What you need to know to beat Runner’s knee (Patellofemoral Pain).

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Just because you’re a runner doesn’t mean you need to have Runner’s knee. Even if it is the most common pain presentation in runners (With an incidence of 15% in runners), there’s plenty you can do steer away from ever getting Runner’s Knee. This is what I use in my Physiotherapy practice and for any ELITE team clients who may have symptoms.

What is it?

Runner’s knee, officially known as Patellofemoral pain, is self-reported diffuse pain around or behind the patella (kneecap) aggravated by activities that load the knee joint, e.g. Squats, stairs, running or jumping. In its early stages, the pain can appear with activity and subside with rest. In its severe stages, even prolonged sitting can also aggravate Patellofemoral pain, such as sitting in the car or on the couch.

Runner’s knee is mostly caused by non-traumatic mechanisms – Often from overtraining where repetitive loads places on the joint exceeds the capacity of the joint to tolerate those loads. This can be seen in runners who go ‘too hard too fast’, or even the general population if they change their loading too rapidly eg. Going on holiday and doing a walking tour when they are usually sedentary.

Underneath the kneecap, there can be a variety of structural changes causing the pain, hence why Patellofemoral pain is only an ‘umbrella term’ to describe pain, not a specific structural condition. It can be due to wear of the joint surfaces underneath the patella (Articular cartilage), abnormal tracking of the patella causing excess friction, inflammation in the joint space etc.

What puts you at risk of Runner’s knee?

The main risk of Runner’s knee reported in the literature is short periods of overuse or a sudden increase in training loads.

Refer to the diagram below – A slide from my Strength training seminar (Figure 1). It shows that in order to stay injury-free, a balance needs to be maintained between mechanical loading and tissue tolerance, with tissue tolerance levels higher than mechanical loading. In cases where there is overtraining or sudden increase in training loads, the body is unaccustomed to these higher loads and without a chance to adapt, the result is joint stress and inflammation in the knee.

Figure 1: Mechanical loading balance

On the other extreme, some people may not necessarily increase their external loads from walking or running, but may have a sudden decrease in joint tissue capacity for example someone who has had knee surgery. Patellafemoral pain can also become a problem for these people with the same imbalance in mechanical load, but rather from a decrease in tissue capacity not an increase in loading from their baseline.

Diagnosis

There’s one thing that people are good at – And that is self-diagnosis from Dr/Physio Google. However, the problem is that Runner’s knee shares the same symptoms and causes as various other front-of the knee pains, and requires specific testing to differentiate the conditions.

Sometimes, as a Physiotherapist, I am still presented with a case where it could be one or the other, and only time can tell which one it is – Especially when there can be concurrence of multiple problems at the same time! The most common condition that is confused with Runner’s knee is Patella tendinopathy, since the pain locations of the two overlap.

Prevention

Prevention is always better than a cure. After reading the above – Prevention may seem obvious: Keep strong and don’t overload yourself suddenly. So here are the two main steps to maintaining that mechanical balance.

Step 1: Progressively overload your running training. Whether you’re starting out, years into training, or returning from injury, remember that the body adapts incredibly well, but it needs time and consistency to do so. You may have heard the magic number to increase your running distances by 10% each week, and there is some truth to that. Increase your distances by anywhere between 10-20%, but at the same time, make sure you deload every 3-5 weeks by 20-30%. These numbers are also relevant for other components of loading such as speed, frequency, hills etc.

Step 2: Keep strong. Do your gym work. One of the most significant risk factors for Runner’s knee is quadriceps weakness. Load up with weights and strengthen your quads, glutes, hamstrings, and pretty much the entire lower body. It’s optimal to do a combination of heavy squats and deadlifts, but also accessory single leg work to strengthen each leg independent of the other.

Rehab

If you are already experiencing Runner’s knee symptoms, or occasionally get too excited and do too much, this is what you need to do to rehab your Runner’s knee properly:

Step 1:Find the level of running that you can tolerate PAIN-FREE.  Contrary to popular belief, it is wrong that you need to STOP running completely when you have Runner’s knee. This is because that may be unnecessary sometimes, and may cause more deconditioning than ideal. You may find you can run for 6km before the onset of pain, so what you should do is run 6km 1-2x a week to start your rehab. However, some people may find they run for 20m and the pain starts, that is when a brief period of complete rest or on-the-spot jogging may be appropriate.

Step 2: Start strengthening (If you haven’t already) your hip and knee muscles. The main muscles for the knee is the quads, and the other three crucial muscle groups for running are glutes, hamstrings and calves.

Step 3: Release any tight structures such as the TFL or quads. This is only to relieve symptoms in the highly painful stages, and should only be used in the early stages since it doesn’t treat the root cause of the problem (The mechanical loading imbalance). Use a foam roller, massage ball or get a Physio to release these structures and give you release.

Step 4: Do steps 2+3 in conjunction with other Physiotherapy modalities such as taping, massage, orthotics etc. Once again, these modalities are more symptom relievers so that you CAN participate in strengthening rehab ASAP. These may not be required and can be weaned as soon as pain is not too debilitating.

Step 5: Continue strengthening until you can build up your running loads that are pain-fee. This is a continuous step from step 1. The 10% rule may not be applicable in rehab, since your tissue tolerance is lowered and may be more sensitive. Test your ability to gradually increase ONE of running distance, frequency, speed, elevation etc one week at a time. You will know if it’s pain-free, otherwise if you experience pain during or up to one day after the run, then you need to take it back one step.

Wrapping it up

Hopefully, there is something you can takeaway from this blog post. The prevention and management of Runner’s knee is not complex, but does require consistent attention to training detail. Feel free to share with any running friends who have experienced the (annoying) Runner’s knee and let me know what you think of this!