Achilles tendinopathy: causes, rehab and recovery

What Achilles tendinopathy is

The Achilles tendon connects the calf muscles to the heel bone. It is the thickest and strongest tendon in the body, and it acts as a spring during walking, running and jumping. Tendinopathy develops when the tendon is repeatedly loaded more than it can adapt to, leading to pain, stiffness and reduced tolerance for running and jumping.

There are two main types. Mid-portion tendinopathy affects the middle of the tendon, roughly 2 to 6 cm above the heel, and often causes a thickened, tender area. Insertional tendinopathy affects the point where the tendon attaches to the heel bone, and is often aggravated by stretching the calf and by shoes that press on the back of the heel.

Common causes and who gets it

It is common in runners and in people aged roughly 30 to 60, particularly those who play sport in bursts. It often follows a change in load:

• A quick increase in running distance, speed or hills
• Adding lots of jumping, skipping or plyometric work
• A HYROX block that stacks running, sled pushes, lunges and burpee broad jumps
• Switching to lower-drop or minimal shoes quickly
• Returning to training after a break at the same volume as before

Other factors that make tendons less tolerant include higher body weight, diabetes, high cholesterol and some medicines, particularly fluoroquinolone antibiotics. If you develop Achilles pain while taking one of these antibiotics, speak to your GP or pharmacist promptly.

Typical symptoms

The classic pattern is stiffness and pain in the tendon first thing in the morning, which eases as you get moving. Runners often find the tendon sore at the start of a run, easing as they warm up, then worse later that day or the next morning. The tendon may feel thickened or tender to squeeze.

Insertional tendinopathy causes pain right at the back of the heel and is often worse walking uphill, climbing stairs, or wearing shoes with a stiff heel counter. Sudden, severe pain with a feeling of being kicked is different and suggests a rupture, which needs urgent assessment.

What a physio assessment looks at

Your physio will ask about your training, footwear, health and medicines, then examine the tendon to pinpoint where it hurts and check its integrity with a squeeze test. They will measure calf strength and endurance, often by counting single-leg calf raises, and watch you hop and walk.

They will also rule out other causes of pain at the back of the ankle and heel. Ultrasound or MRI is not usually needed to start treatment, and changes on scans do not always match symptoms.

Expect a clear plan that fits your week: which runs to keep, which to swap for cycling or rowing, and how often to do the calf work. Consistency over months is what changes a tendon, so the plan needs to be realistic for your life.

What usually helps

The treatment with the strongest evidence is a progressive calf loading programme, performed consistently over at least 12 weeks. It usually starts with isometric holds and double-leg calf raises, progresses to single-leg and weighted calf raises with both a straight and bent knee, and finally adds faster movements such as hopping and skipping before a full return to running and jumping.

Load management runs alongside. That usually means reducing running volume and speed for a while, avoiding hills and sprinting, and choosing flatter routes, rather than stopping completely. For insertional tendinopathy, do calf raises on a flat floor rather than dropping the heel off a step, avoid calf stretches, and a small heel lift in the shoe may help. Shockwave therapy has some evidence for persistent cases. Steroid injections into the Achilles are generally avoided because of concerns about tendon rupture.

What you can start with at home

1. Isometric calf holds: rise onto your toes on both feet, hold for 30 to 45 seconds, 4 to 5 times.
2. Double-leg calf raises, 3 sets of 15, slow up and slow down.
3. Single-leg calf raises with a straight knee, building to 3 sets of 15, then adding weight.
4. Seated or bent-knee calf raises for the deeper calf muscle, 3 sets of 15.
5. Keep running within a level of pain that settles by the next morning, on flat routes.

When you are ready to rebuild running volume, our guide to returning to running after injury sets out the stages, and our guide to HYROX running training covers building volume sensibly for race preparation.

Footwear matters for some people. Avoid switching shoe types suddenly while the tendon is sore, and if the back of your shoe presses on a painful insertion, try a different pair or a heel pad. A consistent routine counts for more than any single piece of kit.

Recovery time and when to get help

Tendons adapt slowly. Many people improve meaningfully over 12 weeks of consistent loading, but full recovery commonly takes 3 to 6 months and sometimes longer, especially for insertional pain. The on-site physio at Lycan Strength can plan your loading and return to running, with 20% off for members; book a physio appointment online.

• Go to A&E the same day if you felt a kick, snap or sudden sharp pain at the back of the ankle and now cannot push off or stand on tiptoe.
• Call NHS 111 or see a GP urgently if the tendon is hot, red and swollen, or you have a fever.
• Speak to your GP or pharmacist promptly if Achilles pain started while taking fluoroquinolone antibiotics.
• Call NHS 111 or see a GP urgently for a swollen, warm, painful calf. Call 999 with chest pain or breathlessness.

Questions