Tendons are very strong, but not very flexible, and the Achilles tendon is no exception. This means that the Achilles tendon can only stretch so far before it becomes inflamed (known as tendonitis) or tears.
What Is an Achilles Tendon?
The Achilles tendon is the largest tendon in the body. It joins the gastrocnemius (calf) and the soleus muscles of the lower leg to the heel bone of the foot. Causes
It's important to become acquainted with the different conditions that affect the Achilles tendon, considering they require unique attention and therapy, some more urgent than others.
The two most common causes of Achilles tendon pain are Achilles tendonitis and Achilles tendonosis.1 While these conditions sound similar, they describe unique phenomenons—one more acute and the other more chronic.
Achilles tendonitis is an acute, inflammatory injury of the Achilles tendon that most commonly affects athletes, especially runners, or people who play sports that require lots of starting and stopping, such as tennis.
The prominent symptom of Achilles tendonitis is pain, often described as burning, that worsens with activity.2 The location of the pain may vary—it can be felt closer to the bottom of the calf muscle, along the actual tendon, or lower down near the heel bone.
Along with pain, there may be mild swelling and warmth over the Achilles tendon, as well as morning stiffness in both the heel and calf that eases as a person warms up and stretches their ankle and leg.2
Besides active individuals or those who suddenly begin or increase an exercise regimen, failing to warm up the calf muscles before exercising is another potential trigger for the development of Achilles tendonitis. The tighter the calf muscles, the more tension that's placed on the Achilles tendon.
Exercising in sneakers that are worn-out or are not meant to be used for aerobic exercise can also cause Achilles tendonitis, as can these other factors:
Cold weather training
Foot misalignment or flat fleet
Poor running form
Leg length discrepancy
Another cause of Achilles tendonitis is the development of a bony growth on the back of the ankle—either a bone spur from arthritis or a Haglund's deformity from wearing poor-fitting shoes.3 The bony growth may rub on the Achilles tendon and cause pain and inflammation.
Having a medical condition like psoriasis, high blood pressure, and obesity (which puts pressure on the tendon) has also been linked to a higher risk for developing Achilles tendonitis.4
Rarely, a class of antibiotic drugs called fluoroquinolones has been associated with Achilles tendonitis and rupture (described below).
Unlike Achilles tendonitis, which describes an acutely inflamed tendon, Achilles tendonosis describes a chronic, degenerating tendon that results from untreated tendonitis. With Achilles tendonosis, the collagen fibers that make up the tendon deteriorate or break down. This deterioration causes not only pain in the tendon but also the formation of scar tissue, which may lead to permanent thickening.5
The tricky part is that while the inflammation of Achilles tendonitis can ease up with proper treatment and heal well, some cases are not accompanied by pain—so a person does not actually know there is a problem until tendonosis has developed (where there is always pain).
Achilles tendon rupture, when the tendon fibers tear and separate, either partially or completely, is rare.
Achilles Tendon Rupture
In order for the Achilles tendon to rupture, a sudden force is usually exerted on the tendon, often occurring during a strenuous form of exercise that requires sudden pivoting of the foot, as in playing basketball. That said, even a trip where your foot is used to break a fall or a sudden step off a curb can sometimes be enough to overstretch and tear the tendon.
When the Achilles tendon does rupture, along with severe heel pain, some people hear a "pop" or "snap," and there may be a visible gap where the tendon is torn.6 Usually, with a tendon rupture, a person cannot walk or bear weight on their foot, although a small subset of people still can.
When to See a Doctor
It's important to seek out medical attention if you develop pain in the back of your leg, anywhere from your heel to your calf. Other symptoms that warrant a doctor's visit include:
Leg or ankle stiffness or soreness
Swelling over the Achilles tendon
Difficulty standing on your tiptoes
Signs of an infection like redness or warmth around the ankle or leg
If you develop symptoms suggestive of a possible Achilles tendon rupture, such as sudden, severe pain at the back of the leg and/or trouble bearing weight on a leg, seek immediate medical attention.
The diagnosis of Achilles tendon pain is generally done clinically, meaning your doctor will ask you questions about your pain and perform a physical examination. If a rupture is suspected, imaging with magnetic resonance imaging (MRI) or ultrasound is warranted.
A thorough physical exam of your foot and ankle is perhaps the key to diagnosing the culprit behind your Achilles tendon pain.
Some prime elements of the physical examination include inspecting and palpating (pressing on) the area around the Achilles tendon for swelling, warmth, crepitus (popping sensation), and tenderness; all of these features may be present with acute Achilles tendonitis. With Achilles tendonosis, besides tendon pain with palpation, the tendon may feel thick or there may be small bumps along the tendon, signifying areas of scar tissue and fibrosis.
A doctor can sometimes diagnose an Achilles tendon rupture by palpating the tendon. Another physical exam clue for an Achilles tendon rupture is bruising over the tendon, especially if the blood tracks beneath the malleolus (the bone that projects out on each ankle).
As part of the physical exam for Achilles tendon pain, your doctor will perform the Thompson test, also called the calf squeeze test. During this test, a person lies flat on the exam table with his or her feet hanging over the edge. The doctor will then squeeze on the calf muscle, which should flex the toes downward (called plantar flexion). If this does not occur, the test is positive for an Achilles tendon rupture.
Chronic Achilles tendon symptoms would generally be investigated with an x-ray of the foot, which can identify issues like bone spurs or degeneration.
An ultrasound or an MRI is used to make or confirm a diagnosis of an Achilles tendon rupture.
When you see your doctor for Achilles tendon pain, your doctor will consider several other conditions. Some of the more common conditions include an ankle sprain, stress fracture, or heel bursitis (called calcaneal bursitis).
Bruising around the Achilles tendon may be seen with an ankle sprain or a stress fracture, as well as an Achilles tendon rupture, so an X-ray is needed to distinguish among these conditions. With calcaneal bursitis, there is usually palpable tenderness where the tendon inserts into the heel bone. On the other hand, with Achilles tendonitis, the tendon pain is usually higher up— about two to six centimeters above the insertion site.
Other conditions that may be considered include:
Inflammatory arthritis (for example, rheumatoid arthritis or gout)
Blood clot in the calf (called deep venous thrombosis)
Infection (for example, osteomyelitis or cellulitis)
Bone cyst or cancer (rare)
In these above instances, along with a thorough physical exam, blood tests or imaging tests, like an ultrasound or X-ray, may be used to confirm a diagnosis.
For example, a Doppler ultrasound can rule out a blood clot in the calf, and an X-ray can reveal classic osteoarthritis changes in the ankle.
Likewise, with rheumatoid arthritis, a person will usually have an elevated anti-cyclic citrullinated peptide (anti-CCP) blood level, along with other symptoms of RA like fatigue and joint pain.7
If a doctor is worried about an infection in the heel bone or in the skin near the tendon, identification of inflammatory markers (for example, erythrocyte sedimentation rate) and/or an elevated white blood cell count is helpful.
There are numerous treatments involved with treating Achilles tendon pain, including activity modification, medication, physical therapy, and possibly, surgery.1 The key to healing and recovering well is to keep on top of your care and follow your therapy regimen from start to finish.
Self-care strategies can be utilized to treat Achilles tendonitis and be helpful in the immediate care of a possible Achilles tendon rupture.
Reduce Activity or Rest
If you are diagnosed with Achilles tendonitis, it is not necessary to stop activity completely, as long as you pay attention to muscle soreness and reduce activity accordingly. Be sure to begin gentle calf stretching after exercise when the muscle and tendon are still warm and flexible.
For the initial care of an Achilles tendon rupture, rest is imperative, until you receive further guidance from an orthopedic surgeon.
For Achilles tendonitis, ice during the initial onset of pain, along with post-exercise ice may be helpful.
For a suspected rupture, be sure to place ice immediately on the tendon and elevate your leg on route to the emergency room.
Besides reducing activity and ice, keeping your tendon from moving around too much by wrapping your ankle with an elastic bandage or tape is important if you have Achilles tendonitis.
Likewise, an orthopedic surgeon will immobilize your ankle, often with a splint, until you undergo surgery for an Achilles tendon rupture.
For Achilles tendonitis and tendonosis, shoe orthotics can be used to correct foot misalignments (if, for example, flat feet, are believed to be causing or contributing to Achilles tendon pain). For anyone with Achilles tendonitis or tendonosis, heel lift orthotics can unload stress on the tendon and ease pain.
To reduce the pain from any Achilles tendon problem, talk to your doctor about taking a nonsteroidal anti-inflammatory (NSAID).
While a common misconception, corticosteroid injections are not recommended for Achilles tendon pain.5
For Achilles tendonitis, once your doctor thinks you are ready, it's a good idea to begin exercises that strengthen the calf muscle. Toe raises, balancing on your toes, and wall stretching are useful exercises. Eccentric strength training is also a popular and beneficial therapy option, as is deep friction massage of the gastrocnemius and soleus muscle, both of which attach to the Achilles tendon.
If you develop Achilles tendonosis, it's important to talk with your doctor about being referred to a special rehabilitation program that focuses on a slow, progressive heavy load exercise regimen.
Instrument-assisted soft tissue mobilization (IASTM) is an interesting modality sometimes used in the treatment of Achilles tendonosis. This therapy works by using an instrument to re-stimulate the body's inflammatory process, which then triggers the formation of new collagen within the tendon.8
With regards to an Achilles tendon rupture, surgery might be necessary, and physical therapy is absolutely critical for a full recovery thereafter, which can take three to six months.5
An Achilles tendon rupture sometimes requires surgical repair by an orthopedic surgeon within days of the injury.9 During surgery, the two ends of the separated tendon are sutured together.
Keep in mind, an Achilles partial tendon tear is sometimes treated like Achilles tendonosis (conservatively and nonsurgically). An orthopedic surgeon will make this decision, which depends on a number of factors, like the severity of the tear, your age, your medical history, and your normal level of activity.
Partial tendon tears tend to be particularly painful. So, if surgery is not performed, immobilization in a controlled ankle motion boot is sometimes recommended, along with physical therapy or home exercises to prevent loss of muscle strength in the foot and ankle.
The biggest cause of Achilles tendon problems is ignoring early warning signs and pushing through the pain. With that, if your Achilles's tendon is sore or aches, you need to pay attention and rest it immediately.
Moreover, stretching before you exercise is important for preventing an Achilles tendon injury. Some basic stretches include the following:
Achilles tendon stretch
Plantar fascia stretch (Maintaining some flexibility along the bottom of the foot, can also improve Achilles tendon health.)
Besides stretching, be sure you begin exercising slowly and then ramp up your pace—in other words, allow for a proper warm-up.
Some experts also believe that eccentric strengthening of the Achilles tendon, gastrocnemius, and soleus muscles may reduce the risk of Achilles tendonitis and calf strain.5
Other tips that may help prevent an Achilles tendinitis include:
Always wear shoes that provide adequate cushioning for your heel and good arch support
Avoid running on hard surfaces
Avoid exercising outside in cold weather
A Word From Verywell
If you or a loved one is experiencing Achilles tendon pain, know that you are not alone—it's a common condition, albeit a frustrating one to deal with. The good news is that with proper treatment, the vast majority of people get better. Even if your condition becomes chronic, a good rehabilitation program should be able to get you back on track.