Updated: Jun 1
Achilles Tendonitis/Tendinopathy Exercise Series:
Isometric exercises for Achilles tendinopathy – How they work and when to use them (this article)
In this article, we discuss how isometric exercises (a muscle contraction held for a while without movement) can help kick-start your Achilles tendonitis rehabilitation process, especially if your tendon is very irritable. Remember, if you need more help with an Achilles injury, you're welcome to consult one of our team via video call.
The terms tendinitis, tendonitis, tendinosis, and tendinopathy mean the same thing for all practical purposes, and we use these interchangeably in our articles.
In this article:
Ali also discusses isometric exercises in this video:
What are isometric exercises?
Isometric exercises mean a hold or a static contraction (no movement). As you are reading this, tense your buttocks as hard as you can – this is an isometric contraction. Your muscles contract, but your body does not move.
For the Achilles tendon and calf muscles, an isometric exercise would be raising up on your toes and then just holding that position.
What are the benefits of isometric exercises for an injured tendon?
Isometric exercises are often included in tendon rehab because they are thought to:
Help reduce tendon pain.
Help to strengthen the injured tendon.
But do they work? What does the research tell us?
Can isometric exercises reduce Achilles tendon pain?
Well, the jury is still out on this one.
There is a piece of research that got everyone thinking, and it seemed to prove that if people do isometric exercises for the muscles related to their tendinopathy, this can cause pain relief. This research was specifically done on the knee for patellar tendinopathy.
Recently, researchers have tried to replicate this study and have looked at isometrics for pain relief for a variety of tendon problems all over the body, including the Achilles. The outcome from all of these studies showed that isometrics exercises are no better than exercise with movement (isotonics) for reducing pain in tendinopathy. Whilst they helped for some patients, they had no effect for others, and sometimes they even increased pain. Not so helpful after all.
The key is to remember that this is a longstanding condition that takes a few months to resolve, and this is just the starting point. For Achilles tendinopathy, rehabilitation success should not be measured in immediate pain reduction – it will come with time and perseverance.
Can isometrics help to strengthen your tendon?
When to use isometric exercises for Achilles tendinopathy/tendonitis
There has been a change in focus in Achilles rehabilitation. Research has found that pain is not detrimental for recovery, and it may even be beneficial to feel a small amount (niggle level) whilst doing rehabilitation exercises for tendinopathies.
The key is to start your exercises at a level that is right for you and progress your exercises by making them more and more challenging over weeks to months as your tendon's symptoms improve and function returns.
When we assess your Achilles tendon at TreatMyAchilles.com we look at your tendon's capacity, i.e. what activities you can do and what that feels like when you do it. We all have different starting points due to our tendon's current level of injury, fitness levels, other health issues, and goals and aspirations.
Therefore, doing isometric exercises is the right starting point for you if:
You find isometric exercises challenging,
They cause no more than an acceptable level of pain,
And you can't yet progress to more challenging exercises (like isotonic exercises).
If isometric exercises are too easy, and you are able to do more challenging movements, then you do not need to start here.
How isometric exercises can be adapted for Achilles tendinopathy rehab
Like with all rehab exercises, isometric calf raises should be adapted to suit the individual patient. Some of the things to consider include:
Support: Should they be done on two legs or one? This will depend on what your tendon can currently tolerate and, like all the other things in this list, is something your physio will test during your assessment.
Load: Should they be done with bodyweight only or added weight? This will depend on your tendon's current strength and sensitivity. It is currently advised to train the tendon at the highest load it will tolerate without significantly increasing symptoms.
Position: If you experience pain when lifting all the way up into a calf raise, it may be best to start by only lifting halfway up. As your tendon recovers, you'll eventually be able to go full range.
Hold time: In the research, the aim is usually to hold the contractions for 45 seconds. But this can often be too much if your tendon is very irritable, so starting with shorter holds and slowly increasing the time is often best.
The number of repetitions and how often you do them (daily, more than once a day, or every other day) will also depend on what your tendon currently tolerates and how quickly your body can adapt to the load.
As you grow stronger and your tendon regains some strength, the isometric exercises should also be progressed to become more challenging. For instance, if your tendon is very sensitive, you may start with double-leg holds, which can then be progressed to single-leg holds or by simply adding weight while remaining on two legs.
How we can help
Need more help with your Achilles injury? You’re welcome to consult one of the team at TMA online via video call for an assessment of your injury and a tailored treatment plan.
We're all UK Chartered Physiotherapists with Master’s Degrees related to Sports & Exercise Medicine. But at Treat My Achilles we don't just value qualifications; all of us also have a wealth of experience working with athletes across a broad variety of sports, ranging from recreationally active people to professional athletes. You can meet the team here.
About the Author:
Rio, E., Kidgell, D., Purdam, C., Gaida, J., Moseley, G.L., Pearce, A.J. and Cook, J., 2015. Isometric exercise induces analgesia and reduces inhibition in patellar tendinopathy. Br J Sports Med, 49(19), pp.1277-1283.
O’Neill, S., Radia, J., Bird, K., Rathleff, M.S., Bandholm, T., Jorgensen, M. and Thorborg, K., 2019. Acute sensory and motor response to 45-S heavy isometric holds for the plantar flexors in patients with Achilles tendinopathy. Knee Surgery, Sports Traumatology, Arthroscopy, 27(9), pp.2765-2773.
Clifford, C., et al. (2020). "Effectiveness of isometric exercise in the management of tendinopathy: a systematic review and meta-analysis of randomised trials." BMJ Open Sport & Exercise Medicine 6(1): e000760.