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Health condition · Clinically reviewed

Patellar tendonitis, otherwise known as jumper's knee.

"Tendonitis" and "tendinitis" describe the same overuse injury of the patellar tendon. For our full clinical guide, see patellar tendinitis.

Jump to treatment
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Why trust this guide

  • 01

    Clinically reviewed

    Written by our editorial team and reviewed by a registered UK clinician before publication.

  • 02

    Sourced from guidance

    Checked against NICE, NHS and peer-reviewed sports medicine sources you can see at the end.

  • 03

    Current for 2026

    Reflects modern UK guidance on eccentric strengthening, load management and shockwave therapy.

Key facts

Patellar tendonitis at a glance.

The essentials, in plain English - including how this spelling relates to our fuller patellar tendinitis guide.

  • Also called

    Patellar tendonitis is the same condition as patellar tendinitis - see our main guide to patellar tendinitis for the full detail.

  • Common name

    "Jumper's knee" - an overuse tendinopathy of the patellar tendon, common in jumping and sprinting sports.

  • Where it hurts

    Pain sits at the inferior pole of the kneecap, right where the tendon attaches, and is worse with loading.

  • Who gets it

    Basketball, volleyball, athletics and football players - anyone with repetitive jumping or sudden direction changes.

  • Diagnosis

    Clinical exam plus ultrasound or MRI when the picture is unclear or symptoms persist.

  • Mainstay treatment

    Eccentric strengthening exercises and graded load management, with shockwave therapy or PRP for stubborn cases.

Why this guide matters

One condition, two common spellings.

Whichever spelling brought you here, the clinical picture and treatment are identical. Three points shape everything else on this page.

  • Tendonitis and tendinitis are the same

    Both spellings refer to overuse injury of the patellar tendon - there is no clinical difference between them.

  • Load management is the treatment

    Eccentric strengthening and graded return to sport outperform rest alone for tendon healing.

  • Early action prevents chronic pain

    Addressing symptoms early, rather than pushing through, reduces the risk of a persistent, harder-to-treat tendinopathy.

How the diagnosis is made

From knee pain to a clear plan.

The steps a UK GP, physiotherapist or sports medicine clinician will normally follow, in order.

  1. 01

    Assessing

    History and load review

    When the pain started, which sports or activities provoke it, and how training load has changed recently.

  2. 02

    Assessing

    Palpation and single-leg test

    Tenderness at the inferior pole of the patella and pain on single-leg decline squat are classic findings.

  3. 03

    Confirming

    Ultrasound

    First-line imaging - shows tendon thickening, hypoechoic areas and neovascularity.

  4. 04

    Confirming

    MRI if uncertain

    Reserved for atypical presentations, suspected partial tears or before considering injections or surgery.

  5. 05

    Planning

    Rule out other knee causes

    Patellofemoral pain, patella instability and quadriceps tendinopathy can look similar and need excluding.

  6. 06

    Planning

    Physiotherapy referral

    A structured eccentric loading programme is started early rather than waiting for symptoms to settle alone.

Typical timeline: a first assessment to a structured plan in a single visit.

Symptoms

What patellar tendonitis feels like.

The classic pattern of tendon pain that worsens with jumping and loading - and the one sign that means urgent review.

  • Pain at the tendon

    Sharp or aching pain directly below the kneecap, at the inferior pole of the patella.

  • Worse with loading

    Jumping, running, squatting and stairs provoke symptoms - especially landing from a jump.

  • Morning stiffness

    Stiffness and tenderness after rest, easing slightly with gentle movement.

  • Mild swelling

    Some tenderness and mild swelling over the tendon, though marked swelling is uncommon.

  • Reduced jump performance

    Athletes often notice reduced power and confidence in jumping or landing.

  • Progressive if ignored

    Untreated overload can progress from mild ache to pain that limits daily activity.

  • Red flag - sudden snap

    A sudden tearing sensation with inability to straighten the knee suggests a patellar tendon rupture - urgent assessment needed.

Treatment

How patellar tendonitis is treated.

Eccentric strengthening and load management first, with shockwave therapy or PRP for cases that don't settle.

  • Eccentric strengthening

    The evidence-based cornerstone - typically decline-board squats, progressed gradually under physiotherapy guidance.

  • Activity modification

    Temporarily reducing jumping and sprinting load while keeping the tendon moving with pain-appropriate exercise.

  • Physiotherapy programme

    A structured, staged loading plan that rebuilds tendon capacity and addresses technique and strength deficits.

  • Ice and simple analgesia

    Useful for symptom relief in flare-ups, though not a substitute for load management.

  • Shockwave therapy

    Extracorporeal shockwave therapy for persistent cases that have not responded to a proper loading programme.

  • PRP injection

    Platelet-rich plasma is considered for chronic, treatment-resistant tendinopathy in some clinics.

  • Bracing or taping

    A patellar strap can reduce load through the tendon during sport while rehabilitation continues.

  • Surgery (rare)

    Reserved for a small minority who fail extended conservative treatment, or for confirmed tendon rupture.

What this guide is based on

The sources behind every claim on this page.

UK national guidance and sports medicine 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 or physiotherapist knows your knee and history and can tell you which parts apply to you. If in doubt, get seen.

  • NICE Clinical Knowledge Summaries. Knee pain - assessment.

  • NHS. Knee tendonitis and knee pain information.

  • British Journal of Sports Medicine. Eccentric exercise for patellar tendinopathy.

  • Royal College of General Practitioners. Sports injury guidance.

Red flags

When knee pain needs urgent attention.

Most patellar tendonitis is manageable with physiotherapy. These situations aren't - and need urgent review.

  • Sudden inability to straighten the knee

    Suggests a patellar tendon rupture, especially after a fall or forceful jump landing - needs urgent orthopaedic assessment.

  • A palpable gap above the kneecap

    Combined with weakness on straight-leg raise, this is suggestive of a tendon tear needing same-day review.

  • Significant swelling or deformity

    Marked swelling, bruising or a visibly high-riding kneecap after injury warrants urgent imaging.

  • Fever with a hot, swollen knee

    Consider septic arthritis rather than tendinopathy - this needs emergency care.

  • Pain not improving after 6 to 8 weeks

    Persistent symptoms despite a proper eccentric loading programme deserve a specialist sports medicine or physiotherapy review.

Living with it

A treatable injury, with a clear ladder.

Four things that make the biggest difference to recovery - sensible loading, patience with the programme, a good warm-up and asking for help early.

A quiet reminder

Tendons respond to consistent loading, not rest alone.

A steady, well-supervised programme kept up for months usually beats intermittent effort or complete avoidance.

  1. 01 Load

    Manage, don't avoid

    Complete rest often makes tendons weaker - controlled, progressive loading is usually more effective.

  2. 02 Patience

    Give it 8 to 12 weeks

    Tendon rehabilitation is slow - most eccentric programmes need consistent effort over months, not days.

  3. 03 Warm-up

    Warm up properly

    A thorough warm-up and gradual return to jumping sport reduces the chance of flare-ups.

  4. 04 Escalate

    Ask for help if stuck

    If a home programme isn't working, a physiotherapist or sports medicine clinician can tailor the loading plan.

Frequently asked

Everything we get asked about patellar tendonitis.

Quick answers on spelling, causes, exercises and when to escalate.

  • Is patellar tendonitis the same as patellar tendinitis?

    Yes - "tendonitis" and "tendinitis" are two accepted spellings of the same condition, an overuse injury of the patellar tendon. For our fuller clinical guide, see our patellar tendinitis page.

  • What causes patellar tendonitis?

    Repetitive loading of the patellar tendon, typically from jumping sports like basketball and volleyball, causes microtrauma that outpaces the tendon's ability to repair itself, leading to tendinopathy.

  • How is it different from jumper's knee?

    They are the same condition - "jumper's knee" is simply the common name for patellar tendonitis, reflecting how frequently it affects jumping athletes.

  • What is the best exercise for patellar tendonitis?

    Eccentric strengthening, particularly decline-board squats, has the strongest evidence base. A physiotherapist can guide the correct progression for your stage of injury.

  • Do I need to stop sport completely?

    Not usually. Most people benefit from modifying training load rather than complete rest, staying active within a pain-appropriate range while rehabilitation progresses.

  • When is shockwave therapy or PRP considered?

    These are reserved for persistent cases that have not responded to a properly structured eccentric loading programme over several months.

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