What Achilles tendinopathy is
The Achilles is the thickest tendon in the body, transmitting force from the calf to the heel, and it handles loads of six to eight times body weight when running. Tendinopathy describes a change in its structure and pain-processing under repeated load that exceeded its capacity to adapt.
Two patterns matter clinically. Midportion tendinopathy sits two to six centimetres above the heel bone and accounts for around two thirds of cases. Insertional tendinopathy sits right where the tendon meets the heel bone and behaves differently, particularly around stretching and heel position.
The hallmark symptom is morning stiffness. Pain and stiffness in the first few steps out of bed, easing over ten or fifteen minutes, then returning after a period of sitting, is close to diagnostic.
What causes it
The cause is almost always a change in load that outpaced adaptation. Tendons adapt more slowly than muscles and considerably more slowly than the cardiovascular system, which is why the fitness to run further arrives before the tendon capacity to tolerate it.
Typical triggers are a jump in weekly mileage, adding hill or speed work, a change to flatter shoes, or a return to running after a break at the volume you finished on rather than the volume you should restart at.
Common triggers
- A rapid increase in running volume or intensity, particularly hills and speed work
- Returning after a layoff at pre-break volume
- A change in footwear, especially to a lower heel-to-toe drop
- Calf weakness, measured most usefully by single-leg heel raise capacity
- Age between 30 and 50, when tendon turnover slows
- Fluoroquinolone antibiotics, which carry a recognised association with tendon injury and rupture
The single best functional measure is single-leg heel raise capacity. A healthy calf should manage around 25 controlled full-range repetitions on one leg. Most people arriving with Achilles pain manage eight to twelve on the affected side, and often not many more on the other. That number gives an objective target, tracks progress week to week, and usually explains how the problem started in the first place.
What the evidence says
Progressive loading is the best-supported treatment. Alfredson's eccentric heel drop protocol, three sets of fifteen twice daily, has strong trial support for midportion tendinopathy. Heavy slow resistance protocols achieve comparable results with a considerably lower time burden, which makes adherence better.
Insertional tendinopathy responds poorly to the classic eccentric protocol performed off a step, because dorsiflexion beyond neutral compresses the tendon against the heel bone. Loading performed on flat ground, without dropping the heel below level, is better tolerated and better supported.
Continued running is generally safe within a pain-monitoring rule. Trials using a scale where pain up to 5 out of 10 during running is acceptable, provided it settles by the next morning, found no worse outcomes than complete rest, with better adherence and fitness.
Shockwave therapy has reasonable evidence as an adjunct, particularly for insertional cases and for midportion cases that have not responded to three months of loading. It works best combined with a loading programme rather than instead of one.
Corticosteroid injection into or around the Achilles is avoided, given the association with tendon rupture.
Recovery timeline
Expect three to six months for a well-established case, and longer if it has been going for a year. Early cases caught within six weeks often settle in eight to twelve weeks.
Morning stiffness is the most useful progress marker. A tendon that used to need fifteen minutes to loosen and now needs three is improving, even if the run still feels the same.
| Stage | ✓ Do this | ✗ Avoid this |
|---|---|---|
| Weeks 1–2 | Establish a baseline heel raise count. Start isometric calf holds for pain relief. Reduce, rather than stop, running volume. | Complete rest, or stretching an insertional tendon into deep dorsiflexion |
| Weeks 2–12 | Heavy slow resistance calf work three times a week, straight and bent knee. Progress load every fortnight. | Staying at the same weight for three months |
| Weeks 6–16 | Add plyometric and spring loading: skipping, hops, then strides, before returning to speed work. | Reintroducing hills and intervals in the same week |
| Ongoing | Two calf sessions a week as maintenance. Increase mileage gradually with a planned down week. | Dropping calf work the month the pain goes |
How we treat it at Kingsway
Treating a painful Achilles
The assessment establishes which pattern you have, measures calf capacity, and looks at the training history that produced it.
- Palpation to locate the pain precisely, which separates midportion from insertional
- Single-leg heel raise capacity measured on both sides and recorded
- Soft tissue release and IASTM through the calf complex and the tendon's paratenon
- Ankle joint mobilisation where dorsiflexion range is restricted
- Radial shockwave therapy for cases past three months, or insertional cases from the outset
- A loading programme matched to your pattern, with a running pain rule written down
This condition rewards a longer relationship than most. Sessions every two to three weeks over three to four months, tracking heel raise capacity each time, is a typical course. The ten session package generally fits it better than paying per visit.
When to get it checked
Book an assessment if Achilles pain has lasted more than three weeks, if morning stiffness is persistent, or if it has stopped you running. Get seen urgently after any sudden sharp pain with a sensation of being kicked in the back of the ankle, since that can indicate a rupture.
See a doctor or go to A&E if
- Sudden sharp pain with a snapping sensation, and difficulty pushing off or standing on tiptoe
- A palpable gap in the tendon
- Marked swelling, redness or heat over the tendon
- Recent fluoroquinolone antibiotic use with new Achilles pain, which warrants prompt review
- Pain that is severe, constant and unrelated to activity
Common questions
Can I keep running?
Usually yes, within a pain rule. The commonly used version allows pain up to 5 out of 10 during the run, provided it has settled by the following morning and your morning stiffness is not getting worse week to week.
If either of those conditions fails, reduce volume for a week rather than stopping altogether.
Should I stretch my calf?
For midportion tendinopathy, gentle calf stretching is usually fine and often feels helpful.
For insertional tendinopathy, deep stretching that pushes the ankle past neutral compresses the tendon against the heel bone and commonly makes it worse. Loading on flat ground is the better choice there.
Do heel raises in shoes count?
A small heel lift can be genuinely useful in insertional cases, reducing compression at the attachment. Many people find a 6 to 10 mm lift makes early loading much more comfortable.
It is a temporary aid rather than a fix, and it comes out gradually as capacity improves.
Is shockwave worth it?
It is a reasonable adjunct for cases that have already had a proper loading programme for three months without enough progress, and for insertional cases from earlier on.
It works alongside loading rather than replacing it. Shockwave with no exercise programme rarely holds.