What are tendinopathies?

People running at the 2007 20 kilometer road r...

Tendinopathy is the scientific name for chronic tendon disorder. In this post we will explain the basic science behind tendinopathies, and why they are so difficult to treat. As always, an understanding of what is happening will help you to manage them better.

Tendinopathies are extremely common, especially between athletic people. They are characterised by pain during activity, local tenderness and loss of strength and movement. As they can stop a sporting career in its tracks, or force you to change sports, it is important that you take them seriously. They can occur in almost any tendon. Examples include chronic Achilles tendinitis and patellar tendinitis (jumper’s knee), but as inflammation is not the main problem, tendinitis is a misnomer.

The right amount of exercise

Tendons consist mainly of collagen bundles and tenocytes. The latter are cells that respond to mechanical loading by forming new collagen fibres to replace the old and injured ones. To keep your tendons healthy you have therefore to load your tendons enough to stimulate your tenocytes. This explains why adequate training makes your tendons stronger, and why the right amount of mechanical loading will improve the healing of acute tendon injuries.

Overuse and micro trauma

Scientists are still struggling to understand what exactly happens when a tendinopathy develops. As yet, most of them think that due to overuse and micro trauma the tenocytes lose their ability to produce quality collagen fibres. The new fibres are inadequate, disorganised and slack, and loading them mechanically does not stimulate the tenocytes anymore. In a further attempt to repair the tendon, new blood vessels are formed and infiltrate the lesion. Nerves typically accompany these new vessels, and only now the tendon becomes painful.

The whole process corresponds therefore to a failed healing response and degeneration, and pain only develops at the end. Furthermore, as a tendon can degenerate without pain, it can rupture without any warning signs.

How can I treat a tendinopathy?

Patients are offered many different treatments, but, except for eccentric exercise training, there is not much evidence for any of them. That does not mean that they are useless, it only means that we need more research.

Non steroidal anti-inflammatory drugs (NSAID) might reduce the pain a little in the beginning, but they are not helpful and are therefore best avoided.

Eccentric exercise treatment

In 1998, Alfredson and colleagues introduced eccentric exercise training to treat chronic Achilles tendinitis, and since then the technique has been used for other tendinopathies as well.

An eccentric contraction is an action whereby the muscle contracts and lengthens at the same time. If you stand with the ball of your foot on a stair and lower your heel, you contract your calf muscles eccentrically, and when you come down the stairs you do the same with your quadriceps muscles.The Achilles' tendon. PD image from Gray's Ana...

Alfredson showed that performing eccentric exercises on a daily basis for 12 weeks reduced the pain of chronic mid-tendon Achilles tendinopathy in 90% of the cases. The patients performed sets of 15 repetitions twice a day, building up to 180 repetitions a day. When the movement became pain free, they started doing the exercises carrying weights in a backpack. Alfredson advised to work trough pain unless it was severe, and to use his regimen together with other physiotherapy techniques, such as relative rest, massage, ultrasound… After 12 weeks, most of his patients could return to their previous activity levels, even though they had to continue with a maintenance treatment.

It is not completely clear how eccentric exercise training works. Researchers have noticed that during eccentric contractions the forces in the tendon tend to fluctuate. These fluctuations could be an important stimulus for the tenocytes to produce collagen and to remodel the tendon. If this is correct, the number of contractions and the speed at which you perform them will be more important than adding weight.

Will I get rid of it?

After successful treatment, most people continue to feel some mild pain, even though they can return to their previous sport activities.

Even if the pain has completely gone, you will be at a high risk of recurrence, as the tendon can still be degenerated even if it is not painful anymore. You will therefore have to “manage” your tendon, by making sure that you give it enough time to recover after hard workouts, and that you keep doing maintenance exercises. You will continue to improve over time.

Disclaimer: this article is for general information only, and does not replace medical advice. It cannot be used to diagnose, or guide treatment or prevention. If you have any concerns or questions, you should talk to a qualified health provider.


H Alfredson and J Cook. A treatment algorithm for managing Achilles tendinopathy: new treatment options. Br J Sports Med. 2007; 41(4): 211–216.

K Gravare Sibernagel, R Thomee, B Erikson and J Karlsson.  Full symptomatic recovery does not ensure full recovery of muscle‐tendon function in patients with Achilles tendinopathy. Br J Sports Med. 2007; 41(4): 276–280.

J  Rees, G Lichtwark, R Wolman and A Wilson. The mechanism for efficacy of eccentric loading in Achilles tendon injury; an in vivo study in humans. Rheumatology. 2008; 47 (10): 1493-1497.

A Scott, E Huisman and K Khan. Conservative treatment of chronic Achilles tendinopathy. CMAJ. 2011; 183(10): 1159-1165.

Y Xu and G Murell. The basic science of tendinopathy. Clin Orthop Relat Res. 2008; 466(7): 1528-1538.


6 thoughts on “What are tendinopathies?

  1. This has encouraged me to get back to my PT exercises for my achilles tendinitis – it gives me hope that I can get rid of that last, lingering stiffness!

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