Jumper’s knee, also known as patellar tendinitis, is an overuse injury of the patellar tendon that causes pain under the kneecap. The tendon connects the kneecap to the lower leg and, with the quadriceps, straightens the knee. Patellar tendonitis develops when repetitive sprinting or jumping inflames and overloads the tendon — common in basketball, volleyball, running, and football.

Dr Masci treats jumper’s knee at his London clinics. This guide covers the symptoms, the exercises that genuinely work, and the treatments to choose and avoid. For the clinical overview, see our patellar tendinopathy guide.

What causes patellar tendonitis?

Too much sport, too soon. A jump in training volume or intensity swells the tendon, causing pain and reduced performance. The pain usually occurs near where the tendon attaches to the kneecap, which bears the highest forces. Unlike Achilles or hamstring tendonitis, patellar tendon changes often begin in the teenage years, setting athletes up for pain in adulthood.

Symptoms of jumper’s knee

Patellar tendonitis causes pain right below the kneecap, at the site of tendon swelling. The pain worsens with high-intensity running or jumping and settles 1–2 days after sport. It can also flare with sitting or driving, and the tendon is usually swollen and tender to the touch.

Ultrasound confirms the tendon thickening below the kneecap and often shows new blood vessels growing into the tendon — a likely source of pain. MRI helps rule out other causes of pain under the kneecap, such as kneecap arthritis or fat-pad impingement.

jumpers knee tendonitis on ultrasound

Patellofemoral pain vs patellar tendinitis

It can be hard to tell whether pain comes from the patellar tendon or the kneecap joint. Patellofemoral (kneecap) pain usually sits around or behind the kneecap rather than just below it, and it flares with walking, cycling, and sitting — unlike patellar tendonitis, which points to the joint as the source, and taping the kneecap, which eases the pain.

Patellar stress fracture vs patellar tendonitis

A rare but important mimic in jumping athletes is a stress fracture at the lower pole of the kneecap. The giveaway: stress-fracture pain worsens with continued activity, whereas patellar tendonitis warms up and eases with activity. This matters because the treatment is the opposite — rest for a stress fracture, loading for tendonitis.

Jumper’s knee treatment

Patellar tendonitis is genuinely hard to treat, and the road to recovery is long. We start with simple measures:

  • Avoid kneeling on the front of the knee
  • Limit deep knee bends to 90 degrees or less in daily life and exercise.
  • Patellar tendon taping or a strap just below the swollen tendon eases pain for some. 
  • Modify activity — a period of relative rest from sport, with cross-training to maintain fitness.
  • Anti-inflammatory tablets such as ibuprofen for a short course. 

Exercise therapy: the foundation

Exercise is essential, and it must be a supervised, progressive strengthening programme. Studies show that quadriceps strengthening improves pain and function.

We recommend a heavy-loading programme of three or four exercises targeting the whole leg — single-leg knee extension, single-leg incline press, and reverse lunges build the quadriceps, while seated and standing calf raises and hamstring curls or hip thrusters strengthen above and below the knee. Once strength is good, add plyometrics — skipping, hopping, running — every 2–3 days.

Should you aim for strength goals?

Yes. We suggest aiming to:

  • Squat your body weight
  • Reach 40–60 kg on a single-leg knee extension
  • Press 1–1.5× body weight on a single-leg incline press

What if rehab stalls?

For complex cases that don’t improve with simple treatment, we add:

  • GTN patches: nitric-oxide patches worn over the tendon during rehab to reduce pain and aid healing
  • Collagen supplements: hydrolysed collagen taken 30 minutes before loading exercises, which improves tendon pain more than exercise alone

Are injections an option for jumper’s knee?

Generally, no — this is where jumper’s knee differs from most tendons. Cortisone worsens patellar tendonitis and must be avoided. A study comparing a cortisone shot with exercise and shockwave found the cortisone group did worse at 3–6 months. PRP, used with mixed success elsewhere, shows little effect in patellar tendonitis in high-level athletes in Dr Masci’s own research. Overall, injections are unrewarding for this tendon, which is why the procedures below matter more here than anywhere else.

Procedures for stubborn jumper’s knee

Tendon scraping

Tendon scraping uses ultrasound to strip the pain-generating nerves and vessels from the tendon’s surface. When done via keyhole, it yields over 80% improvement when combined with rehab — far better than traditional surgery and with an earlier return to sport.

A new procedure called the percutaneous tendon scraping procedure, performed by Dr Masci, is suitable for some cases of patellar tendinopathy. In these cases, Dr Masci performs a tendon scraping procedure using a needle with a special blade. This procedure is less invasive than arthroscopic tendon scraping, with a faster recovery time and return to sport. However, not all cases are suitable for a needle tendon scraping. Dr Masci will need to assess you to determine whether you are a candidate for this innovative, less invasive procedure. 

Please see this article on tendon scraping, which discusses the less invasive needle scraping in detail. 

Tenex procedure

The Tenex procedure uses ultrasonic energy to remove damaged tendon tissue while sparing the healthy part. Minimally invasive and done under local anaesthetic, it carries an 80–90% success rate with less risk than surgery — a strong option for jumper’s knee that has failed everything else.

Why avoid traditional surgery?

Open surgery, cutting out the diseased tendon, has only a 50% success rate. Keyhole tendon scraping has superseded it.

Frequently asked questions about jumper’s knee

How long does jumper’s knee take to heal?

Expect months of consistent rehab, sometimes 6–12. Patellar tendon recovery is slower than most tendons, but persistence with progressive strengthening is what gets athletes back to sport.

Can I keep playing sports with jumper’s knee?

Often, yes — at reduced load. Keep pain at about 3/10 or less during and after, avoid deep knee bends and heavy jumping while it settles, and keep up the strengthening. GTN patches let many athletes train through rehab.

Why does the pain settle during activity, then return later?

This “warm-up” pattern is characteristic of patellar tendonitis — the tendon loosens with activity, then stiffens and aches hours later. A stress fracture, by contrast, hurts more as activity continues, which is an important distinction.

What’s the single most important treatment?

Progressive strengthening. Every other treatment — patches, shockwave, procedures — works best alongside a structured exercise programme, never instead of it.

Final word from Sport Doctor London about jumper’s knee

Jumper’s knee, or patellar tendonitis, is a stubborn cause of pain under the kneecap in jumping and sprinting athletes. Treatment is built on progressive strengthening, with GTN patches, shockwave, and collagen for cases that stall. Injections — cortisone,e especially — are best avoided here. For genuinely resistant cases, tendon scraping or Tenex outperforms traditional surgery.

To book a one-stop knee assessment with Dr Masci in London, contact his team here or call +44 (0) 203 488 0350.

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