Achilles Tendinopathy: A Practical Rehab Guide for Runners

Achilles tendon pain has a typical pattern. You get out of bed and the back of your heel is stiff and sore for the first few steps. You start a run and it aches for the first kilometre or two, then eases off as you warm up. A few hours later, or the next morning, it's back, sometimes worse than before.

Because the pain fades once you're warm, it's easy to keep running through it for weeks. That's often how a minor problem becomes a stubborn one. Achilles tendinopathy can drag on for months if it's managed badly. Managed well, most runners recover and get back to full training.

This guide explains what Achilles tendinopathy is, why it happens, why rest alone rarely fixes it, the exercises with the strongest evidence, and a staged plan for getting back to running.

What is Achilles tendinopathy?

The Achilles tendon connects your calf muscles (gastrocnemius and soleus) to your heel bone. It's the thickest and strongest tendon in the body, and it takes huge forces during running, several times your body weight with each stride.

Achilles tendinopathy is pain, stiffness and reduced function in the tendon, usually caused by load. There are two main types:

• Midportion tendinopathy: pain 2 to 6 cm above where the tendon attaches to the heel. This is the most common type in runners, and the focus of this guide.
• Insertional tendinopathy: pain right where the tendon attaches to the heel bone. It's managed slightly differently, mainly by avoiding exercises that stretch the tendon over the edge of a step.

Tendinitis or tendinopathy?

You'll often hear "Achilles tendinitis". The "-itis" suggests inflammation. But in long-standing Achilles pain, the tendon usually shows changes in its structure (disorganised collagen, increased water and cells) rather than classic inflammation. That's why "tendinopathy" is the preferred term, and why anti-inflammatory tablets alone rarely solve it.

Jill Cook and Craig Purdam's 2009 "continuum model" describes how a tendon responds to load. With a sudden increase in load, the tendon can become reactive and painful. With continued overload, it can move towards more lasting structural change. The model helps explain why getting load right, neither too much nor too little, is the key to treatment.

Symptoms

• Pain and stiffness in the tendon, usually 2 to 6 cm above the heel.
• Stiffness first thing in the morning or after sitting, easing with movement.
• Pain at the start of running that may ease during the run, then return afterwards.
• Tenderness when you squeeze the tendon.
• Sometimes visible thickening or a lump in the tendon.

Why it happens

Achilles tendinopathy is common in runners. A study by Urho Kujala and colleagues of former elite athletes found that by age 45, about half of former middle- and long-distance runners had experienced Achilles tendinopathy, compared with a small fraction of a comparison group of non-athletes.

As with most running injuries, the usual trigger is a change in load that the tendon isn't ready for:

• A rapid increase in weekly distance.
• Adding speed work, hills or track sessions.
• Switching to lower-drop or minimal shoes, which load the Achilles more.
• Returning to running after a break.
• Changing surfaces, such as moving to more hills or soft sand.

Other factors that can contribute include reduced calf strength, age (tendons become less able to adapt quickly from middle age), previous Achilles problems, and some medical conditions and medications. Under-eating and poor recovery may also reduce the tendon's ability to adapt.

Tendons adapt to load more slowly than muscles. Your fitness and muscles can be ready for more training weeks before your tendons are. That mismatch is why tendon problems often appear a few weeks into a new training block.

Why rest alone rarely works

Resting completely usually eases the pain. But tendons need load to stay strong. After weeks of rest, the tendon is less able to handle running than before, and the pain returns when you start again.

The clinical practice guidelines published by the American Physical Therapy Association in 2018, led by RobRoy Martin, recommend exercise-based loading programmes as the main treatment for midportion Achilles tendinopathy, alongside education and load management. Complete rest isn't recommended.

Can you keep running?

Often, yes. A 2007 randomised trial by Karin Grävare Silbernagel and colleagues compared Achilles patients who continued running and jumping during rehab, guided by a pain-monitoring model, with patients who rested from running for six weeks. Both groups did the same exercise programme. Outcomes were similar, showing that continuing activity within limits didn't slow recovery.

The pain-monitoring model

• Pain during activity can go up to about 5 out of 10, where 0 is no pain and 10 is the worst imaginable.
• Pain after activity should settle by the next morning.
• Morning pain and stiffness shouldn't be getting worse from week to week.

If all three hold, the current level of running is acceptable. If not, reduce volume, speed or hills until they do. Note that this threshold is higher than the one often used for bone injuries like shin splints. Tendons tolerate some pain during loading.

The best exercises for Achilles tendinopathy

Two approaches have the strongest evidence. Both involve progressively loading the calf and tendon over at least 12 weeks.

Option 1: eccentric heel drops (the Alfredson protocol)

In 1998, Håkan Alfredson and colleagues published a study in which runners with chronic Achilles pain did heavy eccentric calf exercises for 12 weeks. All returned to their previous running levels, whereas a comparison group who had surgery needed much longer.

The protocol:

• Stand on a step on both feet, rise onto your toes.
• Shift onto the painful leg and slowly lower your heel below the step over about three seconds.
• Use the other leg (or both legs) to rise back up.
• Do it with a straight knee and a bent knee.
• 3 sets of 15 reps, twice a day, every day, for 12 weeks.
• Add weight in a backpack as it becomes easy.

It's a high-volume programme and some discomfort is expected. Many people find it hard to stick to twice a day.

Option 2: heavy slow resistance (HSR)

In 2015, Rodrigo Beyer and colleagues compared the eccentric protocol with heavy slow resistance training in a randomised trial. HSR involved three sessions a week of slow, heavy calf raises, both seated and standing, with weight increasing over 12 weeks. Both programmes produced similar improvements, but patient satisfaction tended to be higher in the HSR group, and it took less time each week.

The HSR approach:

Each rep takes about six seconds: three seconds up, three seconds down. Do three exercises each session: seated calf raise (machine or weight on knees), standing calf raise with a straight knee, and a calf raise on a leg press machine. Three sessions a week, with a rest day between.

Which should you choose?

Both work. HSR is often easier to stick with because it's three times a week rather than twice daily. Choose whichever you'll actually do consistently for 12 weeks.

A staged rehab plan

Stage 1: settle irritability (1 to 2 weeks)

• Reduce running to a level within the pain-monitoring limits.
• Isometric calf holds: stand on one leg on a step, rise halfway onto your toes and hold for 30 to 45 seconds. Repeat 4 to 5 times, once or twice a day. These often ease pain.
• Cross-train if running is too painful: cycling and swimming usually load the Achilles less.

Stage 2: build strength (weeks 2 to 12)

• Start the HSR or eccentric programme.
• Progress the load steadily, guided by the pain-monitoring model.
• Keep running at a tolerable level.

Stage 3: add spring (from around week 6 to 8)

Tendons need to handle fast, springy loading for running. Once you can do heavy single-leg calf raises comfortably, add:

• Pogo hops on both legs, then one leg.
• Skipping.
• Small forward hops.
• Start with 2 to 3 sets of 10 to 20 contacts, twice a week.

Stage 4: return to full running

• Increase weekly volume gradually.
• Add hills, speed work and track sessions one at a time, with at least a week between new elements.
• Keep two calf strength sessions a week going long term.

What about shoes, heel lifts and other treatments?

• Heel lifts: a small heel lift can reduce tendon strain and ease pain in the short term. Useful while you build strength.
• Shoes: if you recently switched to very low-drop or minimal shoes, go back to your previous shoes for now.
• Stretching: fine if it feels good, but it isn't the main treatment.
• Massage and foam rolling: may ease calf tightness, but won't fix the tendon on their own.
• Shockwave therapy: may help some people who don't respond to exercise, usually alongside it.
• Injections: corticosteroid injections near the Achilles aren't generally recommended, because of concerns about weakening the tendon. Other injection treatments have mixed evidence.
• Surgery: rarely needed, and only after a long period of well-done rehab hasn't worked.

How long does recovery take?

Tendons are slow. Most rehab programmes run for at least 12 weeks, and many people need three to six months to return fully to their previous training. Some improvement in pain usually comes within the first few weeks, but strength and tendon capacity take longer.

The most common mistake is stopping the exercises as soon as pain fades. The tendon may feel better long before it's strong enough to handle full training. Keep going with calf strength work for the full programme, and keep a maintenance version going afterwards.

Preventing Achilles problems

• Increase training gradually, especially speed work, hills and total volume.
• Do calf strength work all year, not just when injured. Our strength training guide for runners includes calf exercises you can keep in your routine.
• Change shoes gradually, especially when moving to lower-drop models.
• Respect early warning signs. Morning stiffness that's building over a week or two is the time to adjust training.
• Recover well. Sleep and enough food give your tendons the resources to adapt.

A sample rehab week

Check morning stiffness each day. If it's worse than usual, keep the next day's running shorter or swap it for cross-training.

Common rehab mistakes

• Stopping the exercises when pain fades. The tendon needs months of loading to build capacity.
• Exercises too light. Bodyweight calf raises become too easy quickly. Add weight.
• Jumping back to speed work too soon. Fast running, hills and track work load the tendon heavily. Add them last.
• Complete rest. Tendons need load to recover.
• Changing too many things at once, such as new shoes, new training plan and new surfaces in the same month.

Insertional Achilles pain: what's different

If your pain is right where the tendon attaches to the heel bone, rather than higher up, the approach changes slightly. Dropping the heel below a step compresses the tendon against the heel bone and can aggravate insertional pain. Do calf raises on flat ground instead, and avoid deep stretching. Heel lifts and shoes with a slightly higher drop often help in the short term. A physiotherapist can confirm which type you have.

Achilles problems in older runners

Achilles tendinopathy becomes more common from middle age, as tendons adapt more slowly to changes in load. Masters runners benefit from making calf strength work a permanent part of their training, increasing volume and intensity more gradually, and allowing more recovery between hard sessions.

When to see a professional

See a doctor or sports physiotherapist if:

• You have any signs of a possible rupture (sudden snap, can't rise onto your toes).
• Pain isn't improving after three or four weeks of sensible load management and exercise.
• The tendon is very swollen, red or hot.
• You have pain in both Achilles tendons with no obvious training reason, or other joint problems.
• You're unsure whether your pain is midportion or insertional.

A physiotherapist can confirm the diagnosis, tailor the exercise programme and guide your return to running. If you have pain at the front of the knee as well, our guide to runner's knee covers that.

The bottom line

Achilles tendinopathy is a load problem, and the solution is load: the right amount, progressed patiently. Complete rest rarely works. Heavy, slow calf strengthening, guided by a pain-monitoring model and continued for at least 12 weeks, gives most runners their best chance of a full recovery. Be patient, keep doing the exercises after the pain fades, and build your running back gradually.

Frequently asked questions

Sources and further reading

1. Silbernagel KG, et al. Continued sports activity, using a pain-monitoring model, during rehabilitation in patients with Achilles tendinopathy: a randomized controlled study. The American Journal of Sports Medicine, 2007;35(6):897-906. DOI PubMed
2. Alfredson H, et al. Heavy-load eccentric calf muscle training for the treatment of chronic Achilles tendinosis. The American Journal of Sports Medicine, 1998;26(3):360-6. DOI PubMed
3. Beyer R, et al. Heavy Slow Resistance Versus Eccentric Training as Treatment for Achilles Tendinopathy: A Randomized Controlled Trial. The American Journal of Sports Medicine, 2015;43(7):1704-11. DOI PubMed
4. Martin RL, et al. Achilles Pain, Stiffness, and Muscle Power Deficits: Midportion Achilles Tendinopathy Revision 2018. The Journal of Orthopaedic and Sports Physical Therapy, 2018;48(5):A1-A38. DOI PubMed
5. Cook JL, Purdam CR. Is tendon pathology a continuum? A pathology model to explain the clinical presentation of load-induced tendinopathy. British Journal of Sports Medicine, 2009;43(6):409-16. DOI PubMed
6. Kujala UM, et al. Cumulative incidence of achilles tendon rupture and tendinopathy in male former elite athletes. Clinical Journal of Sport Medicine : Official Journal of the Canadian Academy of Sport Medicine, 2005;15(3):133-5. DOI PubMed