Achilles tendinopathy is pain and stiffness in the Achilles tendon caused by the tendon’s load capacity falling behind the demands placed on it, not by inflammation, despite the old name “Achilles tendinitis”. It typically builds gradually as an ache or stiffness at the back of the heel or mid-tendon, often worse first thing in the morning or at the start of a run.
The underlying mechanism is a mismatch between what the tendon’s collagen structure can currently tolerate and the load it is repeatedly asked to absorb, usually from a change in running volume, hill work, footwear, or standing load. The tendon does not need to be torn or “inflamed” for this to hurt; it can simply be overloaded.
If your pain built gradually with no sudden pop, snap or inability to push off, the sensible first step is the self-check below, followed by graded calf loading rather than rest or stretching alone. A sudden snap, a feeling of being kicked in the calf, or inability to rise on your toes changes the picture and is covered in the red flags section.
This guide covers what is happening in the tendon, why morning pain is so predictable, what the evidence says about loading versus rest, a self-check, and how we treat it at Woodford Physio.
Why “tendinitis” is the wrong word for most Achilles pain
Most Achilles pain is a tendon structure problem from cumulative overload, not active inflammation, which is why anti-inflammatory approaches alone rarely fix it.
Healthy tendon is made of tightly organised collagen fibres that handle huge tensile loads, several times body weight during running, every stride. When load repeatedly exceeds what the tendon can adapt to, the collagen structure becomes disorganised and the tendon thickens as it tries to cope, a process called tendinopathy. This is a failed adaptation response, not a bout of inflammation waiting to be calmed down with rest and ice. That distinction matters practically: rest lets pain settle temporarily because demand drops, but it does nothing to rebuild the tendon’s capacity to tolerate load, so symptoms tend to return as soon as running resumes. The tendon needs a stimulus to remodel and strengthen, which is why loading, not avoidance, is the foundation of recovery.
What causes it and who gets it
Achilles tendinopathy is most common in runners who increase volume, intensity or hill work too quickly, and in anyone with reduced calf strength or ankle mobility feeding extra strain through the tendon.
We see it often in runners across Marple, Heaton Moor and Woodford building up for an autumn race, in five-a-side and racquet sport players doing repeated push-off and change of direction, and in people who have simply increased standing or walking load after a period of inactivity. A sudden switch to unfamiliar footwear, or a jump in hill sessions, is a common trigger because both can increase the tensile demand on the tendon per stride. Reduced ankle dorsiflexion range and weak calf muscles are also common findings, since they force the tendon to absorb more of the load that the ankle joint and calf muscle would otherwise share.
Why the first steps in the morning hurt most
Morning and first-step pain happens because the tendon has had hours without load, and the first loaded steps ask a sensitised structure to work before it has “warmed into” tolerating compression and stretch again.
This is not a sign the tendon has worsened overnight. Tendon tissue fluid content and stiffness change with rest, and a tendinopathic tendon in particular is more reactive to the first loading cycles after a period of inactivity, whether that is overnight sleep or a long car journey. The pain typically eases within five to ten minutes of gentle movement as the tendon adjusts, then can return later with higher-load activity like running. Understanding this pattern matters because many people wrongly read morning pain as proof they should rest completely, when in fact a brief, gentle warm-up of calf raises before the day’s first loaded steps, alongside the structured programme below, is the more useful response.
Self-check: is this likely Achilles tendinopathy, and what to try first
| Question | If yes | If no |
|---|---|---|
| 1. Gradual onset, no sudden snap or “kicked in the calf” feeling? | Consistent with tendinopathy. Continue. | See red flags below first. |
| 2. Pain and stiffness worse at the start of activity, easing after five to ten minutes? | Classic tendinopathy pattern. | Still worth assessment. |
| 3. Can you rise onto your toes on the affected leg, even if it hurts? | Reassuring; graded loading usually appropriate. | Needs same-day assessment before loading. |
| 4. Is pain easing, steady, or worsening week on week with normal activity? | Continue sensible loading. | Book an assessment. |
If you answered “yes” to questions 1 to 3, begin daily calf raises within a pain range of 3/10 or less, hold running volume steady rather than increasing it, and avoid hill sprints for one to two weeks. Not settling within two to three weeks, or a different pattern: book an assessment rather than continuing to guess.
What the evidence actually says
Evidence strongly favours progressive calf loading over rest, stretching or anti-inflammatories as the primary treatment for Achilles tendinopathy.
A review of Achilles tendinopathy management for general practice reports that exercise-based programmes built around eccentric calf training have the best evidence base, with around 82% of patients recovering within three months, and specifically recommends that patients “adjust their usual activity” rather than stop altogether. A separate randomised controlled trial comparing heavy slow resistance training against the traditional eccentric (Alfredson) protocol found both approaches produced comparable improvements in pain and function at twelve months, giving people a choice of loading style rather than one single “correct” protocol, since heavy slow resistance is often better tolerated and easier to progress in a gym setting. Where evidence is more mixed is on how quickly to progress load and whether adding manual therapy or shockwave speeds recovery; current consensus is that consistency of loading over at least twelve weeks matters more than the specific exercise chosen.
When to worry: red flags for the Achilles tendon
Most Achilles pain is tendinopathy and is not an emergency, but a sudden injury needs same-day assessment rather than a physiotherapy booking.
Seek urgent medical assessment (GP, 111, or A&E/999 if severe) for: a sudden snap, pop, or a sensation of being kicked or hit in the back of the calf during activity, which can indicate a tendon rupture; inability to rise onto your toes or push off when walking following such an event; visible swelling or a gap felt in the tendon; or calf pain with swelling, warmth and redness that could indicate a blood clot rather than a tendon problem, which needs same-day medical review. The NHS Scotland Achilles rupture pathway notes rupture risk during tendinopathy is low, but any of the signs above should not wait for a routine appointment.
How we assess and treat Achilles tendinopathy at Woodford Physio
Assessment includes a running and training history, palpation to locate whether the problem sits mid-tendon or at the heel insertion (which changes the loading programme), calf strength and ankle mobility testing, and often a simple single-leg heel raise capacity test to establish your starting point. Rick’s background across elite sport, including pitch-side work with Sale Sharks and Blackburn Rovers, informs a running-mechanics and load-management view of Achilles problems rather than treating the tendon in isolation from training habits. Initial assessments run 45 minutes, and the calf loading programme is progressed week to week using your pain and heel-raise capacity as the guide, typically starting isometric or slow concentric work before building to heavier or eccentric loading. This sits within our wider sports injury treatment service, and for runners rebuilding training volume afterwards our physio rehab programme carries the plan through to full return to running.
Common questions
Is Achilles tendinopathy the same as Achilles tendinitis?
Not quite. Tendinitis implies active inflammation, while tendinopathy describes a structural, load-related change in the tendon with little true inflammation present in most cases. The distinction matters because it explains why rest and anti-inflammatories alone often do not resolve symptoms, while progressive loading does.
Should I stop running completely with Achilles tendinopathy?
Usually not. Complete rest reduces pain temporarily but does not rebuild the tendon’s load capacity, so symptoms often return once running resumes. Reducing volume and avoiding hills or speed work for one to two weeks while starting calf loading tends to work better than stopping entirely.
How long does Achilles tendinopathy take to recover?
Many people see meaningful improvement within six to twelve weeks of consistent calf loading, though a tendon that has been overloaded for months before treatment starts can take longer, sometimes three to six months for full return to demanding running. Progress is rarely a straight line.
Do I need a scan for Achilles pain?
Not usually for a typical gradual-onset presentation. Ultrasound or MRI is more useful when a partial tear or rupture is suspected, when red flags are present, or when a structured loading programme has not helped after a proper trial.
Does stretching help Achilles tendinopathy?
Gentle stretching is not harmful for most people, but it is not the primary driver of recovery and can occasionally provoke insertional Achilles pain if overdone. Progressive strength loading has considerably stronger evidence behind it than stretching alone.
Why does my Achilles hurt most in the first few minutes of a run?
The tendon has had a period without load, whether overnight or from a long day sitting, and the first loaded steps ask a sensitised structure to work before it adjusts. This typically eases within five to ten minutes and is not a sign of worsening damage, though it is worth heeding if pain climbs rather than settles as you continue.
About the author
Rick Porter is a JEMS-certified physiotherapist with twenty years in elite sport, including Sale Sharks, Blackburn Rovers and McLaren F1, and lectures at university level on movement and rehabilitation. He specialises in load-management based rehabilitation for runners and field-sport athletes. Book an appointment with Rick.
Book your Achilles assessment
If Achilles pain is limiting your running or daily activity, book an appointment for a full assessment and a loading plan built around your tendon’s current capacity. Not sure physiotherapy is the right step? Book a free 15-minute telephone consultation first.