Runner's Knee and Common Running Knee Injuries: Causes, Treatment and Prevention

Is running bad for your knees? The short answer is that running isn’t inherently harmful to your knees. Research suggests that recreational running may actually support joint health rather than damage it, though, like any physical activity, it does carry some risk of injury if training load, technique, or footwear aren't right.

What matters most is how you run, not the fact that you run at all. Here, we explain the most common running knee injuries, how to recognise the symptoms, and what steps you can take to reduce your risk. We'll also cover treatment options and advise when it's worth seeking medical help.

Knee pain after running – is it normal?

Some mild muscle soreness after a run is normal, especially if you increased your distance, did sprint work, or ran up inclines. This dull, generalised ache, known as delayed onset muscle soreness, or DOMS, is simply your muscles adapting to exercise and usually eases within a day or two.

However, not all post-run knee pain is the same. If you experience sharp or intense pain, pain that’s localised to the knee joint, or discomfort that doesn’t settle with rest, this is worth paying attention to. These sensations are different from ordinary muscle soreness and may indicate that something needs addressing, whether that’s a technique issue, a training load problem, or an injury that needs treatment. 

As a general guide, mild, generalised soreness that fades within 48 hours is usually nothing to worry about. Pain that is sharp, persistent, worsening, or located specifically in the knee joint is a sign to stop, rest, and consider seeking advice.

Is running bad for your knees?

Running is not inherently bad for your knees. Despite longstanding concerns that it causes joint damage or arthritis, the evidence points the other way. Studies of recreational runners have shown that regular running can actually reduce the risk of knee osteoarthritis, partly by strengthening the muscles and soft tissues that support the joint.

However, runners do experience knee injuries, with knee pain being one of the most common running injuries. But in most cases, this comes down to specific, avoidable factors: overtraining, poor running form, or inappropriate footwear. Most running knee injuries are preventable, and that's what the rest of this guide covers.

How does running cause knee injuries?

While running itself isn’t inherently damaging to knees, running-related knee injuries can and do happen. 

Most running knee injuries occur when the tissues around the knee — muscles, tendons, and ligaments — are exposed to more load or strain than they can tolerate. This can happen through repetitive impact that accumulates over time, muscle imbalances or poor running gait that places strain in the wrong places, running on hard surfaces that increase stress on the joint, or a sudden twist that directs force in the wrong direction.

Training errors are among the most common contributing factors. These include:

• Increasing training intensity too quickly – one of the most common causes of running injuries

• Not allowing enough rest between sessions
• Wearing poor-fitting or unsupportive footwear
• Running exclusively on hard surfaces
• Poor running gait or muscle imbalances
• Pre-existing biomechanical factors, such as flat feet, which can affect how load is distributed through the knee

Knee areas prone to injury

Most knee pain after running is typically caused by damage to the soft tissues in the knees. This includes:

• Articular cartilage: The smooth tissue covering the ends of the thigh bone, shin bone, and the back of the kneecap (patella), which allows the joint to move freely.
• Menisci: Two cartilage discs that sit between the thigh bone and shin bone, acting as shock absorbers and helping to stabilise the knee.
• Ligaments: Fibrous connective tissue that joins bones to other bones. The four major knee ligaments — the ACL, PCL, MCL, and LCL — can each be sprained or torn.
• Tendons: Connective tissue that attaches muscles to bones. In the knee, the patellar tendon and quadriceps tendon are most commonly affected in runners.

The most common knee injuries in runners

While knee pain from running can have a range of causes, certain knee injuries occur more frequently among runners. Common knee injuries from running include:

Runner’s knee (Patellofemoral Pain Syndrome)

Also called patellofemoral pain syndrome (PFPS), this is one of the most common causes of knee pain in runners. 

• Runner’s knee causes pain around or behind the kneecap, especially when running downhill, climbing stairs, or after sitting for long periods
• PFPS is often linked to muscle imbalances, overuse, and poor running mechanics
• Treatment usually involves rest and strengthening exercises, with physiotherapy needed in more serious or persistent cases
• Supportive footwear and gait assessment can help prevent runner’s knee from recurring

IT band syndrome

Iliotibial (IT) band syndrome occurs when the connective tissue running along the outside of the thigh from the hip down to the knee becomes irritated. 

• IT band syndrome causes sharp pain on the outer side of the knee
• It is more common in long-distance runners and those increasing mileage too quickly
• It’s often related to tight hip muscles or poor running biomechanics
• Treatment includes rest, temporary activity modification, stretching, and physiotherapy if required

Patellar tendinopathy (jumper’s knee)

Patellar tendinopathy occurs when the patellar tendon, which connects the kneecap to the shinbone, becomes overstressed and irritated through repetitive strain and overuse.

• It causes pain just below the kneecap, during or after exercise, that develops gradually over time
• It is more common in runners who train intensely or on hard surfaces
• Treatment includes rest, reducing running intensity, and physiotherapy in more persistent cases
• Strengthening exercises can help manage the condition and prevent recurrence

Meniscus tear

The meniscus is cartilage that cushions the knee joint, acting as a shock absorber between the thighbone and shinbone. It can be damaged gradually over time or through a sudden twisting movement. 

• Symptoms can include pain, swelling, stiffness, and clicking sensations when bending the knee
• Some runners experience locking or difficulty fully straightening their knee
• Mild tears may improve with rest and physiotherapy
• More severe tears usually require imaging and surgical treatment

Knee bursitis

Knee bursitis (also called prepatellar bursitis or kneecap bursitis) occurs when the small fluid-filled sacs that cushion the knee joint become inflamed and swollen, putting pressure on surrounding structures and causing pain and stiffness.

• Symptoms include swelling, tenderness, pain, and warmth around the knee
• It is most often triggered by repetitive pressure or a sudden increase in training load
• Rest, ice, and anti-inflammatory medication can help relieve symptoms
• Persistent bursitis may require specialist assessment

ACL and PCL injuries

The anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) help stabilise the knee joint. While more commonly associated with contact sports, runners can also experience ligament damage, particularly after falls, twists, or sudden changes in direction. 

• Both ACL and PCL injuries cause swelling, pain, and knee instability
• An ACL injury may also produce a popping sensation at the time of injury
• Mild injuries (strains and small tears) may improve with bracing, physiotherapy, and rehabilitation
• More severe injuries (such as full tears) will require knee surgery, such as ACL reconstruction surgery

How to prevent knee injuries when running?

Although not every running injury is avoidable, these steps can significantly reduce your risk: 

1. Build mileage and intensity gradually: Increasing your training load too quickly is one of the most common causes of running injury. Follow the 10% rule — aim to increase your mileage or intensity by no more than 10% per week.
2. Invest in the right running shoes: Supportive shoes suited to your gait and foot type improve shock absorption and reduce strain on the knees. Replace worn-out shoes regularly.
3. Work on your running style: Running with a good gait is one of the best ways to avoid overuse injuries. You may be able to make improvements on your own, but investing in some time with a physiotherapist or other specialist can pay dividends. Discover more about how to run without damaging your knees.
4. Strengthen your hips, glutes, and quads: Weakness in these muscle groups places extra load on the knee joint. Regular strength training can improve stability, balance, and running mechanics. Discover the 10 best knee exercises for runners.
5. Warm-up and cool down properly: Dynamic stretching before a run and gentle stretching afterwards prepares your muscles for exercise and aids recovery.
6. Mix in low-impact cross-training: Swimming, cycling, or other low-impact activities maintain fitness while giving your knees a break from repetitive impact.
7. Listen to your body: Persistent soreness, swelling, or pain shouldn’t be ignored. Rest days and prompt attention to niggles can prevent minor issues from becoming serious injuries.

How to treat knee pain after running

If you're looking for ways to stop knee pain when running, or to treat an existing injury, the right approach depends on the underlying cause and the severity of your symptoms. The following may be needed:

1. The RICE method: For mild injuries, the RICE approach is often an effective first step:
• Rest: Reduce or avoid activities that worsen pain
• Ice: Apply an ice pack for 15–20 minutes several times a day
• Compression: Use a knee support or compression bandage to reduce swelling and provide stability
• Elevation: Keep your knee raised to help reduce swelling
2. Over-the-counter medication: Anti-inflammatory medications, such as ibuprofen, may help reduce pain and swelling in the short term. However, medication should not be used to mask pain and continue training. If you need it regularly, that’s a sign to seek further advice.
3. Physiotherapy: A physiotherapist can assess your movement patterns, recommend targeted strengthening exercises, and help improve your running mechanics to support recovery and reduce the risk of recurrence. Find out more about how physiotherapy can help.
4. Imaging and specialist assessment: If symptoms are severe, persistent, or associated with instability, imaging – such as an MRI scan, X-ray, or CT scan – may be recommended to identify any structural damage.
5. Surgical treatment: While many running injuries resolve without surgery, some conditions do require specialist treatment. Procedures such as ACL reconstruction, cartilage repair, or knee replacement surgery may be considered in more advanced or persistent cases.

When should you see a doctor for running knee pain?

Certain symptoms need to be assessed promptly by a healthcare professional. Seek medical advice if you experience any of the following:

• Significant swelling around the knee
• Difficulty bearing weight
• Locking, catching, or the knee giving way
• Severe or worsening pain
• Symptoms that do not improve with rest

For most running-related knee injuries, a GP or physiotherapist is a good first port of call. If symptoms persist, worsen, or a structural injury is suspected, they can refer you to an orthopaedic specialist for further investigation and treatment.

If you’re experiencing ongoing knee pain, a specialist assessment can help identify the cause and guide the right treatment plan. Find out more about therapeutic treatments for knee injuries and the knee surgery options available at Ramsay Health Care.

To book an appointment, call us on 0808 223 0500 or get in touch online.

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