Achilles tendinopathy
Evidence: strong
Progressive loading is the best-evidenced first-line treatment for Achilles tendinopathy, with eccentric and heavy-slow resistance giving similar results. The one distinction that changes the programme is location: midportion disease tolerates loading into full dorsiflexion off a step, while insertional disease does worse with it and should be loaded on flat ground. Either way it takes months.
Not medical advice
This is a general knowledge base, not medical or dietary advice. If you are injured, unwell or weighing up a supplement or a change to your diet, speak to a doctor, physiotherapist or registered dietitian who knows your situation.
The Achilles is the tendon most often blamed in runners, and Achilles tendinopathy is the headline case of the general pattern described on the tendinopathy page: a load-related, degenerative tendon problem, not an inflammatory one, that responds to graded loading rather than rest (Cook & Purdam 2009). The general principles all hold here. What is specific to the Achilles is the clinical split that decides how you load it.
Midportion versus insertional
Achilles tendinopathy comes in two forms, and they are not interchangeable. Midportion disease sits in the body of the tendon, roughly 2-6 cm above the heel, where you can usually feel a thickened, tender spot. Insertional disease sits right at the calcaneal attachment, where the tendon meets the heel bone. The distinction is not academic: it changes the rehab, because the bottom of a below-horizontal heel drop compresses the insertion against the bone, and a compressed insertion does not respond like a loaded midportion.
The classic eccentric programme was developed and tested on midportion tendinopathy. Alfredson’s original study had recreational runners drop the heel below the level of a step into full dorsiflexion, three sets of fifteen twice a day for twelve weeks; all fifteen returned to running while a conventionally treated group went to surgery (Alfredson et al. 1998). That below-horizontal range is the active ingredient for midportion disease.
For insertional tendinopathy, the same full-dorsiflexion drop tends to make things worse. When the protocol was applied to insertional cases it succeeded in only about a third of patients; restricting the heel drop to floor level, stopping at neutral rather than dropping below the step, lifted satisfaction to about two-thirds with a large fall in pain (Jonsson et al. 2008). The practical rule: load midportion disease through the full off-a-step range, and load insertional disease on flat ground with the dorsiflexion limited.
Work out which one you have first
Point to where it hurts. A tender, thickened band a few centimetres up the tendon is midportion; pain and bony tenderness right at the heel is insertional. Getting this wrong, and doing deep below-horizontal heel drops on an insertional tendon, is a common way to stall rehab (Jonsson et al. 2008).
Loading is first-line, and the style barely matters
Beyond the location question, the Achilles follows the general tendon rules. Loading beats passive treatment: systematic reviews find loading-based exercise the best-supported treatment for midportion Achilles tendinopathy, outperforming ultrasound, rest and other passive modalities (loading reviews 2015). Eccentric (Alfredson) loading and heavy-slow resistance produce similar outcomes head to head, with mean VISA-A scores rising from 74 at 12 weeks to 87 at one year and no difference between groups, though heavy-slow resistance won on satisfaction and convenience (Beyer et al. 2015). Pick the one you will actually do. See strength training for runners for how this work fits a wider programme.
Pain monitoring, not pain avoidance
You do not have to keep an irritable Achilles pain-free during rehab. The Silbernagel pain-monitoring model allows discomfort up to about 5 out of 10 during loading, provided it settles to baseline by the next morning and does not climb week to week; patients who kept running within that rule did as well as those who rested (Silbernagel et al. 2007). Pain inside that window is acceptable; pain that lingers into the next day or worsens means the load was too high.
It takes months
The hardest part is the timescale. Meaningful change takes weeks and full recovery often runs to three months or more, with continued improvement out to a year (Beyer et al. 2015). Tendon adapts slowly and there is no shortcut. Injections, in particular, can give short-term relief but tend to underperform loading over the long run (Kongsgaard et al. 2009), which is why graded loading, not a needle, is first-line. Returning to full mileage is a gradual, symptom-guided process; see return to running.
A workable course: settle an irritable tendon with isometric or light loading, progress to heavy-slow resistance two to three times a week, choosing the off-a-step range for midportion disease and the flat-ground range for insertional, and keep some running going as long as it stays within the pain rule. For where the Achilles sits among other running injuries, see running injuries, common overuse injuries and the wider context in the basics.