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Health condition

Achilles tendon strain, a partial tear - not a rupture, and not just tendinopathy.

When some but not all of the tendon fibres tear, the plan is protected loading in a walking boot and a graded return - not surgery, but not quick either.

Jump to treatment
A radiographer guides a patient onto the bed of an advanced 3 Tesla MRI scanner in a London imaging suite

Why trust this guide

  • 01

    Editorial team

    Written by our editorial team from the UK sources listed on each page.

  • 02

    Sourced from guidance

    Checked against BOA/BOFAS, NICE CKS and peer-reviewed sports-medicine sources you can see at the end.

  • 03

    Current for 2026

    Reflects modern UK practice - CAM boot with heel wedge, graded loading and imaging to distinguish partial from complete rupture.

Key facts

Achilles strain at a glance.

A partial tear of the Achilles - distinct from tendinopathy, tendinitis and complete rupture. The grade is what shapes the plan.

  • What it is

    A partial tear of the Achilles tendon - some fibres disrupt but the tendon is not fully through, so the calf-to-heel connection is preserved.

  • Not the same as

    Distinct from tendinopathy (chronic overload), tendinitis (acute inflammation) and complete rupture (full loss of continuity).

  • How it happens

    A sudden calf explosion - a sprinter push-off, a jumping landing or a missed step off a kerb - overloads the tendon past its yield point.

  • Grading

    Grade I mild (under 10% of fibres), Grade II moderate (10-90%), Grade III complete rupture - each grade drives a different plan.

  • Key clinical test

    Simmonds/Thompson calf-squeeze test - if the foot still plantarflexes, the tendon has continuity and the tear is partial, not complete.

  • Imaging

    Ultrasound or MRI grades the tear and measures any fibre gap - the numbers change management, not just the label.

Why this guide matters

Right injury, right pathway.

Partial Achilles tears sit between chronic tendinopathy and outright rupture. Getting the grading right is what saves people from either doing too little or being rushed into surgery.

  • It is not tendinopathy

    Tendinopathy is a chronic overload injury. A strain is a discrete tearing event with sudden pain, swelling and often a pop.

  • It is not a rupture

    A complete rupture loses tendon continuity - the Thompson test fails. That injury goes to foot-and-ankle surgery, not a walking boot alone.

  • Grade drives everything

    Grade I and II are managed conservatively with protected loading and calf rehab. Grade III is a surgical conversation. Imaging tells you which one you have.

How the diagnosis is made

From the pitch or the pavement to a clear plan.

A structured history, a focused examination, the Thompson test and, in most cases, an ultrasound - together they answer the only question that matters early on: partial, or complete?

  1. 01

    Assessing

    History of the moment

    A clear "pop" or "kick from behind" during push-off, jumping or stepping off - along with sudden posterior-heel pain and difficulty pushing off.

  2. 02

    Assessing

    Focused examination

    Look for calf swelling, bruising and a palpable gap or tender thickening 2 to 6 cm above the heel insertion.

  3. 03

    Assessing

    Simmonds/Thompson test

    Prone, knee bent, calf squeeze - preserved plantarflexion suggests continuity (partial tear); absent movement suggests complete rupture.

  4. 04

    Confirming

    Ultrasound scan

    Real-time imaging shows fibre disruption, tendon thickness and dynamic behaviour on gentle dorsiflexion - excellent for grading partial tears.

  5. 05

    Confirming

    MRI when detail is needed

    Reserved for equivocal cases, mid-substance vs insertional injuries or when a gap measurement will change the surgical decision.

  6. 06

    Planning

    Grade the injury

    Grade I (mild, under 10%), Grade II (moderate, 10-90%) or Grade III (complete rupture) - each has a different pathway.

  7. 07

    Planning

    Referral decision

    Grade III (rupture) goes to foot-and-ankle surgery for consideration of repair - see our Achilles tendon repair page. Grade I to II is managed conservatively.

Typical timeline: clinical assessment and imaging within days - a clear plan by the end of the first week.

Symptoms

What a partial tear feels like.

A sudden mechanism, a pop or snap, and a calf-heel unit that no longer pushes off cleanly - plus the sign that tells us the tendon is still connected.

  • Sudden posterior-heel pain

    A sharp pain low in the calf or above the heel at the moment of push-off, jump landing or missed step.

  • Audible "pop" or snap

    A perceived kick, snap or pop from behind - often mistaken for being struck by another player or a stone.

  • Swelling and bruising

    Localised swelling and a bruise that tracks down toward the heel and ankle over the first 24 to 72 hours.

  • Palpable tenderness or gap

    Tenderness 2 to 6 cm above the heel insertion; sometimes a subtle dip or thickening the examiner can feel.

  • Weak push-off

    Difficulty rising on tip-toes or pushing off during walking - a strong clue the calf-tendon unit is not transmitting force normally.

  • Antalgic gait

    A flat-footed, limping gait to avoid loading the tendon - and reduced stride length on the affected side.

  • Preserved plantarflexion

    The foot still moves down on calf squeeze - a reassuring sign the tendon has continuity (partial, not complete tear).

  • Red flag - absent Thompson response

    No plantarflexion on calf squeeze strongly suggests complete rupture - urgent orthopaedic referral within days, not weeks.

Treatment

How a partial Achilles tear is treated.

Protected loading in a CAM boot with heel wedges, followed by a graded calf-strength programme and a staged return to sport over 8 to 16 weeks.

  • Protected weight-bearing (CAM boot + heel wedge)

    The mainstay for Grade I to II tears - a walking boot with 2 to 3 cm heel wedges offloads the tendon while allowing safe walking. Typically 2 to 4 weeks with staged wedge removal.

  • Relative rest and load management

    Stop the offending sport, avoid unprotected walking and any explosive push-off for the first 6 to 12 weeks - the tendon needs time before it is asked to sprint again.

  • Graduated calf-strengthening programme

    Progressive isometric then heavy-slow eccentric calf work under physiotherapist guidance - the single strongest driver of tendon healing and re-tear prevention.

  • Gradual return to running

    A staged return over 8 to 16 weeks - walking, then jogging on level ground, then straight-line running, then change-of-direction and finally sport-specific loading.

  • Simple analgesia

    Paracetamol first-line; short courses of NSAIDs used cautiously in the first 48 hours - long-term NSAIDs are avoided because they may impair tendon healing.

  • Adjunct - PRP or shockwave

    Platelet-rich plasma injection and extracorporeal shockwave therapy are sometimes offered - evidence in partial Achilles tears is limited and inconsistent.

  • Refer for surgical repair (Grade III)

    A complete rupture is a different injury with a different pathway - see our Achilles tendon repair page. Delayed diagnosis of rupture worsens outcomes.

  • Avoid full weight-bearing on the unprotected tendon

    For the first 6 to 12 weeks, unprotected walking, stairs and any push-off risk extending a partial tear into a complete one.

What this guide is based on

The sources behind every claim on this page.

UK national guidance and specialist society standards, current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your GP, physiotherapist or orthopaedic surgeon knows your leg and your history and can tell you which parts apply to you. If in doubt, get seen.

  • British Orthopaedic Foot and Ankle Society (BOFAS). Achilles tendon injury guidance.

  • NICE Clinical Knowledge Summary. Achilles tendinopathy and tendon injury.

  • BMJ Best Practice. Achilles tendon rupture and partial tear - assessment and management.

  • UK Sports Medicine consensus statements on Achilles tendon loading and return-to-play.

Red flags

When Achilles pain needs urgent attention.

Most partial tears are managed in primary care and physiotherapy. These are the situations that push the injury toward urgent orthopaedic assessment or imaging.

  • Absent Thompson test response

    No plantarflexion on calf squeeze - strongly suggests complete rupture. Needs orthopaedic referral within days.

  • Palpable gap in the tendon

    A definite step or gap on palpation over the tendon body - treat as a complete rupture until imaging proves otherwise.

  • Total inability to push off

    Complete loss of active plantarflexion strength - even walking is markedly impaired. Do not delay imaging.

  • Delayed presentation (over 2 weeks)

    A tear that has scarred in a lengthened position is harder to repair and worse for function - urgent specialist opinion.

  • Recent fluoroquinolone antibiotics

    Ciprofloxacin and similar drugs raise the risk of tendon rupture - flag this history to the treating clinician.

  • Long-term oral steroids

    Chronic steroid use weakens tendon and delays healing - management may need adjustment.

  • Systemic inflammatory disease

    Rheumatoid arthritis, seronegative spondyloarthropathies and gout can produce atypical tendon injury patterns.

  • Bilateral symptoms

    Simultaneous bilateral Achilles injury is rare and points to a systemic driver - review medications and metabolic health.

  • Signs of deep vein thrombosis

    Unilateral calf swelling and tenderness after immobilisation may be DVT rather than the tendon - urgent assessment.

Living with it

A recoverable injury, with a slow and steady ladder.

Four things that make the biggest difference - wearing the boot, doing the calf work, respecting the timeline and getting re-imaged if things move backwards.

A quiet reminder

Tendon time is not calendar time.

Tendon remodels slowly. Weeks 4 to 12 feel like nothing is happening - it is, at the fibre level. Trust the plan.

  1. 01 Protect

    Wear the boot as prescribed

    The CAM boot with heel wedges is doing real work - taking shortcuts in weeks 1 to 4 is the commonest cause of re-injury.

  2. 02 Load

    Do the calf-strength programme

    Heavy-slow calf work is boring, effective and non-negotiable - it drives healing and rebuilds capacity for return to sport.

  3. 03 Time

    Give it 8 to 16 weeks

    Tendon remodels slowly. Return to running is staged over months, not weeks - rushing the calendar is what turns a partial tear into a bigger problem.

  4. 04 Escalate

    Re-image if things go backwards

    A sudden worsening of pain, a new pop or a fresh loss of push-off deserves a repeat scan - occasionally a partial tear extends.

Frequently asked

Everything we get asked about Achilles strains.

Quick answers on grading, the Thompson test, boots, timelines and injections.

  • What is an Achilles tendon strain?

    A partial tear of the Achilles tendon in which some but not all of the fibres are disrupted. The tendon retains continuity, so the calf can still transmit force to the heel - unlike a complete rupture, which is a different injury with a different pathway.

  • How is a partial tear told apart from a complete rupture?

    The Simmonds/Thompson test is the key bedside sign - a preserved plantarflexion on calf squeeze suggests continuity (partial), an absent response suggests complete rupture. Ultrasound or MRI grades the tear and measures any gap, which is what actually changes the plan.

  • Do I need surgery for a partial Achilles tear?

    Usually not. Grade I and II partial tears are managed with a walking boot and heel wedges, a graded calf-strengthening programme and a staged return to running. Complete ruptures (Grade III) are the cases that go to foot-and-ankle surgery for consideration of repair.

  • How long will I be in the walking boot?

    Typically 2 to 4 weeks in a CAM boot with 2 to 3 cm of heel wedge, then a staged wedge removal over the following weeks. The exact schedule depends on the grade and how comfortably you are loading the leg - your clinician will individualise it.

  • When can I return to running?

    Most partial tears follow a staged 8 to 16 week return: walking without the boot, then jogging on level ground, then straight-line running, then change of direction and finally sport-specific loading. Trying to skip stages is the single biggest cause of re-tear.

  • Do PRP or shockwave injections help?

    They are sometimes offered as adjuncts, but the evidence for platelet-rich plasma and extracorporeal shockwave in acute partial Achilles tears is limited and inconsistent. Protected loading and calf strengthening remain the treatments that are known to work.

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