Achilles tendonitis: Causes, treatment, and prevention

Anatomy

The Achilles tendon is the thick white tendon that attaches your calf muscles (gastrocnemius and soleus) to the back of your heel bone. It acts like a spring that propels you forward when you walk, run, or jump.

It’s made up of thousands of collagen fibers, all tightly packed in parallel. It’s this parallel arrangement that gives the tendon its strength. When you develop Achilles tendinopathy or tendonitis, a part of the tendon is injured and the collagen fibers in that area becomes disorganized, causing it to lose some of its strength. You may even notice a bump in the tendon. You can read more about what happens in the tendon and how it heals in this article.

What’s the difference between Achilles tendonitis and tendinopathy?

There is no difference. These are all names that are used to describe the same condition.

Medical names that end in “itis” usually indicate that the condition is caused by inflammation. However, research has shown that inflammation doesn’t actually play a big part in ongoing tendon pain and therefor some researchers feel that calling it a tendonitis isn’t accurate and that it should rather be called a tendinopathy. We’ll be using both terms throughout the articles.

What causes Achilles tendonitis?

Achilles tendonitis or tendinopathy is an overuse injury. It most commonly develops slowly, over time, when you don’t allow your tendon enough recovery time between training sessions. However, it can also develop due to a sudden overload e.g. if you do a training session or race that is much harder than what you’re used to (more hilly or faster or further).

Switching from wearing shoes with a heel to suddenly wearing flat shoes (either for walking or running) can also cause the Achilles to overload.

How to diagnose Achilles tendonitis

When you have Achilles tendonitis/tendinopathy, you’ll feel the pain either in the middle of the tendon (mid-portion Achilles tendinopathy) or where the tendon attaches to the heel bone (insertional Achilles tendinopathy). It’s important to distinguish between these two areas because the treatment for them is slightly different.

Typically the pain comes on gradually and initially you may just notice a bit of discomfort in your Achilles at the start of a training session which then goes away as you warm up. However, the pain and stiffness usually return several hours after your session. It can feel especially stiff and uncomfortable first thing in the morning and walking down stairs may be a challenge.

If you continue to train on an injured tendon, the pain may increase to a point where it stops you from training and even hurts to just walk.

Achilles tendonitis treatment

When your tendon is injured, it doesn’t have enough strength to cope with all the sports and activities you want to do. Research has shown that the most effective treatment for Achilles tendonitis/tendinopathy consists of relative rest combined with a progressive strength training program.

Relative rest

You don’t have to rest your tendon completely. In fact, it may feel worse if you don’t move it at all. Relative rest means that you just reduce your activities (walking, running, jumping etc.) to a level that does not aggravate your tendon.

By how much you have to reduce your activities will depend on the extent of your injury. Some people may be able to continue doing some running, but just at a slower speed and less often, while others will have to replace running with lower impact activities like walking or cycling.

Strength training

Your tendon can only rebuild and fully regain its strength if you follow a progressive strength training program. A typical rehab plan starts with low load, easy exercises and, as your tendon grows stronger, progresses to include high load and complex exercises like plyometrics. The Achilles tendonitis/tendinopathy treatment plan in the Exakt Health app guides you through this process and helps you progress the exercise intensity at the right time.

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The exercises that you do for mid-portion Achilles tendinopathy are slightly different from what you should do when you have insertional Achilles tendinopathy. We’ll discussed this in a lot more detail in future blog posts.

Calf/Achilles stretches

There’s a common misconception that tight calves are part of what causes Achilles tendonitis and doctors and physios often prescribe calf stretches as part of the treatment. However, this advice is outdated and doing calf/Achilles stretches for Achilles tendonitis can often make the pain worse.

Anti-inflammatory medication

Anti-inflammatory medication (like ibuprofen and naproxen) usually doesn’t help much for tendon pain and recent research has shown that it may even interfere with healing so it’s best not to use it when you have tendonitis. Please speak to your doctor before you change any medication.

Ice

Ice can be useful to reduce pain, but it doesn’t actually make this injury heal any faster. Apply it intermittently if you feel you need it, but there’s not need to ice your tendon on a regular basis.

Massage

Massage may be useful to temporarily reduce pain and tightness in your calf, but it does not speed up the healing process. It is only strength training that can restore your tendon’s strength. Strong massage on the injured part of the tendon can often make it hurt more, so be gentle.

How long does Achilles tendonitis take to heal?

Tendons take a very long time to heal. You can significantly reduce your healing time by seeking the correct treatment as soon as possible. As a rough guide you can expect that:

How to prevent Achilles tendonitis

As I mentioned earlier, Achilles tendonitis/tendinopathy is an overuse injury. It’s therefore no surprise that the top 3 prevention tips all relate to training errors:

1. Avoid sudden increases in running intensity or volume. The current guidelines suggest that a 10% week-on-week increase is the way to go.
2. Allow enough recovery time (at least 48 hours) after intense training sessions.
3. Vary your training intensity – don’t go to the limit in every session.
4. Do regular strength training for your calves, core, and legs in general. This will reduce the load on the Achilles tendon.
5. When changing from a high heel-toe drop to a more minimalist flat shoe, transition slowly to allow your Achilles and calves to adapt.