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Achilles Tendinitis Rehab Basics

Evidence-based guidelines for recovering as quickly as possible

Paul Ingraham, updated

Achilles tendinitis is one of several common repetitive strain injuries (RSI). The giant tendon can be stressed until it becomes acutely irritated and then, in some people, it stubbornly refuses to heal — either because it keeps getting re-irritated, and/or because it’s just naturally difficult for tendon to recover, and that phenomenon is worse in some people.

All of the well-known RSIs have a lot in common. I provide more detailed information about the nature of the beast in a separate guide (see Repetitive Strain Injuries Tutorial). That article dives deep into questions like: are RSIs really inflamed? Do we get them because of things like biomechanical assymetry, poor ergonomics, a screwy gate? And much more. This article is a brief guide to treatment and rehabilitation only.

Tendon never truly “heals,” it just gets patched (and you can’t rush it)

You cannot ever undo the damage done to connective tissue by overuse and inflammation. There is basically zero turnover of that tissue.1

Luckily, the body can lay down a fresh layer of connective tissue. So a cruddy old tendon can become a rotten core wrapped in a fresh and fully functional outer layer. “Healing”! So at least there’s that.

The first rule of tendinitis rehab is to just accept that there’s no known method of actually speeding or facilitating that process. Both accelerated or regenerative healing are not serious options for Achilles tendinitis. (More about high-tech regenerative treatments below.)

Load management in principle

The basic template for all injury rehab is to “calm shit down” and then “build shit up,”2 also known as “load management.” That is, first you rest, soothe, comfort, reassure, protect … and then you gradually introduce easy, artificial challenges, and then more difficult functional ones, slowly “demonstrating” to your brain and tendons that painless function is possible and eventually required.

The challenge is to keep your tendons in the Goldilocks zone: stimulated enough to heal, but not so much that you re-irritate the tendon. It’s a challenge because the Goldilocks zone changes as you heal, and so you have to keep up with it… which is a bit error-prone. Many factors affect our vulnerability to load.3 This uncertainty is the main source of error in rehab: we can never be sure how much stimulation is enough or too much.

So bog standard rehab for tendinitis usually consists of:

Ten years after doing this kind of rehab, 76% of about a hundred patients were back to normal, with no sign of serious consequences of the steroid injections.4 But 24% were not — after a decade! Those numbers tell a clear story: most people are probably eventually going to be fine with standard therapy, but clearly not everyone.

Don’t underestimate the importance of rest

If there’s a “trick” to load management, it’s that the initial resting phase is important — probably more important than most people realize.5 And the build-shit-up phase is slower and more baby-steppy than most people realize. Especially with &*[email protected]# tendinitis.

It’s also largely just a matter of simply not interfering with natural healing by re-irritating it, so please really make sure you take it quite easy for a quite a while. Avoid spikes in tendon loading like the plague in the early stages.

Stimulating new tendon growth

Exactly how to inspire the body to lay down that fresh layer is, of course, not totally clear. We know it’s possible, but it probably requires a just-right amount/kind of exercise stimulation that is impossible to be sure of.

In general it just means progressively loading the tendon, asking it to do its job a little more each week over many weeks.

And what is it’s job? The major function of the Achilles tendon is that is a giant elastic that absorbs some energy during part of your stride, and gives some of it back during another part, kind of like regenerative braking in an electric car. Anything that doesn’t use that system won’t be very challenging/stressful to the tendon.

But you also can’t start out asking it to do its entire job, anymore than you send someone back to work the day after they’ve had a major surgery. One thing at a time. So you start out with easier, less functional challenges, like heel raises. Lots and lots of heel raises, very easy at first, but slowly getting harder over many weeks and months, eventually working up to fairly high loads. As you go, you start to mix in more functional challenges, which mostly means walking and jogging, but in quite small doses initially.

Isometric contractions for Achilles tendinitis

In 2017 study, a high profile study suggested that isometric contractions are an effective treatment for Achilles tendinitis.6 This has become quite trendy since then. (Amazing how one study can do that, when it never should.)

Iso-what? Isometric contractions are non-moving contractions, so basically clenching. Isometric loading of the Achilles tendon is easily achieved by simply standing on the edge of a step or curb, suspending the heel. Just stand there, with tension on your tendons.

concentric contraction = contraction while shortening
isometric contraction = contraction without changing length (“clenching”)
eccentric contraction = contraction while lengthening (“braking”)

So does it work? Probably not. There’s conflicting evidence and failed replication7 now, so… meh.8

One could argue that isometric contractions are not a functional stimulus, and so they are unlikely to do much good, and the lack of consistent, persuasive results isn’t surprising.

Eccentric exercise for Achilles tendinitis

An eccentric contraction is a contraction while lengthening, also sometimes called a braking contraction. This type of contraction is more efficient than concentric (harder work for less energy), and causes more soreness. The canonical example of an eccentric contraction is the biceps while lowering a barbell.

The eccentric contraction relevant to Achilles tendinitis is the calf muscle. When you stand up on your toes, the calf contracts concentrically to lift you up. If you hold the position, that’s an isometric contraction. And then as you lower your heels down the calf contracts eccentrically. So a standard heel raise (with a bit of a pause at the top) uses all three.

The high “efficiency” of eccentric contractions makes them potentially useful for rehab.9 Eccentric exercise (EE) is often prescribed for tendinopathy in particular, because it seems to “improve symptoms,”10 and could even be a rare example of truly evidence-based rehab.11

On the other hand, nothing is ever that tidy in sports medicine. Even if it is helping, recent evidence shows that EE may not actually be changing the tendon,12 which is probably what most people would hope and assume — a novel stimulus, with an interesting and useful tissue response, would be of great interest.

And some experts are just not impressed by eccentric exercise therapy, despite some positive studies: “There is no convincing clinical evidence to demonstrate that isolated eccentric loading exercise improves clinical outcomes more than other loading therapies.”13

I bet “it depends.” If exercising eccentrically is useful in rehab, it’s not clearly established yet.

Emphasizing the eccentric

Normal heel raises include equal doses of concentric and eccentric contraction. What goes up must come down! How do you separate them? You have to make a point of eliminating the concentric — which means that you just don’t do the “raise” part of heel raises. You stand on the edge, lower your heel, and then rather than lifting back up again, you just take the load off with your other leg, reset, and repeat. Just never raise with calf you’re exercise. For whatever it’s worth.

Pain relief

Masking symptoms,” especially with medications, is often maligned. But sometimes symptoms need masking! If you need a little pain relief during activity you cannot avoid (and many of us have activities we cannot avoid, like childcare and careers that naturally involve some tendon loading):

Just bear in mind that pain-relief and load management are natural enemies. Pain is generally a useful warning that we’re pushing tissue too hard. If you mute that signal, it’s much easier to accidentally leave the Goldilocks zone.

And also beware of overusing Voltaren or any other non-steroidal anti-inflammatory drug (like ibuprofen): there is some evidence that these drugs can actually interfere with healing.15 Which really sucks.

Regenerative medicine

There are some emerging high-tech treatments intended to stimulate/accelerate tendon tissue growth. These are exciting possibilities, but I think you should save your money for now.

This website has a salamander for a mascot/logo because that critter has genuinely amazing powers of regenerative healing. We know it’s possible because salamanders do it: the only macroscopic animal with that superpower.

But we certainly don’t have it yet. We’ll probably get some real regenerative medicine eventually, but it’s still early days. Meanwhile, there are several companies racing to market on this. Their value can only be based on hype, because none of them have been adequately tested yet. Tendoncel is the most prominent I know of, and by their own admission they are still testing their product.

So there’s just no basis for confidence about any regenerative therapy for tendons at this time. It’s implausible on its face, because there are extremely few precedents for clearly successful regenerative medicine in humans, and many conspicuous failures.

That doesn’t mean it won’t work, but it does mean that the bar for the evidence is very high, and even if we see evidence of efficacy soon, it will definitely still not be enough: it will have to be replicated independently.

So we’re ways off yet, probably another couple of years at least.

There’s not really much to it

Someday I will expand this guide into a book, and go on and on and on for 50x as long, delving into all the weird little details — but the bottom line won’t really differ much from what you’ve seen here. “Progressive loading” is mostly all there is to know. Shhhhh. Our little secret.

About Paul Ingraham

Headshot of Paul Ingraham, short hair, neat beard, suit jacket.

I am a science writer, former massage therapist, and I was the assistant editor at ScienceBasedMedicine.org for several years. I have had my share of injuries and pain challenges as a runner and ultimate player. My wife and I live in downtown Vancouver, Canada. See my full bio and qualifications, or my blog, Writerly. You might run into me on Facebook or Twitter.

What’s new in this article?

MayScience update: added some fresh evidence about the efficacy of standard rehab methods (not bad, not great either).

MayAdded section about eccentric exercise. Improved layout of embedded video of heel raises. Lots of editing. Added caveats about pain-killers.

MayAdded section about regenerative medicine.

MayPublication.

Notes

  1. Heinemeier KM, Schjerling P, Heinemeier J, Magnusson SP, Kjaer M. Lack of tissue renewal in human adult Achilles tendon is revealed by nuclear bomb (14)C. FASEB J. 2013 May;27(5):2074–9. PubMed #23401563.  PainSci #53171. 

    There is basically no turnover in tendon tissue in adults (as measured in the Achilles tendon in this experiment).

    And how do we know this? Because NUKULAR BOMBAS! The atomic signatures of the era of nuclear bomb testing are still written into the tendons of people who were alive at the time, trapped like bubbles of ancient air in an ice core.

    Incredible. Very cool science. Indeed, probably the coolest tendon study that has ever been or ever will be.

    BACK TO TEXT
  2. Tweet, Sep 24, 2014, Greg Lehman (@GregLehman), physical therapist and chiropractor. BACK TO TEXT
  3. Soligard T, Schwellnus M, Alonso JM, et al. How much is too much? (Part 1) International Olympic Committee consensus statement on load in sport and risk of injury. Br J Sports Med. 2016 Sep;50(17):1030–41. PubMed #27535989. 

    This is the first of a pair of papers (with Schwellnus) about the risks of athletic training and competition intensity (load). Is load a risk for injury and illness? How much is too much? Is too little a problem? These papers were prepared by a panel of experts for the International Olympic Committee, and both them use many words to say the same things formally — but they are good points. Here they are in plain English:

    • There’s not enough research, surprise surprise, and what we do know is mostly from limited data about a few specific sports. But there’s enough to be confident that “load management” overall is definitely important.
    • Both illness and injury seem to have a similar relationship to load — lots of overlap.
    • Too much and not enough load probably increase the risk of both injury and illness. You want to be in the goldilocks zone! But the devil is in the details …
    • Not everyone is vulnerable to high load, and elite athletes are the most notable exception: they are relatively immune to the risks of overload, probably because of genetic gifts. Everyone else gets weeded out!
    • Big load changes — dialing intensity up or down too fast — are much bigger risks than absolute load. If you methodically work your way up to a high load, it may even be protective.
    • “Load” can also refer to non-sport stressors and “internal” loads, which are legion. Psychology, for instance, probably does matter: anything from daily hassles to major emotional challenges, as well as stresses related to sport itself.

    BACK TO TEXT
  4. Johannsen F, Jensen S, Wetke E. 10-year follow-up after standardised treatment for Achilles tendinopathy. BMJ Open Sport Exerc Med. 2018;4(1):e000415. PubMed #30305926.  PainSci biblio.  BACK TO TEXT
  5. PS Ingraham. The Art of Rest: The finer points of resting strategy when recovering from injury and chronic pain (hint: it’s a bit trickier than you might think). PainScience.com. 4568 words. Resting “properly” is trickier and more critical part of injury rehabilitation than most people realize, and is often at odds with a culture tradition of aggressive therapeutic exercise (“no pain, no gain”). This article explores the rationale for resting, and tactical considerations like how to rest anatomy that you need to use for your job, and how to know how much rest is enough. BACK TO TEXT
  6. Gravare Silbernagel K, Vicenzino BT, Rathleff MS, Thorborg K. Isometric exercise for acute pain relief: is it relevant in tendinopathy management? Br J Sports Med. 2019 May. PubMed #31076398.  BACK TO TEXT
  7. Holden S, Lyng K, Graven-Nielsen T. The Acute Effect of Isometric Versus Isotonic Resistance Exercise in Patients With Patellar Tendinopathy—does contraction type matter? A randomised crossover trial. {Presented at the Scandinavian Sports Medicine Conference, Copenhagen, Denmark, 2019}. 2019. PainSci #52445.  BACK TO TEXT
  8. Gravare Silbernagel K, Vicenzino BT, Rathleff MS, Thorborg K. Isometric exercise for acute pain relief: is it relevant in tendinopathy management? Br J Sports Med. 2019 May. PubMed #31076398.  BACK TO TEXT
  9. Hessel et al: “The high force and low energy cost of eccentric contractions makes them particularly well suited for athletic training and rehabilitation. Eccentric exercise is commonly prescribed for treatment of a variety of conditions including sarcopenia, osteoporosis, and tendinosis.” BACK TO TEXT
  10. Frizziero A, Vittadini F, Fusco A, Giombini A, Masiero S. Efficacy of eccentric exercise in lower limb tendinopathies in athletes. J Sports Med Phys Fitness. 2016 Nov;56(11):1352–1358. PubMed #26609968.  “Eccentric exercise (EE) is considered a fundamental therapeutic resource, especially for the treatment of Achilles and patellar tendinopathies.” BACK TO TEXT
  11. Rees JD, Wolman RL, Wilson A. Eccentric exercises; why do they work, what are the problems and how can we improve them? Br J Sports Med. 2009 Apr;43(4):242–6. PubMed #18981040.  “Eccentric exercises (EE) have proved successful in the management of chronic tendinopathy, particularly of the Achilles and patellar tendons, where they have been shown to be effective in controlled trials.” BACK TO TEXT
  12. Drew BT, Smith TO, Littlewood C, Sturrock B. Do structural changes (eg, collagen/matrix) explain the response to therapeutic exercises in tendinopathy: a systematic review. Br J Sports Med. 2014 Jun;48(12):966–72. PubMed #23118117.  “The available literature does not support observable structural change as an explanation for the response of therapeutic exercise except for some support from heavy-slow resistance training.” It’s conceivable that moderate intensity eccentric contractions are just somewhat closer to the real goal of “heavy-slow resistance training” — a shortcut. BACK TO TEXT
  13. Couppé C, Svensson RB, Silbernagel KG, Langberg H, Magnusson SP. Eccentric or Concentric Exercises for the Treatment of Tendinopathies? J Orthop Sports Phys Ther. 2015 Nov;45(11):853–63. PubMed #26471850.  BACK TO TEXT
  14. Heinemeier KM, Øhlenschlæger TF, Mikkelsen UR, et al. Effects of anti-inflammatory (NSAID) treatment on human tendinopathic tissue. J Appl Physiol (1985). 2017 Nov;123(5):1397–1405. PubMed #28860166.  This study reported that “tendinopathic cells are not responsive to ibuprofen.” BACK TO TEXT
  15. Bittermann A, Gao S, Rezvani S, et al. Oral Ibuprofen Interferes with Cellular Healing Responses in a Murine Model of Achilles Tendinopathy. J Musculoskelet Disord Treat. 2018;4(2). PubMed #30687812.  PainSci #52446.  “We conclude that the use of Ibuprofen for pain relief during inflammatory phases of tendinopathy, might interfere with the normal processes of extracellular matrix remodeling and cellular control of expression of inflammatory and wound healing genes.” BACK TO TEXT