Achilles Tendinopathy Explained

With February on the horizon and just 12 weeks to go before London Marathon, training intensity will be heating up with those longer distances coming to the fore. In a continuation of the running injuries segment, the aim of this blog is to consider potential issues with the achilles tendon and what we can do about them. Please don’t take this as a fully extensive teaching of the ins and outs of this injury, rather this is a snap shot with some guidance that will assist most people most of the time. For persistent issues with your achilles I advise you to go and see a clinician to help you resolve the issue.

A common injury I see this time of year, especially in runners, is Achilles Tendinopathy. The achilles is the tendon attaching your calf muscles (gastrocnemius and soleus) to the heel bone and tendinopathy basically just means that there has been some disruption to the normal state of the tendon. This condition normally manifests as pain in the middle of the tendon that may or may not be accompanied by a swollen appearance. This is a “mid-portion” tendinopathy. Sometimes the pain may be lower more towards the heel and this is called an “insertional tendinopathy”. This is an important differentiation to make as the management of each is different, the focus within this blog is on mid-portion tendinopathy management.

How do I know if I’ve got a tendinopathy?

The typical pattern is of pain initially starting after activity and settling with rest. As the condition progresses you might experience pain at the start of a run, for example, and then as the tendon “warms up” the pain eases only for it to become sore again on completion of the run. Over time you may then start to notice pain and stiffness in the tendon on getting out of bed in the morning, or the pain may be aggravated by less strenuous activity. The tendon is likely to become sore to touch as well, and if it is an insertional tendinopathy the pressure from the back of your shoe becomes very uncomfortable.

What causes it?

The most common cause is doing too much too soon at too high a frequency. Essentially, we’ve got our training progressions wrong. Or it may be that the total amount exercise you do per week has increased just by engaging in short runs. For example, if you walk 3 miles every day for your commute, then even adding 15 miles spread over three runs per week is doubling your step count. Sometimes it might be the introduction of a new activity such as a weekend away hiking on undulating terrain. Other factors to consider are your running style and broader biomechanics such as calf strength and muscle control throughout the rest of the lower limb and core.

*** KEY POINT – Tendons are made of something called Type 1 Collagen – this is prime fillet, proper pukka collagen. When you exercise above a certain threshold (specific to your fitness) you stress the tendons which causes changes within the tissue. The graphic below which was produced by Magnussen et al(1) shows that in the first 24 hours after exercise that the collagen content of a tendon changes by an increase in synthesis and degradation before reaching an overall positive net synthesis at the 72 hour mark after exercise.  It is important to understand this as training without adequate recovery times between sessions can lead to a net degradation (aka a net loss) of collagen and ultimately lead to overuse injuries such as an achilles tendinopathy. ***

What can you do about it?

Very simply you need to improve the ability of the tendon to withstand repetitive loading and stress to make it more robust and durable to the demands you are asking of it. This may be through specific strengthening exercises, it may be through altering running style, it may through addressing how much load you are putting on the achilles or it may be (and likely is) a combination of these reasons.

How do we improve the robustness? We get you stronger. Whilst there may be other contributing factors to the issue and rehabilitation may need to address additional factors such as weakness of gluteal and core muscles, a key aspect is to focus more locally on calf strength. The value of seeing a clinician for an assessment will enable you to identify all areas that need addressing.

For now, we shall look more specifically at the calf muscles. There are multiple ways to strengthen the calf muscles in terms of type of muscle contractions i.e. isometric, eccentric, concentric or plyometric. There are also many different variations of exercises too. But the good news is, as one study(2) showed, long term outcomes between exercise types were similar. In this study they compared eccentric training (heel drops off a step) and slow heavy resistance training (heel raises with additional weight like a barbell). The biggest difference was the frequency of exercise participation. Eccentric heel drops were performed daily whereas slow heavy resistance training was performed just three times a week. This means that really, as long as we are loading (exercising) the tendon in an appropriate manner then things will improve. It also offers guidance on ways to fit rehabilitation into your already hectic schedule.

A note of caution though – calf stretches are not recommended, particularly in the acute phase of the problem, as stretching causes compression to the tendon which may elevate pain levels.

So how should you rehab? I recommend training in a variety of ways in order to expose the tendon to a different type of stress and strain and improve its robustness in multiple ways. Initially its important to exercise in a manner in which we are encouraging pain levels to settle and so exercise prescription should be quite specific to the individual and their pain levels. Too much loading and the tendon may deteriorate, too little loading and the tendon doesn’t get stimulated enough to strengthen. It’s your classic Goldilocks situation!

The graphic below from Mascaro’s work(3) shows how you might progress your rehab plan as the tendon adapts.

For some examples of exercises that can be used as either general calf conditioning or for rehabilitation purposes exercises click here. These are just a small selection of exercises and by no means exhaustive.

Additional considerations

Using a heel raise in your shoe can help to take some stretch off the achilles tendon when you are walking in the early phase of the problem to help assist pain relief. Taping may be used, although this remains a contentious area over its true value.

*** KEY POINT *** You should not stop exercising entirely for more than a few days (pain depending). Absolute rest is actually considered a contraindication now. There is a difference between adjusting the amount of running or exercise that you do and stopping completely. Sometimes you may need to focus on calf strengthening for a short period but remember, you need to load the tendon to get it better, and keeping you doing the things that you enjoy should be a part of that.

As mentioned, achilles tendinopathy is an in-depth topic and this blog was designed to consider the basics in relation to cause and understanding of the problem. It is always advisable to seek the guidance of a clinician in order to have an accurate diagnosis and to be guided through rehabilitation. However, by including calf conditioning work in your routine you may be able to negate it happening at all!

Happy training.


  1. Magnusson SP, Langberg H, Kjaer M. The pathogenesis of tendinopathy: balancing the response to loading. Nat Rev Rheumatol. 6. United States2010. p. 262-8.
  2. Beyer R, Kongsgaard M, Hougs Kjaer B, Ohlenschlaeger T, Kjaer M, Magnusson SP. Heavy Slow Resistance Versus Eccentric Training as Treatment for Achilles Tendinopathy: A Randomized Controlled Trial. Am J Sports Med. 2015;43(7):1704-11.
  3. Mascaró Vilella A, Cos MÁ, Morral Fernández A, Roig Tomás A, Purdam C, Cook JL. Load management in tendinopathy: Clinical progression for Achilles and patellar tendinopathy. Apunts: Medicina de l’esport, ISSN-e 1886-6581, ISSN 0213-3717, Vol 53, Nº 197, 2018, págs 19-27. 2018.