MSK · Achilles

Achilles Pain — Tendinopathy or Rupture?

One builds slowly over weeks. The other happens in a second, and is missed surprisingly often. Telling them apart is the most important thing on this page.

Runner pausing on a path holding the back of the lower leg above the heel

A suspected rupture is same-day, not next week

A sudden snap or pop at the back of the ankle — often described as feeling kicked from behind — with difficulty pushing off, rising onto the toes, or walking normally, needs assessment today. Go to A&E or an urgent treatment centre, or call NHS 111. Outcomes are better when a rupture is treated early, and a proportion are missed at first because people can often still walk. Do not book a routine scan and wait.

Away from that scenario, most Achilles pain is tendinopathy: a gradual, load-related problem that builds over weeks. It is stiff and sore in the morning, eases as you warm up, and complains again afterwards.

Telling Them Apart

Rupture or tendinopathy?

Tendinopathy Rupture
Onset Gradual, over weeks Sudden, a single moment — often a snap or pop
Typical trigger An increase in running, hills or speed work Pushing off — sprinting, jumping, a racquet sport
Pain now Sore, stiff, worse in the morning Sometimes surprisingly little after the initial pain
Pushing off / on tiptoes Uncomfortable but possible Weak or impossible on that leg
The tendon itself Thickened, tender, continuous May have a palpable gap
What to do Load management, physiotherapy, scan if not settling Same-day urgent assessment
The Scan

What ultrasound shows

The Achilles is superficial, large and easy to follow along its length, which makes it one of the structures ultrasound assesses best. A scan shows tendon thickening and the disorganised tissue of tendinopathy, distinguishes mid-portion problems from insertional ones at the heel bone, identifies partial tears, and finds the associated bursitis that often accompanies insertional pain.

Crucially, it is a moving test: with the ankle flexed and pointed, a rupture can be seen as the tendon ends separate, and the gap measured. That real-time assessment is genuinely useful for a surgeon deciding between surgical and non-surgical management — but it is assessment that belongs in an urgent care setting on the day, not a scan you book for next week.

Where the distinction matters clinically: mid-portion and insertional tendinopathy respond to different loading programmes, so naming which one you have changes the rehab, not just the label.

At IUS London

How the appointment runs

  1. 1
    BookingFor persistent tendon pain, not for a suspected rupture — that goes to urgent care today. No referral, no preparation, 30 minutes.
  2. 2
    The scanLying face down with the feet over the end of the couch. The tendon is followed from the calf to its insertion, at rest and with the ankle moving.
  3. 3
    What we assessTendon thickness and structure, mid-portion versus insertional involvement, partial tears, bursitis, and the other side for comparison.
  4. 4
    ResultsExplained on screen as we scan, with the written report usually within two hours — detailed enough for a physiotherapist to build the right loading programme.
FAQs

Your questions answered

Can you walk on a ruptured Achilles?
Often yes, which is exactly why ruptures get missed. Other muscles can still point the foot down, so walking may be possible while pushing off properly is not. If a snap happened, get it assessed the same day even if you walked home.
How long does Achilles tendinopathy take to settle?
Months rather than weeks, and progressive loading is what shifts it. Improvement is usually gradual and non-linear — that is normal for tendons rather than a sign of something being missed.
What is the difference between mid-portion and insertional?
Where along the tendon the problem sits — a few centimetres above the heel, or right at the bone. It matters because the rehab differs: insertional problems generally tolerate less stretch into dorsiflexion, so a programme that helps one can aggravate the other.
Should I rest completely?
Usually not. Complete rest tends to leave the tendon less capable. Reducing the provoking loads while continuing to work the tendon in tolerable ranges is the general direction — a physiotherapist should set the specifics.
Do I need an MRI instead?
Rarely for the Achilles. Ultrasound is well suited to this tendon and adds the advantage of moving assessment. MRI is reserved for complex cases or surgical planning.
Is a lump on the tendon serious?
A thickened, tender area is typical of tendinopathy and usually not sinister. It is worth having characterised if it is growing, if it is painless, or if it does not fit the usual pattern.
Related

Where to go from here

HeelHeel Pain

Plantar fasciitis and what else causes first-step pain.

Read the guide →KneeKnee Pain After Exercise

What ultrasound answers about a painful knee — and what it cannot.

Read the guide →ScansOther MSK Scans

Calf, hamstring, groin and other soft tissue areas.

See scans →

Name the problem, target the rehab

The whole tendon assessed at rest and moving — mid-portion or insertional, partial tearing, bursitis — explained on screen as we scan, with the written report usually within two hours for your physiotherapist.

From £169
Ankle ultrasound scan

Ankle scan

5a Lucerne Mews
Kensington, London W8 4ED
3 mins from Notting Hill Gate

This article is general information about Achilles pain, not individual medical advice. A suspected rupture — a sudden snap with difficulty pushing off — needs same-day urgent assessment, not a booked scan. See NHS guidance on tendonitis and tendon injuries. We provide diagnostic ultrasound only; we do not offer injections or surgery.

Written and clinically reviewed by the HCPC-registered sonographers who perform this scan at IUS London — a CQC-registered diagnostic ultrasound clinic (Provider ID 1-2775844974). Your own findings are explained to you at the scan and set out in your report.

Author: Yianni Kiromitis, Senior Sonographer, HCPC RA38415 — over 20 years’ experience in NHS and private ultrasound
Medically reviewed: 9 August 2026