Why does my Achilles tendon hurt?

The Achilles tendon is the largest and strongest tendon in the human body. So why does it cause so many problems? The most common cause of Achilles pain is a condition called Achilles tendinopathy. Here we’ll discuss the common causes and ideas for treatment.

What is Achilles tendinopathy?

The Achilles tendon is situated at the back of your foot, and connects the lower section of your calf muscle to your heel bone.

Achilles tendinopathy is an overuse injury of the Achilles tendon. When it is loaded (with running, walking, jumping etc), the tendon develops microscopic tears, which leads to temporary weakness. These can take time to repair, but as they do, the tendon becomes stronger.

Achilles tendonitis by Injury Map is licensed under CC BY 4.0.

However, if you continue with the loading activity during this process (e.g. more running), the tendon is unable to repair itself and begins to wear down. This is know as tendinopathy.

You may have heard of the term “tendinitis”, but the name has changed in recent years. The reason for the change to “tendinopathy” is research now suggests that there is minimal inflammation involved in the condition (itis = inflammation). We have more information on the tendinitis discussion in our tennis/golfers elbow blog.

Stages of tendinopathy

Tendinopathy can be divided into stages. At first, you have a reactive tendinopathy, where the tendon has a “reactive response” to overload, and becomes stiffer to help it withstand load more effectively.

Think about spaghetti. A tendon with reactive tendinopathy would be like uncooked spaghetti. Most of the time the fibres within the tendon are still aligned but the tendon becomes stiffer in response to the load.

This is usually an acute condition (has been present for 6 weeks or less) and is more common in younger people.

As the problem develops, it becomes a degenerative tendinopathy. These tend to be present for 3 months or longer (a chronic condition), and often can be slow, grumbling injuries that gradually worsen with time. In degenerative tendinopathy, the tendons structure has changed. Often they can become thicker and nodules form along the tendon.

In our spaghetti example, think about cooking the spaghetti and then throwing it on the ground. The fibres of the tendon are no longer aligned and so there is a lot less strength in the tendon.

There are different approaches in treatment for the different stages of the tendinopathy. We will discuss reactive tendinopathy here. We cover degenerative achilles tendinopathy in another blog.

What causes Achilles tendinopathy?

The main cause of Achilles tendinopathy is repetitive strain. This usually comes about as a result of sports like running, tennis or badminton. Hill walking or running also puts extra strain on the Achilles tendon.

Running puts an enormous strain on your Achilles tendon.

It has been suggested that on average, between 6-12 times your body weight will transfer through your Achilles tendon with each stride when running!

The human body is AMAZING and can deal with this, but it is important to factor in a period of rest to allow the tendon to recover and adapt to the load you are putting through it.

People who have recently taken up running or have increased their weekly distance or speed rapidly are at risk of Achilles tendinopathy. If you do not factor in time to rest, the tendon does not have time to heal and repair and so you complete runs on a weakened tendon, leading to further injury. Have a look at our previous blog for more information on reducing the risk of injury when running.

What to do about reactive Achilles tendinopathy

Reactive (or acute tendinopathy) is the first stage of tendon injury. The Achilles tendon becomes painful and sometimes swelling is present. Often this can feel more painful and stiff first thing in the morning as you put your foot to the ground. It is important to treat this early, so the tendon damage does not continue and progress to degenerative Achilles tendinopathy.

Step 1: Reduce the load

It’s important to reduce the load on the Achilles to a level that the tendon can manage. Some people with more mild cases are able to continue running with this injury, but may need to considerably reduce the distance or speed of their runs. If this is you, make sure you are only running whilst the Achilles is pain free and stop if you get any pain during the run, or within 24 hours afterwards.

If you are unable to run without pain, then STOP. Continue with walking as your pain allows you to and give the tendon chance to heal and repair. Sometimes in as little as a week you may notice your symptoms start to settle.

Some people benefit from using gel heel cups to reduce the load on the Achilles tendon. We found a great set from Cosyinsofa - see the link to buy from Amazon.

*This is the equipment that we use and recommend fully. You won’t pay a penny more, but First Line Physio will earn a small commission if you purchase the equipment following this link. This contributes to the running costs of the blog.**

Alternatively, speak to your physiotherapist about taping methods for your Achilles. Both of these options can change the forces going through the tendon and may allow you to continue running.

Step 2: Reduce the pain

Ice is helpful to reduce pain in reactive Achilles tendinopathy. Use a bag of frozen peas wrapped in a damp tea towel and apply to the area for up to 10 minutes. You can do this several times a day if it helps. Our previous blog post on ice has more information about how and when to apply it.

It’s important to avoid stretching exercises in the reactive phase, as this increases compression on the tendon. The gel heel cups mentioned above can help to reduce stretching forces through the Achilles as well as reducing the load.

Step 3: Improve tendon strength

It can be helpful to work on gentle exercises to help strengthen the tendon. Controlled load helps to stimulate the tendon’s healing process. Completing isometric exercises (where the muscle is under tension without movement) is a great starting point.

Isometric heel raises

Standing with both feet on the floor.

Hold onto the back of a chair/kitchen side/a wall for balance if you need to.

Slowly come up onto your toes. Do not go all of way up, but stop halfway between the floor and the highest point you feel able to go.

Hold the halfway position for 10 seconds.

Repeat 10 times.

These exercises should not be painful at all. If you find that they aggravate your symptoms, try putting more weight through the uninjured leg to reduce some of the load on your injured Achilles. You may also want to try this exercise in sitting if your symptoms are really irritable.

Symptoms tend to improve between 1-6 weeks with reactive Achilles tendinopathy. It’s important to return to training gradually once your symptoms have settled. The tendon can be very sensitive to increases in load, and can become reactive if training is progressed too quickly. Speak to your physiotherapist about the best ways to do this and make sure you are honest with them (and yourself!) about how much you are doing.

If you find that your Achilles begins to hurt again, reduce the amount of training for a couple of weeks and ease back into it gently. It may seem frustrating, but it’s much less frustrating than developing a chronic tendinopathy, which can take months to recover!

This is absolutely not written to substitute medical advice and it is always important to see a qualified health care professional for a formal diagnosis. If the exercise cause pain during or after completion, discontinue and consult a physiotherapist.

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