Achilles Tendonitis

What Causes Achilles Tendonitis?

Achilles tendonitis — more accurately called Achilles tendinopathy — is pain in the Achilles tendon, the thick cord running from your calf muscles to your heel bone. It’s a load tolerance issue: the tendon is being asked to handle more load than it’s currently capable of managing.

There are two main types, and location matters:

Mid-portion Achilles tendinopathy: Pain 2-6 cm above the heel, in the middle section of the tendon. This is the most common type. The tendon often feels thick or nodular when you press on it. Pain is worse with running, jumping, and going up on your toes.

Insertional Achilles tendinopathy: Pain right at the heel where the tendon attaches to the bone. Often associated with a bony bump (heel spur) and can be more stubborn to treat than mid-portion. Worse with push-off activities and sometimes painful when wearing shoes that press on the area.

Common causes include sudden increases in running volume or intensity, introducing hill running or speed work before building adequate calf strength, returning to sport after time off, poor calf strength, and inadequate recovery between training sessions.

I see this constantly among runners across Liverpool, Chester, and Merseyside who’ve ramped up mileage for a marathon, footballers in Cheshire doing pre-season without proper conditioning, and gym-goers who’ve added high-volume jumping or plyometric work without progressive build-up.

How Achilles Tendonitis Develops

It usually starts gradually. A bit of stiffness in the Achilles first thing in the morning or at the start of a run. You warm up, it eases, you keep training. Then it starts lingering. Soon you’re limping in the morning, struggling with stairs, and cutting runs short because the pain won’t settle.

Acute Onset (Training Load Spike)

The classic trigger: you increase running volume for a race, start doing hill sprints, ramp up football training, or return to sport after time off.

Your Achilles hasn’t had time to adapt to the increased load. Tendons adapt slower than muscles — they need progressive, gradual load increases over weeks and months. When you exceed that capacity, the tendon structure starts to break down and becomes painful.

This is very treatable if caught early. Load management and structured progressive loading usually get acute cases sorted within 8-12 weeks.

Chronic/Reactive-On-Degenerative Pattern

You’ve had Achilles pain on and off for months or years. It flares up with training, settles when you rest, flares up again when you return.

This happens because you never addressed the underlying problem — the tendon has lost capacity and hasn’t been properly rehabbed. Resting settles pain temporarily, but when you return to running at the same intensity, the tendon can’t handle it.

Chronic Achilles tendinopathy often shows degenerative changes on ultrasound — areas of thickening, disorganised tendon structure, sometimes calcification. This sounds alarming, but it doesn’t mean the tendon is doomed. Degenerative tendons can still be loaded progressively and can improve significantly with the right rehab approach.

These cases need serious commitment — 12-16 weeks or longer of consistent progressive loading. Shockwave therapy alongside rehab often helps chronic cases that haven’t responded to loading alone.

Insertional Achilles Tendinopathy

This is pain right at the back of the heel where the tendon attaches to the bone. It’s less common than mid-portion tendinopathy but tends to be more stubborn.

Often there’s a bony spur visible on X-ray at the attachment site. People assume the spur is the problem, but it’s usually an incidental finding — plenty of people have heel spurs with no pain.

Insertional tendinopathy can be aggravated by shoes that press on the back of the heel, hills (particularly downhill running), and activities involving repetitive push-off like sprinting or jumping.

Treatment is similar to mid-portion tendinopathy — progressive loading — but it often takes longer to settle and sometimes needs additional interventions like shockwave therapy or, in resistant cases, surgical referral.

What You Can Expect in Your Assessment

I’ll take a detailed history — when the pain started, what makes it worse, how it behaves during and after activity, what you’ve tried already, and what your goals are. Whether that’s getting back to marathon training along the Chester Greenway, returning to football for a Merseyside club, or just being able to walk without limping.

Then I’ll assess your Achilles — palpation to identify the exact location of pain and any thickening or nodules, range of movement in your ankle, calf strength testing, and loading tests like single-leg calf raises and hopping to reproduce symptoms and assess function.

I’ll watch you walk, jog if symptoms allow, and assess your running mechanics to see if there are contributing factors like poor foot strike or calf weakness.

By the end of the session, you’ll have:

Do I Need a Scan?

Maybe. Many cases of Achilles tendinopathy can be diagnosed and managed clinically without imaging.

Ultrasound is useful if:

• We need to confirm the diagnosis and rule out other causes of heel/ankle pain
• We want to assess tendon structure and see whether there’s degeneration, partial tearing, or reactive changes — this helps guide prognosis and treatment intensity
• Symptoms aren’t improving as expected and we need to reconsider the diagnosis
• You’re an athlete needing detailed prognostic information for return-to-sport planning

Ultrasound is excellent for Achilles tendons — it’s dynamic, I can assess the full length of the tendon and see exactly where the pathology is, and it’s cheaper than MRI.

MRI is rarely needed unless there’s concern about a complete Achilles rupture or significant associated injuries.

If imaging is needed, I’ll guide you on the best route — private ultrasound if you want results quickly, or NHS referral via your GP if you’re happy to wait.

Why Rest Alone Doesn’t Work

People rest from running and sport, the Achilles pain settles a bit, they return to activity, and within days or weeks it flares up again. This is the classic reactive tendinopathy pattern.

Here’s why: rest reduces pain by removing the aggravating load, but it doesn’t rebuild the tendon’s capacity to handle load. Tendons need controlled loading to stimulate adaptation and strengthen.

When you return to running at the same volume and intensity you were doing before resting, you’re asking a deconditioned tendon to handle loads it couldn’t manage before. It breaks down again.

Complete rest also leads to further weakening of the calf muscles, which puts even more stress on the Achilles when you return to activity.

What Does Achilles Tendonitis Rehab Involve?

Here’s what most Achilles tendinopathy rehab programmes include:

Isometric calf loading: Early-stage exercises where you load the calf and Achilles without movement — like calf raises held at the top position. This reduces pain in the short term and starts the tendon adaptation process.

Eccentric calf strengthening: The gold standard for mid-portion Achilles tendinopathy. Eccentric exercises (slowly lowering down from a calf raise) load the tendon in a lengthened position and have strong research support. These are tough — expect some discomfort during the exercise — but they work.

Progressive loading: We start with body weight, then add load (weighted vest, dumbbells, barbell) as tolerated. The goal is to progressively overload the tendon so it adapts and gets stronger. This takes weeks, not days.

Load management: Reducing running volume, avoiding hills and speed work, modifying training to stay within tolerable pain levels while building capacity. Complete cessation isn’t always necessary — it depends on severity.

Running reintroduction: Once you’ve built adequate strength and the tendon is less reactive, we reintroduce running gradually — flat routes, easy pace, low volume initially, then progressive build-up over weeks.

Shockwave therapy (for chronic cases): If you’ve had Achilles tendinopathy for over 3 months and it’s not responding to loading alone, shockwave therapy can be highly effective. It stimulates tendon remodelling and reduces pain. I offer this alongside structured loading programmes.

Return-to-sport criteria: You don’t just go back when it feels okay. You need to demonstrate adequate calf strength (usually single-leg calf raises for 25+ reps pain-free, or close to symmetry with the other side), pass hopping tests, and complete sport-specific training without significant pain before you’re cleared to return.

How Long Does Recovery Take?

Realistic timescales for Achilles tendinopathy:

Acute mid-portion tendinopathy (less than 6 weeks): 8-12 weeks with structured progressive loading. You won’t be completely out of running — we modify it and work within tolerable pain levels.

Chronic mid-portion tendinopathy (over 3 months): 12-16 weeks, sometimes longer. The longer you’ve had it, the more degenerative changes there are, and the longer it takes to rebuild capacity. But even chronic cases respond to progressive loading if you’re consistent.

Insertional tendinopathy: 12-20 weeks. This type is slower to respond than mid-portion. It requires patience and often needs shockwave therapy or other adjunct treatments alongside loading.

Return to running: Varies, but typically 6-10 weeks for acute cases, 12-16 weeks for chronic cases. This assumes you’re progressing through rehab phases appropriately and symptoms are settling.

Return to full training and sport: 12-16 weeks for acute cases, 16-24 weeks for chronic cases. Tendons are slow to adapt. Trying to rush this usually results in setbacks.

The key variable is consistency with progressive loading exercises. If you do the calf strengthening programme 4-5 times per week and manage training load appropriately, you’ll see improvement. If you’re sporadic with rehab and keep trying to push through significant pain during running, recovery drags on indefinitely.

When to Book an Assessment

If you’ve felt a sudden pop in the back of your ankle during activity and now can’t push up onto your toes, don’t wait for a physio appointment — get yourself to A&E. That’s a potential Achilles rupture and needs urgent assessment.

For everyone else: Achilles tendinopathy is very treatable. It takes time and consistent effort, but you don’t need to live with it or give up running permanently.

Location and Booking

I run a clinic in Chester, with appointments available Monday, Wednesday, Thursday, and Friday.

Whether you’re a runner across Cheshire with chronic Achilles pain limiting training, a footballer from Chester struggling with pre-season, or a gym-goer from Cheshire dealing with stubborn insertional tendinopathy, I can help.

Book online to see available slots, or get in touch if you’ve got questions before booking.

No hard sell. No obligation. Just honest physio focused on getting your Achilles properly rehabbed with a progressive loading plan that actually works.