Achilles Tendinopathy: Load It, Don't Just Rest It

If your Achilles is stiff and sore for the first ten minutes every morning, then loosens up, then flares again whenever you push the mileage, you probably have tendinopathy. The instinct is to rest it. For most people that instinct quietly makes the tendon worse.

Why "tendinitis" is the wrong word

The old name was Achilles tendinitis, and the "-itis" implied active inflammation that rest and anti-inflammatories would settle. The current understanding is different. A tendon that has hurt for weeks or months is usually showing a load-capacity problem, not a hot inflammatory one. The tissue has been asked to do more than it can currently tolerate, and it has started to change in structure rather than simply swell.

That is why the term shifted to tendinopathy, and why the 2024 JOSPT clinical practice guideline frames management around restoring the tendon's capacity rather than chasing inflammation. It matters for treatment, because the fix for a structure that cannot carry enough load is to rebuild the load it can carry. Total rest does the opposite. It detrains the tendon and the calf around it, so the tissue you return to is weaker than the one you stopped on.

This is not permission to ignore pain. It is a reason to stop treating an aching Achilles as something you wait out.

Mid-portion and insertional are not the same problem

Where the tendon hurts changes the plan, so it is the first thing we sort out. The two common patterns are mid-portion and insertional, and people often assume they have one when the picture points to the other.

Mid-portion tendinopathy sits in the body of the tendon, a few centimetres above the heel bone. The 2018 JOSPT guideline describes the typical presentation as pain roughly two to six centimetres above where the tendon attaches, coming on gradually, and tender when you pinch that stretch of tendon. This is the version most loading research has studied.

Insertional tendinopathy sits lower, right where the tendon meets the heel bone. It tends to be grumpier with positions that compress the tendon against the bone, which is part of why deep heel drops off a step, the classic mid-portion exercise, can aggravate an insertional tendon. The loading principle is the same for both, but the range you work through and the speed of progression differ. Getting this wrong is a common reason a sensible-looking rehab plan stalls. If you are not sure which one you have, that distinction is one of the first things a physiotherapy assessment is for.

Loading is the first-line treatment, and the evidence is decent

The unglamorous core of Achilles rehab is progressive strengthening of the calf and tendon. Two protocols dominate the research. The older one is Alfredson's eccentric programme, where you lower slowly under load through heel drops. The newer one is heavy slow resistance, where you load the calf through both the lifting and lowering phases against progressively heavier resistance, fewer reps, slower tempo.

Both work. A 2023 systematic review and meta-analysis in BMC Sports Science, Medicine and Rehabilitation found eccentric exercise produced meaningful pain improvement in mid-portion Achilles tendinopathy compared with rest or other conservative care, while noting heavy slow resistance performed similarly in several trials. A 2015 randomized controlled trial in the American Journal of Sports Medicine compared the two directly and found equally good lasting results, with higher patient satisfaction and adherence in the heavy slow resistance group at twelve weeks. The practical read is that the best protocol is often the one you will actually keep doing, which is why we match it to your schedule, equipment, and how the tendon behaves rather than prescribing one by default.

A few things that surprise people. Some discomfort during loading is acceptable and does not mean damage. We watch how the tendon settles by the next morning, not how it feels mid-exercise, and we use that morning stiffness as the dial for progressing or holding. Runners and active adults often keep some running going through rehab rather than stopping cold, with volume and surface adjusted to symptom response. The aim is to load the tendon enough to provoke adaptation without tipping it into a flare it cannot recover from overnight.

Where shockwave and other add-ons fit

Shockwave therapy comes up often, usually for a tendon that has plateaued. The honest version of the evidence is that it can help, mostly as an addition to loading rather than instead of it. A 2022 systematic review in Cureus found extracorporeal shockwave therapy can reduce pain and improve function in mid-portion Achilles tendinopathy, and concluded the best results came from combining it with eccentric exercise, not from using it alone.

The evidence is also weaker for insertional tendinopathy than for mid-portion, and the trial quality across the board is modest. So we treat shockwave the way we treat it for heel pain, as a tool for a stubborn tendon that has had a genuine run of loading and stalled, not a day-one shortcut. We walked through the costing and session-count side of that decision in our shockwave plantar fasciitis post, and the same principle applies here. Coverage and current pricing for any add-on live on our rates page.

Other adjuncts, including hands-on treatment, isometric holds for pain relief on a flared day, and footwear or heel-lift tweaks for insertional cases, have a place. None of them replace the loading programme. They make it tolerable enough to keep going.

How long this actually takes

Tendons are slow tissue. They respond to load over months, not days, and rushing the progression is the fastest way to restart the clock. We are deliberately not putting a week count on recovery here, because honest timelines depend on how long it has been sore, which pattern you have, your training demands, and how consistently the loading gets done.

What we can say from clinic experience is that the people who recover well are rarely the ones who rested longest. They are the ones who loaded consistently, progressed patiently, and treated each flare as feedback to adjust the dose rather than a signal to stop. The tendon that gets stronger is the one that keeps being asked to work, just within a ceiling that rises week by week.

Running mechanics and training load matter too, because a tendon that keeps getting reloaded the same way it broke down tends to keep breaking down. A running assessment looks at cadence, footwear, and how fast you have been ramping mileage, which is often where the original overload came from.

When to get it looked at

Most Achilles pain is tendinopathy, but not all of it. Sudden sharp pain with a sense that something snapped, a feeling of being kicked in the back of the ankle, or a sudden inability to push off needs same-day medical assessment, not a loading programme, because that pattern can mean a tendon rupture. Pain that is worse at night and unrelated to activity, or swelling with redness and warmth, also deserves a physician's eyes first.

For the more typical grumbling, stiff-in-the-morning Achilles that keeps interrupting your training, the strongest outcomes happen when loading starts early and stays consistent. If yours has plateaued after an honest run of rehab, or you are not sure whether you are dealing with mid-portion or insertional pain, book a physiotherapy assessment and we will sort out the pattern and the plan. The same staged, load-it-don't-rest-it logic applies to other lower-limb tendons too, including the patellar tendon in jumper's knee and the broader rebuild work in runner's knee.

Frequently asked questions

Should I rest my Achilles tendon until the pain goes away? No. Complete rest tends to deload the tendon and the calf, so you return weaker. The current approach, reflected in the 2024 JOSPT guideline, is progressive loading rather than waiting the pain out, though the dose has to be matched to your symptoms.

Is it okay to exercise through some Achilles pain? Often, yes. Some discomfort during loading is acceptable as long as the tendon settles by the next morning. We use morning stiffness as the gauge for whether to progress or hold, rather than how it feels mid-exercise.

What is the difference between mid-portion and insertional Achilles tendinopathy? Mid-portion pain sits in the body of the tendon a few centimetres above the heel, while insertional pain sits right where the tendon meets the heel bone. They share the same loading principle but differ in the range and speed you progress, so deep heel drops that help one can aggravate the other.

Does shockwave therapy fix Achilles tendinopathy? Not on its own. A 2022 Cureus review found shockwave can reduce pain and improve function in mid-portion cases, with the best results when it is combined with loading exercise rather than used alone. We reserve it for a tendon that has stalled after a real loading effort.

How long does Achilles tendinopathy take to recover? It varies, and honestly it is usually months rather than weeks. The timeline depends on how long it has been sore, the pattern you have, your activity demands, and how consistently you load it, so your physiotherapist will set expectations after assessing it.

Can I keep running with Achilles tendinopathy? Frequently, yes, with adjustments. Many active adults keep some running going through rehab with volume, pace, and surface scaled to how the tendon responds. A running assessment helps find the training load or mechanics that caused the overload in the first place.

This article is general information, not personal medical advice. A regulated practitioner can confirm whether the patterns described apply to you.

Sources

• Achilles Pain, Stiffness, and Muscle Power Deficits: Midportion Achilles Tendinopathy Revision 2024 (JOSPT clinical practice guideline)
• Achilles Pain, Stiffness, and Muscle Power Deficits: Midportion Achilles Tendinopathy Revision 2018 (JOSPT clinical practice guideline)
• Eccentric exercise is more effective than other exercises in the treatment of mid-portion Achilles tendinopathy: systematic review and meta-analysis, 2023
• Heavy Slow Resistance Versus Eccentric Training as Treatment for Achilles Tendinopathy: A Randomized Controlled Trial, 2015
• The Effectiveness of Extracorporeal Shockwave Therapy for Midportion Achilles Tendinopathy: A Systematic Review, 2022