Knee pain after running: the main causes

Why can your knee hurt after running?

The knee absorbs stress with every stride. A recent increase in volume, speed or elevation gain can exceed the ability of a tendon, a muscle or the joint to recover.

Knee pain after running is not always immediate: discomfort may appear a few hours after the session. For other runners, it starts after a specific distance. Note when it occurs and exactly where.

What does the location of the pain mean?

This table presents possible explanations. Several structures are close together and can produce similar symptoms. An examination is necessary if the pain persists or shows unusual signs.

Patellofemoral pain syndrome

Patellofemoral pain syndrome, often called “runner’s knee”, causes diffuse pain at the front of the knee or behind the kneecap. It is encouraged by repeated bending under load. Stairs, squats and prolonged sitting can also bring it on.

Treatment focuses on running load, quadriceps and hip strength, and control of the lower limb. A physiotherapist can also assess cadence and running surface.

Iliotibial band syndrome

Pain on the outside of the knee when running often suggests iliotibial band syndrome. The discomfort frequently appears after a fairly consistent running time and eases when you stop. Downhills and cambered roads are sometimes poorly tolerated.

Our article on iliotibial band syndrome details the symptoms, strengthening and return to running.

Knee tendinopathies

The patellar tendon connects the kneecap to the tibia. Well-localised pain below the kneecap, sensitive to jumps and accelerations, may indicate tendinopathy. On the inner side, a few centimetres below the joint, the pes anserine tendons can also become painful after an increase in load.

Treatment temporarily reduces stress on the tendon and gradually strengthens it. A professional may suggest isometric exercises, followed by squats and dynamic variations.

Meniscus, ligaments and traumatic injuries

A twist, a fall or a poorly controlled change of direction can damage the meniscus or a ligament. Rapid swelling, locking, a feeling of the knee giving way or being unable to fully straighten the knee warrants an examination.

A stress injury develops more subtly. The pain is concentrated on one point, appears earlier during the run, and may then affect walking or occur at rest.

What to do right after the session?

Reduce or stop running when the pain changes your stride. Cold wrapped in a cloth can provide relief for 10 to 20 minutes. Light compression and elevation can be comfortable if the knee is slightly swollen.

Over the following days, keep your activities within a tolerable range. Avoid testing the knee every day with a full run.

Note the exact location, when it appeared, any changes to your training and how it responds the next day. This information will help the professional.

How to return to running?

Your return begins when walking, stairs and basic movements are comfortable, with no swelling. Start by alternating slow running and walking on flat ground.

If symptoms remain mild for 24 hours, increase just one element. Speed, hills and downhills come back after several well-tolerated sessions.

To plan your first sessions, also see our advice on how to return to running gradually and the guide to electrostimulation for running.

Electrostimulation in runner recovery

TENS can support the relief of diagnosed pain. EMS can complement work on the quadriceps, hamstrings or glutes as part of a progressive programme. The choice of area and programme depends on the cause of the knee pain.

The Duo Sport 2 offers guided programmes for preparation, recovery and pain relief. A swollen, locked or unstable knee must be examined before any use on the area.

For pain at the front of the knee, also see the Bluetens guide to electrostimulation and patellar syndrome.

When to seek prompt medical advice?

Seek a prompt assessment if you cannot bear weight, or if the knee is very painful, deformed or severely swollen. Locking, giving way, redness with warmth or fever also require medical advice.

For less intense pain, seek advice if it does not improve after a week without running, returns each time you resume or starts to affect daily life. Early treatment helps identify the cause and maintain a suitable level of activity.

FAQ

Frequently asked questions

Why does my knee only hurt after running?

Cumulative load can irritate a tissue without immediately causing pain. The discomfort then appears during the cool-down or a few hours later. When it appears remains useful information for the assessment.

Can you run with mild knee pain?

Mild discomfort can sometimes be tolerated within a supervised plan. Stop if it gets worse, changes your stride or is stronger the next day.

Are shoes always to blame?

Shoes can contribute if they are worn, uncomfortable or recently changed. Load, recovery and muscle capacity also matter.

Does cold treat the cause?

Cold can temporarily reduce discomfort. It does not correct overload, weakness or an injury. Recovery depends mainly on the diagnosis, load management and appropriate rehabilitation.

Medical sources

• NHS: knee pain and running injuries

• AAOS: patellofemoral pain syndrome