be very painful, some may be tempted to ask the doctor about a corticosteroid injection in the area. While such injections do offer a potent anti-inflammatory effect, if they’re injected improperly, such as directly into a tendon, the drug will blunt the synthesis of collagen protein, weakening the tendon and possibly resulting in a future rupture. Corticosteroid injections offer nothing more than a Band-Aid effect; they don’t promote healing in any way. When the threat of anthrax as a major weapon of terrorists was in the news, many people were asking their doctors for a specific antibiotic that could prevent anthrax-related disease. Cipro is in a class of antibiotics known as fluoroquinolones that have a strange side effect not seen with other antibiotics: They appear to cause tendon damage. While that isn’t a common effect, more than 100 cases of serious tendon pathology have been reported in the medical literature, and it’s been traced to those antibiotics.
Another class of drugs that may interfere with collagen metabolism are anabolic steroids. In several published animal-based studies, using large doses of anabolic steroids appeared to interfere with efficient collagen deposition in tendons, resulting in a weakening of tendon structure. On the other hand, a study that examined tendon structure during surgical repair in human subjects who had used anabolic steroids found no structural changes in collagen that would make a person susceptible to tendon injuries.3 A recent study even showed that using a popular injectable anabolic steroid called nandrolone decanoate (Deca-Durabolin) speeded the healing of rotator cuff injuries.4
Some have speculated that bodybuilders and other athletes who use steroids are more prone to tendon injuries because their muscles become so strong that they exceed the tendons’ ability to transmit force. The problem with that theory is that tendons are far stronger than muscles. On the other hand, if the results of animal-based studies prove true with humans’that is, if anabolic steroids do weaken tendon structure’then users may indeed be predisposed to both acute and chronic tendon injuries. Currently, no such evidence exists to prove that contention.
A recent study examined the use of ultrasound physical therapy and dietary supplements in 40 people with chronic tendon injuries.5 The subjects were divided into two groups, with one group getting the actual supplements and the other getting a placebo. Both groups got 16 sessions of ultrasound treatment during the 32 days of the study.
The results? Those getting the real supplement reported a 99 percent decrease in pain score compared to a 31 percent decrease in the placebo group, while mobility increased by 53 percent in the actual supplement group vs. 11 percent in the placebo group.
The supplement that proved so effective at pain reduction consisted of a mixture of omega-3 fatty acids from fish oil, gamma-linoleic acid and various antioxidants. The idea was that the combination of supplements would reduce pain by reducing inflammation. Both fish oil fatty acids and gamma-linoleic acid, commonly found in supplements such as borage and primrose oils, decrease the level of inflammatory compounds in the body, while dietary antioxidants blunt the effects of free radicals.
Future treatments of tendon injuries will likely be far more effective than those available now. Gene therapy, for example, may be used to deliver various tendon growth factors directly into injured areas. Tendon growth factors include insulinlike growth factor 1 (IGF-1), transforming growth factor-beta, vascular endothelial growth factor, platelet-derived growth factor and basic fibroblast growth factor. They assist tendon healing by promoting enhanced collagen and elastin synthesis and greater blood flow to the area. A common observation among some athletes is that growth hormone appears to speed tendon healing. Technically, the effect isn’t due to growth hormone, but rather to GH promotion of IGF-1 release.
An injection of an experimental growth factor called cartilage-derived morphogenetic protein-2 (CDMP-2) led to a 39 percent strength increase in treated tendons after only eight days and one injection.6 No doubt such substances will revolutionize the treatment of stubborn tendon injuries in the future.
In the meantime the best way to avoid chronic tendon injuries is to use common sense. Maintain good form during all exercises, and don’t try to lift weights that are clearly too heavy for you. Most important: Don’t try to work through the pain. Pain is your body’s signal that something’s wrong, and you should heed that signal.
References
1 Virchenko, O., et al. (2004). Parecoxib impairs early tendon repair but improves later remodeling. Am J Sports Med. 32:1743-1747.
2 Bestwick, C.S., et al. (2004). Reactive oxygen species and tendinopathy: do they matter? Brit J Sports Med. 38:672-673.
3 Evans, N.A., et al. (1998). Ultrastructural analysis of ruptured tendon from anabolic steroid users. Injury. 29:769-773.
4 Triantafillopoulos, I.K., et al. (2004). Nandrolone decanoate and load increase remodeling and strength in human supraspinatus bioartifical tendons. Am J Sports Med. 32:934-43.
5 Mavrogenis, S., et al. (2004). The effect of essential fatty acids and antioxidants with physiotherapy treatment in recreational athletes with chronic tendon disorders. Physical Therapy in Sport. 5:194-99.
6 Forslund, C., et al. (2001). Tendon healing stimulated by injected CDMP-2. Med Sci Sports Exerc. 33:685-87. IM
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