If you are a runner who has experienced knee pain, you know just how limiting it can be to your performance. Not being able to run can have a big impact on your fitness and your mood. Injury to the patellar tendon is a common injury seen in runners and can quickly sideline you from your favourite activity.
What is the role of the patellar tendon?
The patellar tendon is an extension of the quadriceps tendon which attaches from the bottom of the patella to the bony prominence at the top of the shin (tibia). It helps keep the patella in line and assists in extending or straightening the knee joint.
This is known as the extensor mechanism.
It allows one to kick a ball, run and stand up!
Part of this allows the knee to bend, and the patellar tendon stretches for the first 30 degrees of knee bend, and then the length remains the same throughout the rest of the bend during weight-bearing knee flexion. This is good to know when developing rehab exercises.
The patellar tendon can be injured when overloaded - either over time or due to acute trauma, leading to partial tears or complete rupture. When there are small tears or microtears that happen over time, this can lead to niggles and eventually to more severe and debilitating knee pain.
What does patellar tendon pain feel like?
All pain experiences are unique to the individual, but commonly the patellar tendon pain is often described as a deep dull ache or sharp and stabbing, particularly through movement.
The first signs of patellar tendinitis are pain and tenderness at the bottom of the patella. This may be accompanied by swelling and a burning feeling in the patella. Initially, pain may be felt when starting an activity or just after a workout, but eventually, pain may be experienced with kneeling down, getting up from squats, climbing stairs or walking uphill.
Does a patellar tendon strapwork or is there a better way to mitigate patellar tendinitis pain?
The short answer is that it depends.
For some, applying pressure to an inflamed tendon may be helpful, but for some, it may further aggravate the condition.
How does the strap work?
By applying pressure to the tendon, it lessens the pressure of knee movement and as a result, decreases loading on the patellar tendon.
Other proposed mechanisms include:
- Reduces patellar compression.
- Prevents excessive sideways shifting of the patella which would increase loading of the tendon
- Decreases tendon length, decreasing strain on the tendon
- Reduces contact pressure and the contact area between the patella and the femur
For best results, you want to pick a high-quality strap that is adjustable for comfort, flexibility and adequate support.
The problem with wearing a patellar strap is that it doesn’t take into consideration the true underlying cause of patellar tendinitis. More often it will ease your pain so that you can continue to be active.
To get to the source, you often have to look above and below, at how one moves above in areas like the neck and trunk and down below in the foot.
Commonly, as Physiotherapists’ we see altered muscular control in the foot, hip, pelvis and trunk. This can be seen as a weakness in the gluteal and quadriceps muscles, muscles of the foot and compromised abdominal wall function.
To mitigate the pain associated with patellar tendinitis you first need to determine the area (s) of the body that are contributing to the increased loading on the patellar tendon. This may mean working on improving trunk control, strength in the glutes, quads and foot. This is best done by seeing a Physiotherapist who will assess you head to toe, determining the impact of your current movement strategies on the function of your knee joint.
How does one recover from patellar tendonitis?
As mentioned above, we often need to look for the underlying cause.
Once you identify the cause and improve the strategies for strength and control of that region (be it the foot, hip or trunk) you can then apply load in a progressive manner to strengthen the patellar tendon.
Tendons are notorious for taking a long time to heal and as a result, patience is required when progressing through a rehabilitation program to load and strengthen the tendon.
Can collagen improve patellar strength?
There is more to tendon healing than just identifying the cause and loading up the tendon with strengthening exercises. As vital as these components are to recovery, other factors like getting adequate rest, proper hydration and eating a healthy balanced diet, such as healthy fats and protein (such as collagen) will go a long way to assisting one to recovery from a tendon-related injury.
The Top 5 exercises to strengthen the patellar tendon
Single leg squat on a decline board
Seated knee extension
Where you start will depend on a number of factors, so there can be some trial and error here. Pick a challenging weight, 70% of max effort. A reduction in pain is a good indication of picking an appropriate weight.
You want to hold the position of the exercise for up to 45 seconds for 5 repetitions. Take a 2-minute rest between repetitions to avoid aggravating the tendon. This should be completed 2-3 times per day aiming to get up to 70% maximal voluntary contraction pain permitting.
As pain settles (less than 3/10 pain) you want to progress to the strengthening the tendon. The most common protocol is an eccentric strengthening protocol, where you start to add a heavy load and stretch the tendon. For example, performing 4 sets of 15 repetitions of a moderately heavy load.
Once you strengthen the tendon, you then want to begin to condition the tendon to maintain strength and build power. Here exercises should be done every 2-3 days. Here picking a load that you can perform 3-4 sets of 6-8 repetitions.
For a return to sport, you then want to add in jumping and hopping type exercises.
The above are guidelines and don’t necessarily account for individual differences and therefore should be treated only as a guideline. If you find yourself struggling to run or perform knee strengthening exercises, get some guidance from a professional. If you do have tendinopathy, keep in mind it will take time for a full recovery but with proper guidance and load management, you can continue to exercise.
DeFrate, L. E., Nha, K. W., Papannagari, R., Moses, J. M., Gill, T. J. and Li, G. The Biomechanical Function of the Patellar Tendon During In-vivo Weight-bearing Flexion. Journal of Biomechanics. 2007; 40 (8); 1716-1722.
Malliaras, P., Cook, J., Purdam, C. and Ebonie, R. Patellar Tendinopathy: Clinical diagnosis, load management, and advice for challenging case presentations. Journal of Orthopaedic & Sports Physical Therapy. 2015; 45 (11); 887-898.
Rudavsky, A., and Cook, J. Physiotherapy management of patellar tendinopathy (jumper's knee). 2014. Journal of Physiotherapy 60: 122–129