Why Does My Knee Hurt When I Run?

Female runner clutching knee with pain after running
Knee pain is one of the most common running injuries

As a sports therapist who is also involved in the local running community, one of the most common complaints I hear is “my knee hurts when I run”. Another common one is “I have bad knees”. Unsurprisingly, given the nature of the sport, the knee is the most frequently injured joint in runners. Luckily though, knee pain, including long-standing “bad knees”, and “runners knee” are treatable more often than not.

There are many different possible causes of knee pain. In my experience however, there are a only a handful of reasons for the majority of knee injury cases.

While there is no substitute for consulting with a qualified sports therapist or physio, this guide will give an overview of the most common causes of knee pain in runners. If you do feel however that you would like more advice on your own knee injury, you can contact me by clicking here or find out more about my sports therapy services by clicking here.

A note on “Runner’s Knee” – This is a catch-all term that is used interchangeably to describe a number of different knee injuries. While it is most commonly applied to Patellofemoral Pain Syndrome, other knee complaints are often blanketed with the same term. Using a term like this can lead to confusion so I tend to avoid it. I will however point out the conditions that are often referred to as “Runner’s Knee”. Admittedly, it can be useful for people who have no interest in the technicalities of their injury – but that’s a whole other debate!

Patellofemoral Pain Syndrome

PFPS / Runner’s Knee

  • Pain felt around the front of the knee or around the edges of the kneecap.
  • General, non-specific, dull pain around the area of the kneecap.
  • Pain after sitting for long periods with the knee bent.
  • Clicking or popping under the kneecap.
  • Pain is increased when running up/downhill or climbing/descending stairs.

Patellofemoral Pain Syndrome is a broad term that is used to explain pain that originates from the patella, or kneecap, and the way it interacts with the knee joint. The pain arises from irritation or weakening of the cartilage behind the patella. Possible causes for this are the patella being pulled too tight in the joint, or being pulled to the side so it does not move seamlessly along its groove as it should.

The exact root cause of PFPS is different in each person. A qualified sports therapist will be able to diagnose where your issues lie and develop a personalised rehab plan. In general though the most common areas that need work are…

  • Pelvic stability & core stability.
  • Co-ordination, proprioception and mobility of the hip, knee and ankle joints.
  • Strength and activation of the glutes, lower back, quads and other hip stabilisers.
  • Assessment of training methods, volume and intensity.
  • Sports massage to help relieve muscular tension.

Iliotibial Band Syndrome

ITBS / IT Band Syndrome / Runner’s Knee

  • Pain towards the outside of the knee.
  • Sharp or stabbing pain.
  • Running downhill or descending stairs makes it worse
  • Pain disappears on rest and can appear and disappear somewhat randomly.

Anatomy of the kneeThe Iliotibial Band (or IT-Band, or ITB) is a very dense, strong and stiff band of fibrous tissue. It runs down from the hip and connects to the lower leg just below the knee. Irritation is caused where the ITB passes over the bony areas of the knee joint – although it is still disputed what the exact cause of the pain is. In fact many aspects of ITBS are disputed. However it is generally accepted that hip strength and stability are often major contributing factors. Also implicated are hip and ankle mobility, running technique problems and issues with training.

As with any injury, a sports injury professional can help you discover where your specific issues lie, and create a customised rehab plan. As a general rule, the most common areas to work on are….

  • Pelvic stability & core stability.
  • Co-ordination, proprioception and mobility of the hip, knee and ankle joints.
  • Strength and activation of the glutes, lower back, quads and other hip stabilisers.
  • Assessment of training methods, volume and intensity.
  • Sports massage to help relieve muscular tension.

You may notice that they are exactly the same as those for PFPS. This is not laziness on my part, but an indication that a large number of knee pain cases actually originate in the hips. A stable and strong pelvis and core creates a strong knee.

For more information on ITBS, check out my article here: IT Band Syndrome Explained

Patellar Tendinopathy

Patellar Tendonitis / Runner’s Knee

  • Pain below the kneecap.
  • Painful and tight when standing up.
  • Stiffness in the morning.
  • Pain increased when jumping, landing or changing direction.

Patellar Tendinopathy is a breakdown in the structure of the tendon that connects your kneecap to your shinbone. This can be caused by a number of issues such as weakness or tightness in the quads, poor lower limb biomechanics or recent changes to training. A good sports therapist or physio will be able to assess the most likely causes of your pain and tailor a specific rehab plan for you. However the most common areas to work on are – yes you guessed it – the same as for the previously discussed injuries.

It's All In The Hips

A common thread running through this discussion is that the source of your knee pain is often not actually in the knee itself, but at the hips, pelvis or core. While each injury and each individual would benefit from specific assessment and diagnosis, following the general principles of glute and hip strengthening is a tried and tested, low-risk and simple method of rehabbing yourself from injury.

Assessing and altering training methods, volume and intensity is also key to recovering quickly from injury. A major contributor to many injuries is an increase in training frequency, time or intensity (FIT – see my article on injury prevention here)

Other Injuries

While the three injuries discussed here are the most common knee injuries for runners, there are of course a number of other injuries that can occur to the knee, such as….

  • Pes Anserine Tendinopathy
  • Meniscus damage
  • Osteoarthritis
  • Ligament sprains
Physiotherapist working with client with a knee injury
A qualified professional can help optimise your recovery from knee injury

This article is designed to give you a general overview of the most common knee injuries for runners. It is no substitute for having your injury assessed and diagnosed by a professionally qualified sports therapist or physio. While general guidelines are given for treatment and rehab of the injuries, a professional can diagnose you more specifically and customise a treatment plan for optimal recovery.


If you would like more advice on your own knee injury, you can contact me by clicking here.

Something To Bear In Mind

While the vast majority of knee pain is due to simple mechanical issues, it is important to look out for potentially more serious issues. If you have any of the following symptoms accompanying your knee pain, it is recommended to have a check-up with a medical professional…

  • Any obvious deformity around the joint.
  • Instability or laxity in the joint.
  • Severe pain following trauma to the area.
  • Joint locking.
  • Other general joint pain, fever, weightloss, rashes, infection or history of illness.
  • Pain at night, especially if it keeps you awake.
  • Inability to bear weight.
  • Pain increasing despite rest.

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