Patellar tendonitis is more commonly known as Jumpers Knee and is caused by microscopic damage to the patella tendon. The patella tendon is the most common place to develop knee tendonitis.
There are other common causes of knee cap pain and Jumpers Knee is often misdiagnosed as Runners Knee, Osgood Schlatters or Chondromalacia Patella, but the most defining characteristic of Patellar Tendonitis is tenderness when you press on the patella tendon, just below the kneecap.
The patella tendon can be found at the front of the knee just under the kneecap and it attaches the quad muscles to the top of the shin bone. It is approximately 2 cm wide, is extremely strong and its job is to work with the quadricep muscles to straighten the leg.
Patellar tendonitis develops when there is repeated excess force placed on the patella tendon, usually during sports. Kicking places a force approx 7x bodyweight on the tendon. The largest force placed on the tendon is during jumping and landing, approx 10x body weight. To be able to jump, the quads work with the calf muscles to propel the body off the ground and during landing, the quads work to stabilise the leg.
If someone is doing lots of kicking or jumping, eg sports players, the strain on the patella tendon becomes too great and microscopic tears develop in the tendon. This may not cause pain initially, but as it progresses, the knee will get gradually more and more painful.
These microscopic tears make the tendon less strong and therefore prone to further damage. The tendon may even completely tear.
Patellar tendinitis usually comes on gradually over time, rather than being caused by a specific incident. The most common symptoms are:
1) Pain just below the knee cap with activity eg jumping, running, squatting
2) Pain with any pressure through the tendon eg touch, kneeling
3) Aching and stiffness after activity
4) Stiffness in the morning
5) Thickening of the tendon
Patella tendonitis can be classified into 4 stages:
Stage 1: Pain only after activity which doesn’t affect function
Stage 2: Pain with initial activity that disappears as you warm up, but returns after activity. Performance is not usually affected.
Stage 3: Prolonged pain during and after activity with increasing difficulty performing at a satisfactory level
Stage 4: Complete tear of the tendon requiring surgical repair
It used to be thought that inflammation was the main cause of Jumpers Knee, hence the name patellar tendonitis (itis = inflammation). However, recent studies have shown that an inflammatory response is actually very rare. It is more common to have degeneration of the tendon, so it is now often referred to as Patellar Tendonosis (osis means degeneration). This explains why non-steroidal anti-inflammatories like ibuprofen usually have little effect on symptoms and they can actually make things worse by slowing down healing.
The body heals Jumpers Knee by producing collagen that repairs the tissue damage, but it takes approx 3 months for the collagen to be laid down and mature to allow the tendon to return to full strength.
There are a number of different treatment options for Patellar Tendonitis and people usually get the most benefit by using a combination of them:
1) Rest: Knee tendonitis is one of those cases where the saying “no pain no gain” does NOT apply. It is really important to rest completely from any activity that causes pain to allow the tendon to heal. It may be up to 3 months before you can return to sports.
2) Ice: Ice packs applied for 10-15 minutes every couple of hours, before and after activity, can help to reduce pain. Visit the Ice Treatment section to find out how to safely and effectively use ice therapy and the ice wrap section for the best ways to apply ice.
3) Knee Straps: In the early stages of Jumpers Knee, knee straps can work really well to reduce the stress going through the patellar tendon and alleviate symptoms. They reduce the cross sectional area of the tendon and the pressure applied by the strap reduces the force going through the tendon. Visit the knee strap section to find out more about them, including recommendations based on customer feedback.
4) Stretches: Tightness in the hips, quads and hamstrings can contribute to Jumpers Knee so it is important to stretch these muscles out. Visit the knee stretches section for simple tests you can do to see if your muscles are tight.
5) Eccentic Muscle Training: Studies have shown that eccentric muscle training (when the muscle lengthens as it works) is the most effective treatment for tendonopathies like Jumpers Knee. Click the link to find a detailed training programme.
6) Muscle Strengthening: Weak glutes can affect the position of the knee and lead to increased force going through the patellar tendon. The simplest way to strengthen the glutes is through Clam and Bridging exercises – visit the knee strengthening section to find out more.
If patellar tendonitis fails to resolve after 6-12 months of rehab,
surgery is performed as a last resort. Surgery involves removing the
degenerative tissue and looks to increase blood flow to the area to
If the patellar tendon ruptures (tears completely), surgery is required to repair the tendon by sewing it back together. After surgery, careful rehabilitation is essential as the tendon will be weak and it usually takes 3-6 months of physical therapy to return to sports.
If this doesn’t seem quite like your pain, see the Front Knee Pain section to find out about the most common causes of pain at the front of the knee, including causes, symptoms and treatment options.
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Updated 12th March 2014
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