Achilles Tendon Injury: Avoiding an 'Achilles Heel'

According to ancient Greek mythology, Achilles, the warrior, was dipped by his mother in the magic waters of the river Styx to make him immortal. However, she held him by the heel, which remained dry. The legend says this left the area vulnerable. Subsequently, he was killed in the Trojan War when Paris shot an arrow into Achilles’s heel. But his name lived on, as the tendon that attaches your calf muscle to the heel bone (calcaneus) was later named for him. In running and many other sports, this area can be just as susceptible as it was for Achilles. This article will explain why the achilles tendon is one of the most commonly injured tendons, how to recognize early signs of injury, and what the proper treatment is.

The muscles to which the achilles tendon attaches are the gastrocnemius and soleus. When these muscles contract during the running stride, they function as plantar flexors (downward motion of the foot), which gives us propulsion forward. When they stretch during the running stride, these muscles help in absorbing the impact of landing as the foot comes towards the knee. Also, since the gastrocnemius crosses the knee joint, when it contracts it helps in flexing your knee during the stride. The forces these muscles generate will affect and be affected by the health of your achilles tendon.

With the above anatomy and biomechanical information in mind, it is easy to see why the achilles is often injured. Common injuries are partial or complete rupture and tendinosis (scar tissue development). Until recently, overuse injuries to tendons such as the achilles were thought to involve inflammation. However, research has shown that there are no inflammatory cells present in most injured tendons. Instead, there are fibroblast cells, which form “scar tissue.” This scar tissue forms when the stress placed on the tendon is too great, causing degenerative microtears. Although the tears are “healed” with this new scar tissue, it is, unfortunately, not as flexible or resilient as the original tissue. Additionally, the most common area of injury to the tendon is about 2 cm above its attachment at the heel. It is thought that this area has less circulation and therefore is prone to the mircrotears.

Injury to the Achilles tendon can either happen suddenly, as in a rupture,or can occur gradually, as with tendinosis, which is the usual case in running. In the sudden injury scenario, recreational athletes often injure an already tightened or weakened calf when it is suddenly stretched or contracted past its normal limits, causing the tear. Although tears can occur in endurance athletes, the common scenario for a tear is a middle-aged person who has gradually lost flexibility and developed adhesions in the calf muscles and around the tendon, probably from years of sitting without regular stretching, and who goes out and plays tennis or softball for the first time in months or years. He or she then stresses muscles and tendon past their current limits, and a tear occurs. So even though the injury may seem sudden, the predisposing factor of decreased calf flexibility was probably present for some time. Likewise, in running and other endurance sports, a loss of calf flexibility and calf muscle/tendon adhesions are also to blame for cases of tendinosis.

To prevent overuse injury to the achilles, addressing the factors leading to tightness and possible scar tissue formation is necessary. Muscle tightness can be a major factor, and two areas are often the culprit: one is the calf, or back of the leg, as mentioned above, and the other is the adductor, or inner thigh muscles. Regular stretching and strengthening of these muscles (exercises described below) will help preserve normal foot motion and prevent overpronation. This is important to prevent, because overpronation, which is the ankle bone “rolling inward” at a greater than normal amount or speed, can overstretch the achilles. Overstretching causes the tendonosis by stressing the tendon and causing the tendon microtears and adhesions (the scar tissue). Tight calf muscles can cause a compensatory overpronation, to make up for the lack of leg bend at the ankle by flattening the arch more than normal. Likewise, tightness in the adductors can lead to the thigh moving inward while running, which then can cause our foot to turn outward, pronating excessively to compensate and keep us moving forward.Overpronation can also exist without any muscle tightness or imbalances, and lead to injury in the same way. Orthotics will correct the overpronation. Calf weakness can also be a factor, as lack of strength will cause overstretching of the achilles. Finally, training errors, such as doing too much speedwork or rapidly increasing training volume, can be causative. So can wearing worn out shoes, which can cause overstretching and tightness which will lead to injury. Unfortunately, often a runner often will only learn about these preventative measures once injured. The good news is that with proper treatment, even the worst cases can be resolved; however the earlier treatment starts, the better.

The type of treatment needed will depend on the stage of the injury. Depending on the severity of injury when treatment is initiated, at least one and as many as three weeks off from running are usually necessary. In the earlier stages of achilles injury, there is usually calf muscle and achilles tightness which causes tightness and pain with either contraction (push off) or stretching. This tightness must be addressed by techniques such as Active Release Technique, which reduces the muscle adhesions and increases flexibility. This reduces stress on the tendon, and often soreness there will decrease without direct treatment of the tendon. If the injury has progressed to swelling around the tendon, ice massage and electrical stimulation will help decrease the edema. This swelling is often felt as a “creaking” feeling when holding the tendon lightly and bending the foot up and down. Or, if the injury involves scar tissue formation, as in the athlete with a history of repeated episodes, cross-friction massage will be needed. Cross-friction works to increase the elasticity of the tendon by “breaking up” the scar tissue and restoring flexibility. Also, if there is restriction in motion of the ankle joint, manipulation of the ankle can help relieve stress on the Achilles. In this acute stage, taping for support and using heel lifts (in both shoes) to decrease stretch on the tendon will speed healing. All of these measures should greatly reduce the severity of the injury within three to six treatments, in most cases.

Once the acute pain stage is over—which means there is only mild to moderate tenderness over the tendon and no more pain on push off—the other factors named above must be addressed. This includes Active Release of any muscle tightness further up from the injury, such as in the adductors. The whole “kinetic chain”, from the leg to the hips, lower back, and even upper back, should be evaluated by analysis of the running form and treatment should address the imbalances found. Orthotics should be prescribed if overpronation is found, and worn-out shoes should be replaced. Stretching should be done the “active” way, by using a towel or stretching cord and contracting the muscles which oppose the calf. While seated with the legs out in front of you, actively contract the muscles in the front of your leg while using the towel or rope to assist near the end of the stretch. Hold for two to three seconds and repeat five to ten times. No pain should be felt at the tendon with these stretches. Stretches for the adductors or any other tight muscles, of course, should also be done. Strengthening exercises should include calf raises, with emphasis on the lowering, or “negative” part of the exercise. Standing on a step, raise up on the toes with both legs, and then lower slowly using a count of five to ten seconds. Repeat for ten repetitions and work up to three sets, after which weights can be added by using a calf-raise machine. Although it is doubtful that these guidelines could have saved the warrior Achilles, they could help save your running.