You felt it first as stiffness. That thick, sore feeling in the back of your heel for the first ten steps out of bed, easing once you got moving. So you kept running. Then it started hurting during runs. Then after. Now it’s there when you walk to the car.
You’ve probably been told to rest it. That advice is the reason it’s still here.
It isn’t tendonitis, and that matters
“Tendonitis” means inflammation of the tendon. For a long-standing Achilles problem, that’s usually not what’s happening.
What’s actually going on is tendinopathy: a failed healing response. The tendon has been loaded more than it could tolerate, the repair process hasn’t kept up, and the tissue has reorganised into something less capable than it was. There’s no significant inflammation to settle. There’s a structure that can’t handle what you’re asking of it.
That distinction changes the whole treatment. If it were inflammation, rest and anti-inflammatories would fix it. Since it’s a capacity problem, rest does the opposite: an unloaded tendon gets weaker, so when you go back to running, you’re asking even less tendon to do the same job.
This is why so many people cycle through six weeks off, feel better, run once, and are back to square one.
Find out which Achilles problem you have first
This is the step most people skip, and it changes what you should do.
Midportion tendinopathy sits in the tendon itself, roughly 2 to 6cm above the heel bone. Squeeze it there and it’s tender and often thickened. This is the more common one and it responds well to standard loading.
Insertional tendinopathy sits right where the tendon attaches to the heel bone. The pain is lower, at the back of the heel itself.
The reason it matters: at end-of-range dorsiflexion, when your toes come up toward your shin, the insertion gets compressed against the heel bone. So the exercises everyone recommends for Achilles pain, the ones where you drop your heel off the edge of a step, can aggravate an insertional problem while helping a midportion one.
If dropping your heel below flat makes it worse, you probably have an insertional problem, and you should be working from flat ground rather than off a step.
The evidence, plainly
- Loading is the treatment. Progressive resistance training is the most consistently supported intervention for Achilles tendinopathy. Nothing passive comes close.
- Eccentric loading works. The Alfredson protocol, a heel-drop programme run twice daily for 12 weeks, has been the reference standard since 1998 and it produces good outcomes.
- Heavy slow resistance works just as well. Later research compared heavy slow resistance training, done three times a week, against the twice-daily eccentric programme. Outcomes were comparable, and people stuck with it more reliably. Three sessions a week beats fourteen you don’t do.
- The load matters more than the protocol. The current picture is that progressive, sufficiently heavy loading drives the result. The exact flavour is less important than doing it consistently and getting heavier over time.
- Some pain during the work is fine. Pain up to about 5 out of 10 during loading is acceptable, and doesn’t lead to worse outcomes, provided it settles by the following morning. Waiting for pain-free before you load is how people stay stuck.
- Scans don’t tell you much. Tendon changes show up on ultrasound and MRI in people with no symptoms at all, and the appearance doesn’t track well with how much it hurts or how you’ll do.
- Avoid cortisone in the Achilles. Corticosteroid injection around the Achilles is associated with tendon rupture and isn’t recommended.
The exercises
Build these in order. Don’t skip ahead because something feels easy on day one.
1. Isometric calf hold
Push up onto the ball of your foot and hold. 5 sets of 30 to 45 seconds, with a minute or two between. Two feet to start, one foot when you can.
Use this early when the tendon is irritable. It gives you a way to load the tissue on days when moving through range is too provocative, and many people find it takes the edge off for a few hours afterwards.
2. Heavy slow calf raise
The main event. Both a straight-knee version, which loads the gastrocnemius, and a bent-knee seated version, which loads the soleus. The soleus takes more load during running than most people realise, and it gets skipped constantly.
Three seconds up, three seconds down. 3 to 4 sets of 6 to 8 reps, three times a week. It should be genuinely heavy by the end of a set.
Midportion: work off a step, letting the heel drop below level. Insertional: stay on flat ground. Don’t drop below level.
3. Load it, then add more
This is the part that gets missed. Six to eight reps means you should need weight. A backpack, a dumbbell, a machine, whatever you have. Then more of it, week on week.
A tendon adapts to the load you give it. If the load never increases, neither does the tendon.
4. Single-leg heel raise, for capacity
Test where you are: how many single-leg heel raises can you do, full range, controlled? Most people should be able to manage well over 20. Runners returning to full training should be comfortably past 25.
Track this. It’s the most useful number you’ve got, because it tells you about capacity rather than about pain.
5. Then, and only then, springs and hops
Running is a spring task. Slow heavy work builds the tendon’s tolerance to load but doesn’t prepare it for rapid stretch and release.
Once the heavy work is solid and symptoms are stable, add pogo hops, skipping and low bounding, starting small. This is the bridge back to running, and it’s the stage people leave out before wondering why it flares on their first run back.
How long this actually takes
Twelve weeks is the realistic minimum for a tendon that’s been sore for months. Three to six months is common. Longstanding cases take longer.
That’s slower than most people want to hear, and I’d rather tell you now than have you decide at week four that it isn’t working.
Tendons remodel slowly. The collagen turnover that changes the structure takes months, not weeks. What moves faster is your symptoms, which often improve well before the tendon itself has caught up. That gap is the trap: you feel better at week five, go back to full training, and undo it.
- Weeks 1 to 4: isometrics plus heavy slow calf raises. Keep running only if it isn’t provoking pain that lingers into the next day.
- Weeks 4 to 8: the load goes up. This is the phase that does the work. Add the seated soleus version if you haven’t.
- Weeks 8 to 12: springs and hops in, running volume rebuilt gradually.
- Beyond: keep the heavy calf work. Two sessions a week is what stops it coming back.
The mistakes that keep people stuck
Stopping when the pain stops. Symptoms improve before capacity does. If you stop loading at that point, you’ve built nothing, and you’re back where you started with a slightly deconditioned tendon.
Stretching it and calling that rehab. Stretching doesn’t build capacity. For an insertional problem, aggressive calf stretching can actively make it worse by compressing the insertion.
Going too light. Three sets of fifteen bodyweight calf raises is not heavy loading. If you can do twenty, it isn’t the exercise that’s going to change anything.
Treating the tendon and ignoring the reason. The tendon failed because of what was going through it. A sudden jump in mileage, new hills, a change of surface or shoes, or calves that were never strong enough for your training load. If none of that changes, neither does the outcome.
When to get it looked at
Get it assessed if you’ve had it more than six weeks and it isn’t trending the right way, if you’re not sure whether it’s midportion or insertional, if it’s stopping you training consistently, or if you had a sudden sharp pain with a snapping sensation and difficulty pushing off, which needs same-day assessment.
Most Achilles problems don’t need a scan and don’t need surgery. What they need is the right load, applied for long enough, in the right place. That’s the whole job, and it’s worth getting the plan right rather than losing another six months to the rest-and-see cycle.