Why Does My Knee Hurt After Running? Common Causes Explained

Knee pain after running is one of the most frequent complaints among recreational and professional runners alike. While running is an excellent cardiovascular activity, it places repeated stress on the knees—particularly the cartilage, ligaments, and supporting muscles. Understanding why your knees hurt after a run is the first step toward effective prevention and management.

In many cases, the pain results from overuse, poor running mechanics, or underlying biomechanical imbalances. Identifying the exact cause helps determine whether rest, rehabilitation, or medical intervention is required.

Runner’s Knee (Patellofemoral Pain Syndrome)

Runner’s knee is a broad term describing pain around the kneecap (patella), usually due to repetitive stress and misalignment. It occurs when the patella doesn’t track properly along the femur during movement, leading to irritation of the joint surfaces.

Common signs include:

• Aching pain behind or around the kneecap

• Worsening pain when walking downstairs or sitting for long periods

• A grinding or clicking sensation when bending the knee

What to do:
Strengthen the quadriceps and hip stabilisers. Consider motion analysis (such as MAI-Motion™) to assess gait and improve joint tracking.

Iliotibial Band (ITB) Syndrome

ITB syndrome causes pain on the outside of the knee, typically after longer or hill-based runs. The iliotibial band—a thick connective tissue running from the hip to the shin—can become tight or inflamed, especially with weak glutes or overpronation.

Typical symptoms include:

• Sharp or burning pain on the outer knee

• Pain that worsens with repetitive bending

• Tenderness to touch along the lateral thigh

What to do:
Address flexibility and muscular imbalance through targeted physiotherapy. Foam rolling and stretching the IT band and hip muscles can help alleviate tension.

Meniscal Irritation or Injury

The meniscus acts as a shock absorber within the knee joint. Repeated load or a twist during running may lead to minor tears or inflammation, especially in older runners or those with a history of injury.

Signs of meniscal involvement:

• Localised joint line pain

• Swelling after activity

• A catching or locking feeling during movement

What to do:
Seek early assessment with imaging such as MRI or onMRI™ to evaluate structural damage. Mild cases may resolve with rest and rehab; severe cases may require specialist intervention.

Tendinopathy or Tendinitis

Repetitive impact from running can lead to inflammation or degeneration of tendons—most commonly the patellar or quadriceps tendon. These conditions develop gradually and are often linked to training errors or biomechanical overload.

Symptoms usually include:

• Pain below the kneecap or at the front of the thigh

• Stiffness in the morning or after rest

• Discomfort during jumping or sprinting

What to do:
Load management and eccentric strengthening exercises are key. Modalities like cryo-ultrasound and regenerative injections (e.g. PRP) may support healing in persistent cases.

Poor Running Mechanics and Footwear

Incorrect technique, overstriding, or running with worn-out shoes can lead to abnormal joint loading. Over time, these factors contribute to uneven pressure across the knee joint, causing pain.

Red flags include:

• Pain in both knees or variable pain

• Symptoms that worsen with certain terrains

• Minimal improvement despite stretching or strengthening

What to do:
Consider gait assessment and professional running analysis. Replace shoes regularly and opt for ones that match your foot shape and running style.

Preventing Knee Pain From Running

Maintaining joint health while running involves more than just mileage tracking. Strengthening surrounding muscles, choosing the right footwear, and allowing adequate rest are all critical components.

Prevention tips:

• Cross-train with cycling or swimming to reduce load

• Avoid increasing distance by more than 10% per week

• Integrate glute and core strengthening exercises

• Warm up thoroughly before each run

Frequently Asked Questions (FAQs)

Should I stop running if my knee hurts?
If pain is sharp or persistent, take a break and reassess your training. Occasional soreness may be normal, but consistent discomfort warrants further evaluation.

Is knee pain always a sign of injury?
Not necessarily. It can be a warning sign of overuse, muscular imbalance, or poor form. Early intervention prevents minor irritation from becoming chronic injury.

Can I run with arthritis?
Yes—many people with early osteoarthritis continue running. However, load should be managed, and complementary therapies (e.g. strengthening, regeneration) are essential to preserve joint health.

How long should I rest after knee pain begins?
Rest for at least 3–5 days and reassess symptoms. If pain persists beyond two weeks, seek a musculoskeletal specialist.

When should I consider seeing a doctor?
If your knee pain is accompanied by swelling, instability, clicking, or night pain, it’s advisable to consult a specialist for imaging and diagnosis.

Can knee pain be fixed without surgery?
Yes—many causes respond well to conservative treatment, including physiotherapy, bracing, and regenerative options. Surgery is usually considered only when these fail.